linux下pl330 DMA控制器驱动分析
2015-06-30 21:57
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#include <linux/kernel.h>
#include <linux/io.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/module.h>
#include <linux/string.h>
#include <linux/delay.h>
#include <linux/interrupt.h>
#include <linux/dma-mapping.h>
#include <linux/dmaengine.h>
#include <linux/amba/bus.h>
#include <linux/amba/pl330.h>
#include <linux/scatterlist.h>
#include <linux/of.h>
#include <linux/of_dma.h>
#include <linux/err.h>
#include "dmaengine.h"
#define PL330_MAX_CHAN 8
#define PL330_MAX_IRQS 32
#define PL330_MAX_PERI 32
enum pl330_cachectrl {
CCTRL0, /* Noncacheable and nonbufferable */
CCTRL1, /* Bufferable only */
CCTRL2, /* Cacheable, but do not allocate */
CCTRL3, /* Cacheable and bufferable, but do not allocate */
INVALID1, /* AWCACHE = 0x1000 */
INVALID2,
CCTRL6, /* Cacheable write-through, allocate on writes only */
CCTRL7, /* Cacheable write-back, allocate on writes only */
};
enum pl330_byteswap {
SWAP_NO,
SWAP_2,
SWAP_4,
SWAP_8,
SWAP_16,
};
/* Register and Bit field Definitions */
#define DS 0x0
#define DS_ST_STOP 0x0
#define DS_ST_EXEC 0x1
#define DS_ST_CMISS 0x2
#define DS_ST_UPDTPC 0x3
#define DS_ST_WFE 0x4
#define DS_ST_ATBRR 0x5
#define DS_ST_QBUSY 0x6
#define DS_ST_WFP 0x7
#define DS_ST_KILL 0x8
#define DS_ST_CMPLT 0x9
#define DS_ST_FLTCMP 0xe
#define DS_ST_FAULT 0xf
#define DPC 0x4
#define INTEN 0x20
#define ES 0x24
#define INTSTATUS 0x28
#define INTCLR 0x2c
#define FSM 0x30
#define FSC 0x34
#define FTM 0x38
#define _FTC 0x40
#define FTC(n) (_FTC + (n)*0x4)
#define _CS 0x100
#define CS(n) (_CS + (n)*0x8)
#define CS_CNS (1 << 21)
#define _CPC 0x104
#define CPC(n) (_CPC + (n)*0x8)
#define _SA 0x400
#define SA(n) (_SA + (n)*0x20)
#define _DA 0x404
#define DA(n) (_DA + (n)*0x20)
#define _CC 0x408
#define CC(n) (_CC + (n)*0x20)
#define CC_SRCINC (1 << 0)
#define CC_DSTINC (1 << 14)
#define CC_SRCPRI (1 << 8)
#define CC_DSTPRI (1 << 22)
#define CC_SRCNS (1 << 9)
#define CC_DSTNS (1 << 23)
#define CC_SRCIA (1 << 10)
#define CC_DSTIA (1 << 24)
#define CC_SRCBRSTLEN_SHFT 4
#define CC_DSTBRSTLEN_SHFT 18
#define CC_SRCBRSTSIZE_SHFT 1
#define CC_DSTBRSTSIZE_SHFT 15
#define CC_SRCCCTRL_SHFT 11
#define CC_SRCCCTRL_MASK 0x7
#define CC_DSTCCTRL_SHFT 25
#define CC_DRCCCTRL_MASK 0x7
#define CC_SWAP_SHFT 28
#define _LC0 0x40c
#define LC0(n) (_LC0 + (n)*0x20)
#define _LC1 0x410
#define LC1(n) (_LC1 + (n)*0x20)
#define DBGSTATUS 0xd00
#define DBG_BUSY (1 << 0)
#define DBGCMD 0xd04
#define DBGINST0 0xd08
#define DBGINST1 0xd0c
#define CR0 0xe00
#define CR1 0xe04
#define CR2 0xe08
#define CR3 0xe0c
#define CR4 0xe10
#define CRD 0xe14
#define PERIPH_ID 0xfe0
#define PERIPH_REV_SHIFT 20
#define PERIPH_REV_MASK 0xf
#define PERIPH_REV_R0P0 0
#define PERIPH_REV_R1P0 1
#define PERIPH_REV_R1P1 2
#define CR0_PERIPH_REQ_SET (1 << 0)
#define CR0_BOOT_EN_SET (1 << 1)
#define CR0_BOOT_MAN_NS (1 << 2)
#define CR0_NUM_CHANS_SHIFT 4
#define CR0_NUM_CHANS_MASK 0x7
#define CR0_NUM_PERIPH_SHIFT 12
#define CR0_NUM_PERIPH_MASK 0x1f
#define CR0_NUM_EVENTS_SHIFT 17
#define CR0_NUM_EVENTS_MASK 0x1f
#define CR1_ICACHE_LEN_SHIFT 0
#define CR1_ICACHE_LEN_MASK 0x7
#define CR1_NUM_ICACHELINES_SHIFT 4
#define CR1_NUM_ICACHELINES_MASK 0xf
#define CRD_DATA_WIDTH_SHIFT 0
#define CRD_DATA_WIDTH_MASK 0x7
#define CRD_WR_CAP_SHIFT 4
#define CRD_WR_CAP_MASK 0x7
#define CRD_WR_Q_DEP_SHIFT 8
#define CRD_WR_Q_DEP_MASK 0xf
#define CRD_RD_CAP_SHIFT 12
#define CRD_RD_CAP_MASK 0x7
#define CRD_RD_Q_DEP_SHIFT 16
#define CRD_RD_Q_DEP_MASK 0xf
#define CRD_DATA_BUFF_SHIFT 20
#define CRD_DATA_BUFF_MASK 0x3ff
#define PART 0x330
#define DESIGNER 0x41
#define REVISION 0x0
#define INTEG_CFG 0x0
#define PERIPH_ID_VAL ((PART << 0) | (DESIGNER << 12))
#define PL330_STATE_STOPPED (1 << 0)
#define PL330_STATE_EXECUTING (1 << 1)
#define PL330_STATE_WFE (1 << 2)
#define PL330_STATE_FAULTING (1 << 3)
#define PL330_STATE_COMPLETING (1 << 4)
#define PL330_STATE_WFP (1 << 5)
#define PL330_STATE_KILLING (1 << 6)
#define PL330_STATE_FAULT_COMPLETING (1 << 7)
#define PL330_STATE_CACHEMISS (1 << 8)
#define PL330_STATE_UPDTPC (1 << 9)
#define PL330_STATE_ATBARRIER (1 << 10)
#define PL330_STATE_QUEUEBUSY (1 << 11)
#define PL330_STATE_INVALID (1 << 15)
#define PL330_STABLE_STATES (PL330_STATE_STOPPED | PL330_STATE_EXECUTING \
| PL330_STATE_WFE | PL330_STATE_FAULTING)
#define CMD_DMAADDH 0x54
#define CMD_DMAEND 0x00
#define CMD_DMAFLUSHP 0x35
#define CMD_DMAGO 0xa0
#define CMD_DMALD 0x04
#define CMD_DMALDP 0x25
#define CMD_DMALP 0x20
#define CMD_DMALPEND 0x28
#define CMD_DMAKILL 0x01
#define CMD_DMAMOV 0xbc
#define CMD_DMANOP 0x18
#define CMD_DMARMB 0x12
#define CMD_DMASEV 0x34
#define CMD_DMAST 0x08
#define CMD_DMASTP 0x29
#define CMD_DMASTZ 0x0c
#define CMD_DMAWFE 0x36
#define CMD_DMAWFP 0x30
#define CMD_DMAWMB 0x13
#define SZ_DMAADDH 3
#define SZ_DMAEND 1
#define SZ_DMAFLUSHP 2
#define SZ_DMALD 1
#define SZ_DMALDP 2
#define SZ_DMALP 2
#define SZ_DMALPEND 2
#define SZ_DMAKILL 1
#define SZ_DMAMOV 6
#define SZ_DMANOP 1
#define SZ_DMARMB 1
#define SZ_DMASEV 2
#define SZ_DMAST 1
#define SZ_DMASTP 2
#define SZ_DMASTZ 1
#define SZ_DMAWFE 2
#define SZ_DMAWFP 2
#define SZ_DMAWMB 1
#define SZ_DMAGO 6
#define BRST_LEN(ccr) ((((ccr) >> CC_SRCBRSTLEN_SHFT) & 0xf) + 1)
#define BRST_SIZE(ccr) (1 << (((ccr) >> CC_SRCBRSTSIZE_SHFT) & 0x7))
#define BYTE_TO_BURST(b, ccr) ((b) / BRST_SIZE(ccr) / BRST_LEN(ccr))
#define BURST_TO_BYTE(c, ccr) ((c) * BRST_SIZE(ccr) * BRST_LEN(ccr))
/*
* With 256 bytes, we can do more than 2.5MB and 5MB xfers per req
* at 1byte/burst for P<->M and M<->M respectively.
* For typical scenario, at 1word/burst, 10MB and 20MB xfers per req
* should be enough for P<->M and M<->M respectively.
*/
#define MCODE_BUFF_PER_REQ 256
/* Use this _only_ to wait on transient states */
#define UNTIL(t, s) while (!(_state(t) & (s))) cpu_relax();
#ifdef PL330_DEBUG_MCGEN
static unsigned cmd_line;
#define PL330_DBGCMD_DUMP(off, x...) do { \
printk("%x:", cmd_line); \
printk(x); \
cmd_line += off; \
} while (0)
#define PL330_DBGMC_START(addr) (cmd_line = addr)
#else
#define PL330_DBGCMD_DUMP(off, x...) do {} while (0)
#define PL330_DBGMC_START(addr) do {} while (0)
#endif
/* The number of default descriptors */
#define NR_DEFAULT_DESC 16
/* Populated by the PL330 core driver for DMA API driver's info */
struct pl330_config {
u32 periph_id;
#define DMAC_MODE_NS (1 << 0)
unsigned int mode;//dma管理线程的安全状态标记，为secure state
unsigned int data_bus_width:10; //AXI接口数据宽度(64bit)
unsigned int data_buf_dep:10;//MFIFO的深度,值为127+1
unsigned int num_chan:4;//通道线程数目 7+1
unsigned int num_peri:6;//外设请求接口数目 3+1
u32 peri_ns;//对应bit位的外设请求接口的安全状态标记，0--secure 1--non secure
unsigned int num_events:6;//dmac支持的事件数目 15+1
u32 irq_ns;//各个中断的安全状态 0--secure 1--non secure
};
/**
* Request Configuration.
* The PL330 core does not modify this and uses the last
* working configuration if the request doesn't provide any.
*
* The Client may want to provide this info only for the
* first request and a request with new settings.
*/
struct pl330_reqcfg {
/* Address Incrementing */
unsigned dst_inc:1;
unsigned src_inc:1;
/*
* For now, the SRC & DST protection levels
* and burst size/length are assumed same.
*/
bool nonsecure;
bool privileged;
bool insnaccess;
unsigned brst_len:5;//用来设置ccr寄存器中dst_burst_len和src_burst_len，这个值要小于等于16
unsigned brst_size:3; //2的幂次方，用于设置ccr中dst_burst_size和src_burst_size
enum pl330_cachectrl dcctl;
enum pl330_cachectrl scctl;
enum pl330_byteswap swap;
struct pl330_config *pcfg;
};
/*
* One cycle of DMAC operation.
