- 根目录:
- drivers
- dma
- at_hdmac.c
/*
* Driver for the Atmel AHB DMA Controller (aka HDMA or DMAC on AT91 systems)
*
* Copyright (C) 2008 Atmel Corporation
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
*
* This supports the Atmel AHB DMA Controller,
*
* The driver has currently been tested with the Atmel AT91SAM9RL
* and AT91SAM9G45 series.
*/
#include <linux/clk.h>
#include <linux/dmaengine.h>
#include <linux/dma-mapping.h>
#include <linux/dmapool.h>
#include <linux/interrupt.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include "at_hdmac_regs.h"
/*
* Glossary
* --------
*
* at_hdmac : Name of the ATmel AHB DMA Controller
* at_dma_ / atdma : ATmel DMA controller entity related
* atc_ / atchan : ATmel DMA Channel entity related
*/
#define ATC_DEFAULT_CFG (ATC_FIFOCFG_HALFFIFO)
#define ATC_DEFAULT_CTRLA (0)
#define ATC_DEFAULT_CTRLB (ATC_SIF(0) \
|ATC_DIF(1))
/*
* Initial number of descriptors to allocate for each channel. This could
* be increased during dma usage.
*/
static unsigned int init_nr_desc_per_channel = 64;
module_param(init_nr_desc_per_channel, uint, 0644);
MODULE_PARM_DESC(init_nr_desc_per_channel,
"initial descriptors per channel (default: 64)");
/* prototypes */
static dma_cookie_t atc_tx_submit(struct dma_async_tx_descriptor *tx);
/*----------------------------------------------------------------------*/
static struct at_desc *atc_first_active(struct at_dma_chan *atchan)
{
return list_first_entry(&atchan->active_list,
struct at_desc, desc_node);
}
static struct at_desc *atc_first_queued(struct at_dma_chan *atchan)
{
return list_first_entry(&atchan->queue,
struct at_desc, desc_node);
}
/**
* atc_alloc_descriptor - allocate and return an initialized descriptor
* @chan: the channel to allocate descriptors for
* @gfp_flags: GFP allocation flags
*
* Note: The ack-bit is positioned in the descriptor flag at creation time
* to make initial allocation more convenient. This bit will be cleared
* and control will be given to client at usage time (during
* preparation functions).
*/
static struct at_desc *atc_alloc_descriptor(struct dma_chan *chan,
gfp_t gfp_flags)
{
struct at_desc *desc = NULL;
struct at_dma *atdma = to_at_dma(chan->device);
dma_addr_t phys;
desc = dma_pool_alloc(atdma->dma_desc_pool, gfp_flags, &phys);
if (desc) {
memset(desc, 0, sizeof(struct at_desc));
INIT_LIST_HEAD(&desc->tx_list);
dma_async_tx_descriptor_init(&desc->txd, chan);
/* txd.flags will be overwritten in prep functions */
desc->txd.flags = DMA_CTRL_ACK;
desc->txd.tx_submit = atc_tx_submit;
desc->txd.phys = phys;
}
return desc;
}
/**
* atc_desc_get - get an unused descriptor from free_list
* @atchan: channel we want a new descriptor for
*/
static struct at_desc *atc_desc_get(struct at_dma_chan *atchan)
{
struct at_desc *desc, *_desc;
struct at_desc *ret = NULL;
unsigned int i = 0;
LIST_HEAD(tmp_list);
spin_lock_bh(&atchan->lock);
list_for_each_entry_safe(desc, _desc, &atchan->free_list, desc_node) {
i++;
if (async_tx_test_ack(&desc->txd)) {
list_del(&desc->desc_node);
ret = desc;
break;
}
dev_dbg(chan2dev(&atchan->chan_common),
"desc %p not ACKed\n", desc);
}
spin_unlock_bh(&atchan->lock);
dev_vdbg(chan2dev(&atchan->chan_common),
"scanned %u descriptors on freelist\n", i);
/* no more descriptor available in initial pool: create one more */
if (!ret) {
ret = atc_alloc_descriptor(&atchan->chan_common, GFP_ATOMIC);
if (ret) {
spin_lock_bh(&atchan->lock);
atchan->descs_allocated++;
spin_unlock_bh(&atchan->lock);
} else {
dev_err(chan2dev(&atchan->chan_common),
"not enough descriptors available\n");
}
}
return ret;
}
/**
* atc_desc_put - move a descriptor, including any children, to the free list
* @atchan: channel we work on
* @desc: descriptor, at the head of a chain, to move to free list
*/
static void atc_desc_put(struct at_dma_chan *atchan, struct at_desc *desc)
{
if (desc) {
struct at_desc *child;
spin_lock_bh(&atchan->lock);
list_for_each_entry(child, &desc->tx_list, desc_node)
