* Tony Lindgren <[email protected]> [170112 16:04]:
> * Grygorii Strashko <[email protected]> [170112 15:43]:
> > @@ -457,38 +449,36 @@ static void push_desc_queue(struct cppi41_channel *c)
> > cppi_writel(reg, cdd->qmgr_mem + QMGR_QUEUE_D(c->q_num));
> > }
> >
> > -static void pending_desc(struct cppi41_channel *c)
> > +static void cppi41_dma_issue_pending(struct dma_chan *chan)
> > {
> > + struct cppi41_channel *c = to_cpp41_chan(chan);
> > struct cppi41_dd *cdd = c->cdd;
> > + int error;
> > + struct cppi41_channel *_c;
> > unsigned long flags;
> >
> > spin_lock_irqsave(&cdd->lock, flags);
> > list_add_tail(&c->node, &cdd->pending);
> > - spin_unlock_irqrestore(&cdd->lock, flags);
> > -}
> > -
> > -static void cppi41_dma_issue_pending(struct dma_chan *chan)
> > -{
> > - struct cppi41_channel *c = to_cpp41_chan(chan);
> > - struct cppi41_dd *cdd = c->cdd;
> > - int error;
> >
> > error = pm_runtime_get(cdd->ddev.dev);
> > - if ((error != -EINPROGRESS) && error < 0) {
> > + if (error < 0) {
> > pm_runtime_put_noidle(cdd->ddev.dev);
> > dev_err(cdd->ddev.dev, "Failed to pm_runtime_get: %i\n",
> > error);
> > -
> > + spin_unlock_irqrestore(&cdd->lock, flags);
> > return;
> > }
> >
> > - if (likely(pm_runtime_active(cdd->ddev.dev)))
> > - push_desc_queue(c);
> > - else
> > - pending_desc(c);
> > + if (!cdd->is_suspended) {
> > + list_for_each_entry_safe(c, _c, &cdd->pending, node) {
> > + push_desc_queue(c);
> > + list_del(&c->node);
> > + };
> > + }
> >
> > pm_runtime_mark_last_busy(cdd->ddev.dev);
> > pm_runtime_put_autosuspend(cdd->ddev.dev);
> > + spin_lock_irqsave(&cdd->lock, flags);
> > }
>
> So always add to the queue no matter, then always flush the queue
> directly if active? Yeah that might work :)
>
> Don't we need spinlock in the list_for_each_entry_safe() to prevent
> it racing with runtime_resume() though?
I could not apply for me as looks like your mail server replaced tabs
with spaces it seems :(
But anyways here's your basic idea plugged into my recent patch and
it seems to work. I maybe have missed something though while reading
so please check.
The pm_runtime_get/mark_last_busy/put_autosuspend and WARN_ON() we
want to keep in cppi41_irq() at least for now :)
And I'm thinking we must also callcppi41_run_queue() with spinlock
held to prevent out of order triggering of the DMA transfers.
Does this look OK to you?
Regards,
Tony
8< -----------------------
diff --git a/drivers/dma/cppi41.c b/drivers/dma/cppi41.c
index d5ba43a87a68..6ee593eb2acb 100644
--- a/drivers/dma/cppi41.c
+++ b/drivers/dma/cppi41.c
@@ -153,6 +153,8 @@ struct cppi41_dd {
/* context for suspend/resume */
unsigned int dma_tdfdq;
+
+ bool is_suspended;
};
#define FIST_COMPLETION_QUEUE 93
@@ -316,11 +318,12 @@ static irqreturn_t cppi41_irq(int irq, void *data)
__iormb();
while (val) {
+ unsigned long flags;
u32 desc, len;
int error;
error = pm_runtime_get(cdd->ddev.dev);
- if (error < 0)
+ if ((error != -EINPROGRESS) && error < 0)
dev_err(cdd->ddev.dev, "%s pm runtime get:
%i\n",
__func__, error);
@@ -340,6 +343,11 @@ static irqreturn_t cppi41_irq(int irq, void *data)
else
len = pd_trans_len(c->desc->pd0);
+ /* This warning should never trigger */
+ spin_lock_irqsave(&cdd->lock, flags);
+ WARN_ON(cdd->is_suspended);
+ spin_unlock_irqrestore(&cdd->lock, flags);
+
c->residue = pd_trans_len(c->desc->pd6) - len;
dma_cookie_complete(&c->txd);
dmaengine_desc_get_callback_invoke(&c->txd, NULL);
@@ -457,20 +465,26 @@ static void push_desc_queue(struct cppi41_channel *c)
cppi_writel(reg, cdd->qmgr_mem + QMGR_QUEUE_D(c->q_num));
}
-static void pending_desc(struct cppi41_channel *c)
+/*
+ * Caller must hold cdd->lock to prevent push_desc_queue()
+ * getting called out of order. We have both cppi41_dma_issue_pending()
+ * and cppi41_runtime_resume() call this function.
+ */
+static void cppi41_run_queue(struct cppi41_dd *cdd)
{
- struct cppi41_dd *cdd = c->cdd;
- unsigned long flags;
+ struct cppi41_channel *c, *_c;
- spin_lock_irqsave(&cdd->lock, flags);
- list_add_tail(&c->node, &cdd->pending);
- spin_unlock_irqrestore(&cdd->lock, flags);
+ list_for_each_entry_safe(c, _c, &cdd->pending, node) {
+ push_desc_queue(c);
+ list_del(&c->node);
+ }
}
static void cppi41_dma_issue_pending(struct dma_chan *chan)
{
struct cppi41_channel *c = to_cpp41_chan(chan);
struct cppi41_dd *cdd = c->cdd;
+ unsigned long flags;
int error;
error = pm_runtime_get(cdd->ddev.dev);
@@ -482,10 +496,11 @@ static void cppi41_dma_issue_pending(struct dma_chan
*chan)
return;
}
- if (likely(pm_runtime_active(cdd->ddev.dev)))
- push_desc_queue(c);
- else
- pending_desc(c);
+ spin_lock_irqsave(&cdd->lock, flags);
+ list_add_tail(&c->node, &cdd->pending);
+ if (!cdd->is_suspended)
+ cppi41_run_queue(cdd);
+ spin_unlock_irqrestore(&cdd->lock, flags);
pm_runtime_mark_last_busy(cdd->ddev.dev);
pm_runtime_put_autosuspend(cdd->ddev.dev);
@@ -1150,6 +1165,11 @@ static int __maybe_unused cppi41_resume(struct device
*dev)
static int __maybe_unused cppi41_runtime_suspend(struct device *dev)
{
struct cppi41_dd *cdd = dev_get_drvdata(dev);
+ unsigned long flags;
+
+ spin_lock_irqsave(&cdd->lock, flags);
+ cdd->is_suspended = true;
+ spin_unlock_irqrestore(&cdd->lock, flags);
WARN_ON(!list_empty(&cdd->pending));
@@ -1159,14 +1179,11 @@ static int __maybe_unused cppi41_runtime_suspend(struct
device *dev)
static int __maybe_unused cppi41_runtime_resume(struct device *dev)
{
struct cppi41_dd *cdd = dev_get_drvdata(dev);
- struct cppi41_channel *c, *_c;
unsigned long flags;
spin_lock_irqsave(&cdd->lock, flags);
- list_for_each_entry_safe(c, _c, &cdd->pending, node) {
- push_desc_queue(c);
- list_del(&c->node);
- }
+ cdd->is_suspended = false;
+ cppi41_run_queue(cdd);
spin_unlock_irqrestore(&cdd->lock, flags);
return 0;
--
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