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WSL2-Linux-Kernel
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WSL2-Linux-Kernel/drivers/dma/dw_dmac.c

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28 KiB
C
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/*
* Driver for the Synopsys DesignWare DMA Controller (aka DMACA on
* AVR32 systems.)
*
* Copyright (C) 2007-2008 Atmel Corporation
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/clk.h>
#include <linux/delay.h>
#include <linux/dmaengine.h>
#include <linux/dma-mapping.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/mm.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include "dw_dmac_regs.h"
/*
* This supports the Synopsys "DesignWare AHB Central DMA Controller",
* (DW_ahb_dmac) which is used with various AMBA 2.0 systems (not all
* of which use ARM any more). See the "Databook" from Synopsys for
* information beyond what licensees probably provide.
*
* The driver has currently been tested only with the Atmel AT32AP7000,
* which does not support descriptor writeback.
*/
/* NOTE: DMS+SMS is system-specific. We should get this information
* from the platform code somehow.
*/
#define DWC_DEFAULT_CTLLO (DWC_CTLL_DST_MSIZE(0) \
| DWC_CTLL_SRC_MSIZE(0) \
| DWC_CTLL_DMS(0) \
| DWC_CTLL_SMS(1) \
| DWC_CTLL_LLP_D_EN \
| DWC_CTLL_LLP_S_EN)
/*
* This is configuration-dependent and usually a funny size like 4095.
* Let's round it down to the nearest power of two.
*
* Note that this is a transfer count, i.e. if we transfer 32-bit
* words, we can do 8192 bytes per descriptor.
*
* This parameter is also system-specific.
*/
#define DWC_MAX_COUNT 2048U
/*
* Number of descriptors to allocate for each channel. This should be
* made configurable somehow; preferably, the clients (at least the
* ones using slave transfers) should be able to give us a hint.
*/
#define NR_DESCS_PER_CHANNEL 64
/*----------------------------------------------------------------------*/
/*
* Because we're not relying on writeback from the controller (it may not
* even be configured into the core!) we don't need to use dma_pool. These
* descriptors -- and associated data -- are cacheable. We do need to make
* sure their dcache entries are written back before handing them off to
* the controller, though.
*/
static struct dw_desc *dwc_first_active(struct dw_dma_chan *dwc)
{
return list_entry(dwc->active_list.next, struct dw_desc, desc_node);
}
static struct dw_desc *dwc_first_queued(struct dw_dma_chan *dwc)
{
return list_entry(dwc->queue.next, struct dw_desc, desc_node);
}
static struct dw_desc *dwc_desc_get(struct dw_dma_chan *dwc)
{
struct dw_desc *desc, *_desc;
struct dw_desc *ret = NULL;
unsigned int i = 0;
spin_lock_bh(&dwc->lock);
list_for_each_entry_safe(desc, _desc, &dwc->free_list, desc_node) {
if (async_tx_test_ack(&desc->txd)) {
list_del(&desc->desc_node);
ret = desc;
break;
}
dev_dbg(&dwc->chan.dev, "desc %p not ACKed\n", desc);
i++;
}
spin_unlock_bh(&dwc->lock);
dev_vdbg(&dwc->chan.dev, "scanned %u descriptors on freelist\n", i);
return ret;
}
static void dwc_sync_desc_for_cpu(struct dw_dma_chan *dwc, struct dw_desc *desc)
{
struct dw_desc *child;
list_for_each_entry(child, &desc->txd.tx_list, desc_node)
dma_sync_single_for_cpu(dwc->chan.dev.parent,
child->txd.phys, sizeof(child->lli),
DMA_TO_DEVICE);
dma_sync_single_for_cpu(dwc->chan.dev.parent,
desc->txd.phys, sizeof(desc->lli),
DMA_TO_DEVICE);
}
/*
* Move a descriptor, including any children, to the free list.
* `desc' must not be on any lists.
