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Subject[PATCH] dmaengine: pl330: get rid of pm_runtime_irq_safe()
Date
As using pm_runtime_irq_safe() causes power domain is always enabled,
we want to get rid of it to reach better power efficiency. For this purpose
we call pm_runtime_get()/pm_runtime_put() only in DMA channel allocate/free
code. DMA channels are always requested and freed in non-atomic context,
so we don't need pm_runtime_irq_safe().

With pm_runtime_irq_safe() enabled the only action performed by
pm_runtime_get()/pm_runtime_put() functions was enabling and disabling
AHB clock, so now we do that manually to avoid using pm_runtime functions
in atomic context.

In result we manage AHB clock as we did before, plus we can disable power
domain when nobody uses DMA controller.

Signed-off-by: Robert Baldyga <r.baldyga@samsung.com>
---
drivers/dma/pl330.c | 57 ++++++++++++++++++++++++++++++++---------------------
1 file changed, 34 insertions(+), 23 deletions(-)

diff --git a/drivers/dma/pl330.c b/drivers/dma/pl330.c
index 0e1f567..5348ab9 100644
--- a/drivers/dma/pl330.c
+++ b/drivers/dma/pl330.c
@@ -1969,6 +1969,7 @@ static inline void fill_queue(struct dma_pl330_chan *pch)
static void pl330_tasklet(unsigned long data)
{
struct dma_pl330_chan *pch = (struct dma_pl330_chan *)data;
+ struct amba_device *pcdev = to_amba_device(pch->dmac->ddma.dev);
struct dma_pl330_desc *desc, *_dt;
unsigned long flags;
bool power_down = false;
@@ -2032,11 +2033,9 @@ static void pl330_tasklet(unsigned long data)
}
spin_unlock_irqrestore(&pch->lock, flags);

- /* If work list empty, power down */
- if (power_down) {
- pm_runtime_mark_last_busy(pch->dmac->ddma.dev);
- pm_runtime_put_autosuspend(pch->dmac->ddma.dev);
- }
+ /* If work list empty, disable clock */
+ if (power_down)
+ amba_pclk_disable(pcdev);
}

bool pl330_filter(struct dma_chan *chan, void *param)
@@ -2077,6 +2076,7 @@ static int pl330_alloc_chan_resources(struct dma_chan *chan)
struct pl330_dmac *pl330 = pch->dmac;
unsigned long flags;

+ pm_runtime_get_sync(pch->dmac->ddma.dev);
spin_lock_irqsave(&pch->lock, flags);

dma_cookie_init(chan);
@@ -2165,10 +2165,15 @@ static int pl330_terminate_all(struct dma_chan *chan)
int pl330_pause(struct dma_chan *chan)
{
struct dma_pl330_chan *pch = to_pchan(chan);
+ struct amba_device *pcdev = to_amba_device(pch->dmac->ddma.dev);
struct pl330_dmac *pl330 = pch->dmac;
unsigned long flags;
+ int ret;
+
+ ret = amba_pclk_enable(pcdev);
+ if (ret < 0)
+ return ret;

- pm_runtime_get_sync(pl330->ddma.dev);
spin_lock_irqsave(&pch->lock, flags);

spin_lock(&pl330->lock);
@@ -2176,8 +2181,7 @@ int pl330_pause(struct dma_chan *chan)
spin_unlock(&pl330->lock);

spin_unlock_irqrestore(&pch->lock, flags);
- pm_runtime_mark_last_busy(pl330->ddma.dev);
- pm_runtime_put_autosuspend(pl330->ddma.dev);
+ amba_pclk_disable(pcdev);

return 0;
}
@@ -2185,11 +2189,16 @@ int pl330_pause(struct dma_chan *chan)
static void pl330_free_chan_resources(struct dma_chan *chan)
{
struct dma_pl330_chan *pch = to_pchan(chan);
+ struct amba_device *pcdev = to_amba_device(pch->dmac->ddma.dev);
unsigned long flags;
+ int ret;

tasklet_kill(&pch->task);