dev_vdbg(chan2dev(&atchan->chan_common),
"moving child desc %p to freelist\n",
child);
list_splice_init(&desc->tx_list, &atchan->free_list);
dev_vdbg(chan2dev(&atchan->chan_common),
"moving desc %p to freelist\n", desc);
list_add(&desc->desc_node, &atchan->free_list);
spin_unlock_bh(&atchan->lock);
}
}
/**
* atc_assign_cookie - compute and assign new cookie
* @atchan: channel we work on
* @desc: descriptor to assign cookie for
*
* Called with atchan->lock held and bh disabled
*/
static dma_cookie_t
atc_assign_cookie(struct at_dma_chan *atchan, struct at_desc *desc)
{
dma_cookie_t cookie = atchan->chan_common.cookie;
if (++cookie < 0)
cookie = 1;
atchan->chan_common.cookie = cookie;
desc->txd.cookie = cookie;
return cookie;
}
/**
* atc_dostart - starts the DMA engine for real
* @atchan: the channel we want to start
* @first: first descriptor in the list we want to begin with
*
* Called with atchan->lock held and bh disabled
*/
static void atc_dostart(struct at_dma_chan *atchan, struct at_desc *first)
{
struct at_dma *atdma = to_at_dma(atchan->chan_common.device);
/* ASSERT: channel is idle */
if (atc_chan_is_enabled(atchan)) {
dev_err(chan2dev(&atchan->chan_common),
"BUG: Attempted to start non-idle channel\n");
dev_err(chan2dev(&atchan->chan_common),
" channel: s0x%x d0x%x ctrl0x%x:0x%x l0x%x\n",
channel_readl(atchan, SADDR),
channel_readl(atchan, DADDR),
channel_readl(atchan, CTRLA),
channel_readl(atchan, CTRLB),
channel_readl(atchan, DSCR));
/* The tasklet will hopefully advance the queue... */
return;
}
vdbg_dump_regs(atchan);
/* clear any pending interrupt */
while (dma_readl(atdma, EBCISR))
cpu_relax();
channel_writel(atchan, SADDR, 0);
channel_writel(atchan, DADDR, 0);
channel_writel(atchan, CTRLA, 0);
channel_writel(atchan, CTRLB, 0);
channel_writel(atchan, DSCR, first->txd.phys);
dma_writel(atdma, CHER, atchan->mask);
vdbg_dump_regs(atchan);
}
/**
* atc_chain_complete - finish work for one transaction chain
* @atchan: channel we work on
* @desc: descriptor at the head of the chain we want do complete
*
* Called with atchan->lock held and bh disabled */
static void
atc_chain_complete(struct at_dma_chan *atchan, struct at_desc *desc)
{
dma_async_tx_callback callback;
void *param;
struct dma_async_tx_descriptor *txd = &desc->txd;
dev_vdbg(chan2dev(&atchan->chan_common),
"descriptor %u complete\n", txd->cookie);
atchan->completed_cookie = txd->cookie;
callback = txd->callback;
param = txd->callback_param;
/* move children to free_list */
list_splice_init(&desc->tx_list, &atchan->free_list);
/* move myself to free_list */
list_move(&desc->desc_node, &atchan->free_list);
/* unmap dma addresses (not on slave channels) */
if (!atchan->chan_common.private) {
struct device *parent = chan2parent(&atchan->chan_common);
if (!(txd->flags & DMA_COMPL_SKIP_DEST_UNMAP)) {
if (txd->flags & DMA_COMPL_DEST_UNMAP_SINGLE)
dma_unmap_single(parent,
desc->lli.daddr,
desc->len, DMA_FROM_DEVICE);
else
dma_unmap_page(parent,
desc->lli.daddr,
desc->len, DMA_FROM_DEVICE);
}
if (!(txd->flags & DMA_COMPL_SKIP_SRC_UNMAP)) {
if (txd->flags & DMA_COMPL_SRC_UNMAP_SINGLE)
dma_unmap_single(parent,
desc->lli.saddr,
desc->len, DMA_TO_DEVICE);
else
dma_unmap_page(parent,
desc->lli.saddr,
desc->len, DMA_TO_DEVICE);
}
}
/*
* The API requires that no submissions are done from a
* callback, so we don't need to drop the lock here
*/
if (callback)
callback(param);
dma_run_dependencies(txd);
}
/**
* atc_complete_all - finish work for all transactions
* @atchan: channel to complete transactions for
*
* Eventually submit queued descriptors if any
*
* Assume channel is idle while calling this function
* Called with atchan->lock held and bh disabled
*/
static void atc_complete_all(struct at_dma_chan *atchan)
{
struct at_desc *desc, *_desc;
LIST_HEAD(list);
dev_vdbg(chan2dev(&atchan->chan_common), "complete all\n");
BUG_ON(atc_chan_is_enabled(atchan));
/*
* Submit queued descriptors ASAP, i.e. before we go through
* the completed ones.