* There may be more than one xfer in a request.
*/
struct pl330_xfer {
u32 src_addr;
u32 dst_addr;
/* Size to xfer */
u32 bytes;
};
/* The xfer callbacks are made with one of these arguments. */
enum pl330_op_err {
/* The all xfers in the request were success. */
PL330_ERR_NONE,
/* If req aborted due to global error. */
PL330_ERR_ABORT,
/* If req failed due to problem with Channel. */
PL330_ERR_FAIL,
};
enum dmamov_dst {
SAR = 0,
CCR,
DAR,
};
enum pl330_dst {
SRC = 0,
DST,
};
enum pl330_cond {
SINGLE,
BURST,
ALWAYS,
};
struct dma_pl330_desc;
struct _pl330_req {
u32 mc_bus;//总线地址，这个地址用于DMAGO指令中
void *mc_cpu;//指令代码的空间地址。8个通道，每个通道2个请求队列，每个
//请求队列的指令代码空间都是独立的
struct dma_pl330_desc *desc;
};
/* ToBeDone for tasklet */
struct _pl330_tbd {
bool reset_dmac;
bool reset_mngr;
u8 reset_chan;
};
/* A DMAC Thread */
struct pl330_thread {
u8 id;//线程的id号，0~7为通道线程，8为管理线程
int ev;//这个线程分配到的事件号
/* If the channel is not yet acquired by any client */
bool free;//true-->线程没有在被使用，false-->线程正在被使用
/* Parent DMAC */
struct pl330_dmac *dmac;//这个指针指向包含该线程的那个pl330_dmac结构体
/* Only two at a time */
struct _pl330_req req[2];
/* Index of the last enqueued request */
unsigned lstenq;
/* Index of the last submitted request or -1 if the DMA is stopped */
int req_running;//当前正在执行的req的索引号
};
enum pl330_dmac_state {
UNINIT,//删除后
INIT,//正常初始化后
DYING,
};
enum desc_status {
/* In the DMAC pool */
FREE,//表示该desc没有被使用，还在pl330_dmac的desc_pool链表中
/*
* Allocated to some channel during prep_xxx
* Also may be sitting on the work_list.
*/
PREP,//表示该desc已经从desc_pool链表中取出，并分配给了某个通道
//线程，也可能位于work_list中
/*
* Sitting on the work_list and already submitted
* to the PL330 core. Not more than two descriptors
* of a channel can be BUSY at any time.
*/
BUSY,//表示该desc正在被处理
/*
* Sitting on the channel work_list but xfer done
* by PL330 core
*/
DONE,//表示该desc位于work_list中，且已经被处理完毕
};
struct dma_pl330_chan {
/* Schedule desc completion */
struct tasklet_struct task;//指向pl330_tasklet函数
/* DMA-Engine Channel */
struct dma_chan chan;
/* List of submitted descriptors */
struct list_head submitted_list;
/* List of issued descriptors */
struct list_head work_list;
/* List of completed descriptors */
struct list_head completed_list;
/* Pointer to the DMAC that manages this channel,
* NULL if the channel is available to be acquired.
* As the parent, this DMAC also provides descriptors
* to the channel.
*/
struct pl330_dmac *dmac;
/* To protect channel manipulation */
spinlock_t lock;
/*
* Hardware channel thread of PL330 DMAC. NULL if the channel is
* available.
*/
struct pl330_thread *thread;//从pl330_dmac中分配一个通道线程
/* For D-to-M and M-to-D channels */
int burst_sz; /* the peripheral fifo width */
int burst_len; /* the number of burst */
dma_addr_t fifo_addr;
/* for cyclic capability */
bool cyclic;
};
struct pl330_dmac {
/* DMA-Engine Device */
struct dma_device ddma;
/* Holds info about sg limitations */
struct device_dma_parameters dma_parms;
/* Pool of descriptors available for the DMAC's channels */
struct list_head desc_pool;//默认会创建16个dma_pl330_desc结构体变量，
//变量，并添加到这个链表中
/* To protect desc_pool manipulation */
spinlock_t pool_lock;
//每个通道存放代码的大小，这里好像是设置为256*2，即每个请求对应256字节的代码空间
unsigned mcbufsz;
/* ioremap'ed address of PL330 registers. */
void __iomem *base;
/* Populated by the PL330 core driver during pl330_add */
struct pl330_config pcfg;
spinlock_t lock;
/* Maximum possible events/irqs */
int events[32];//用来存放这个事件被分配到的线程id号，空闲时为-1
/* BUS address of MicroCode buffer */
dma_addr_t mcode_bus;
/* CPU address of MicroCode buffer */
void *mcode_cpu;//给8个通道线程指令代码分配的内存的虚拟首地址，分配的总内存为8*256*2字节
/* List of all Channel threads */
struct pl330_thread *channels;
/* Pointer to the MANAGER thread */
struct pl330_thread *manager;
/* To handle bad news in interrupt */
struct tasklet_struct tasks;//这个对应pl330_dotask函数
struct _pl330_tbd dmac_tbd;
/* State of DMAC operation */
enum pl330_dmac_state state;
/* Holds list of reqs with due callbacks */
struct list_head req_done;
/* Peripheral channels connected to this DMAC */
unsigned int num_peripherals;
struct dma_pl330_chan *peripherals; //有8个dma_pl330_chan结构体
};
struct dma_pl330_desc {
/* To attach to a queue as child */
struct list_head node;
/* Descriptor for the DMA Engine API */
struct dma_async_tx_descriptor txd;
/* Xfer for PL330 core */
struct pl330_xfer px;//在__pl330_prep_dma_memcpy()函数中初始化
struct pl330_reqcfg rqcfg;
enum desc_status status;
/* The channel which currently holds this desc */
struct dma_pl330_chan *pchan;//当前正在使用这个desc的dma_pl330_chan
enum dma_transfer_direction rqtype;
/* Index of peripheral for the xfer. */
unsigned peri:5;
/* Hook to attach to DMAC's list of reqs with due callback */
struct list_head rqd;
};
struct _xfer_spec {
u32 ccr;
struct dma_pl330_desc *desc;
};
static inline bool _queue_empty(struct pl330_thread *thrd)
{
return thrd->req[0].desc == NULL && thrd->req[1].desc == NULL;
}
static inline bool _queue_full(struct pl330_thread *thrd)
{
return thrd->req[0].desc != NULL && thrd->req[1].desc != NULL;
}
static inline bool is_manager(struct pl330_thread *thrd)
{
return thrd->dmac->manager == thrd;
}
/* If manager of the thread is in Non-Secure mode */
static inline bool _manager_ns(struct pl330_thread *thrd)
{
return (thrd->dmac->pcfg.mode & DMAC_MODE_NS) ? true : false;
}
static inline u32 get_revision(u32 periph_id)
{
return (periph_id >> PERIPH_REV_SHIFT) & PERIPH_REV_MASK;
}
static inline u32 _emit_ADDH(unsigned dry_run, u8 buf[],
enum pl330_dst da, u16 val)
{
if (dry_run)
return SZ_DMAADDH;
buf[0] = CMD_DMAADDH;
buf[0] |= (da << 1);
*((u16 *)&buf[1]) = val;
PL330_DBGCMD_DUMP(SZ_DMAADDH, "\tDMAADDH %s %u\n",
da == 1 ? "DA" : "SA", val);
return SZ_DMAADDH;
}
static inline u32 _emit_END(unsigned dry_run, u8 buf[])
{
if (dry_run)
return SZ_DMAEND;
buf[0] = CMD_DMAEND;
PL330_DBGCMD_DUMP(SZ_DMAEND, "\tDMAEND\n");
return SZ_DMAEND;
}
static inline u32 _emit_FLUSHP(unsigned dry_run, u8 buf[], u8 peri)
{
if (dry_run)
return SZ_DMAFLUSHP;
buf[0] = CMD_DMAFLUSHP;
peri &= 0x1f;
peri <<= 3;
buf[1] = peri;
PL330_DBGCMD_DUMP(SZ_DMAFLUSHP, "\tDMAFLUSHP %u\n", peri >> 3);
return SZ_DMAFLUSHP;
}
static inline u32 _emit_LD(unsigned dry_run, u8 buf[], enum pl330_cond cond)
{
if (dry_run)
return SZ_DMALD;
buf[0] = CMD_DMALD;
if (cond == SINGLE)
buf[0] |= (0 << 1) | (1 << 0);
else if (cond == BURST)
buf[0] |= (1 << 1) | (1 << 0);
PL330_DBGCMD_DUMP(SZ_DMALD, "\tDMALD%c\n",
cond == SINGLE ? 'S' : (cond == BURST ? 'B' : 'A'));
return SZ_DMALD;
}
static inline u32 _emit_LDP(unsigned dry_run, u8 buf[],
enum pl330_cond cond, u8 peri)
{
if (dry_run)
return SZ_DMALDP;
buf[0] = CMD_DMALDP;
if (cond == BURST)
buf[0] |= (1 << 1);
peri &= 0x1f;
peri <<= 3;
buf[1] = peri;
PL330_DBGCMD_DUMP(SZ_DMALDP, "\tDMALDP%c %u\n",
cond == SINGLE ? 'S' : 'B', peri >> 3);
return SZ_DMALDP;
}
static inline u32 _emit_LP(unsigned dry_run, u8 buf[],
unsigned loop, u8 cnt)
{
if (dry_run)
return SZ_DMALP;
buf[0] = CMD_DMALP;
if (loop)
buf[0] |= (1 << 1);
cnt--; /* DMAC increments by 1 internally */
buf[1] = cnt;