- pm_runtime_get_sync(pch->dmac->ddma.dev);
+ ret = amba_pclk_enable(pcdev);
+ if (ret < 0)
+ return;
+
spin_lock_irqsave(&pch->lock, flags);

pl330_release_channel(pch->thread);
@@ -2199,6 +2208,7 @@ static void pl330_free_chan_resources(struct dma_chan *chan)
list_splice_tail_init(&pch->work_list, &pch->dmac->desc_pool);

spin_unlock_irqrestore(&pch->lock, flags);
+ amba_pclk_disable(pcdev);
pm_runtime_mark_last_busy(pch->dmac->ddma.dev);
pm_runtime_put_autosuspend(pch->dmac->ddma.dev);
}
@@ -2206,12 +2216,17 @@ static void pl330_free_chan_resources(struct dma_chan *chan)
int pl330_get_current_xferred_count(struct dma_pl330_chan *pch,
struct dma_pl330_desc *desc)
{
+ struct amba_device *pcdev = to_amba_device(pch->dmac->ddma.dev);
struct pl330_thread *thrd = pch->thread;
struct pl330_dmac *pl330 = pch->dmac;
void __iomem *regs = thrd->dmac->base;
u32 val, addr;
+ int ret;
+
+ ret = amba_pclk_enable(pcdev);
+ if (ret < 0)
+ return ret;

- pm_runtime_get_sync(pl330->ddma.dev);
val = addr = 0;
if (desc->rqcfg.src_inc) {
val = readl(regs + SA(thrd->id));
@@ -2220,8 +2235,8 @@ int pl330_get_current_xferred_count(struct dma_pl330_chan *pch,
val = readl(regs + DA(thrd->id));
addr = desc->px.dst_addr;
}
- pm_runtime_mark_last_busy(pch->dmac->ddma.dev);
- pm_runtime_put_autosuspend(pl330->ddma.dev);
+
+ amba_pclk_disable(pcdev);
return val - addr;
}

@@ -2276,17 +2291,21 @@ out:
static void pl330_issue_pending(struct dma_chan *chan)
{
struct dma_pl330_chan *pch = to_pchan(chan);
+ struct amba_device *pcdev = to_amba_device(pch->dmac->ddma.dev);
unsigned long flags;
+ int ret;

spin_lock_irqsave(&pch->lock, flags);
if (list_empty(&pch->work_list)) {
/*
* Warn on nothing pending. Empty submitted_list may
- * break our pm_runtime usage counter as it is
- * updated on work_list emptiness status.
+ * break our clock usage counter as it is updated on
+ * work_list emptiness status.
*/
WARN_ON(list_empty(&pch->submitted_list));
- pm_runtime_get_sync(pch->dmac->ddma.dev);
+ ret = amba_pclk_enable(pcdev);
+ if (ret < 0)
+ return;
}
list_splice_tail_init(&pch->submitted_list, &pch->work_list);
spin_unlock_irqrestore(&pch->lock, flags);
@@ -2723,10 +2742,6 @@ static int __maybe_unused pl330_suspend(struct device *dev)

pm_runtime_disable(dev);

- if (!pm_runtime_status_suspended(dev)) {
- /* amba did not disable the clock */
- amba_pclk_disable(pcdev);
- }
amba_pclk_unprepare(pcdev);

return 0;
@@ -2741,9 +2756,6 @@ static int __maybe_unused pl330_resume(struct device *dev)
if (ret)
return ret;

- if (!pm_runtime_status_suspended(dev))
- ret = amba_pclk_enable(pcdev);
-
pm_runtime_enable(dev);

return ret;
@@ -2910,7 +2922,6 @@ pl330_probe(struct amba_device *adev, const struct amba_id *id)
pcfg->data_buf_dep, pcfg->data_bus_width / 8, pcfg->num_chan,
pcfg->num_peri, pcfg->num_events);

- pm_runtime_irq_safe(&adev->dev);
pm_runtime_use_autosuspend(&adev->dev);
pm_runtime_set_autosuspend_delay(&adev->dev, PL330_AUTOSUSPEND_DELAY);
pm_runtime_mark_last_busy(&adev->dev);
--
1.9.1


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