*/
if (!list_empty(&atchan->queue))
atc_dostart(atchan, atc_first_queued(atchan));
/* empty active_list now it is completed */
list_splice_init(&atchan->active_list, &list);
/* empty queue list by moving descriptors (if any) to active_list */
list_splice_init(&atchan->queue, &atchan->active_list);
list_for_each_entry_safe(desc, _desc, &list, desc_node)
atc_chain_complete(atchan, desc);
}
/**
* atc_cleanup_descriptors - cleanup up finished descriptors in active_list
* @atchan: channel to be cleaned up
*
* Called with atchan->lock held and bh disabled
*/
static void atc_cleanup_descriptors(struct at_dma_chan *atchan)
{
struct at_desc *desc, *_desc;
struct at_desc *child;
dev_vdbg(chan2dev(&atchan->chan_common), "cleanup descriptors\n");
list_for_each_entry_safe(desc, _desc, &atchan->active_list, desc_node) {
if (!(desc->lli.ctrla & ATC_DONE))
/* This one is currently in progress */
return;
list_for_each_entry(child, &desc->tx_list, desc_node)
if (!(child->lli.ctrla & ATC_DONE))
/* Currently in progress */
return;
/*
* No descriptors so far seem to be in progress, i.e.
* this chain must be done.
*/
atc_chain_complete(atchan, desc);
}
}
/**
* atc_advance_work - at the end of a transaction, move forward
* @atchan: channel where the transaction ended
*
* Called with atchan->lock held and bh disabled
*/
static void atc_advance_work(struct at_dma_chan *atchan)
{
dev_vdbg(chan2dev(&atchan->chan_common), "advance_work\n");
if (list_empty(&atchan->active_list) ||
list_is_singular(&atchan->active_list)) {
atc_complete_all(atchan);
} else {
atc_chain_complete(atchan, atc_first_active(atchan));
/* advance work */
atc_dostart(atchan, atc_first_active(atchan));
}
}
/**
* atc_handle_error - handle errors reported by DMA controller
* @atchan: channel where error occurs
*
* Called with atchan->lock held and bh disabled
*/
static void atc_handle_error(struct at_dma_chan *atchan)
{
struct at_desc *bad_desc;
struct at_desc *child;
/*
* The descriptor currently at the head of the active list is
* broked. Since we don't have any way to report errors, we'll
* just have to scream loudly and try to carry on.
*/
bad_desc = atc_first_active(atchan);
list_del_init(&bad_desc->desc_node);
/* As we are stopped, take advantage to push queued descriptors
* in active_list */
list_splice_init(&atchan->queue, atchan->active_list.prev);
/* Try to restart the controller */
if (!list_empty(&atchan->active_list))
atc_dostart(atchan, atc_first_active(atchan));
/*
* KERN_CRITICAL may seem harsh, but since this only happens
* when someone submits a bad physical address in a
* descriptor, we should consider ourselves lucky that the
* controller flagged an error instead of scribbling over
* random memory locations.
*/
dev_crit(chan2dev(&atchan->chan_common),
"Bad descriptor submitted for DMA!\n");
dev_crit(chan2dev(&atchan->chan_common),
" cookie: %d\n", bad_desc->txd.cookie);
atc_dump_lli(atchan, &bad_desc->lli);
list_for_each_entry(child, &bad_desc->tx_list, desc_node)
atc_dump_lli(atchan, &child->lli);
/* Pretend the descriptor completed successfully */
atc_chain_complete(atchan, bad_desc);
}
/*-- IRQ & Tasklet ---------------------------------------------------*/
static void atc_tasklet(unsigned long data)
{
struct at_dma_chan *atchan = (struct at_dma_chan *)data;
/* Channel cannot be enabled here */
if (atc_chan_is_enabled(atchan)) {
dev_err(chan2dev(&atchan->chan_common),
"BUG: channel enabled in tasklet\n");
return;
}
spin_lock(&atchan->lock);
if (test_and_clear_bit(0, &atchan->error_status))
atc_handle_error(atchan);
else
atc_advance_work(atchan);
spin_unlock(&atchan->lock);
}
static irqreturn_t at_dma_interrupt(int irq, void *dev_id)
{
struct at_dma *atdma = (struct at_dma *)dev_id;
struct at_dma_chan *atchan;
int i;
u32 status, pending, imr;
int ret = IRQ_NONE;