*/
static void dwc_desc_put(struct dw_dma_chan *dwc, struct dw_desc *desc)
{
if (desc) {
struct dw_desc *child;
dwc_sync_desc_for_cpu(dwc, desc);
spin_lock_bh(&dwc->lock);
list_for_each_entry(child, &desc->txd.tx_list, desc_node)
dev_vdbg(&dwc->chan.dev,
"moving child desc %p to freelist\n",
child);
list_splice_init(&desc->txd.tx_list, &dwc->free_list);
dev_vdbg(&dwc->chan.dev, "moving desc %p to freelist\n", desc);
list_add(&desc->desc_node, &dwc->free_list);
spin_unlock_bh(&dwc->lock);
}
}
/* Called with dwc->lock held and bh disabled */
static dma_cookie_t
dwc_assign_cookie(struct dw_dma_chan *dwc, struct dw_desc *desc)
{
dma_cookie_t cookie = dwc->chan.cookie;
if (++cookie < 0)
cookie = 1;
dwc->chan.cookie = cookie;
desc->txd.cookie = cookie;
return cookie;
}
/*----------------------------------------------------------------------*/
/* Called with dwc->lock held and bh disabled */
static void dwc_dostart(struct dw_dma_chan *dwc, struct dw_desc *first)
{
struct dw_dma *dw = to_dw_dma(dwc->chan.device);
/* ASSERT: channel is idle */
if (dma_readl(dw, CH_EN) & dwc->mask) {
dev_err(&dwc->chan.dev,
"BUG: Attempted to start non-idle channel\n");
dev_err(&dwc->chan.dev,
" SAR: 0x%x DAR: 0x%x LLP: 0x%x CTL: 0x%x:%08x\n",
channel_readl(dwc, SAR),
channel_readl(dwc, DAR),
channel_readl(dwc, LLP),
channel_readl(dwc, CTL_HI),
channel_readl(dwc, CTL_LO));
/* The tasklet will hopefully advance the queue... */
return;
}
channel_writel(dwc, LLP, first->txd.phys);
channel_writel(dwc, CTL_LO,
DWC_CTLL_LLP_D_EN | DWC_CTLL_LLP_S_EN);
channel_writel(dwc, CTL_HI, 0);
channel_set_bit(dw, CH_EN, dwc->mask);
}
/*----------------------------------------------------------------------*/
static void
dwc_descriptor_complete(struct dw_dma_chan *dwc, struct dw_desc *desc)
{
dma_async_tx_callback callback;
void *param;
struct dma_async_tx_descriptor *txd = &desc->txd;
dev_vdbg(&dwc->chan.dev, "descriptor %u complete\n", txd->cookie);
dwc->completed = txd->cookie;
callback = txd->callback;
param = txd->callback_param;
dwc_sync_desc_for_cpu(dwc, desc);
list_splice_init(&txd->tx_list, &dwc->free_list);
list_move(&desc->desc_node, &dwc->free_list);
/*
* We use dma_unmap_page() regardless of how the buffers were
* mapped before they were submitted...
*/
if (!(txd->flags & DMA_COMPL_SKIP_DEST_UNMAP))
dma_unmap_page(dwc->chan.dev.parent, desc->lli.dar, desc->len,
DMA_FROM_DEVICE);
if (!(txd->flags & DMA_COMPL_SKIP_SRC_UNMAP))
dma_unmap_page(dwc->chan.dev.parent, desc->lli.sar, 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);
}
static void dwc_complete_all(struct dw_dma *dw, struct dw_dma_chan *dwc)
{
struct dw_desc *desc, *_desc;
LIST_HEAD(list);
if (dma_readl(dw, CH_EN) & dwc->mask) {
dev_err(&dwc->chan.dev,
"BUG: XFER bit set, but channel not idle!\n");
/* Try to continue after resetting the channel... */
channel_clear_bit(dw, CH_EN, dwc->mask);
while (dma_readl(dw, CH_EN) & dwc->mask)
cpu_relax();
}
/*
* Submit queued descriptors ASAP, i.e. before we go through
* the completed ones.
*/
if (!list_empty(&dwc->queue))
dwc_dostart(dwc, dwc_first_queued(dwc));
list_splice_init(&dwc->active_list, &list);
list_splice_init(&dwc->queue, &dwc->active_list);
list_for_each_entry_safe(desc, _desc, &list, desc_node)
dwc_descriptor_complete(dwc, desc);
}
static void dwc_scan_descriptors(struct dw_dma *dw, struct dw_dma_chan *dwc)
{
dma_addr_t llp;
struct dw_desc *desc, *_desc;
struct dw_desc *child;
u32 status_xfer;
/*
* Clear block interrupt flag before scanning so that we don't
* miss any, and read LLP before RAW_XFER to ensure it is
* valid if we decide to scan the list.
