dmaengine/dw_dmac: Replace spin_lock* with irqsave variants and enable submission from callback
dmaengine routines can be called from interrupt context and with interrupts
disabled. Whereas spin_unlock_bh can't be called from such contexts. So this
patch converts all spin_*_bh routines to irqsave variants.
Also, spin_lock() used in tasklet is converted to irqsave variants, as tasklet
can be interrupted, and dma requests from such interruptions may also call
spin_lock.
Now, submission from callbacks are permitted as per dmaengine framework. So we
shouldn't hold any locks while calling callbacks. As locks were taken by parent
routines, so releasing them before calling callbacks doesn't look clean enough.
So, locks are taken inside all routine now, whereever they are required. And
dwc_descriptor_complete is always called without taking locks.
Signed-off-by: Viresh Kumar <viresh.kumar@st.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
diff --git a/drivers/dma/dw_dmac.c b/drivers/dma/dw_dmac.c
index a9755e3..442b98b 100644
--- a/drivers/dma/dw_dmac.c
+++ b/drivers/dma/dw_dmac.c
@@ -93,8 +93,9 @@
struct dw_desc *desc, *_desc;
struct dw_desc *ret = NULL;
unsigned int i = 0;
+ unsigned long flags;
- spin_lock_bh(&dwc->lock);
+ spin_lock_irqsave(&dwc->lock, flags);
list_for_each_entry_safe(desc, _desc, &dwc->free_list, desc_node) {
if (async_tx_test_ack(&desc->txd)) {
list_del(&desc->desc_node);
@@ -104,7 +105,7 @@
dev_dbg(chan2dev(&dwc->chan), "desc %p not ACKed\n", desc);
i++;
}
- spin_unlock_bh(&dwc->lock);
+ spin_unlock_irqrestore(&dwc->lock, flags);
dev_vdbg(chan2dev(&dwc->chan), "scanned %u descriptors on freelist\n", i);
@@ -130,12 +131,14 @@
*/
static void dwc_desc_put(struct dw_dma_chan *dwc, struct dw_desc *desc)
{
+ unsigned long flags;
+
if (desc) {
struct dw_desc *child;
dwc_sync_desc_for_cpu(dwc, desc);
- spin_lock_bh(&dwc->lock);
+ spin_lock_irqsave(&dwc->lock, flags);
list_for_each_entry(child, &desc->tx_list, desc_node)
dev_vdbg(chan2dev(&dwc->chan),
"moving child desc %p to freelist\n",
@@ -143,7 +146,7 @@
list_splice_init(&desc->tx_list, &dwc->free_list);
dev_vdbg(chan2dev(&dwc->chan), "moving desc %p to freelist\n", desc);
list_add(&desc->desc_node, &dwc->free_list);
- spin_unlock_bh(&dwc->lock);
+ spin_unlock_irqrestore(&dwc->lock, flags);
}
}
@@ -202,9 +205,11 @@
void *param = NULL;
struct dma_async_tx_descriptor *txd = &desc->txd;
struct dw_desc *child;
+ unsigned long flags;
dev_vdbg(chan2dev(&dwc->chan), "descriptor %u complete\n", txd->cookie);
+ spin_lock_irqsave(&dwc->lock, flags);
dwc->completed = txd->cookie;
if (callback_required) {
callback = txd->callback;
@@ -241,6 +246,8 @@
}
}
+ spin_unlock_irqrestore(&dwc->lock, flags);
+
if (callback_required && callback)
callback(param);
}
@@ -249,7 +256,9 @@
{
struct dw_desc *desc, *_desc;
LIST_HEAD(list);
+ unsigned long flags;
+ spin_lock_irqsave(&dwc->lock, flags);
if (dma_readl(dw, CH_EN) & dwc->mask) {
dev_err(chan2dev(&dwc->chan),
"BUG: XFER bit set, but channel not idle!\n");
@@ -270,6 +279,8 @@
dwc_dostart(dwc, dwc_first_active(dwc));
}
+ spin_unlock_irqrestore(&dwc->lock, flags);
+
list_for_each_entry_safe(desc, _desc, &list, desc_node)
dwc_descriptor_complete(dwc, desc, true);
}
@@ -280,7 +291,9 @@
struct dw_desc *desc, *_desc;
struct dw_desc *child;
u32 status_xfer;
+ unsigned long flags;
+ spin_lock_irqsave(&dwc->lock, flags);
/*
* Clear block interrupt flag before scanning so that we don't
* miss any, and read LLP before RAW_XFER to ensure it is
@@ -293,35 +306,47 @@
if (status_xfer & dwc->mask) {
/* Everything we've submitted is done */
dma_writel(dw, CLEAR.XFER, dwc->mask);
+ spin_unlock_irqrestore(&dwc->lock, flags);
+
dwc_complete_all(dw, dwc);
return;
}
- if (list_empty(&dwc->active_list))
+ if (list_empty(&dwc->active_list)) {
+ spin_unlock_irqrestore(&dwc->lock, flags);