do {
imr = dma_readl(atdma, EBCIMR);
status = dma_readl(atdma, EBCISR);
pending = status & imr;
if (!pending)
break;
dev_vdbg(atdma->dma_common.dev,
"interrupt: status = 0x%08x, 0x%08x, 0x%08x\n",
status, imr, pending);
for (i = 0; i < atdma->dma_common.chancnt; i++) {
atchan = &atdma->chan[i];
if (pending & (AT_DMA_CBTC(i) | AT_DMA_ERR(i))) {
if (pending & AT_DMA_ERR(i)) {
/* Disable channel on AHB error */
dma_writel(atdma, CHDR, atchan->mask);
/* Give information to tasklet */
set_bit(0, &atchan->error_status);
}
tasklet_schedule(&atchan->tasklet);
ret = IRQ_HANDLED;
}
}
} while (pending);
return ret;
}
/*-- DMA Engine API --------------------------------------------------*/
/**
* atc_tx_submit - set the prepared descriptor(s) to be executed by the engine
* @desc: descriptor at the head of the transaction chain
*
* Queue chain if DMA engine is working already
*
* Cookie increment and adding to active_list or queue must be atomic
*/
static dma_cookie_t atc_tx_submit(struct dma_async_tx_descriptor *tx)
{
struct at_desc *desc = txd_to_at_desc(tx);
struct at_dma_chan *atchan = to_at_dma_chan(tx->chan);
dma_cookie_t cookie;
spin_lock_bh(&atchan->lock);
cookie = atc_assign_cookie(atchan, desc);
if (list_empty(&atchan->active_list)) {
dev_vdbg(chan2dev(tx->chan), "tx_submit: started %u\n",
desc->txd.cookie);
atc_dostart(atchan, desc);
list_add_tail(&desc->desc_node, &atchan->active_list);
} else {
dev_vdbg(chan2dev(tx->chan), "tx_submit: queued %u\n",
desc->txd.cookie);
list_add_tail(&desc->desc_node, &atchan->queue);
}
spin_unlock_bh(&atchan->lock);
return cookie;
}
/**
* atc_prep_dma_memcpy - prepare a memcpy operation
* @chan: the channel to prepare operation on
* @dest: operation virtual destination address
* @src: operation virtual source address
* @len: operation length
* @flags: tx descriptor status flags
*/
static struct dma_async_tx_descriptor *
atc_prep_dma_memcpy(struct dma_chan *chan, dma_addr_t dest, dma_addr_t src,
size_t len, unsigned long flags)
{
struct at_dma_chan *atchan = to_at_dma_chan(chan);
struct at_desc *desc = NULL;
struct at_desc *first = NULL;
struct at_desc *prev = NULL;
size_t xfer_count;
size_t offset;
unsigned int src_width;
unsigned int dst_width;
u32 ctrla;
u32 ctrlb;
dev_vdbg(chan2dev(chan), "prep_dma_memcpy: d0x%x s0x%x l0x%zx f0x%lx\n",
dest, src, len, flags);
if (unlikely(!len)) {
dev_dbg(chan2dev(chan), "prep_dma_memcpy: length is zero!\n");
return NULL;
}
ctrla = ATC_DEFAULT_CTRLA;
ctrlb = ATC_DEFAULT_CTRLB
| ATC_SRC_ADDR_MODE_INCR
| ATC_DST_ADDR_MODE_INCR
| ATC_FC_MEM2MEM;
/*
* We can be a lot more clever here, but this should take care
* of the most common optimization.
*/
if (!((src | dest | len) & 3)) {
ctrla |= ATC_SRC_WIDTH_WORD | ATC_DST_WIDTH_WORD;
src_width = dst_width = 2;
} else if (!((src | dest | len) & 1)) {
ctrla |= ATC_SRC_WIDTH_HALFWORD | ATC_DST_WIDTH_HALFWORD;
src_width = dst_width = 1;
} else {
ctrla |= ATC_SRC_WIDTH_BYTE | ATC_DST_WIDTH_BYTE;
src_width = dst_width = 0;
}
for (offset = 0; offset < len; offset += xfer_count << src_width) {
xfer_count = min_t(size_t, (len - offset) >> src_width,
ATC_BTSIZE_MAX);
desc = atc_desc_get(atchan);
if (!desc)
goto err_desc_get;
desc->lli.saddr = src + offset;
desc->lli.daddr = dest + offset;
desc->lli.ctrla = ctrla | xfer_count;
desc->lli.ctrlb = ctrlb;
desc->txd.cookie = 0;
if (!first) {
first = desc;
} else {
/* inform the HW lli about chaining */
prev->lli.dscr = desc->txd.phys;
/* insert the link descriptor to the LD ring */
list_add_tail(&desc->desc_node,
&first->tx_list);
}
prev = desc;
}
/* First descriptor of the chain embedds additional information */
first->txd.cookie = -EBUSY;
first->len = len;
/* set end-of-link to the last link descriptor of list*/
set_desc_eol(desc);
first->txd.flags = flags; /* client is in control of this ack */