*/
dma_writel(dw, CLEAR.BLOCK, dwc->mask);
llp = channel_readl(dwc, LLP);
status_xfer = dma_readl(dw, RAW.XFER);
if (status_xfer & dwc->mask) {
/* Everything we've submitted is done */
dma_writel(dw, CLEAR.XFER, dwc->mask);
dwc_complete_all(dw, dwc);
return;
}
dev_vdbg(&dwc->chan.dev, "scan_descriptors: llp=0x%x\n", llp);
list_for_each_entry_safe(desc, _desc, &dwc->active_list, desc_node) {
if (desc->lli.llp == llp)
/* This one is currently in progress */
return;
list_for_each_entry(child, &desc->txd.tx_list, desc_node)
if (child->lli.llp == llp)
/* Currently in progress */
return;
/*
* No descriptors so far seem to be in progress, i.e.
* this one must be done.
*/
dwc_descriptor_complete(dwc, desc);
}
dev_err(&dwc->chan.dev,
"BUG: All descriptors done, but channel not idle!\n");
/* Try to continue after resetting the channel... */
channel_clear_bit(dw, CH_EN, dwc->mask);
while (dma_readl(dw, CH_EN) & dwc->mask)
cpu_relax();
if (!list_empty(&dwc->queue)) {
dwc_dostart(dwc, dwc_first_queued(dwc));
list_splice_init(&dwc->queue, &dwc->active_list);
}
}
static void dwc_dump_lli(struct dw_dma_chan *dwc, struct dw_lli *lli)
{
dev_printk(KERN_CRIT, &dwc->chan.dev,
" desc: s0x%x d0x%x l0x%x c0x%x:%x\n",
lli->sar, lli->dar, lli->llp,
lli->ctlhi, lli->ctllo);
}
static void dwc_handle_error(struct dw_dma *dw, struct dw_dma_chan *dwc)
{
struct dw_desc *bad_desc;
struct dw_desc *child;
dwc_scan_descriptors(dw, dwc);
/*
* The descriptor currently at the head of the active list is
* borked. Since we don't have any way to report errors, we'll
* just have to scream loudly and try to carry on.
*/
bad_desc = dwc_first_active(dwc);
list_del_init(&bad_desc->desc_node);
list_splice_init(&dwc->queue, dwc->active_list.prev);
/* Clear the error flag and try to restart the controller */
dma_writel(dw, CLEAR.ERROR, dwc->mask);
if (!list_empty(&dwc->active_list))
dwc_dostart(dwc, dwc_first_active(dwc));
/*
* 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_printk(KERN_CRIT, &dwc->chan.dev,
"Bad descriptor submitted for DMA!\n");
dev_printk(KERN_CRIT, &dwc->chan.dev,
" cookie: %d\n", bad_desc->txd.cookie);
dwc_dump_lli(dwc, &bad_desc->lli);
list_for_each_entry(child, &bad_desc->txd.tx_list, desc_node)
dwc_dump_lli(dwc, &child->lli);
/* Pretend the descriptor completed successfully */
dwc_descriptor_complete(dwc, bad_desc);
}
static void dw_dma_tasklet(unsigned long data)
{
struct dw_dma *dw = (struct dw_dma *)data;
struct dw_dma_chan *dwc;
u32 status_block;
u32 status_xfer;
u32 status_err;
int i;
status_block = dma_readl(dw, RAW.BLOCK);
status_xfer = dma_readl(dw, RAW.XFER);
status_err = dma_readl(dw, RAW.ERROR);
dev_vdbg(dw->dma.dev, "tasklet: status_block=%x status_err=%x\n",
status_block, status_err);
for (i = 0; i < dw->dma.chancnt; i++) {
dwc = &dw->chan[i];
spin_lock(&dwc->lock);
if (status_err & (1 << i))
dwc_handle_error(dw, dwc);
else if ((status_block | status_xfer) & (1 << i))
dwc_scan_descriptors(dw, dwc);
spin_unlock(&dwc->lock);
}
/*
* Re-enable interrupts. Block Complete interrupts are only
* enabled if the INT_EN bit in the descriptor is set. This
* will trigger a scan before the whole list is done.
*/
channel_set_bit(dw, MASK.XFER, dw->all_chan_mask);
channel_set_bit(dw, MASK.BLOCK, dw->all_chan_mask);
channel_set_bit(dw, MASK.ERROR, dw->all_chan_mask);
}
static irqreturn_t dw_dma_interrupt(int irq, void *dev_id)
{
struct dw_dma *dw = dev_id;
u32 status;
dev_vdbg(dw->dma.dev, "interrupt: status=0x%x\n",
dma_readl(dw, STATUS_INT));
/*
* Just disable the interrupts. We'll turn them back on in the
* softirq handler.