PL330_DBGCMD_DUMP(SZ_DMALP, "\tDMALP_%c %u\n", loop ? '1' : '0', cnt);
return SZ_DMALP;
}
struct _arg_LPEND {
enum pl330_cond cond;
bool forever;
unsigned loop;
u8 bjump;
};
static inline u32 _emit_LPEND(unsigned dry_run, u8 buf[],
const struct _arg_LPEND *arg)
{
enum pl330_cond cond = arg->cond;
bool forever = arg->forever;
unsigned loop = arg->loop;
u8 bjump = arg->bjump;
if (dry_run)
return SZ_DMALPEND;
buf[0] = CMD_DMALPEND;
if (loop)
buf[0] |= (1 << 2);
if (!forever)
buf[0] |= (1 << 4);
if (cond == SINGLE)
buf[0] |= (0 << 1) | (1 << 0);
else if (cond == BURST)
buf[0] |= (1 << 1) | (1 << 0);
buf[1] = bjump;
PL330_DBGCMD_DUMP(SZ_DMALPEND, "\tDMALP%s%c_%c bjmpto_%x\n",
forever ? "FE" : "END",
cond == SINGLE ? 'S' : (cond == BURST ? 'B' : 'A'),
loop ? '1' : '0',
bjump);
return SZ_DMALPEND;
}
static inline u32 _emit_KILL(unsigned dry_run, u8 buf[])
{
if (dry_run)
return SZ_DMAKILL;
buf[0] = CMD_DMAKILL;
return SZ_DMAKILL;
}
static inline u32 _emit_MOV(unsigned dry_run, u8 buf[],
enum dmamov_dst dst, u32 val)
{
if (dry_run)
return SZ_DMAMOV;
buf[0] = CMD_DMAMOV;
buf[1] = dst;
*((u32 *)&buf[2]) = val;
PL330_DBGCMD_DUMP(SZ_DMAMOV, "\tDMAMOV %s 0x%x\n",
dst == SAR ? "SAR" : (dst == DAR ? "DAR" : "CCR"), val);
return SZ_DMAMOV;
}
static inline u32 _emit_NOP(unsigned dry_run, u8 buf[])
{
if (dry_run)
return SZ_DMANOP;
buf[0] = CMD_DMANOP;
PL330_DBGCMD_DUMP(SZ_DMANOP, "\tDMANOP\n");
return SZ_DMANOP;
}
static inline u32 _emit_RMB(unsigned dry_run, u8 buf[])
{
if (dry_run)
return SZ_DMARMB;
buf[0] = CMD_DMARMB;
PL330_DBGCMD_DUMP(SZ_DMARMB, "\tDMARMB\n");
return SZ_DMARMB;
}
static inline u32 _emit_SEV(unsigned dry_run, u8 buf[], u8 ev)
{
if (dry_run)
return SZ_DMASEV;
buf[0] = CMD_DMASEV;
ev &= 0x1f;
ev <<= 3;
buf[1] = ev;
PL330_DBGCMD_DUMP(SZ_DMASEV, "\tDMASEV %u\n", ev >> 3);
return SZ_DMASEV;
}
static inline u32 _emit_ST(unsigned dry_run, u8 buf[], enum pl330_cond cond)
{
if (dry_run)
return SZ_DMAST;
buf[0] = CMD_DMAST;
if (cond == SINGLE)
buf[0] |= (0 << 1) | (1 << 0);
else if (cond == BURST)
buf[0] |= (1 << 1) | (1 << 0);
PL330_DBGCMD_DUMP(SZ_DMAST, "\tDMAST%c\n",
cond == SINGLE ? 'S' : (cond == BURST ? 'B' : 'A'));
return SZ_DMAST;
}
static inline u32 _emit_STP(unsigned dry_run, u8 buf[],
enum pl330_cond cond, u8 peri)
{
if (dry_run)
return SZ_DMASTP;
buf[0] = CMD_DMASTP;
if (cond == BURST)
buf[0] |= (1 << 1);
peri &= 0x1f;
peri <<= 3;
buf[1] = peri;
PL330_DBGCMD_DUMP(SZ_DMASTP, "\tDMASTP%c %u\n",
cond == SINGLE ? 'S' : 'B', peri >> 3);
return SZ_DMASTP;
}
static inline u32 _emit_STZ(unsigned dry_run, u8 buf[])
{
if (dry_run)
return SZ_DMASTZ;
buf[0] = CMD_DMASTZ;
PL330_DBGCMD_DUMP(SZ_DMASTZ, "\tDMASTZ\n");
return SZ_DMASTZ;
}
static inline u32 _emit_WFE(unsigned dry_run, u8 buf[], u8 ev,
unsigned invalidate)
{
if (dry_run)
return SZ_DMAWFE;
buf[0] = CMD_DMAWFE;
ev &= 0x1f;
ev <<= 3;
buf[1] = ev;
if (invalidate)
buf[1] |= (1 << 1);
PL330_DBGCMD_DUMP(SZ_DMAWFE, "\tDMAWFE %u%s\n",
ev >> 3, invalidate ? ", I" : "");
return SZ_DMAWFE;
}
static inline u32 _emit_WFP(unsigned dry_run, u8 buf[],
enum pl330_cond cond, u8 peri)
{
if (dry_run)
return SZ_DMAWFP;
buf[0] = CMD_DMAWFP;
if (cond == SINGLE)
buf[0] |= (0 << 1) | (0 << 0);
else if (cond == BURST)
buf[0] |= (1 << 1) | (0 << 0);
else
buf[0] |= (0 << 1) | (1 << 0);
peri &= 0x1f;
peri <<= 3;
buf[1] = peri;
PL330_DBGCMD_DUMP(SZ_DMAWFP, "\tDMAWFP%c %u\n",
cond == SINGLE ? 'S' : (cond == BURST ? 'B' : 'P'), peri >> 3);
return SZ_DMAWFP;
}
static inline u32 _emit_WMB(unsigned dry_run, u8 buf[])
{
if (dry_run)
return SZ_DMAWMB;
buf[0] = CMD_DMAWMB;
PL330_DBGCMD_DUMP(SZ_DMAWMB, "\tDMAWMB\n");
return SZ_DMAWMB;
}
struct _arg_GO {
u8 chan;
u32 addr;
unsigned ns;
};
static inline u32 _emit_GO(unsigned dry_run, u8 buf[],
const struct _arg_GO *arg)
{
u8 chan = arg->chan;
u32 addr = arg->addr;
unsigned ns = arg->ns;
if (dry_run)
return SZ_DMAGO;
buf[0] = CMD_DMAGO;
buf[0] |= (ns << 1);
buf[1] = chan & 0x7;
*((u32 *)&buf[2]) = addr;
return SZ_DMAGO;
}
#define msecs_to_loops(t) (loops_per_jiffy / 1000 * HZ * t)
/* Returns Time-Out */
static bool _until_dmac_idle(struct pl330_thread *thrd)
{
void __iomem *regs = thrd->dmac->base;
unsigned long loops = msecs_to_loops(5);
do {
/* Until Manager is Idle */
if (!(readl(regs + DBGSTATUS) & DBG_BUSY))
break;
cpu_relax();
} while (--loops);
if (!loops)
return true;
return false;
}
static inline void _execute_DBGINSN(struct pl330_thread *thrd,
u8 insn[], bool as_manager)
{
void __iomem *regs = thrd->dmac->base;
u32 val;
val = (insn[0] << 16) | (insn[1] << 24);
if (!as_manager) {
val |= (1 << 0);
val |= (thrd->id << 8); /* Channel Number */
}
writel(val, regs + DBGINST0);
val = *((u32 *)&insn[2]);
writel(val, regs + DBGINST1);
/* If timed out due to halted state-machine */
if (_until_dmac_idle(thrd)) {
dev_err(thrd->dmac->ddma.dev, "DMAC halted!\n");
return;
}
/* Get going */
writel(0, regs + DBGCMD);
}
static inline u32 _state(struct pl330_thread *thrd)
{
void __iomem *regs = thrd->dmac->base;
u32 val;
if (is_manager(thrd))
val = readl(regs + DS) & 0xf;
else
val = readl(regs + CS(thrd->id)) & 0xf;
switch (val) {
case DS_ST_STOP:
return PL330_STATE_STOPPED;
case DS_ST_EXEC:
return PL330_STATE_EXECUTING;
case DS_ST_CMISS:
return PL330_STATE_CACHEMISS;
case DS_ST_UPDTPC:
return PL330_STATE_UPDTPC;
case DS_ST_WFE:
return PL330_STATE_WFE;
case DS_ST_FAULT:
return PL330_STATE_FAULTING;
case DS_ST_ATBRR:
if (is_manager(thrd))
return PL330_STATE_INVALID;
else
return PL330_STATE_ATBARRIER;
case DS_ST_QBUSY:
if (is_manager(thrd))
return PL330_STATE_INVALID;
else
return PL330_STATE_QUEUEBUSY;
case DS_ST_WFP:
if (is_manager(thrd))
return PL330_STATE_INVALID;
else
return PL330_STATE_WFP;
case DS_ST_KILL:
if (is_manager(thrd))
return PL330_STATE_INVALID;
else
return PL330_STATE_KILLING;
case DS_ST_CMPLT:
if (is_manager(thrd))
return PL330_STATE_INVALID;
else
return PL330_STATE_COMPLETING;
case DS_ST_FLTCMP:
if (is_manager(thrd))
return PL330_STATE_INVALID;
else
return PL330_STATE_FAULT_COMPLETING;
default:
return PL330_STATE_INVALID;
}
}
static void _stop(struct pl330_thread *thrd)
{
void __iomem *regs = thrd->dmac->base;
u8 insn[6] = {0, 0, 0, 0, 0, 0};
if (_state(thrd) == PL330_STATE_FAULT_COMPLETING)
UNTIL(thrd, PL330_STATE_FAULTING | PL330_STATE_KILLING);
/* Return if nothing needs to be done */
if (_state(thrd) == PL330_STATE_COMPLETING
|| _state(thrd) == PL330_STATE_KILLING
|| _state(thrd) == PL330_STATE_STOPPED)
return;
_emit_KILL(0, insn);
/* Stop generating interrupts for SEV */
writel(readl(regs + INTEN) & ~(1 << thrd->ev), regs + INTEN);
_execute_DBGINSN(thrd, insn, is_manager(thrd));
}
/* Start doing req 'idx' of thread 'thrd' */
static bool _trigger(struct pl330_thread *thrd)
{
void __iomem *regs = thrd->dmac->base;
struct _pl330_req *req;
struct dma_pl330_desc *desc;
struct _arg_GO go;
unsigned ns;
u8 insn[6] = {0, 0, 0, 0, 0, 0};
int idx;
/* Return if already ACTIVE */
if (_state(thrd) != PL330_STATE_STOPPED)
return true;
idx = 1 - thrd->lstenq;
if (thrd->req[idx].desc != NULL) {
req = &thrd->req[idx];
} else {
idx = thrd->lstenq;
if (thrd->req[idx].desc != NULL)
