- 根目录:
- arch
- arm
- plat-pxa
- dma.c
/*
* linux/arch/arm/plat-pxa/dma.c
*
* PXA DMA registration and IRQ dispatching
*
* Author: Nicolas Pitre
* Created: Nov 15, 2001
* Copyright: MontaVista Software Inc.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/module.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/kernel.h>
#include <linux/interrupt.h>
#include <linux/errno.h>
#include <linux/dma-mapping.h>
#include <asm/irq.h>
#include <asm/memory.h>
#include <mach/hardware.h>
#include <mach/dma.h>
#define DMA_DEBUG_NAME "pxa_dma"
#define DMA_MAX_REQUESTERS 64
struct dma_channel {
char *name;
pxa_dma_prio prio;
void (*irq_handler)(int, void *);
void *data;
spinlock_t lock;
};
static struct dma_channel *dma_channels;
static int num_dma_channels;
/*
* Debug fs
*/
#ifdef CONFIG_DEBUG_FS
#include <linux/debugfs.h>
#include <linux/uaccess.h>
#include <linux/seq_file.h>
static struct dentry *dbgfs_root, *dbgfs_state, **dbgfs_chan;
static int dbg_show_requester_chan(struct seq_file *s, void *p)
{
int pos = 0;
int chan = (int)s->private;
int i;
u32 drcmr;
pos += seq_printf(s, "DMA channel %d requesters list :\n", chan);
for (i = 0; i < DMA_MAX_REQUESTERS; i++) {
drcmr = DRCMR(i);
if ((drcmr & DRCMR_CHLNUM) == chan)
pos += seq_printf(s, "\tRequester %d (MAPVLD=%d)\n", i,
!!(drcmr & DRCMR_MAPVLD));
}
return pos;
}
static inline int dbg_burst_from_dcmd(u32 dcmd)
{
int burst = (dcmd >> 16) & 0x3;
return burst ? 4 << burst : 0;
}
static int is_phys_valid(unsigned long addr)
{
return pfn_valid(__phys_to_pfn(addr));
}
#define DCSR_STR(flag) (dcsr & DCSR_##flag ? #flag" " : "")
#define DCMD_STR(flag) (dcmd & DCMD_##flag ? #flag" " : "")
static int dbg_show_descriptors(struct seq_file *s, void *p)
{
int pos = 0;
int chan = (int)s->private;
int i, max_show = 20, burst, width;
u32 dcmd;
unsigned long phys_desc;
struct pxa_dma_desc *desc;
unsigned long flags;
spin_lock_irqsave(&dma_channels[chan].lock, flags);
phys_desc = DDADR(chan);
pos += seq_printf(s, "DMA channel %d descriptors :\n", chan);
pos += seq_printf(s, "[%03d] First descriptor unknown\n", 0);
for (i = 1; i < max_show && is_phys_valid(phys_desc); i++) {
desc = phys_to_virt(phys_desc);
dcmd = desc->dcmd;
burst = dbg_burst_from_dcmd(dcmd);
width = (1 << ((dcmd >> 14) & 0x3)) >> 1;
pos += seq_printf(s, "[%03d] Desc at %08lx(virt %p)\n",
i, phys_desc, desc);
pos += seq_printf(s, "\tDDADR = %08x\n", desc->ddadr);
pos += seq_printf(s, "\tDSADR = %08x\n", desc->dsadr);
pos += seq_printf(s, "\tDTADR = %08x\n", desc->dtadr);
pos += seq_printf(s, "\tDCMD = %08x (%s%s%s%s%s%s%sburst=%d"
" width=%d len=%d)\n",
dcmd,
DCMD_STR(INCSRCADDR), DCMD_STR(INCTRGADDR),
DCMD_STR(FLOWSRC), DCMD_STR(FLOWTRG),
DCMD_STR(STARTIRQEN), DCMD_STR(ENDIRQEN),
DCMD_STR(ENDIAN), burst, width,
dcmd & DCMD_LENGTH);
phys_desc = desc->ddadr;
}
if (i == max_show)
pos += seq_printf(s, "[%03d] Desc at %08lx ... max display reached\n",
i, phys_desc);
else
pos += seq_printf(s, "[%03d] Desc at %08lx is %s\n",
i, phys_desc, phys_desc == DDADR_STOP ?