return;
+ }
dev_vdbg(chan2dev(&dwc->chan), "scan_descriptors: llp=0x%x\n", llp);
list_for_each_entry_safe(desc, _desc, &dwc->active_list, desc_node) {
/* check first descriptors addr */
- if (desc->txd.phys == llp)
+ if (desc->txd.phys == llp) {
+ spin_unlock_irqrestore(&dwc->lock, flags);
return;
+ }
/* check first descriptors llp */
- if (desc->lli.llp == llp)
+ if (desc->lli.llp == llp) {
/* This one is currently in progress */
+ spin_unlock_irqrestore(&dwc->lock, flags);
return;
+ }
list_for_each_entry(child, &desc->tx_list, desc_node)
- if (child->lli.llp == llp)
+ if (child->lli.llp == llp) {
/* Currently in progress */
+ spin_unlock_irqrestore(&dwc->lock, flags);
return;
+ }
/*
* No descriptors so far seem to be in progress, i.e.
* this one must be done.
*/
+ spin_unlock_irqrestore(&dwc->lock, flags);
dwc_descriptor_complete(dwc, desc, true);
+ spin_lock_irqsave(&dwc->lock, flags);
}
dev_err(chan2dev(&dwc->chan),
@@ -336,6 +361,7 @@
list_move(dwc->queue.next, &dwc->active_list);
dwc_dostart(dwc, dwc_first_active(dwc));
}
+ spin_unlock_irqrestore(&dwc->lock, flags);
}
static void dwc_dump_lli(struct dw_dma_chan *dwc, struct dw_lli *lli)
@@ -350,9 +376,12 @@
{
struct dw_desc *bad_desc;
struct dw_desc *child;
+ unsigned long flags;
dwc_scan_descriptors(dw, dwc);
+ spin_lock_irqsave(&dwc->lock, flags);
+
/*
* The descriptor currently at the head of the active list is
* borked. Since we don't have any way to report errors, we'll
@@ -382,6 +411,8 @@
list_for_each_entry(child, &bad_desc->tx_list, desc_node)
dwc_dump_lli(dwc, &child->lli);
+ spin_unlock_irqrestore(&dwc->lock, flags);
+
/* Pretend the descriptor completed successfully */
dwc_descriptor_complete(dwc, bad_desc, true);
}
@@ -406,6 +437,8 @@
static void dwc_handle_cyclic(struct dw_dma *dw, struct dw_dma_chan *dwc,
u32 status_block, u32 status_err, u32 status_xfer)
{
+ unsigned long flags;
+
if (status_block & dwc->mask) {
void (*callback)(void *param);
void *callback_param;
@@ -416,11 +449,9 @@
callback = dwc->cdesc->period_callback;
callback_param = dwc->cdesc->period_callback_param;
- if (callback) {
- spin_unlock(&dwc->lock);
+
+ if (callback)
callback(callback_param);
- spin_lock(&dwc->lock);
- }
}
/*
@@ -434,6 +465,9 @@
dev_err(chan2dev(&dwc->chan), "cyclic DMA unexpected %s "
"interrupt, stopping DMA transfer\n",
status_xfer ? "xfer" : "error");
+
+ spin_lock_irqsave(&dwc->lock, flags);
+
dev_err(chan2dev(&dwc->chan),
" SAR: 0x%x DAR: 0x%x LLP: 0x%x CTL: 0x%x:%08x\n",
channel_readl(dwc, SAR),
@@ -457,6 +491,8 @@
for (i = 0; i < dwc->cdesc->periods; i++)
dwc_dump_lli(dwc, &dwc->cdesc->desc[i]->lli);
+
+ spin_unlock_irqrestore(&dwc->lock, flags);
}
}
@@ -480,7 +516,6 @@
for (i = 0; i < dw->dma.chancnt; i++) {
dwc = &dw->chan[i];
- spin_lock(&dwc->lock);
if (test_bit(DW_DMA_IS_CYCLIC, &dwc->flags))
dwc_handle_cyclic(dw, dwc, status_block, status_err,
status_xfer);
@@ -488,7 +523,6 @@
dwc_handle_error(dw, dwc);
else if ((status_block | status_xfer) & (1 << i))
dwc_scan_descriptors(dw, dwc);
- spin_unlock(&dwc->lock);
}
/*
@@ -543,8 +577,9 @@
struct dw_desc *desc = txd_to_dw_desc(tx);
struct dw_dma_chan *dwc = to_dw_dma_chan(tx->chan);
dma_cookie_t cookie;
+ unsigned long flags;
- spin_lock_bh(&dwc->lock);
+ spin_lock_irqsave(&dwc->lock, flags);
cookie = dwc_assign_cookie(dwc, desc);
/*
@@ -564,7 +599,7 @@
list_add_tail(&desc->desc_node, &dwc->queue);
}
- spin_unlock_bh(&dwc->lock);
+ spin_unlock_irqrestore(&dwc->lock, flags);
return cookie;
}
@@ -826,6 +861,7 @@
struct dw_dma_chan *dwc = to_dw_dma_chan(chan);
struct dw_dma *dw = to_dw_dma(chan->device);
struct dw_desc *desc, *_desc;
+ unsigned long flags;
LIST_HEAD(list);
/* Only supports DMA_TERMINATE_ALL */
@@ -838,7 +874,7 @@
* channel. We still have to poll the channel enable bit due
* to AHB/HSB limitations.