*/
channel_clear_bit(dw, MASK.XFER, dw->all_chan_mask);
channel_clear_bit(dw, MASK.BLOCK, dw->all_chan_mask);
channel_clear_bit(dw, MASK.ERROR, dw->all_chan_mask);
status = dma_readl(dw, STATUS_INT);
if (status) {
dev_err(dw->dma.dev,
"BUG: Unexpected interrupts pending: 0x%x\n",
status);
/* Try to recover */
channel_clear_bit(dw, MASK.XFER, (1 << 8) - 1);
channel_clear_bit(dw, MASK.BLOCK, (1 << 8) - 1);
channel_clear_bit(dw, MASK.SRC_TRAN, (1 << 8) - 1);
channel_clear_bit(dw, MASK.DST_TRAN, (1 << 8) - 1);
channel_clear_bit(dw, MASK.ERROR, (1 << 8) - 1);
}
tasklet_schedule(&dw->tasklet);
return IRQ_HANDLED;
}
/*----------------------------------------------------------------------*/
static dma_cookie_t dwc_tx_submit(struct dma_async_tx_descriptor *tx)
{
struct dw_desc *desc = txd_to_dw_desc(tx);
struct dw_dma_chan *dwc = to_dw_dma_chan(tx->chan);
dma_cookie_t cookie;
spin_lock_bh(&dwc->lock);
cookie = dwc_assign_cookie(dwc, desc);
/*
* REVISIT: We should attempt to chain as many descriptors as
* possible, perhaps even appending to those already submitted
* for DMA. But this is hard to do in a race-free manner.
*/
if (list_empty(&dwc->active_list)) {
dev_vdbg(&tx->chan->dev, "tx_submit: started %u\n",
desc->txd.cookie);
dwc_dostart(dwc, desc);
list_add_tail(&desc->desc_node, &dwc->active_list);
} else {
dev_vdbg(&tx->chan->dev, "tx_submit: queued %u\n",
desc->txd.cookie);
list_add_tail(&desc->desc_node, &dwc->queue);
}
spin_unlock_bh(&dwc->lock);
return cookie;
}
static struct dma_async_tx_descriptor *
dwc_prep_dma_memcpy(struct dma_chan *chan, dma_addr_t dest, dma_addr_t src,
size_t len, unsigned long flags)
{
struct dw_dma_chan *dwc = to_dw_dma_chan(chan);
struct dw_desc *desc;
struct dw_desc *first;
struct dw_desc *prev;
size_t xfer_count;
size_t offset;
unsigned int src_width;
unsigned int dst_width;
u32 ctllo;
dev_vdbg(&chan->dev, "prep_dma_memcpy d0x%x s0x%x l0x%zx f0x%lx\n",
dest, src, len, flags);
if (unlikely(!len)) {
dev_dbg(&chan->dev, "prep_dma_memcpy: length is zero!\n");
return NULL;
}
/*
* We can be a lot more clever here, but this should take care
* of the most common optimization.
*/
if (!((src | dest | len) & 3))
src_width = dst_width = 2;
else if (!((src | dest | len) & 1))
src_width = dst_width = 1;
else
src_width = dst_width = 0;
ctllo = DWC_DEFAULT_CTLLO
| DWC_CTLL_DST_WIDTH(dst_width)
| DWC_CTLL_SRC_WIDTH(src_width)
| DWC_CTLL_DST_INC
| DWC_CTLL_SRC_INC
| DWC_CTLL_FC_M2M;
prev = first = NULL;
for (offset = 0; offset < len; offset += xfer_count << src_width) {
xfer_count = min_t(size_t, (len - offset) >> src_width,
DWC_MAX_COUNT);
desc = dwc_desc_get(dwc);
if (!desc)
goto err_desc_get;
desc->lli.sar = src + offset;
desc->lli.dar = dest + offset;
desc->lli.ctllo = ctllo;
desc->lli.ctlhi = xfer_count;
if (!first) {
first = desc;
} else {
prev->lli.llp = desc->txd.phys;
dma_sync_single_for_device(chan->dev.parent,
prev->txd.phys, sizeof(prev->lli),