return &first->txd;
err_desc_get:
atc_desc_put(atchan, first);
return NULL;
}
/**
* atc_prep_slave_sg - prepare descriptors for a DMA_SLAVE transaction
* @chan: DMA channel
* @sgl: scatterlist to transfer to/from
* @sg_len: number of entries in @scatterlist
* @direction: DMA direction
* @flags: tx descriptor status flags
*/
static struct dma_async_tx_descriptor *
atc_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl,
unsigned int sg_len, enum dma_data_direction direction,
unsigned long flags)
{
struct at_dma_chan *atchan = to_at_dma_chan(chan);
struct at_dma_slave *atslave = chan->private;
struct at_desc *first = NULL;
struct at_desc *prev = NULL;
u32 ctrla;
u32 ctrlb;
dma_addr_t reg;
unsigned int reg_width;
unsigned int mem_width;
unsigned int i;
struct scatterlist *sg;
size_t total_len = 0;
dev_vdbg(chan2dev(chan), "prep_slave_sg: %s f0x%lx\n",
direction == DMA_TO_DEVICE ? "TO DEVICE" : "FROM DEVICE",
flags);
if (unlikely(!atslave || !sg_len)) {
dev_dbg(chan2dev(chan), "prep_dma_memcpy: length is zero!\n");
return NULL;
}
reg_width = atslave->reg_width;
ctrla = ATC_DEFAULT_CTRLA | atslave->ctrla;
ctrlb = ATC_DEFAULT_CTRLB | ATC_IEN;
switch (direction) {
case DMA_TO_DEVICE:
ctrla |= ATC_DST_WIDTH(reg_width);
ctrlb |= ATC_DST_ADDR_MODE_FIXED
| ATC_SRC_ADDR_MODE_INCR
| ATC_FC_MEM2PER;
reg = atslave->tx_reg;
for_each_sg(sgl, sg, sg_len, i) {
struct at_desc *desc;
u32 len;
u32 mem;
desc = atc_desc_get(atchan);
if (!desc)
goto err_desc_get;
mem = sg_dma_address(sg);
len = sg_dma_len(sg);
mem_width = 2;
if (unlikely(mem & 3 || len & 3))
mem_width = 0;
desc->lli.saddr = mem;
desc->lli.daddr = reg;
desc->lli.ctrla = ctrla
| ATC_SRC_WIDTH(mem_width)
| len >> mem_width;
desc->lli.ctrlb = ctrlb;
if (!first) {
first = desc;
} else {
/* inform the HW lli about chaining */
prev->lli.dscr = desc->txd.phys;
/* insert the link descriptor to the LD ring */
list_add_tail(&desc->desc_node,
&first->tx_list);
}
prev = desc;
total_len += len;
}
break;
case DMA_FROM_DEVICE:
ctrla |= ATC_SRC_WIDTH(reg_width);
ctrlb |= ATC_DST_ADDR_MODE_INCR
| ATC_SRC_ADDR_MODE_FIXED
| ATC_FC_PER2MEM;
reg = atslave->rx_reg;
for_each_sg(sgl, sg, sg_len, i) {
struct at_desc *desc;
u32 len;
u32 mem;
desc = atc_desc_get(atchan);
if (!desc)
goto err_desc_get;
mem = sg_dma_address(sg);
len = sg_dma_len(sg);
mem_width = 2;
if (unlikely(mem & 3 || len & 3))
mem_width = 0;
desc->lli.saddr = reg;
desc->lli.daddr = mem;
desc->lli.ctrla = ctrla
| ATC_DST_WIDTH(mem_width)
| len >> reg_width;
desc->lli.ctrlb = ctrlb;
if (!first) {
first = desc;
} else {
/* inform the HW lli about chaining */
prev->lli.dscr = desc->txd.phys;
/* insert the link descriptor to the LD ring */
list_add_tail(&desc->desc_node,
&first->tx_list);
}
prev = desc;
total_len += len;
}
break;
default:
return NULL;
}
/* set end-of-link to the last link descriptor of list*/
set_desc_eol(prev);
/* First descriptor of the chain embedds additional information */
first->txd.cookie = -EBUSY;
first->len = total_len;
/* first link descriptor of list is responsible of flags */
first->txd.flags = flags; /* client is in control of this ack */
return &first->txd;
err_desc_get:
dev_err(chan2dev(chan), "not enough descriptors available\n");
atc_desc_put(atchan, first);
return NULL;
}
static int atc_control(struct dma_chan *chan, enum dma_ctrl_cmd cmd,
unsigned long arg)
{
struct at_dma_chan *atchan = to_at_dma_chan(chan);
struct at_dma *atdma = to_at_dma(chan->device);
struct at_desc *desc, *_desc;
LIST_HEAD(list);
/* Only supports DMA_TERMINATE_ALL */
if (cmd != DMA_TERMINATE_ALL)
return -ENXIO;
/*
* This is only called when something went wrong elsewhere, so
* we don't really care about the data. Just disable the
* channel. We still have to poll the channel enable bit due
* to AHB/HSB limitations.