req = &thrd->req[idx];
else
req = NULL;
}
/* Return if no request */
if (!req)
return true;
desc = req->desc;
ns = desc->rqcfg.nonsecure ? 1 : 0;
/* See 'Abort Sources' point-4 at Page 2-25 */
if (_manager_ns(thrd) && !ns)
dev_info(thrd->dmac->ddma.dev, "%s:%d Recipe for ABORT!\n",
__func__, __LINE__);
go.chan = thrd->id;
go.addr = req->mc_bus;
go.ns = ns;
_emit_GO(0, insn, &go);
/* Set to generate interrupts for SEV */
writel(readl(regs + INTEN) | (1 << thrd->ev), regs + INTEN);
/* Only manager can execute GO */
_execute_DBGINSN(thrd, insn, true);
thrd->req_running = idx;
return true;
}
static bool _start(struct pl330_thread *thrd)
{
switch (_state(thrd)) {
case PL330_STATE_FAULT_COMPLETING:
UNTIL(thrd, PL330_STATE_FAULTING | PL330_STATE_KILLING);
if (_state(thrd) == PL330_STATE_KILLING)
UNTIL(thrd, PL330_STATE_STOPPED)
case PL330_STATE_FAULTING:
_stop(thrd);
case PL330_STATE_KILLING:
case PL330_STATE_COMPLETING:
UNTIL(thrd, PL330_STATE_STOPPED)
case PL330_STATE_STOPPED:
return _trigger(thrd);
case PL330_STATE_WFP:
case PL330_STATE_QUEUEBUSY:
case PL330_STATE_ATBARRIER:
case PL330_STATE_UPDTPC:
case PL330_STATE_CACHEMISS:
case PL330_STATE_EXECUTING:
return true;
case PL330_STATE_WFE: /* For RESUME, nothing yet */
default:
return false;
}
}
static inline int _ldst_memtomem(unsigned dry_run, u8 buf[],
const struct _xfer_spec *pxs, int cyc)
{
int off = 0;
struct pl330_config *pcfg = pxs->desc->rqcfg.pcfg;
/* check lock-up free version */
if (get_revision(pcfg->periph_id) >= PERIPH_REV_R1P0) {
while (cyc--) {
off += _emit_LD(dry_run, &buf[off], ALWAYS);
off += _emit_ST(dry_run, &buf[off], ALWAYS);
}
} else {
while (cyc--) {
off += _emit_LD(dry_run, &buf[off], ALWAYS);
off += _emit_RMB(dry_run, &buf[off]);
off += _emit_ST(dry_run, &buf[off], ALWAYS);
off += _emit_WMB(dry_run, &buf[off]);
}
}
return off;
}
static inline int _ldst_devtomem(unsigned dry_run, u8 buf[],
const struct _xfer_spec *pxs, int cyc)
{
int off = 0;
while (cyc--) {
off += _emit_WFP(dry_run, &buf[off], SINGLE, pxs->desc->peri);
off += _emit_LDP(dry_run, &buf[off], SINGLE, pxs->desc->peri);
off += _emit_ST(dry_run, &buf[off], ALWAYS);
off += _emit_FLUSHP(dry_run, &buf[off], pxs->desc->peri);
}
return off;
}
static inline int _ldst_memtodev(unsigned dry_run, u8 buf[],
const struct _xfer_spec *pxs, int cyc)
{
int off = 0;
while (cyc--) {
off += _emit_WFP(dry_run, &buf[off], SINGLE, pxs->desc->peri);
off += _emit_LD(dry_run, &buf[off], ALWAYS);
off += _emit_STP(dry_run, &buf[off], SINGLE, pxs->desc->peri);
off += _emit_FLUSHP(dry_run, &buf[off], pxs->desc->peri);
}
return off;
}
static int _bursts(unsigned dry_run, u8 buf[],
const struct _xfer_spec *pxs, int cyc)
{
int off = 0;
switch (pxs->desc->rqtype) {
case DMA_MEM_TO_DEV:
off += _ldst_memtodev(dry_run, &buf[off], pxs, cyc);
break;
case DMA_DEV_TO_MEM:
off += _ldst_devtomem(dry_run, &buf[off], pxs, cyc);
break;
case DMA_MEM_TO_MEM:
off += _ldst_memtomem(dry_run, &buf[off], pxs, cyc);
break;
default:
off += 0x40000000; /* Scare off the Client */
break;
}
return off;
}
/* Returns bytes consumed and updates bursts */
static inline int _loop(unsigned dry_run, u8 buf[],
unsigned long *bursts, const struct _xfer_spec *pxs)
{
int cyc, cycmax, szlp, szlpend, szbrst, off;
unsigned lcnt0, lcnt1, ljmp0, ljmp1;
struct _arg_LPEND lpend;
/* Max iterations possible in DMALP is 256 */
if (*bursts >= 256*256) {
lcnt1 = 256;
lcnt0 = 256;
cyc = *bursts / lcnt1 / lcnt0;
} else if (*bursts > 256) {
lcnt1 = 256;
lcnt0 = *bursts / lcnt1;
cyc = 1;
} else {
lcnt1 = *bursts;
lcnt0 = 0;
cyc = 1;
}
szlp = _emit_LP(1, buf, 0, 0);
szbrst = _bursts(1, buf, pxs, 1);
lpend.cond = ALWAYS;
lpend.forever = false;
lpend.loop = 0;
lpend.bjump = 0;
szlpend = _emit_LPEND(1, buf, &lpend);
if (lcnt0) {
szlp *= 2;
szlpend *= 2;
}
/*
* Max bursts that we can unroll due to limit on the
* size of backward jump that can be encoded in DMALPEND
* which is 8-bits and hence 255
*/
cycmax = (255 - (szlp + szlpend)) / szbrst;//cyc的最大值，即代码量不能超过256字节
cyc = (cycmax < cyc) ? cycmax : cyc;
off = 0;
if (lcnt0) {
off += _emit_LP(dry_run, &buf[off], 0, lcnt0);
ljmp0 = off;
}
off += _emit_LP(dry_run, &buf[off], 1, lcnt1);
ljmp1 = off;
off += _bursts(dry_run, &buf[off], pxs, cyc);
lpend.cond = ALWAYS;
lpend.forever = false;
lpend.loop = 1;
lpend.bjump = off - ljmp1;
off += _emit_LPEND(dry_run, &buf[off], &lpend);
if (lcnt0) {
lpend.cond = ALWAYS;
lpend.forever = false;
lpend.loop = 0;
lpend.bjump = off - ljmp0;
off += _emit_LPEND(dry_run, &buf[off], &lpend);
}
*bursts = lcnt1 * cyc;
if (lcnt0)
*bursts *= lcnt0;
return off;
}
static inline int _setup_loops(unsigned dry_run, u8 buf[],
const struct _xfer_spec *pxs)
{
struct pl330_xfer *x = &pxs->desc->px;
u32 ccr = pxs->ccr;
unsigned long c, bursts = BYTE_TO_BURST(x->bytes, ccr);
int off = 0;
while (bursts) {
c = bursts;
//返回的c值为这个函数实际所能完成的burst数目
off += _loop(dry_run, &buf[off], &c, pxs);
bursts -= c;
}
return off;
}
static inline int _setup_xfer(unsigned dry_run, u8 buf[],
const struct _xfer_spec *pxs)
{
struct pl330_xfer *x = &pxs->desc->px;
int off = 0;
/* DMAMOV SAR, x->src_addr */
off += _emit_MOV(dry_run, &buf[off], SAR, x->src_addr);
/* DMAMOV DAR, x->dst_addr */
off += _emit_MOV(dry_run, &buf[off], DAR, x->dst_addr);
/* Setup Loop(s) */
off += _setup_loops(dry_run, &buf[off], pxs);
return off;
}
/*
* A req is a sequence of one or more xfer units.
* Returns the number of bytes taken to setup the MC for the req.
*/
///为第index个请求编写一段汇编指令代码，并存放在系统内存地址mc_cpu处
//返回指令代码的大小off(byte)
static int _setup_req(unsigned dry_run, struct pl330_thread *thrd,
unsigned index, struct _xfer_spec *pxs)
{
struct _pl330_req *req = &thrd->req[index];
struct pl330_xfer *x;
u8 *buf = req->mc_cpu;
int off = 0;
PL330_DBGMC_START(req->mc_bus);
/* DMAMOV CCR, ccr */
off += _emit_MOV(dry_run, &buf[off], CCR, pxs->ccr);
x = &pxs->desc->px;
//要传输的字节数必须是burst大小的整数倍
if (x->bytes % (BRST_SIZE(pxs->ccr) * BRST_LEN(pxs->ccr)))
return -EINVAL;
off += _setup_xfer(dry_run, &buf[off], pxs);
/* DMASEV peripheral/event */
off += _emit_SEV(dry_run, &buf[off], thrd->ev);
/* DMAEND */
off += _emit_END(dry_run, &buf[off]);//使线程进入stop状态
return off;
}
static inline u32 _prepare_ccr(const struct pl330_reqcfg *rqc)
{
u32 ccr = 0;
if (rqc->src_inc)
ccr |= CC_SRCINC;
if (rqc->dst_inc)
ccr |= CC_DSTINC;
/* We set same protection levels for Src and DST for now */
if (rqc->privileged)
ccr |= CC_SRCPRI | CC_DSTPRI;
if (rqc->nonsecure)
ccr |= CC_SRCNS | CC_DSTNS;
if (rqc->insnaccess)
ccr |= CC_SRCIA | CC_DSTIA;
ccr |= (((rqc->brst_len - 1) & 0xf) << CC_SRCBRSTLEN_SHFT);
ccr |= (((rqc->brst_len - 1) & 0xf) << CC_DSTBRSTLEN_SHFT);
ccr |= (rqc->brst_size << CC_SRCBRSTSIZE_SHFT);
ccr |= (rqc->brst_size << CC_DSTBRSTSIZE_SHFT);
ccr |= (rqc->scctl << CC_SRCCCTRL_SHFT);
ccr |= (rqc->dcctl << CC_DSTCCTRL_SHFT);
ccr |= (rqc->swap << CC_SWAP_SHFT);
return ccr;
}
/*
* Submit a list of xfers after which the client wants notification.
* Client is not notified after each xfer unit, just once after all
* xfer units are done or some error occurs.