DMA_TO_DEVICE);
list_add_tail(&desc->desc_node,
&first->txd.tx_list);
}
prev = desc;
}
if (flags & DMA_PREP_INTERRUPT)
/* Trigger interrupt after last block */
prev->lli.ctllo |= DWC_CTLL_INT_EN;
prev->lli.llp = 0;
dma_sync_single_for_device(chan->dev.parent,
prev->txd.phys, sizeof(prev->lli),
DMA_TO_DEVICE);
first->txd.flags = flags;
first->len = len;
return &first->txd;
err_desc_get:
dwc_desc_put(dwc, first);
return NULL;
}
static struct dma_async_tx_descriptor *
dwc_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl,
unsigned int sg_len, enum dma_data_direction direction,
unsigned long flags)
{
struct dw_dma_chan *dwc = to_dw_dma_chan(chan);
struct dw_dma_slave *dws = dwc->dws;
struct dw_desc *prev;
struct dw_desc *first;
u32 ctllo;
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(&chan->dev, "prep_dma_slave\n");
if (unlikely(!dws || !sg_len))
return NULL;
reg_width = dws->slave.reg_width;
prev = first = NULL;
sg_len = dma_map_sg(chan->dev.parent, sgl, sg_len, direction);
switch (direction) {
case DMA_TO_DEVICE:
ctllo = (DWC_DEFAULT_CTLLO
| DWC_CTLL_DST_WIDTH(reg_width)
| DWC_CTLL_DST_FIX
| DWC_CTLL_SRC_INC
| DWC_CTLL_FC_M2P);
reg = dws->slave.tx_reg;
for_each_sg(sgl, sg, sg_len, i) {
struct dw_desc *desc;
u32 len;
u32 mem;
desc = dwc_desc_get(dwc);
if (!desc) {
dev_err(&chan->dev,
"not enough descriptors available\n");
goto err_desc_get;
}
mem = sg_phys(sg);
len = sg_dma_len(sg);
mem_width = 2;
if (unlikely(mem & 3 || len & 3))
mem_width = 0;
desc->lli.sar = mem;
desc->lli.dar = reg;
desc->lli.ctllo = ctllo | DWC_CTLL_SRC_WIDTH(mem_width);
desc->lli.ctlhi = len >> mem_width;
if (!first) {
first = desc;
} else {
prev->lli.llp = desc->txd.phys;
dma_sync_single_for_device(chan->dev.parent,
prev->txd.phys,
sizeof(prev->lli),
DMA_TO_DEVICE);
list_add_tail(&desc->desc_node,
&first->txd.tx_list);
}
prev = desc;
total_len += len;
}
break;
case DMA_FROM_DEVICE:
ctllo = (DWC_DEFAULT_CTLLO
| DWC_CTLL_SRC_WIDTH(reg_width)
| DWC_CTLL_DST_INC
| DWC_CTLL_SRC_FIX
| DWC_CTLL_FC_P2M);
reg = dws->slave.rx_reg;
for_each_sg(sgl, sg, sg_len, i) {
struct dw_desc *desc;
u32 len;
u32 mem;
desc = dwc_desc_get(dwc);
if (!desc) {
dev_err(&chan->dev,
"not enough descriptors available\n");
goto err_desc_get;
}
mem = sg_phys(sg);
len = sg_dma_len(sg);
mem_width = 2;
if (unlikely(mem & 3 || len & 3))
mem_width = 0;
desc->lli.sar = reg;
desc->lli.dar = mem;
desc->lli.ctllo = ctllo | DWC_CTLL_DST_WIDTH(mem_width);
desc->lli.ctlhi = len >> reg_width;
if (!first) {
first = desc;
} else {
prev->lli.llp = desc->txd.phys;
dma_sync_single_for_device(chan->dev.parent,
prev->txd.phys,
sizeof(prev->lli),
DMA_TO_DEVICE);
list_add_tail(&desc->desc_node,
&first->txd.tx_list);
}
prev = desc;
total_len += len;
}
break;
default:
return NULL;
}
if (flags & DMA_PREP_INTERRUPT)
/* Trigger interrupt after last block */
prev->lli.ctllo |= DWC_CTLL_INT_EN;
prev->lli.llp = 0;
dma_sync_single_for_device(chan->dev.parent,