*/
spin_lock_bh(&atchan->lock);
dma_writel(atdma, CHDR, atchan->mask);
/* confirm that this channel is disabled */
while (dma_readl(atdma, CHSR) & atchan->mask)
cpu_relax();
/* active_list entries will end up before queued entries */
list_splice_init(&atchan->queue, &list);
list_splice_init(&atchan->active_list, &list);
/* Flush all pending and queued descriptors */
list_for_each_entry_safe(desc, _desc, &list, desc_node)
atc_chain_complete(atchan, desc);
spin_unlock_bh(&atchan->lock);
return 0;
}
/**
* atc_tx_status - poll for transaction completion
* @chan: DMA channel
* @cookie: transaction identifier to check status of
* @txstate: if not %NULL updated with transaction state
*
* If @txstate is passed in, upon return it reflect the driver
* internal state and can be used with dma_async_is_complete() to check
* the status of multiple cookies without re-checking hardware state.
*/
static enum dma_status
atc_tx_status(struct dma_chan *chan,
dma_cookie_t cookie,
struct dma_tx_state *txstate)
{
struct at_dma_chan *atchan = to_at_dma_chan(chan);
dma_cookie_t last_used;
dma_cookie_t last_complete;
enum dma_status ret;
spin_lock_bh(&atchan->lock);
last_complete = atchan->completed_cookie;
last_used = chan->cookie;
ret = dma_async_is_complete(cookie, last_complete, last_used);
if (ret != DMA_SUCCESS) {
atc_cleanup_descriptors(atchan);
last_complete = atchan->completed_cookie;
last_used = chan->cookie;
ret = dma_async_is_complete(cookie, last_complete, last_used);
}
spin_unlock_bh(&atchan->lock);
dma_set_tx_state(txstate, last_complete, last_used, 0);
dev_vdbg(chan2dev(chan), "tx_status: %d (d%d, u%d)\n",
cookie, last_complete ? last_complete : 0,
last_used ? last_used : 0);
return ret;
}
/**
* atc_issue_pending - try to finish work
* @chan: target DMA channel
*/
static void atc_issue_pending(struct dma_chan *chan)
{
struct at_dma_chan *atchan = to_at_dma_chan(chan);
dev_vdbg(chan2dev(chan), "issue_pending\n");
spin_lock_bh(&atchan->lock);
if (!atc_chan_is_enabled(atchan)) {
atc_advance_work(atchan);
}
spin_unlock_bh(&atchan->lock);
}
/**
* atc_alloc_chan_resources - allocate resources for DMA channel
* @chan: allocate descriptor resources for this channel
* @client: current client requesting the channel be ready for requests
*
* return - the number of allocated descriptors
*/
static int atc_alloc_chan_resources(struct dma_chan *chan)
{
struct at_dma_chan *atchan = to_at_dma_chan(chan);
struct at_dma *atdma = to_at_dma(chan->device);
struct at_desc *desc;
struct at_dma_slave *atslave;
int i;
u32 cfg;
LIST_HEAD(tmp_list);
dev_vdbg(chan2dev(chan), "alloc_chan_resources\n");
/* ASSERT: channel is idle */
if (atc_chan_is_enabled(atchan)) {
dev_dbg(chan2dev(chan), "DMA channel not idle ?\n");
return -EIO;
}
cfg = ATC_DEFAULT_CFG;
atslave = chan->private;
if (atslave) {
/*
* We need controller-specific data to set up slave
* transfers.
*/
BUG_ON(!atslave->dma_dev || atslave->dma_dev != atdma->dma_common.dev);
/* if cfg configuration specified take it instad of default */
if (atslave->cfg)
cfg = atslave->cfg;
}
/* have we already been set up?