*/
static int pl330_submit_req(struct pl330_thread *thrd,
struct dma_pl330_desc *desc)
{
struct pl330_dmac *pl330 = thrd->dmac;
struct _xfer_spec xs;
unsigned long flags;
void __iomem *regs;
unsigned idx;
u32 ccr;
int ret = 0;
/* No Req or Unacquired Channel or DMAC */
if (!desc || !thrd || thrd->free)
return -EINVAL;
regs = thrd->dmac->base;
if (pl330->state == DYING
|| pl330->dmac_tbd.reset_chan & (1 << thrd->id)) {
dev_info(thrd->dmac->ddma.dev, "%s:%d\n",
__func__, __LINE__);
return -EAGAIN;
}
//如果当前是外设和内存间传输，且当前外设号大于外设数目，则出错
if (desc->rqtype != DMA_MEM_TO_MEM &&
desc->peri >= pl330->pcfg.num_peri) {
dev_info(thrd->dmac->ddma.dev,
"%s:%d Invalid peripheral(%u)!\n",
__func__, __LINE__, desc->peri);
return -EINVAL;
}
spin_lock_irqsave(&pl330->lock, flags);
//判断thrd当中的请求队列是否已满
if (_queue_full(thrd)) {
ret = -EAGAIN;
goto xfer_exit;
}
//判断线程是否在non-secure状态
if (!_manager_ns(thrd))
desc->rqcfg.nonsecure = 0;
else
desc->rqcfg.nonsecure = 1;
//根据rqcfg的参数，组合出ccr寄存器的值
ccr = _prepare_ccr(&desc->rqcfg);
//获取当前空闲的那个队列的索引
idx = thrd->req[0].desc == NULL ? 0 : 1;
xs.ccr = ccr;
xs.desc = desc;
/* First dry run to check if req is acceptable */
ret = _setup_req(1, thrd, idx, &xs);
if (ret < 0)//当请求传输的总字节数与一次burst传输的字节数不是整数倍时会出错
goto xfer_exit;
//当程序指令的字节数超过所分配的系统内存一半大小时出错
if (ret > pl330->mcbufsz / 2) {
dev_info(pl330->ddma.dev, "%s:%d Trying increasing mcbufsz\n",
__func__, __LINE__);
ret = -ENOMEM;
goto xfer_exit;
}
/* Hook the request */
thrd->lstenq = idx;
thrd->req[idx].desc = desc;
_setup_req(0, thrd, idx, &xs);
ret = 0;
xfer_exit:
spin_unlock_irqrestore(&pl330->lock, flags);
return ret;
}
static void dma_pl330_rqcb(struct dma_pl330_desc *desc, enum pl330_op_err err)
{
struct dma_pl330_chan *pch;
unsigned long flags;
if (!desc)
return;
pch = desc->pchan;
/* If desc aborted */
if (!pch)
return;
spin_lock_irqsave(&pch->lock, flags);
desc->status = DONE;//这个desc已经被成功的完成了，将其状态设置为DONE
spin_unlock_irqrestore(&pch->lock, flags);
tasklet_schedule(&pch->task);//调用pl330_tasklet，开始新任务
}
static void pl330_dotask(unsigned long data)
{
struct pl330_dmac *pl330 = (struct pl330_dmac *) data;
unsigned long flags;
int i;
spin_lock_irqsave(&pl330->lock, flags);
/* The DMAC itself gone nuts */
if (pl330->dmac_tbd.reset_dmac) {
pl330->state = DYING;
/* Reset the manager too */
pl330->dmac_tbd.reset_mngr = true;
/* Clear the reset flag */
pl330->dmac_tbd.reset_dmac = false;
}
if (pl330->dmac_tbd.reset_mngr) {
_stop(pl330->manager);
/* Reset all channels */
pl330->dmac_tbd.reset_chan = (1 << pl330->pcfg.num_chan) - 1;
/* Clear the reset flag */
pl330->dmac_tbd.reset_mngr = false;
}
for (i = 0; i < pl330->pcfg.num_chan; i++) {
if (pl330->dmac_tbd.reset_chan & (1 << i)) {
struct pl330_thread *thrd = &pl330->channels[i];
void __iomem *regs = pl330->base;
enum pl330_op_err err;
_stop(thrd);
if (readl(regs + FSC) & (1 << thrd->id))
err = PL330_ERR_FAIL;
else
err = PL330_ERR_ABORT;
spin_unlock_irqrestore(&pl330->lock, flags);
dma_pl330_rqcb(thrd->req[1 - thrd->lstenq].desc, err);
dma_pl330_rqcb(thrd->req[thrd->lstenq].desc, err);
spin_lock_irqsave(&pl330->lock, flags);
thrd->req[0].desc = NULL;
thrd->req[1].desc = NULL;
thrd->req_running = -1;
/* Clear the reset flag */
pl330->dmac_tbd.reset_chan &= ~(1 << i);
}
}
spin_unlock_irqrestore(&pl330->lock, flags);
return;
}
/* Returns 1 if state was updated, 0 otherwise */
///执行完一次传输后都会调用这个中断处理函数
static int pl330_update(struct pl330_dmac *pl330)
{
struct dma_pl330_desc *descdone, *tmp;
unsigned long flags;
void __iomem *regs;
u32 val;
int id, ev, ret = 0;
regs = pl330->base;
spin_lock_irqsave(&pl330->lock, flags);
val = readl(regs + FSM) & 0x1;//检测DMA主线程是否在Faulting状态
if (val)
pl330->dmac_tbd.reset_mngr = true;//在Faulting状态
else
pl330->dmac_tbd.reset_mngr = false;//不在Faulting状态
//返回8个通道线程的Faulting状态标记
val = readl(regs + FSC) & ((1 << pl330->pcfg.num_chan) - 1);
pl330->dmac_tbd.reset_chan |= val;
if (val) {
int i = 0;
while (i < pl330->pcfg.num_chan) {
if (val & (1 << i)) {
dev_info(pl330->ddma.dev,
"Reset Channel-%d\t CS-%x FTC-%x\n",
i, readl(regs + CS(i)),
readl(regs + FTC(i)));
_stop(&pl330->channels[i]);
}
i++;
}
}
/* Check which event happened i.e, thread notified */
val = readl(regs + ES);
if (pl330->pcfg.num_events < 32
&& val & ~((1 << pl330->pcfg.num_events) - 1)) {
pl330->dmac_tbd.reset_dmac = true;
dev_err(pl330->ddma.dev, "%s:%d Unexpected!\n", __func__,
__LINE__);
ret = 1;
goto updt_exit;
}
//ES寄存器的第N位为1，表示事件N发生了
for (ev = 0; ev < pl330->pcfg.num_events; ev++) {
if (val & (1 << ev)) { /* Event occurred */
struct pl330_thread *thrd;
u32 inten = readl(regs + INTEN);
int active;
/* Clear the event */
if (inten & (1 << ev))
writel(1 << ev, regs + INTCLR);//清除这个中断标记
ret = 1;
id = pl330->events[ev];
thrd = &pl330->channels[id];
active = thrd->req_running;
if (active == -1) /* Aborted */
continue;
/* Detach the req */
descdone = thrd->req[active].desc;
thrd->req[active].desc = NULL;//清空这个请求队列
/* Get going again ASAP */
_start(thrd);//重新启动线程
//因为这里是for循环，所以如果有多个desc完成的话，就将这些desc通过
//rqd节点添加到req_done链表中，便于for循环后的处理
list_add_tail(&descdone->rqd, &pl330->req_done);
}
}
//遍历req_done链表中的desc,进行处理
list_for_each_entry_safe(descdone, tmp, &pl330->req_done, rqd) {
list_del(&descdone->rqd);
spin_unlock_irqrestore(&pl330->lock, flags);
dma_pl330_rqcb(descdone, PL330_ERR_NONE);
spin_lock_irqsave(&pl330->lock, flags);
}
updt_exit:
spin_unlock_irqrestore(&pl330->lock, flags);
if (pl330->dmac_tbd.reset_dmac
|| pl330->dmac_tbd.reset_mngr
|| pl330->dmac_tbd.reset_chan) {
ret = 1;
tasklet_schedule(&pl330->tasks);
}
return ret;
}
/* Reserve an event */
static inline int _alloc_event(struct pl330_thread *thrd)
{
struct pl330_dmac *pl330 = thrd->dmac;
int ev;
for (ev = 0; ev < pl330->pcfg.num_events; ev++)
if (pl330->events[ev] == -1) {
pl330->events[ev] = thrd->id;
return ev;
}
return -1;
}
static bool _chan_ns(const struct pl330_dmac *pl330, int i)
{
return pl330->pcfg.irq_ns & (1 << i);
}
/* Upon success, returns IdentityToken for the
* allocated channel, NULL otherwise.
*/
static struct pl330_thread *pl330_request_channel(struct pl330_dmac *pl330)
{
struct pl330_thread *thrd = NULL;
unsigned long flags;
int chans, i;
if (pl330->state == DYING)
return NULL;
chans = pl330->pcfg.num_chan;
spin_lock_irqsave(&pl330->lock, flags);
for (i = 0; i < chans; i++) {
thrd = &pl330->channels[i];
if ((thrd->free) && (!_manager_ns(thrd) ||
_chan_ns(pl330, i))) {
thrd->ev = _alloc_event(thrd);//为这个空闲的通道线程分配一个事件号
if (thrd->ev >= 0) {
thrd->free = false;//表示这个通道线程已经被使用
thrd->lstenq = 1;
thrd->req[0].desc = NULL;
thrd->req[1].desc = NULL;
thrd->req_running = -1;
break;
}
}
thrd = NULL;
}
spin_unlock_irqrestore(&pl330->lock, flags);
return thrd;
}
/* Release an event */
static inline void _free_event(struct pl330_thread *thrd, int ev)
{
struct pl330_dmac *pl330 = thrd->dmac;
/* If the event is valid and was held by the thread */
if (ev >= 0 && ev < pl330->pcfg.num_events
&& pl330->events[ev] == thrd->id)
pl330->events[ev] = -1;
}
static void pl330_release_channel(struct pl330_thread *thrd)
{
struct pl330_dmac *pl330;
unsigned long flags;
if (!thrd || thrd->free)
return;
_stop(thrd);
dma_pl330_rqcb(thrd->req[1 - thrd->lstenq].desc, PL330_ERR_ABORT);
dma_pl330_rqcb(thrd->req[thrd->lstenq].desc, PL330_ERR_ABORT);
pl330 = thrd->dmac;
spin_lock_irqsave(&pl330->lock, flags);
_free_event(thrd, thrd->ev);
thrd->free = true;
spin_unlock_irqrestore(&pl330->lock, flags);
}
/* Initialize the structure for PL330 configuration, that can be used
* by the client driver the make best use of the DMAC
*/
static void read_dmac_config(struct pl330_dmac *pl330)
{
void __iomem *regs = pl330->base;
u32 val;
val = readl(regs + CRD) >> CRD_DATA_WIDTH_SHIFT;
val &= CRD_DATA_WIDTH_MASK;//AXI接口数据宽度(bit),假设val为3，则这个值为8*8=64bit
pl330->pcfg.data_bus_width = 8 * (1 << val);
val = readl(regs + CRD) >> CRD_DATA_BUFF_SHIFT;
val &= CRD_DATA_BUFF_MASK;
pl330->pcfg.data_buf_dep = val + 1;//MFIFO的深度，值为127+1
val = readl(regs + CR0) >> CR0_NUM_CHANS_SHIFT;
val &= CR0_NUM_CHANS_MASK;
val += 1;
pl330->pcfg.num_chan = val;//通道线程数目 7+1
val = readl(regs + CR0);
if (val & CR0_PERIPH_REQ_SET) {
//为1，表示DMAC支持外设请求接口
val = (val >> CR0_NUM_PERIPH_SHIFT) & CR0_NUM_PERIPH_MASK;
val += 1;
pl330->pcfg.num_peri = val;//外设请求接口数目 3+1
pl330->pcfg.peri_ns = readl(regs + CR4);
} else {
pl330->pcfg.num_peri = 0;
}
val = readl(regs + CR0);
if (val & CR0_BOOT_MAN_NS)//管理线程的安全状态 1--no secure 0--secure
pl330->pcfg.mode |= DMAC_MODE_NS;
else
pl330->pcfg.mode &= ~DMAC_MODE_NS;
val = readl(regs + CR0) >> CR0_NUM_EVENTS_SHIFT;
val &= CR0_NUM_EVENTS_MASK;
val += 1;
pl330->pcfg.num_events = val;//dmac支持的事件数目 15+1
pl330->pcfg.irq_ns = readl(regs + CR3);
}
static inline void _reset_thread(struct pl330_thread *thrd)
{
struct pl330_dmac *pl330 = thrd->dmac;
thrd->req[0].mc_cpu = pl330->mcode_cpu
+ (thrd->id * pl330->mcbufsz);
thrd->req[0].mc_bus = pl330->mcode_bus
+ (thrd->id * pl330->mcbufsz);
thrd->req[0].desc = NULL;
thrd->req[1].mc_cpu = thrd->req[0].mc_cpu
+ pl330->mcbufsz / 2;
thrd->req[1].mc_bus = thrd->req[0].mc_bus
+ pl330->mcbufsz / 2;
thrd->req[1].desc = NULL;
thrd->req_running = -1;
}
static int dmac_alloc_threads(struct pl330_dmac *pl330)
{
int chans = pl330->pcfg.num_chan;
struct pl330_thread *thrd;
int i;
/* Allocate 1 Manager and 'chans' Channel threads */
pl330->channels = kzalloc((1 + chans) * sizeof(*thrd),
GFP_KERNEL);
if (!pl330->channels)
return -ENOMEM;
/* Init Channel threads */
for (i = 0; i < chans; i++) {
thrd = &pl330->channels[i];
thrd->id = i;
thrd->dmac = pl330;
_reset_thread(thrd);//初始化各个通道线程的req[]成员
thrd->free = true;
}
/* MANAGER is indexed at the end */
thrd = &pl330->channels[chans];
thrd->id = chans;
thrd->dmac = pl330;
thrd->free = false;
pl330->manager = thrd;
return 0;
}
static int dmac_alloc_resources(struct pl330_dmac *pl330)
{
int chans = pl330->pcfg.num_chan;
int ret;
/*
* Alloc MicroCode buffer for 'chans' Channel threads.