"DDADR_STOP" : "invalid");
spin_unlock_irqrestore(&dma_channels[chan].lock, flags);
return pos;
}
static int dbg_show_chan_state(struct seq_file *s, void *p)
{
int pos = 0;
int chan = (int)s->private;
u32 dcsr, dcmd;
int burst, width;
static char *str_prio[] = { "high", "normal", "low" };
dcsr = DCSR(chan);
dcmd = DCMD(chan);
burst = dbg_burst_from_dcmd(dcmd);
width = (1 << ((dcmd >> 14) & 0x3)) >> 1;
pos += seq_printf(s, "DMA channel %d\n", chan);
pos += seq_printf(s, "\tPriority : %s\n",
str_prio[dma_channels[chan].prio]);
pos += seq_printf(s, "\tUnaligned transfer bit: %s\n",
DALGN & (1 << chan) ? "yes" : "no");
pos += seq_printf(s, "\tDCSR = %08x (%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s)\n",
dcsr, DCSR_STR(RUN), DCSR_STR(NODESC),
DCSR_STR(STOPIRQEN), DCSR_STR(EORIRQEN),
DCSR_STR(EORJMPEN), DCSR_STR(EORSTOPEN),
DCSR_STR(SETCMPST), DCSR_STR(CLRCMPST),
DCSR_STR(CMPST), DCSR_STR(EORINTR), DCSR_STR(REQPEND),
DCSR_STR(STOPSTATE), DCSR_STR(ENDINTR),
DCSR_STR(STARTINTR), DCSR_STR(BUSERR));
pos += seq_printf(s, "\tDCMD = %08x (%s%s%s%s%s%s%sburst=%d width=%d"
" len=%d)\n",
dcmd,
DCMD_STR(INCSRCADDR), DCMD_STR(INCTRGADDR),
DCMD_STR(FLOWSRC), DCMD_STR(FLOWTRG),
DCMD_STR(STARTIRQEN), DCMD_STR(ENDIRQEN),
DCMD_STR(ENDIAN), burst, width, dcmd & DCMD_LENGTH);
pos += seq_printf(s, "\tDSADR = %08x\n", DSADR(chan));
pos += seq_printf(s, "\tDTADR = %08x\n", DTADR(chan));
pos += seq_printf(s, "\tDDADR = %08x\n", DDADR(chan));
return pos;
}
static int dbg_show_state(struct seq_file *s, void *p)
{
int pos = 0;
/* basic device status */
pos += seq_printf(s, "DMA engine status\n");
pos += seq_printf(s, "\tChannel number: %d\n", num_dma_channels);
return pos;
}
#define DBGFS_FUNC_DECL(name) \
static int dbg_open_##name(struct inode *inode, struct file *file) \
{ \
return single_open(file, dbg_show_##name, inode->i_private); \
} \
static const struct file_operations dbg_fops_##name = { \
.owner = THIS_MODULE, \
.open = dbg_open_##name, \
.llseek = seq_lseek, \
.read = seq_read, \
.release = single_release, \
}
DBGFS_FUNC_DECL(state);
DBGFS_FUNC_DECL(chan_state);
DBGFS_FUNC_DECL(descriptors);
DBGFS_FUNC_DECL(requester_chan);
static struct dentry *pxa_dma_dbg_alloc_chan(int ch, struct dentry *chandir)
{
char chan_name[11];
struct dentry *chan, *chan_state = NULL, *chan_descr = NULL;
struct dentry *chan_reqs = NULL;
void *dt;
scnprintf(chan_name, sizeof(chan_name), "%d", ch);
chan = debugfs_create_dir(chan_name, chandir);
dt = (void *)ch;
if (chan)
chan_state = debugfs_create_file("state", 0400, chan, dt,
&dbg_fops_chan_state);
if (chan_state)
chan_descr = debugfs_create_file("descriptors", 0400, chan, dt,
&dbg_fops_descriptors);
if (chan_descr)
chan_reqs = debugfs_create_file("requesters", 0400, chan, dt,
&dbg_fops_requester_chan);
if (!chan_reqs)
goto err_state;
return chan;
err_state:
debugfs_remove_recursive(chan);
return NULL;
}
static void pxa_dma_init_debugfs(void)
{
int i;
struct dentry *chandir;
dbgfs_root = debugfs_create_dir(DMA_DEBUG_NAME, NULL);
if (IS_ERR(dbgfs_root) || !dbgfs_root)
goto err_root;
dbgfs_state = debugfs_create_file("state", 0400, dbgfs_root, NULL,
&dbg_fops_state);
if (!dbgfs_state)