prev->txd.phys, sizeof(prev->lli),
DMA_TO_DEVICE);
first->len = total_len;
return &first->txd;
err_desc_get:
dwc_desc_put(dwc, first);
return NULL;
}
static void dwc_terminate_all(struct dma_chan *chan)
{
struct dw_dma_chan *dwc = to_dw_dma_chan(chan);
struct dw_dma *dw = to_dw_dma(chan->device);
struct dw_desc *desc, *_desc;
LIST_HEAD(list);
/*
* 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(&dwc->lock);
channel_clear_bit(dw, CH_EN, dwc->mask);
while (dma_readl(dw, CH_EN) & dwc->mask)
cpu_relax();
/* active_list entries will end up before queued entries */
list_splice_init(&dwc->queue, &list);
list_splice_init(&dwc->active_list, &list);
spin_unlock_bh(&dwc->lock);
/* Flush all pending and queued descriptors */
list_for_each_entry_safe(desc, _desc, &list, desc_node)
dwc_descriptor_complete(dwc, desc);
}
static enum dma_status
dwc_is_tx_complete(struct dma_chan *chan,
dma_cookie_t cookie,
dma_cookie_t *done, dma_cookie_t *used)
{
struct dw_dma_chan *dwc = to_dw_dma_chan(chan);
dma_cookie_t last_used;
dma_cookie_t last_complete;
int ret;
last_complete = dwc->completed;
last_used = chan->cookie;
ret = dma_async_is_complete(cookie, last_complete, last_used);
if (ret != DMA_SUCCESS) {
dwc_scan_descriptors(to_dw_dma(chan->device), dwc);
last_complete = dwc->completed;
last_used = chan->cookie;
ret = dma_async_is_complete(cookie, last_complete, last_used);
}
if (done)
*done = last_complete;
if (used)
*used = last_used;
return ret;
}
static void dwc_issue_pending(struct dma_chan *chan)
{
struct dw_dma_chan *dwc = to_dw_dma_chan(chan);
spin_lock_bh(&dwc->lock);
if (!list_empty(&dwc->queue))
dwc_scan_descriptors(to_dw_dma(chan->device), dwc);
spin_unlock_bh(&dwc->lock);
}
static int dwc_alloc_chan_resources(struct dma_chan *chan,
struct dma_client *client)
{
struct dw_dma_chan *dwc = to_dw_dma_chan(chan);
struct dw_dma *dw = to_dw_dma(chan->device);
struct dw_desc *desc;
struct dma_slave *slave;
struct dw_dma_slave *dws;
int i;
u32 cfghi;
u32 cfglo;
dev_vdbg(&chan->dev, "alloc_chan_resources\n");
/* Channels doing slave DMA can only handle one client. */
if (dwc->dws || client->slave) {
if (chan->client_count)
return -EBUSY;
}
/* ASSERT: channel is idle */
if (dma_readl(dw, CH_EN) & dwc->mask) {
dev_dbg(&chan->dev, "DMA channel not idle?\n");
return -EIO;
}
dwc->completed = chan->cookie = 1;
cfghi = DWC_CFGH_FIFO_MODE;
cfglo = 0;
slave = client->slave;
if (slave) {
/*
* We need controller-specific data to set up slave
* transfers.
*/
BUG_ON(!slave->dma_dev || slave->dma_dev != dw->dma.dev);
dws = container_of(slave, struct dw_dma_slave, slave);
dwc->dws = dws;
cfghi = dws->cfg_hi;
cfglo = dws->cfg_lo;
} else {
dwc->dws = NULL;
}
channel_writel(dwc, CFG_LO, cfglo);
channel_writel(dwc, CFG_HI, cfghi);
/*
* NOTE: some controllers may have additional features that we
* need to initialize here, like "scatter-gather" (which
* doesn't mean what you think it means), and status writeback.