* A channel's buffer offset is (Channel_Id * MCODE_BUFF_PERCHAN)
*/
//分配指令代码空间，8*256*2字节
pl330->mcode_cpu = dma_alloc_coherent(pl330->ddma.dev,
chans * pl330->mcbufsz,
&pl330->mcode_bus, GFP_KERNEL);
if (!pl330->mcode_cpu) {
dev_err(pl330->ddma.dev, "%s:%d Can't allocate memory!\n",
__func__, __LINE__);
return -ENOMEM;
}
//为pl330中的8个通道线程和1个管理线程分配空间，并初始化它们的成员
ret = dmac_alloc_threads(pl330);
if (ret) {
dev_err(pl330->ddma.dev, "%s:%d Can't to create channels for DMAC!\n",
__func__, __LINE__);
dma_free_coherent(pl330->ddma.dev,
chans * pl330->mcbufsz,
pl330->mcode_cpu, pl330->mcode_bus);
return ret;
}
return 0;
}
static int pl330_add(struct pl330_dmac *pl330)
{
void __iomem *regs;
int i, ret;
regs = pl330->base;
//检测periph_id(Peripheral Identification Registers)的[19：0]是否为0x41330
if ((pl330->pcfg.periph_id & 0xfffff) != PERIPH_ID_VAL) {
dev_err(pl330->ddma.dev, "PERIPH_ID 0x%x !\n",
pl330->pcfg.periph_id);
return -EINVAL;
}
/* Read the configuration of the DMAC */
read_dmac_config(pl330);//填充pl330->pcfg (pl330_config)
if (pl330->pcfg.num_events == 0) {
dev_err(pl330->ddma.dev, "%s:%d Can't work without events!\n",
__func__, __LINE__);
return -EINVAL;
}
spin_lock_init(&pl330->lock);
INIT_LIST_HEAD(&pl330->req_done);//初始化req_done链表
/* Use default MC buffer size if not provided */
if (!pl330->mcbufsz)
pl330->mcbufsz = MCODE_BUFF_PER_REQ * 2;
/* Mark all events as free */
for (i = 0; i < pl330->pcfg.num_events; i++)
pl330->events[i] = -1;
/* Allocate resources needed by the DMAC */
ret = dmac_alloc_resources(pl330);//分配指令空间以及创建通道线程和管理线程
if (ret) {
dev_err(pl330->ddma.dev, "Unable to create channels for DMAC\n");
return ret;
}
tasklet_init(&pl330->tasks, pl330_dotask, (unsigned long) pl330);
pl330->state = INIT;
return 0;
}
static int dmac_free_threads(struct pl330_dmac *pl330)
{
struct pl330_thread *thrd;
int i;
/* Release Channel threads */
for (i = 0; i < pl330->pcfg.num_chan; i++) {
thrd = &pl330->channels[i];
pl330_release_channel(thrd);
}
/* Free memory */
kfree(pl330->channels);
return 0;
}
static void pl330_del(struct pl330_dmac *pl330)
{
pl330->state = UNINIT;
tasklet_kill(&pl330->tasks);
/* Free DMAC resources */
dmac_free_threads(pl330);//释放通道线程和管理线程的空间
dma_free_coherent(pl330->ddma.dev,//释放指令空间
pl330->pcfg.num_chan * pl330->mcbufsz, pl330->mcode_cpu,
pl330->mcode_bus);
}
/* forward declaration */
static struct amba_driver pl330_driver;
static inline struct dma_pl330_chan *
to_pchan(struct dma_chan *ch)
{
if (!ch)
return NULL;
return container_of(ch, struct dma_pl330_chan, chan);
}
static inline struct dma_pl330_desc *
to_desc(struct dma_async_tx_descriptor *tx)
{
return container_of(tx, struct dma_pl330_desc, txd);
}
static inline void fill_queue(struct dma_pl330_chan *pch)
{
struct dma_pl330_desc *desc;
int ret;
list_for_each_entry(desc, &pch->work_list, node) {
/* If already submitted */
if (desc->status == BUSY)
continue;
//因为执行到此时work_list中的desc只有BUSY和PREP状态，所以如果
//是PREP状态则执行以下函数将这个desc添加到线程的请求队列中
ret = pl330_submit_req(pch->thread, desc);
if (!ret) {//如果这个desc成功的添加到请求队列中，则将其设置为BUSY状态
desc->status = BUSY;
} else if (ret == -EAGAIN) {
/* QFull or DMAC Dying */
break;
} else {
//如果这个desc是非法的，则将其设置为DONE状态，并通过tasklet_schedule
//重新调用pl330_tasklet
desc->status = DONE;
dev_err(pch->dmac->ddma.dev, "%s:%d Bad Desc(%d)\n",
__func__, __LINE__, desc->txd.cookie);
tasklet_schedule(&pch->task);
}
}
}
static void pl330_tasklet(unsigned long data)
{
struct dma_pl330_chan *pch = (struct dma_pl330_chan *)data;
struct dma_pl330_desc *desc, *_dt;
unsigned long flags;
spin_lock_irqsave(&pch->lock, flags);
//遍历work_list中的desc单元，将status为DONE的desc从work_list移动到completed_list中
list_for_each_entry_safe(desc, _dt, &pch->work_list, node)
if (desc->status == DONE) {
if (!pch->cyclic)
dma_cookie_complete(&desc->txd);
list_move_tail(&desc->node, &pch->completed_list);
}
/* Try to submit a req imm. next to the last completed cookie */
fill_queue(pch);//将work_list中状态为PREP的desc添加到线程中空闲的请求队列中
/* Make sure the PL330 Channel thread is active */
spin_lock(&pch->thread->dmac->lock);
_start(pch->thread);//确保通道线程处于开启状态
spin_unlock(&pch->thread->dmac->lock);
while (!list_empty(&pch->completed_list)) {
dma_async_tx_callback callback;
void *callback_param;
desc = list_first_entry(&pch->completed_list,
struct dma_pl330_desc, node);
callback = desc->txd.callback;
callback_param = desc->txd.callback_param;
if (pch->cyclic) {
//如果该通道是循环通道，则将completed_list中的desc的状态
//设置为PREP,并重新移动到work_list链表中
desc->status = PREP;
list_move_tail(&desc->node, &pch->work_list);
} else {
//如果该通道不是循环通道，则将completed_list中的desc的状态
//设置为FREE，并回收到pl330_damc的desc_pool链表中
desc->status = FREE;
list_move_tail(&desc->node, &pch->dmac->desc_pool);
}
dma_descriptor_unmap(&desc->txd);
//这个desc执行完后，调用DMA描述符dma_async_tx_descriptor中设置的
//callback函数，该callback函数源于使用DMA通道的设备驱动
if (callback) {
spin_unlock_irqrestore(&pch->lock, flags);
callback(callback_param);
spin_lock_irqsave(&pch->lock, flags);
}
}
spin_unlock_irqrestore(&pch->lock, flags);
}
bool pl330_filter(struct dma_chan *chan, void *param)
{
u8 *peri_id;
if (chan->device->dev->driver != &pl330_driver.drv)
return false;
peri_id = chan->private;
return *peri_id == (unsigned long)param;
}
EXPORT_SYMBOL(pl330_filter);
static struct dma_chan *of_dma_pl330_xlate(struct of_phandle_args *dma_spec,
struct of_dma *ofdma)
{
int count = dma_spec->args_count;
struct pl330_dmac *pl330 = ofdma->of_dma_data;
unsigned int chan_id;
if (!pl330)
return NULL;
if (count != 1)
return NULL;
chan_id = dma_spec->args[0];
if (chan_id >= pl330->num_peripherals)
return NULL;
return dma_get_slave_channel(&pl330->peripherals[chan_id].chan);
}
//为dma_chan指针所在的dma_pl330_chan分配一个pl330_dmac中的通道线程
//设置dma_pl330_chan的一些参数
static int pl330_alloc_chan_resources(struct dma_chan *chan)
{
struct dma_pl330_chan *pch = to_pchan(chan);
struct pl330_dmac *pl330 = pch->dmac;
unsigned long flags;
spin_lock_irqsave(&pch->lock, flags);
dma_cookie_init(chan);
pch->cyclic = false;
//从pl330中分配一个没有被使用的通道线程
pch->thread = pl330_request_channel(pl330);
if (!pch->thread) {
spin_unlock_irqrestore(&pch->lock, flags);
return -ENOMEM;
}
tasklet_init(&pch->task, pl330_tasklet, (unsigned long) pch);
spin_unlock_irqrestore(&pch->lock, flags);
return 1;
}
static int pl330_control(struct dma_chan *chan, enum dma_ctrl_cmd cmd, unsigned long arg)
{
struct dma_pl330_chan *pch = to_pchan(chan);
struct dma_pl330_desc *desc;
unsigned long flags;
struct pl330_dmac *pl330 = pch->dmac;
struct dma_slave_config *slave_config;
LIST_HEAD(list);
switch (cmd) {
case DMA_TERMINATE_ALL://终止线程
spin_lock_irqsave(&pch->lock, flags);
spin_lock(&pl330->lock);
_stop(pch->thread);//先让线程进入stop状态
spin_unlock(&pl330->lock);
pch->thread->req[0].desc = NULL;
pch->thread->req[1].desc = NULL;
pch->thread->req_running = -1;
/* Mark all desc done */
list_for_each_entry(desc, &pch->submitted_list, node) {
desc->status = FREE;
dma_cookie_complete(&desc->txd);
}
list_for_each_entry(desc, &pch->work_list , node) {
desc->status = FREE;
dma_cookie_complete(&desc->txd);
}
list_for_each_entry(desc, &pch->completed_list , node) {
desc->status = FREE;
dma_cookie_complete(&desc->txd);
}
//将dma_pl330_chan中三个链表中的desc单元全部存放回pl330_dmac的desc_pool链表
list_splice_tail_init(&pch->submitted_list, &pl330->desc_pool);
list_splice_tail_init(&pch->work_list, &pl330->desc_pool);
list_splice_tail_init(&pch->completed_list, &pl330->desc_pool);
spin_unlock_irqrestore(&pch->lock, flags);
break;
case DMA_SLAVE_CONFIG:
slave_config = (struct dma_slave_config *)arg;
if (slave_config->direction == DMA_MEM_TO_DEV) {
if (slave_config->dst_addr)
pch->fifo_addr = slave_config->dst_addr;
if (slave_config->dst_addr_width)
pch->burst_sz = __ffs(slave_config->dst_addr_width);
if (slave_config->dst_maxburst)
pch->burst_len = slave_config->dst_maxburst;
} else if (slave_config->direction == DMA_DEV_TO_MEM) {
if (slave_config->src_addr)
pch->fifo_addr = slave_config->src_addr;
if (slave_config->src_addr_width)
pch->burst_sz = __ffs(slave_config->src_addr_width);
if (slave_config->src_maxburst)
pch->burst_len = slave_config->src_maxburst;
}
break;
default:
dev_err(pch->dmac->ddma.dev, "Not supported command.\n");
return -ENXIO;
}
return 0;
}
static void pl330_free_chan_resources(struct dma_chan *chan)
{
struct dma_pl330_chan *pch = to_pchan(chan);
unsigned long flags;
tasklet_kill(&pch->task);
spin_lock_irqsave(&pch->lock, flags);
pl330_release_channel(pch->thread);
pch->thread = NULL;
if (pch->cyclic)
list_splice_tail_init(&pch->work_list, &pch->dmac->desc_pool);
spin_unlock_irqrestore(&pch->lock, flags);
}
static enum dma_status
pl330_tx_status(struct dma_chan *chan, dma_cookie_t cookie,
struct dma_tx_state *txstate)
{
return dma_cookie_status(chan, cookie, txstate);
}
static void pl330_issue_pending(struct dma_chan *chan)
{
struct dma_pl330_chan *pch = to_pchan(chan);
unsigned long flags;
spin_lock_irqsave(&pch->lock, flags);
//将submitted_list中的desc移动到work_list中
//submitted_list是在pl330_tx_submit函数中填充的
list_splice_tail_init(&pch->submitted_list, &pch->work_list);
spin_unlock_irqrestore(&pch->lock, flags);
pl330_tasklet((unsigned long)pch);
}
/*
* We returned the last one of the circular list of descriptor(s)
* from prep_xxx, so the argument to submit corresponds to the last
* descriptor of the list.