goto err_state;
dbgfs_chan = kmalloc(sizeof(*dbgfs_state) * num_dma_channels,
GFP_KERNEL);
if (!dbgfs_chan)
goto err_alloc;
chandir = debugfs_create_dir("channels", dbgfs_root);
if (!chandir)
goto err_chandir;
for (i = 0; i < num_dma_channels; i++) {
dbgfs_chan[i] = pxa_dma_dbg_alloc_chan(i, chandir);
if (!dbgfs_chan[i])
goto err_chans;
}
return;
err_chans:
err_chandir:
kfree(dbgfs_chan);
err_alloc:
err_state:
debugfs_remove_recursive(dbgfs_root);
err_root:
pr_err("pxa_dma: debugfs is not available\n");
}
static void __exit pxa_dma_cleanup_debugfs(void)
{
debugfs_remove_recursive(dbgfs_root);
}
#else
static inline void pxa_dma_init_debugfs(void) {}
static inline void pxa_dma_cleanup_debugfs(void) {}
#endif
int pxa_request_dma (char *name, pxa_dma_prio prio,
void (*irq_handler)(int, void *),
void *data)
{
unsigned long flags;
int i, found = 0;
/* basic sanity checks */
if (!name || !irq_handler)
return -EINVAL;
local_irq_save(flags);
do {
/* try grabbing a DMA channel with the requested priority */
for (i = 0; i < num_dma_channels; i++) {
if ((dma_channels[i].prio == prio) &&
!dma_channels[i].name) {
found = 1;
break;
}
}
/* if requested prio group is full, try a hier priority */
} while (!found && prio--);
if (found) {
DCSR(i) = DCSR_STARTINTR|DCSR_ENDINTR|DCSR_BUSERR;
dma_channels[i].name = name;
dma_channels[i].irq_handler = irq_handler;
dma_channels[i].data = data;
} else {
printk (KERN_WARNING "No more available DMA channels for %s\n", name);
i = -ENODEV;
}
local_irq_restore(flags);
return i;
}
EXPORT_SYMBOL(pxa_request_dma);
void pxa_free_dma (int dma_ch)
{
unsigned long flags;
if (!dma_channels[dma_ch].name) {
printk (KERN_CRIT
"%s: trying to free channel %d which is already freed\n",
__func__, dma_ch);
return;
}
local_irq_save(flags);
DCSR(dma_ch) = DCSR_STARTINTR|DCSR_ENDINTR|DCSR_BUSERR;
dma_channels[dma_ch].name = NULL;
local_irq_restore(flags);
}
EXPORT_SYMBOL(pxa_free_dma);
static irqreturn_t dma_irq_handler(int irq, void *dev_id)
{
int i, dint = DINT;
struct dma_channel *channel;
while (dint) {
i = __ffs(dint);
dint &= (dint - 1);
channel = &dma_channels[i];
if (channel->name && channel->irq_handler) {
channel->irq_handler(i, channel->data);
} else {
/*
* IRQ for an unregistered DMA channel:
* let's clear the interrupts and disable it.
*/
printk (KERN_WARNING "spurious IRQ for DMA channel %d\n", i);
DCSR(i) = DCSR_STARTINTR|DCSR_ENDINTR|DCSR_BUSERR;
}
}
return IRQ_HANDLED;
}
int __init pxa_init_dma(int irq, int num_ch)
{
int i, ret;
dma_channels = kzalloc(sizeof(struct dma_channel) * num_ch, GFP_KERNEL);
if (dma_channels == NULL)
return -ENOMEM;
/* dma channel priorities on pxa2xx processors:
* ch 0 - 3, 16 - 19 <--> (0) DMA_PRIO_HIGH
* ch 4 - 7, 20 - 23 <--> (1) DMA_PRIO_MEDIUM
* ch 8 - 15, 24 - 31 <--> (2) DMA_PRIO_LOW
*/
for (i = 0; i < num_ch; i++) {
DCSR(i) = 0;
dma_channels[i].prio = min((i & 0xf) >> 2, DMA_PRIO_LOW);
spin_lock_init(&dma_channels[i].lock);
}
ret = request_irq(irq, dma_irq_handler, 0, "DMA", NULL);
if (ret) {
printk (KERN_CRIT "Wow! Can't register IRQ for DMA\n");
kfree(dma_channels);
return ret;
}
num_dma_channels = num_ch;
pxa_dma_init_debugfs();
return 0;
}