*/
- spin_lock_bh(&dwc->lock);
+ spin_lock_irqsave(&dwc->lock, flags);
channel_clear_bit(dw, CH_EN, dwc->mask);
@@ -849,7 +885,7 @@
list_splice_init(&dwc->queue, &list);
list_splice_init(&dwc->active_list, &list);
- spin_unlock_bh(&dwc->lock);
+ spin_unlock_irqrestore(&dwc->lock, flags);
/* Flush all pending and queued descriptors */
list_for_each_entry_safe(desc, _desc, &list, desc_node)
@@ -873,9 +909,7 @@
ret = dma_async_is_complete(cookie, last_complete, last_used);
if (ret != DMA_SUCCESS) {
- spin_lock_bh(&dwc->lock);
dwc_scan_descriptors(to_dw_dma(chan->device), dwc);
- spin_unlock_bh(&dwc->lock);
last_complete = dwc->completed;
last_used = chan->cookie;
@@ -896,10 +930,8 @@
{
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)
@@ -911,6 +943,7 @@
int i;
u32 cfghi;
u32 cfglo;
+ unsigned long flags;
dev_vdbg(chan2dev(chan), "alloc_chan_resources\n");
@@ -948,16 +981,16 @@
* doesn't mean what you think it means), and status writeback.
*/
- spin_lock_bh(&dwc->lock);
+ spin_lock_irqsave(&dwc->lock, flags);
i = dwc->descs_allocated;
while (dwc->descs_allocated < NR_DESCS_PER_CHANNEL) {
- spin_unlock_bh(&dwc->lock);
+ spin_unlock_irqrestore(&dwc->lock, flags);
desc = kzalloc(sizeof(struct dw_desc), GFP_KERNEL);
if (!desc) {
dev_info(chan2dev(chan),
"only allocated %d descriptors\n", i);
- spin_lock_bh(&dwc->lock);
+ spin_lock_irqsave(&dwc->lock, flags);
break;
}
@@ -969,7 +1002,7 @@
sizeof(desc->lli), DMA_TO_DEVICE);
dwc_desc_put(dwc, desc);
- spin_lock_bh(&dwc->lock);
+ spin_lock_irqsave(&dwc->lock, flags);
i = ++dwc->descs_allocated;
}
@@ -978,7 +1011,7 @@
channel_set_bit(dw, MASK.BLOCK, dwc->mask);
channel_set_bit(dw, MASK.ERROR, dwc->mask);
- spin_unlock_bh(&dwc->lock);
+ spin_unlock_irqrestore(&dwc->lock, flags);
dev_dbg(chan2dev(chan),
"alloc_chan_resources allocated %d descriptors\n", i);
@@ -991,6 +1024,7 @@
struct dw_dma_chan *dwc = to_dw_dma_chan(chan);
struct dw_dma *dw = to_dw_dma(chan->device);
struct dw_desc *desc, *_desc;
+ unsigned long flags;
LIST_HEAD(list);
dev_dbg(chan2dev(chan), "free_chan_resources (descs allocated=%u)\n",
@@ -1001,7 +1035,7 @@
BUG_ON(!list_empty(&dwc->queue));
BUG_ON(dma_readl(to_dw_dma(chan->device), CH_EN) & dwc->mask);
- spin_lock_bh(&dwc->lock);
+ spin_lock_irqsave(&dwc->lock, flags);
list_splice_init(&dwc->free_list, &list);
dwc->descs_allocated = 0;
@@ -1010,7 +1044,7 @@
channel_clear_bit(dw, MASK.BLOCK, dwc->mask);
channel_clear_bit(dw, MASK.ERROR, dwc->mask);
- spin_unlock_bh(&dwc->lock);
+ spin_unlock_irqrestore(&dwc->lock, flags);