*/
//将tx所在的desc以及该desc后面所链接的一系列desc全部添加到
//dma_pl330_chan的submitted_list中
static dma_cookie_t pl330_tx_submit(struct dma_async_tx_descriptor *tx)
{
struct dma_pl330_desc *desc, *last = to_desc(tx);
struct dma_pl330_chan *pch = to_pchan(tx->chan);
dma_cookie_t cookie;
unsigned long flags;
spin_lock_irqsave(&pch->lock, flags);
/* Assign cookies to all nodes */
while (!list_empty(&last->node)) {
desc = list_entry(last->node.next, struct dma_pl330_desc, node);
if (pch->cyclic) {
desc->txd.callback = last->txd.callback;
desc->txd.callback_param = last->txd.callback_param;
}
dma_cookie_assign(&desc->txd);
list_move_tail(&desc->node, &pch->submitted_list);
}
cookie = dma_cookie_assign(&last->txd);
list_add_tail(&last->node, &pch->submitted_list);
spin_unlock_irqrestore(&pch->lock, flags);
return cookie;
}
static inline void _init_desc(struct dma_pl330_desc *desc)
{
desc->rqcfg.swap = SWAP_NO;
desc->rqcfg.scctl = CCTRL0;
desc->rqcfg.dcctl = CCTRL0;
desc->txd.tx_submit = pl330_tx_submit;
INIT_LIST_HEAD(&desc->node);
}
/* Returns the number of descriptors added to the DMAC pool */
static int add_desc(struct pl330_dmac *pl330, gfp_t flg, int count)
{
struct dma_pl330_desc *desc;
unsigned long flags;
int i;
desc = kcalloc(count, sizeof(*desc), flg);
if (!desc)
return 0;
spin_lock_irqsave(&pl330->pool_lock, flags);
for (i = 0; i < count; i++) {
_init_desc(&desc[i]);//初始化描述符结构
//将这个描述符添加到desc_pool链表中
list_add_tail(&desc[i].node, &pl330->desc_pool);
}
spin_unlock_irqrestore(&pl330->pool_lock, flags);
return count;
}
//从pl330的desc_pool链表中获取第一个dma_pl330_desc单元，并将这个单元从链表中删除
static struct dma_pl330_desc *pluck_desc(struct pl330_dmac *pl330)
{
struct dma_pl330_desc *desc = NULL;
unsigned long flags;
spin_lock_irqsave(&pl330->pool_lock, flags);
if (!list_empty(&pl330->desc_pool)) {//检测desc_pool是否为空
//获取第一个desc
desc = list_entry(pl330->desc_pool.next,
struct dma_pl330_desc, node);
list_del_init(&desc->node);//将这个desc从链表中删除，并将节点初始化为空
desc->status = PREP;
desc->txd.callback = NULL;
}
spin_unlock_irqrestore(&pl330->pool_lock, flags);
return desc;
}
static struct dma_pl330_desc *pl330_get_desc(struct dma_pl330_chan *pch)
{
struct pl330_dmac *pl330 = pch->dmac;
u8 *peri_id = pch->chan.private;
struct dma_pl330_desc *desc;
/* Pluck one desc from the pool of DMAC */
desc = pluck_desc(pl330);
/* If the DMAC pool is empty, alloc new */
if (!desc) {
if (!add_desc(pl330, GFP_ATOMIC, 1))
return NULL;
/* Try again */
desc = pluck_desc(pl330);
if (!desc) {
dev_err(pch->dmac->ddma.dev,
"%s:%d ALERT!\n", __func__, __LINE__);
return NULL;
}
}
/* Initialize the descriptor */
desc->pchan = pch;
desc->txd.cookie = 0;
async_tx_ack(&desc->txd);
desc->peri = peri_id ? pch->chan.chan_id : 0;
desc->rqcfg.pcfg = &pch->dmac->pcfg;
dma_async_tx_descriptor_init(&desc->txd, &pch->chan);
return desc;
}
//初始化desc中pl330_xfer变量，设置源地址，目的地址，数据大小
static inline void fill_px(struct pl330_xfer *px,
dma_addr_t dst, dma_addr_t src, size_t len)
{
px->bytes = len;
px->dst_addr = dst;
px->src_addr = src;
}
static struct dma_pl330_desc *
__pl330_prep_dma_memcpy(struct dma_pl330_chan *pch, dma_addr_t dst,
dma_addr_t src, size_t len)
{
struct dma_pl330_desc *desc = pl330_get_desc(pch);
if (!desc) {
dev_err(pch->dmac->ddma.dev, "%s:%d Unable to fetch desc\n",
__func__, __LINE__);
return NULL;
}
/*
* Ideally we should lookout for reqs bigger than
* those that can be programmed with 256 bytes of
* MC buffer, but considering a req size is seldom
* going to be word-unaligned and more than 200MB,
* we take it easy.
* Also, should the limit is reached we'd rather
* have the platform increase MC buffer size than
* complicating this API driver.
*/
fill_px(&desc->px, dst, src, len);
return desc;
}
/* Call after fixing burst size */
static inline int get_burst_len(struct dma_pl330_desc *desc, size_t len)
{
struct dma_pl330_chan *pch = desc->pchan;
struct pl330_dmac *pl330 = pch->dmac;
int burst_len;
burst_len = pl330->pcfg.data_bus_width / 8;
burst_len *= pl330->pcfg.data_buf_dep;//执行这一步后，burst_len为MFIFO的大小（1024B）
burst_len >>= desc->rqcfg.brst_size;
/* src/dst_burst_len can't be more than 16 */
if (burst_len > 16)
burst_len = 16;
//计算一个最大的burst_len，使得len是brst_len*(2^brst_size)的整数倍
while (burst_len > 1) {
if (!(len % (burst_len << desc->rqcfg.brst_size)))
break;
burst_len--;
}
return burst_len;
}
static struct dma_async_tx_descriptor *pl330_prep_dma_cyclic(
struct dma_chan *chan, dma_addr_t dma_addr, size_t len,
size_t period_len, enum dma_transfer_direction direction,
unsigned long flags)
{
struct dma_pl330_desc *desc = NULL, *first = NULL;
struct dma_pl330_chan *pch = to_pchan(chan);
struct pl330_dmac *pl330 = pch->dmac;
unsigned int i;
dma_addr_t dst;
dma_addr_t src;
if (len % period_len != 0)
return NULL;
//检测是否是内存与外设间传输
if (!is_slave_direction(direction)) {
dev_err(pch->dmac->ddma.dev, "%s:%d Invalid dma direction\n",
__func__, __LINE__);
return NULL;
}
for (i = 0; i < len / period_len; i++) {
desc = pl330_get_desc(pch);
if (!desc) {
dev_err(pch->dmac->ddma.dev, "%s:%d Unable to fetch desc\n",
__func__, __LINE__);
if (!first)
return NULL;
spin_lock_irqsave(&pl330->pool_lock, flags);
while (!list_empty(&first->node)) {
desc = list_entry(first->node.next,
struct dma_pl330_desc, node);
list_move_tail(&desc->node, &pl330->desc_pool);
}
list_move_tail(&first->node, &pl330->desc_pool);
spin_unlock_irqrestore(&pl330->pool_lock, flags);
return NULL;
}
switch (direction) {
case DMA_MEM_TO_DEV:
desc->rqcfg.src_inc = 1;
desc->rqcfg.dst_inc = 0;
src = dma_addr;
dst = pch->fifo_addr;
break;
case DMA_DEV_TO_MEM:
desc->rqcfg.src_inc = 0;
desc->rqcfg.dst_inc = 1;
src = pch->fifo_addr;
dst = dma_addr;
break;
default:
break;
}
desc->rqtype = direction;
desc->rqcfg.brst_size = pch->burst_sz;
desc->rqcfg.brst_len = 1;
fill_px(&desc->px, dst, src, period_len);
if (!first)
first = desc;
else
list_add_tail(&desc->node, &first->node);
dma_addr += period_len;
}
if (!desc)
return NULL;
pch->cyclic = true;
desc->txd.flags = flags;
return &desc->txd;
}
static struct dma_async_tx_descriptor *
pl330_prep_dma_memcpy(struct dma_chan *chan, dma_addr_t dst,
dma_addr_t src, size_t len, unsigned long flags)
{
struct dma_pl330_desc *desc;
struct dma_pl330_chan *pch = to_pchan(chan);
struct pl330_dmac *pl330 = pch->dmac;
int burst;
if (unlikely(!pch || !len))
return NULL;
desc = __pl330_prep_dma_memcpy(pch, dst, src, len);
if (!desc)
return NULL;
desc->rqcfg.src_inc = 1;
desc->rqcfg.dst_inc = 1;
desc->rqtype = DMA_MEM_TO_MEM;
//总结一下所做的工作就是：
//计算desc->rqcfg.brst_size和desc->rqcfg.brst_len使其满足：len是
//2^brst_size的整数倍，len是brst_len*(2^brst_size)的整数倍
/* Select max possible burst size */
burst = pl330->pcfg.data_bus_width / 8;;//获取AXI总线的数据宽度
while (burst > 1) {
if (!(len % burst))
break;
burst /= 2;
}
desc->rqcfg.brst_size = 0;
while (burst != (1 << desc->rqcfg.brst_size))
desc->rqcfg.brst_size++;
desc->rqcfg.brst_len = get_burst_len(desc, len);
desc->txd.flags = flags;
return &desc->txd;
}
static void __pl330_giveback_desc(struct pl330_dmac *pl330,
struct dma_pl330_desc *first)
{
unsigned long flags;
struct dma_pl330_desc *desc;
if (!first)
return;
spin_lock_irqsave(&pl330->pool_lock, flags);
while (!list_empty(&first->node)) {
desc = list_entry(first->node.next,
struct dma_pl330_desc, node);
list_move_tail(&desc->node, &pl330->desc_pool);
}
list_move_tail(&first->node, &pl330->desc_pool);
spin_unlock_irqrestore(&pl330->pool_lock, flags);
}
static struct dma_async_tx_descriptor *
pl330_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl,