*/
spin_lock_bh(&dwc->lock);
i = dwc->descs_allocated;
while (dwc->descs_allocated < NR_DESCS_PER_CHANNEL) {
spin_unlock_bh(&dwc->lock);
desc = kzalloc(sizeof(struct dw_desc), GFP_KERNEL);
if (!desc) {
dev_info(&chan->dev,
"only allocated %d descriptors\n", i);
spin_lock_bh(&dwc->lock);
break;
}
dma_async_tx_descriptor_init(&desc->txd, chan);
desc->txd.tx_submit = dwc_tx_submit;
desc->txd.flags = DMA_CTRL_ACK;
INIT_LIST_HEAD(&desc->txd.tx_list);
desc->txd.phys = dma_map_single(chan->dev.parent, &desc->lli,
sizeof(desc->lli), DMA_TO_DEVICE);
dwc_desc_put(dwc, desc);
spin_lock_bh(&dwc->lock);
i = ++dwc->descs_allocated;
}
/* Enable interrupts */
channel_set_bit(dw, MASK.XFER, dwc->mask);
channel_set_bit(dw, MASK.BLOCK, dwc->mask);
channel_set_bit(dw, MASK.ERROR, dwc->mask);
spin_unlock_bh(&dwc->lock);
dev_dbg(&chan->dev,
"alloc_chan_resources allocated %d descriptors\n", i);
return i;
}
static void dwc_free_chan_resources(struct dma_chan *chan)
{
struct dw_dma_chan *dwc = to_dw_dma_chan(chan);
struct dw_dma *dw = to_dw_dma(chan->device);
struct dw_desc *desc, *_desc;
LIST_HEAD(list);
dev_dbg(&chan->dev, "free_chan_resources (descs allocated=%u)\n",
dwc->descs_allocated);
/* ASSERT: channel is idle */
BUG_ON(!list_empty(&dwc->active_list));
BUG_ON(!list_empty(&dwc->queue));
BUG_ON(dma_readl(to_dw_dma(chan->device), CH_EN) & dwc->mask);
spin_lock_bh(&dwc->lock);
list_splice_init(&dwc->free_list, &list);
dwc->descs_allocated = 0;
dwc->dws = NULL;
/* Disable interrupts */
channel_clear_bit(dw, MASK.XFER, dwc->mask);
channel_clear_bit(dw, MASK.BLOCK, dwc->mask);
channel_clear_bit(dw, MASK.ERROR, dwc->mask);
spin_unlock_bh(&dwc->lock);
list_for_each_entry_safe(desc, _desc, &list, desc_node) {
dev_vdbg(&chan->dev, " freeing descriptor %p\n", desc);
dma_unmap_single(chan->dev.parent, desc->txd.phys,
sizeof(desc->lli), DMA_TO_DEVICE);
kfree(desc);
}
dev_vdbg(&chan->dev, "free_chan_resources done\n");
}
/*----------------------------------------------------------------------*/
static void dw_dma_off(struct dw_dma *dw)
{
dma_writel(dw, CFG, 0);
channel_clear_bit(dw, MASK.XFER, dw->all_chan_mask);
channel_clear_bit(dw, MASK.BLOCK, dw->all_chan_mask);
channel_clear_bit(dw, MASK.SRC_TRAN, dw->all_chan_mask);
channel_clear_bit(dw, MASK.DST_TRAN, dw->all_chan_mask);
channel_clear_bit(dw, MASK.ERROR, dw->all_chan_mask);
while (dma_readl(dw, CFG) & DW_CFG_DMA_EN)
cpu_relax();
}
static int __init dw_probe(struct platform_device *pdev)
{
struct dw_dma_platform_data *pdata;
struct resource *io;
struct dw_dma *dw;
size_t size;
int irq;
int err;
int i;
pdata = pdev->dev.platform_data;
if (!pdata || pdata->nr_channels > DW_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 dw_dma);
size += pdata->nr_channels * sizeof(struct dw_dma_chan);
dw = kzalloc(size, GFP_KERNEL);
if (!dw)
return -ENOMEM;
if (!request_mem_region(io->start, DW_REGLEN, pdev->dev.driver->name)) {
err = -EBUSY;
goto err_kfree;
}
memset(dw, 0, sizeof *dw);
dw->regs = ioremap(io->start, DW_REGLEN);
if (!dw->regs) {
err = -ENOMEM;
goto err_release_r;
}
dw->clk = clk_get(&pdev->dev, "hclk");
if (IS_ERR(dw->clk)) {
err = PTR_ERR(dw->clk);
goto err_clk;
}
clk_enable(dw->clk);
/* force dma off, just in case */
dw_dma_off(dw);
err = request_irq(irq, dw_dma_interrupt, 0, "dw_dmac", dw);
if (err)
goto err_irq;
platform_set_drvdata(pdev, dw);
tasklet_init(&dw->tasklet, dw_dma_tasklet, (unsigned long)dw);
dw->all_chan_mask = (1 << pdata->nr_channels) - 1;
INIT_LIST_HEAD(&dw->dma.channels);
for (i = 0; i < pdata->nr_channels; i++, dw->dma.chancnt++) {
struct dw_dma_chan *dwc = &dw->chan[i];