list_for_each_entry_safe(desc, _desc, &list, desc_node) {
dev_vdbg(chan2dev(chan), " freeing descriptor %p\n", desc);
@@ -1035,13 +1069,14 @@
{
struct dw_dma_chan *dwc = to_dw_dma_chan(chan);
struct dw_dma *dw = to_dw_dma(dwc->chan.device);
+ unsigned long flags;
if (!test_bit(DW_DMA_IS_CYCLIC, &dwc->flags)) {
dev_err(chan2dev(&dwc->chan), "missing prep for cyclic DMA\n");
return -ENODEV;
}
- spin_lock(&dwc->lock);
+ spin_lock_irqsave(&dwc->lock, flags);
/* assert channel is idle */
if (dma_readl(dw, CH_EN) & dwc->mask) {
@@ -1054,7 +1089,7 @@
channel_readl(dwc, LLP),
channel_readl(dwc, CTL_HI),
channel_readl(dwc, CTL_LO));
- spin_unlock(&dwc->lock);
+ spin_unlock_irqrestore(&dwc->lock, flags);
return -EBUSY;
}
@@ -1069,7 +1104,7 @@
channel_set_bit(dw, CH_EN, dwc->mask);
- spin_unlock(&dwc->lock);
+ spin_unlock_irqrestore(&dwc->lock, flags);
return 0;
}
@@ -1085,14 +1120,15 @@
{
struct dw_dma_chan *dwc = to_dw_dma_chan(chan);
struct dw_dma *dw = to_dw_dma(dwc->chan.device);
+ unsigned long flags;
- spin_lock(&dwc->lock);
+ spin_lock_irqsave(&dwc->lock, flags);
channel_clear_bit(dw, CH_EN, dwc->mask);
while (dma_readl(dw, CH_EN) & dwc->mask)
cpu_relax();
- spin_unlock(&dwc->lock);
+ spin_unlock_irqrestore(&dwc->lock, flags);
}
EXPORT_SYMBOL(dw_dma_cyclic_stop);
@@ -1121,17 +1157,18 @@
unsigned int reg_width;
unsigned int periods;
unsigned int i;
+ unsigned long flags;
- spin_lock_bh(&dwc->lock);
+ spin_lock_irqsave(&dwc->lock, flags);
if (!list_empty(&dwc->queue) || !list_empty(&dwc->active_list)) {
- spin_unlock_bh(&dwc->lock);
+ spin_unlock_irqrestore(&dwc->lock, flags);
dev_dbg(chan2dev(&dwc->chan),
"queue and/or active list are not empty\n");
return ERR_PTR(-EBUSY);
}
was_cyclic = test_and_set_bit(DW_DMA_IS_CYCLIC, &dwc->flags);
- spin_unlock_bh(&dwc->lock);
+ spin_unlock_irqrestore(&dwc->lock, flags);
if (was_cyclic) {
dev_dbg(chan2dev(&dwc->chan),
"channel already prepared for cyclic DMA\n");
@@ -1245,13 +1282,14 @@
struct dw_dma *dw = to_dw_dma(dwc->chan.device);
struct dw_cyclic_desc *cdesc = dwc->cdesc;
int i;
+ unsigned long flags;
dev_dbg(chan2dev(&dwc->chan), "cyclic free\n");
if (!cdesc)
return;
- spin_lock_bh(&dwc->lock);
+ spin_lock_irqsave(&dwc->lock, flags);
channel_clear_bit(dw, CH_EN, dwc->mask);
while (dma_readl(dw, CH_EN) & dwc->mask)
@@ -1261,7 +1299,7 @@
dma_writel(dw, CLEAR.ERROR, dwc->mask);
dma_writel(dw, CLEAR.XFER, dwc->mask);
- spin_unlock_bh(&dwc->lock);
+ spin_unlock_irqrestore(&dwc->lock, flags);
for (i = 0; i < cdesc->periods; i++)
dwc_desc_put(dwc, cdesc->desc[i]);