unsigned int sg_len, enum dma_transfer_direction direction,
unsigned long flg, void *context)
{
struct dma_pl330_desc *first, *desc = NULL;
struct dma_pl330_chan *pch = to_pchan(chan);
struct scatterlist *sg;
int i;
dma_addr_t addr;
if (unlikely(!pch || !sgl || !sg_len))
return NULL;
addr = pch->fifo_addr;
first = NULL;
for_each_sg(sgl, sg, sg_len, i) {
desc = pl330_get_desc(pch);
if (!desc) {
struct pl330_dmac *pl330 = pch->dmac;
dev_err(pch->dmac->ddma.dev,
"%s:%d Unable to fetch desc\n",
__func__, __LINE__);
__pl330_giveback_desc(pl330, first);
return NULL;
}
if (!first)
first = desc;
else
list_add_tail(&desc->node, &first->node);
if (direction == DMA_MEM_TO_DEV) {
desc->rqcfg.src_inc = 1;
desc->rqcfg.dst_inc = 0;
fill_px(&desc->px,
addr, sg_dma_address(sg), sg_dma_len(sg));
} else {
desc->rqcfg.src_inc = 0;
desc->rqcfg.dst_inc = 1;
fill_px(&desc->px,
sg_dma_address(sg), addr, sg_dma_len(sg));
}
desc->rqcfg.brst_size = pch->burst_sz;
desc->rqcfg.brst_len = 1;
desc->rqtype = direction;
}
/* Return the last desc in the chain */
desc->txd.flags = flg;
return &desc->txd;
}
static irqreturn_t pl330_irq_handler(int irq, void *data)
{
if (pl330_update(data))
return IRQ_HANDLED;
else
return IRQ_NONE;
}
#define PL330_DMA_BUSWIDTHS \
BIT(DMA_SLAVE_BUSWIDTH_UNDEFINED) | \
BIT(DMA_SLAVE_BUSWIDTH_1_BYTE) | \
BIT(DMA_SLAVE_BUSWIDTH_2_BYTES) | \
BIT(DMA_SLAVE_BUSWIDTH_4_BYTES) | \
BIT(DMA_SLAVE_BUSWIDTH_8_BYTES)
static int pl330_dma_device_slave_caps(struct dma_chan *dchan,
struct dma_slave_caps *caps)
{
caps->src_addr_widths = PL330_DMA_BUSWIDTHS;
caps->dstn_addr_widths = PL330_DMA_BUSWIDTHS;
caps->directions = BIT(DMA_DEV_TO_MEM) | BIT(DMA_MEM_TO_DEV);
caps->cmd_pause = false;
caps->cmd_terminate = true;
caps->residue_granularity = DMA_RESIDUE_GRANULARITY_DESCRIPTOR;
return 0;
}
static int
pl330_probe(struct amba_device *adev, const struct amba_id *id)
{
struct dma_pl330_platdata *pdat;
struct pl330_config *pcfg;
struct pl330_dmac *pl330;
struct dma_pl330_chan *pch, *_p;
struct dma_device *pd;
struct resource *res;
int i, ret, irq;
int num_chan;
pdat = dev_get_platdata(&adev->dev);
//dma_set_mask用来设置dma寻址限制，比如有些dma只能在低24位寻址
//dma_set_coherent_mask用来设置dma一致性掩码
ret = dma_set_mask_and_coherent(&adev->dev, DMA_BIT_MASK(32));
if (ret)
return ret;
/* Allocate a new DMAC and its Channels */
pl330 = devm_kzalloc(&adev->dev, sizeof(*pl330), GFP_KERNEL);
if (!pl330) {
dev_err(&adev->dev, "unable to allocate mem\n");
return -ENOMEM;
}
pl330->mcbufsz = pdat ? pdat->mcbuf_sz : 0;
res = &adev->res;
pl330->base = devm_ioremap_resource(&adev->dev, res);
if (IS_ERR(pl330->base))
return PTR_ERR(pl330->base);
amba_set_drvdata(adev, pl330);//adev->dev.driver_data = pl330_dmac
for (i = 0; i < AMBA_NR_IRQS; i++) {
irq = adev->irq[i];
if (irq) {
//向系统申请dmac用到的9个中断号，irq是要申请的硬件中断号
//pl330_irq_handler是中断处理函数（顶半部）
//pl330是要传递给处理函数的参数
ret = devm_request_irq(&adev->dev, irq,
pl330_irq_handler, 0,
dev_name(&adev->dev), pl330);
if (ret)//返回0表示成功
return ret;
} else {
break;
}
}
pcfg = &pl330->pcfg;
pcfg->periph_id = adev->periphid;
ret = pl330_add(pl330);
if (ret)
return ret;
INIT_LIST_HEAD(&pl330->desc_pool);
spin_lock_init(&pl330->pool_lock);
//创建16个dma_pl330_desc结构体变量，添加到pl330->desc_pool链表中
if (!add_desc(pl330, GFP_KERNEL, NR_DEFAULT_DESC))
dev_warn(&adev->dev, "unable to allocate desc\n");
pd = &pl330->ddma;
INIT_LIST_HEAD(&pd->channels);
/* Initialize channel parameters */
if (pdat)
num_chan = max_t(int, pdat->nr_valid_peri, pcfg->num_chan);
else
num_chan = max_t(int, pcfg->num_peri, pcfg->num_chan);
pl330->num_peripherals = num_chan;
//分配8个dma_pl330_chan结构体
pl330->peripherals = kzalloc(num_chan * sizeof(*pch), GFP_KERNEL);
if (!pl330->peripherals) {
ret = -ENOMEM;
dev_err(&adev->dev, "unable to allocate pl330->peripherals\n");
goto probe_err2;
}
//初始化8个dma_pl330_chan结构体，并通过dma_pl330_chan->chan.device_node
//添加到pl330->ddma->channels这个链表中
for (i = 0; i < num_chan; i++) {
pch = &pl330->peripherals[i];
if (!adev->dev.of_node)
pch->chan.private = pdat ? &pdat->peri_id[i] : NULL;
else
pch->chan.private = adev->dev.of_node;
INIT_LIST_HEAD(&pch->submitted_list);
INIT_LIST_HEAD(&pch->work_list);
INIT_LIST_HEAD(&pch->completed_list);
spin_lock_init(&pch->lock);
pch->thread = NULL;
pch->chan.device = pd;
pch->dmac = pl330;
/* Add the channel to the DMAC list */
list_add_tail(&pch->chan.device_node, &pd->channels);
}
//初始化dma_device结构体
pd->dev = &adev->dev;
if (pdat) {
pd->cap_mask = pdat->cap_mask;
} else {
//以下代码是用来设置pd->cap_mask的。在其他驱动中使用dma_request_channel申
//请dma通道时，会传入一个mask值，这个mask值会与cap_mask做比较，来确定dma
//是否具有某个功能，如DMA_MEMCPY表示这个dma拥有内存到内存拷贝的功能。
dma_cap_set(DMA_MEMCPY, pd->cap_mask);
if (pcfg->num_peri) {
dma_cap_set(DMA_SLAVE, pd->cap_mask);
dma_cap_set(DMA_CYCLIC, pd->cap_mask);
dma_cap_set(DMA_PRIVATE, pd->cap_mask);
}
}
pd->device_alloc_chan_resources = pl330_alloc_chan_resources;
pd->device_free_chan_resources = pl330_free_chan_resources;
pd->device_prep_dma_memcpy = pl330_prep_dma_memcpy;
pd->device_prep_dma_cyclic = pl330_prep_dma_cyclic;
pd->device_tx_status = pl330_tx_status;
pd->device_prep_slave_sg = pl330_prep_slave_sg;
pd->device_control = pl330_control;
pd->device_issue_pending = pl330_issue_pending;//开启DMA传输功能
pd->device_slave_caps = pl330_dma_device_slave_caps;
ret = dma_async_device_register(pd); //向内核注册dma_device结构体
if (ret) {
dev_err(&adev->dev, "unable to register DMAC\n");
goto probe_err3;
}
if (adev->dev.of_node) {
ret = of_dma_controller_register(adev->dev.of_node, //注册dma控制器
of_dma_pl330_xlate, pl330);
if (ret) {
dev_err(&adev->dev,
"unable to register DMA to the generic DT DMA helpers\n");
}
}
adev->dev.dma_parms = &pl330->dma_parms;
/*
* This is the limit for transfers with a buswidth of 1, larger
* buswidths will have larger limits.
*/
ret = dma_set_max_seg_size(&adev->dev, 1900800);
if (ret)
dev_err(&adev->dev, "unable to set the seg size\n");
dev_info(&adev->dev,
"Loaded driver for PL330 DMAC-%d\n", adev->periphid);
dev_info(&adev->dev,
"\tDBUFF-%ux%ubytes Num_Chans-%u Num_Peri-%u Num_Events-%u\n",
pcfg->data_buf_dep, pcfg->data_bus_width / 8, pcfg->num_chan,
pcfg->num_peri, pcfg->num_events);
return 0;
probe_err3:
/* Idle the DMAC */
list_for_each_entry_safe(pch, _p, &pl330->ddma.channels,
chan.device_node) {
/* Remove the channel */
list_del(&pch->chan.device_node);
/* Flush the channel */
pl330_control(&pch->chan, DMA_TERMINATE_ALL, 0);
pl330_free_chan_resources(&pch->chan);
}
probe_err2:
pl330_del(pl330);
return ret;
}
static int pl330_remove(struct amba_device *adev)
{
struct pl330_dmac *pl330 = amba_get_drvdata(adev);
struct dma_pl330_chan *pch, *_p;
if (adev->dev.of_node)
of_dma_controller_free(adev->dev.of_node);
dma_async_device_unregister(&pl330->ddma);
/* Idle the DMAC */
list_for_each_entry_safe(pch, _p, &pl330->ddma.channels,
chan.device_node) {
/* Remove the channel */
list_del(&pch->chan.device_node);
/* Flush the channel */
pl330_control(&pch->chan, DMA_TERMINATE_ALL, 0);
pl330_free_chan_resources(&pch->chan);
}
pl330_del(pl330);
return 0;
}
static struct amba_id pl330_ids[] = {
{
.id = 0x00041330,
.mask = 0x000fffff,
},
{ 0, 0 },
};
MODULE_DEVICE_TABLE(amba, pl330_ids);
static struct amba_driver pl330_driver = {
.drv = {
.owner = THIS_MODULE,
.name = "dma-pl330",
},
.id_table = pl330_ids,
.probe = pl330_probe,
.remove = pl330_remove,
};
module_amba_driver(pl330_driver);
MODULE_AUTHOR("Jaswinder Singh <jassi.brar@samsung.com>");
MODULE_DESCRIPTION("API Driver for PL330 DMAC");
MODULE_LICENSE("GPL");
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