dwc->chan.device = &dw->dma;
dwc->chan.cookie = dwc->completed = 1;
dwc->chan.chan_id = i;
list_add_tail(&dwc->chan.device_node, &dw->dma.channels);
dwc->ch_regs = &__dw_regs(dw)->CHAN[i];
spin_lock_init(&dwc->lock);
dwc->mask = 1 << i;
INIT_LIST_HEAD(&dwc->active_list);
INIT_LIST_HEAD(&dwc->queue);
INIT_LIST_HEAD(&dwc->free_list);
channel_clear_bit(dw, CH_EN, dwc->mask);
}
/* Clear/disable all interrupts on all channels. */
dma_writel(dw, CLEAR.XFER, dw->all_chan_mask);
dma_writel(dw, CLEAR.BLOCK, dw->all_chan_mask);
dma_writel(dw, CLEAR.SRC_TRAN, dw->all_chan_mask);
dma_writel(dw, CLEAR.DST_TRAN, dw->all_chan_mask);
dma_writel(dw, CLEAR.ERROR, dw->all_chan_mask);
channel_clear_bit(dw, MASK.XFER, dw->all_chan_mask);
channel_clear_bit(dw, MASK.BLOCK, dw->all_chan_mask);
channel_clear_bit(dw, MASK.SRC_TRAN, dw->all_chan_mask);
channel_clear_bit(dw, MASK.DST_TRAN, dw->all_chan_mask);
channel_clear_bit(dw, MASK.ERROR, dw->all_chan_mask);
dma_cap_set(DMA_MEMCPY, dw->dma.cap_mask);
dma_cap_set(DMA_SLAVE, dw->dma.cap_mask);
dw->dma.dev = &pdev->dev;
dw->dma.device_alloc_chan_resources = dwc_alloc_chan_resources;
dw->dma.device_free_chan_resources = dwc_free_chan_resources;
dw->dma.device_prep_dma_memcpy = dwc_prep_dma_memcpy;
dw->dma.device_prep_slave_sg = dwc_prep_slave_sg;
dw->dma.device_terminate_all = dwc_terminate_all;
dw->dma.device_is_tx_complete = dwc_is_tx_complete;
dw->dma.device_issue_pending = dwc_issue_pending;
dma_writel(dw, CFG, DW_CFG_DMA_EN);
printk(KERN_INFO "%s: DesignWare DMA Controller, %d channels\n",
pdev->dev.bus_id, dw->dma.chancnt);
dma_async_device_register(&dw->dma);
return 0;
err_irq:
clk_disable(dw->clk);
clk_put(dw->clk);
err_clk:
iounmap(dw->regs);
dw->regs = NULL;
err_release_r:
release_resource(io);
err_kfree:
kfree(dw);
return err;
}
static int __exit dw_remove(struct platform_device *pdev)
{
struct dw_dma *dw = platform_get_drvdata(pdev);
struct dw_dma_chan *dwc, *_dwc;
struct resource *io;
dw_dma_off(dw);
dma_async_device_unregister(&dw->dma);
free_irq(platform_get_irq(pdev, 0), dw);
tasklet_kill(&dw->tasklet);
list_for_each_entry_safe(dwc, _dwc, &dw->dma.channels,
chan.device_node) {
list_del(&dwc->chan.device_node);
channel_clear_bit(dw, CH_EN, dwc->mask);
}
clk_disable(dw->clk);
clk_put(dw->clk);
iounmap(dw->regs);
dw->regs = NULL;
io = platform_get_resource(pdev, IORESOURCE_MEM, 0);
release_mem_region(io->start, DW_REGLEN);
kfree(dw);
return 0;
}
static void dw_shutdown(struct platform_device *pdev)
{
struct dw_dma *dw = platform_get_drvdata(pdev);
dw_dma_off(platform_get_drvdata(pdev));
clk_disable(dw->clk);
}
static int dw_suspend_late(struct platform_device *pdev, pm_message_t mesg)
{
struct dw_dma *dw = platform_get_drvdata(pdev);
dw_dma_off(platform_get_drvdata(pdev));
clk_disable(dw->clk);
return 0;
}
static int dw_resume_early(struct platform_device *pdev)
{
struct dw_dma *dw = platform_get_drvdata(pdev);
clk_enable(dw->clk);
dma_writel(dw, CFG, DW_CFG_DMA_EN);
return 0;
}
static struct platform_driver dw_driver = {
.remove = __exit_p(dw_remove),
.shutdown = dw_shutdown,
.suspend_late = dw_suspend_late,
.resume_early = dw_resume_early,
.driver = {
.name = "dw_dmac",
},
};
static int __init dw_init(void)
{
return platform_driver_probe(&dw_driver, dw_probe);
}
module_init(dw_init);
static void __exit dw_exit(void)
{
platform_driver_unregister(&dw_driver);
}
module_exit(dw_exit);
MODULE_LICENSE("GPL v2");
MODULE_DESCRIPTION("Synopsys DesignWare DMA Controller driver");
MODULE_AUTHOR("Haavard Skinnemoen <haavard.skinnemoen@atmel.com>");
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