* reconfigure channel but no need to reallocate descriptors */
if (!list_empty(&atchan->free_list))
return atchan->descs_allocated;
/* Allocate initial pool of descriptors */
for (i = 0; i < init_nr_desc_per_channel; i++) {
desc = atc_alloc_descriptor(chan, GFP_KERNEL);
if (!desc) {
dev_err(atdma->dma_common.dev,
"Only %d initial descriptors\n", i);
break;
}
list_add_tail(&desc->desc_node, &tmp_list);
}
spin_lock_bh(&atchan->lock);
atchan->descs_allocated = i;
list_splice(&tmp_list, &atchan->free_list);
atchan->completed_cookie = chan->cookie = 1;
spin_unlock_bh(&atchan->lock);
/* channel parameters */
channel_writel(atchan, CFG, cfg);
dev_dbg(chan2dev(chan),
"alloc_chan_resources: allocated %d descriptors\n",
atchan->descs_allocated);
return atchan->descs_allocated;
}
/**
* atc_free_chan_resources - free all channel resources
* @chan: DMA channel
*/
static void atc_free_chan_resources(struct dma_chan *chan)
{
struct at_dma_chan *atchan = to_at_dma_chan(chan);
struct at_dma *atdma = to_at_dma(chan->device);
struct at_desc *desc, *_desc;
LIST_HEAD(list);
dev_dbg(chan2dev(chan), "free_chan_resources: (descs allocated=%u)\n",
atchan->descs_allocated);
/* ASSERT: channel is idle */
BUG_ON(!list_empty(&atchan->active_list));
BUG_ON(!list_empty(&atchan->queue));
BUG_ON(atc_chan_is_enabled(atchan));
list_for_each_entry_safe(desc, _desc, &atchan->free_list, desc_node) {
dev_vdbg(chan2dev(chan), " freeing descriptor %p\n", desc);
list_del(&desc->desc_node);
/* free link descriptor */
dma_pool_free(atdma->dma_desc_pool, desc, desc->txd.phys);
}
list_splice_init(&atchan->free_list, &list);
atchan->descs_allocated = 0;
dev_vdbg(chan2dev(chan), "free_chan_resources: done\n");
}
/*-- Module Management -----------------------------------------------*/
/**
* at_dma_off - disable DMA controller
* @atdma: the Atmel HDAMC device
*/
static void at_dma_off(struct at_dma *atdma)
{
dma_writel(atdma, EN, 0);
/* disable all interrupts */
dma_writel(atdma, EBCIDR, -1L);
/* confirm that all channels are disabled */
while (dma_readl(atdma, CHSR) & atdma->all_chan_mask)
cpu_relax();
}
static int __init at_dma_probe(struct platform_device *pdev)
{
struct at_dma_platform_data *pdata;
struct resource *io;
struct at_dma *atdma;
size_t size;
int irq;
int err;
int i;
/* get DMA Controller parameters from platform */
pdata = pdev->dev.platform_data;
if (!pdata || pdata->nr_channels > AT_DMA_MAX_NR_CHANNELS)
return -EINVAL;
io = platform_get_resource(pdev, IORESOURCE_MEM, 0);
if (!io)
return -EINVAL;
irq = platform_get_irq(pdev, 0);
if (irq < 0)
return irq;
size = sizeof(struct at_dma);
size += pdata->nr_channels * sizeof(struct at_dma_chan);
atdma = kzalloc(size, GFP_KERNEL);
if (!atdma)
return -ENOMEM;
/* discover transaction capabilites from the platform data */
atdma->dma_common.cap_mask = pdata->cap_mask;
atdma->all_chan_mask = (1 << pdata->nr_channels) - 1;
size = io->end - io->start + 1;
if (!request_mem_region(io->start, size, pdev->dev.driver->name)) {
err = -EBUSY;
goto err_kfree;
}
atdma->regs = ioremap(io->start, size);
if (!atdma->regs) {
err = -ENOMEM;
goto err_release_r;
}
atdma->clk = clk_get(&pdev->dev, "dma_clk");
if (IS_ERR(atdma->clk)) {
err = PTR_ERR(atdma->clk);
goto err_clk;
}
clk_enable(atdma->clk);
/* force dma off, just in case */
at_dma_off(atdma);
err = request_irq(irq, at_dma_interrupt, 0, "at_hdmac", atdma);
if (err)
goto err_irq;
platform_set_drvdata(pdev, atdma);
/* create a pool of consistent memory blocks for hardware descriptors */
atdma->dma_desc_pool = dma_pool_create("at_hdmac_desc_pool",
&pdev->dev, sizeof(struct at_desc),
4 /* word alignment */, 0);
if (!atdma->dma_desc_pool) {
dev_err(&pdev->dev, "No memory for descriptors dma pool\n");
err = -ENOMEM;
goto err_pool_create;
}
/* clear any pending interrupt */
while (dma_readl(atdma, EBCISR))
cpu_relax();
/* initialize channels related values */
INIT_LIST_HEAD(&atdma->dma_common.channels);
for (i = 0; i < pdata->nr_channels; i++, atdma->dma_common.chancnt++) {
struct at_dma_chan *atchan = &atdma->chan[i];
atchan->chan_common.device = &atdma->dma_common;
atchan->chan_common.cookie = atchan->completed_cookie = 1;
atchan->chan_common.chan_id = i;
list_add_tail(&atchan->chan_common.device_node,
&atdma->dma_common.channels);
atchan->ch_regs = atdma->regs + ch_regs(i);
spin_lock_init(&atchan->lock);
atchan->mask = 1 << i;
INIT_LIST_HEAD(&atchan->active_list);
INIT_LIST_HEAD(&atchan->queue);
INIT_LIST_HEAD(&atchan->free_list);
tasklet_init(&atchan->tasklet, atc_tasklet,
(unsigned long)atchan);
atc_enable_irq(atchan);
}
/* set base routines */
atdma->dma_common.device_alloc_chan_resources = atc_alloc_chan_resources;
atdma->dma_common.device_free_chan_resources = atc_free_chan_resources;
atdma->dma_common.device_tx_status = atc_tx_status;
atdma->dma_common.device_issue_pending = atc_issue_pending;
atdma->dma_common.dev = &pdev->dev;
/* set prep routines based on capability */
if (dma_has_cap(DMA_MEMCPY, atdma->dma_common.cap_mask))
atdma->dma_common.device_prep_dma_memcpy = atc_prep_dma_memcpy;
if (dma_has_cap(DMA_SLAVE, atdma->dma_common.cap_mask)) {
atdma->dma_common.device_prep_slave_sg = atc_prep_slave_sg;
atdma->dma_common.device_control = atc_control;
}
dma_writel(atdma, EN, AT_DMA_ENABLE);
dev_info(&pdev->dev, "Atmel AHB DMA Controller ( %s%s), %d channels\n",
dma_has_cap(DMA_MEMCPY, atdma->dma_common.cap_mask) ? "cpy " : "",
dma_has_cap(DMA_SLAVE, atdma->dma_common.cap_mask) ? "slave " : "",
atdma->dma_common.chancnt);
dma_async_device_register(&atdma->dma_common);
return 0;
err_pool_create:
platform_set_drvdata(pdev, NULL);
free_irq(platform_get_irq(pdev, 0), atdma);
err_irq:
clk_disable(atdma->clk);
clk_put(atdma->clk);
err_clk:
iounmap(atdma->regs);
atdma->regs = NULL;
err_release_r:
release_mem_region(io->start, size);
err_kfree:
kfree(atdma);
return err;
}
static int __exit at_dma_remove(struct platform_device *pdev)
{
struct at_dma *atdma = platform_get_drvdata(pdev);
struct dma_chan *chan, *_chan;
struct resource *io;
at_dma_off(atdma);
dma_async_device_unregister(&atdma->dma_common);
dma_pool_destroy(atdma->dma_desc_pool);
platform_set_drvdata(pdev, NULL);
free_irq(platform_get_irq(pdev, 0), atdma);
list_for_each_entry_safe(chan, _chan, &atdma->dma_common.channels,
device_node) {
struct at_dma_chan *atchan = to_at_dma_chan(chan);
/* Disable interrupts */
atc_disable_irq(atchan);
tasklet_disable(&atchan->tasklet);
tasklet_kill(&atchan->tasklet);
list_del(&chan->device_node);
}
clk_disable(atdma->clk);
clk_put(atdma->clk);
iounmap(atdma->regs);
atdma->regs = NULL;
io = platform_get_resource(pdev, IORESOURCE_MEM, 0);
release_mem_region(io->start, io->end - io->start + 1);
kfree(atdma);
return 0;
}
static void at_dma_shutdown(struct platform_device *pdev)
{
struct at_dma *atdma = platform_get_drvdata(pdev);
at_dma_off(platform_get_drvdata(pdev));
clk_disable(atdma->clk);
}
static int at_dma_suspend_noirq(struct device *dev)
{
struct platform_device *pdev = to_platform_device(dev);
struct at_dma *atdma = platform_get_drvdata(pdev);
at_dma_off(platform_get_drvdata(pdev));
clk_disable(atdma->clk);
return 0;
}
static int at_dma_resume_noirq(struct device *dev)
{
struct platform_device *pdev = to_platform_device(dev);
struct at_dma *atdma = platform_get_drvdata(pdev);
clk_enable(atdma->clk);
dma_writel(atdma, EN, AT_DMA_ENABLE);
return 0;
}
static const struct dev_pm_ops at_dma_dev_pm_ops = {
.suspend_noirq = at_dma_suspend_noirq,
.resume_noirq = at_dma_resume_noirq,
};
static struct platform_driver at_dma_driver = {
.remove = __exit_p(at_dma_remove),
.shutdown = at_dma_shutdown,
.driver = {
.name = "at_hdmac",
.pm = &at_dma_dev_pm_ops,
},
};
static int __init at_dma_init(void)
{
return platform_driver_probe(&at_dma_driver, at_dma_probe);
}
subsys_initcall(at_dma_init);
static void __exit at_dma_exit(void)
{
platform_driver_unregister(&at_dma_driver);
}
module_exit(at_dma_exit);
MODULE_DESCRIPTION("Atmel AHB DMA Controller driver");
MODULE_AUTHOR("Nicolas Ferre <nicolas.ferre@atmel.com>");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:at_hdmac");