2012-10-17 04:12:39

by Inderpal Singh

Subject: [PATCH] DMA: PL330: Add runtime pm support

At the pl330's probe point the device is already in runtime resume state.
Hence to manage the device with runtime, the probe should do pm_runtime_put
and remove should do pm_runtime_get to balance with probe.

And in between, the device is being get/put at alloc_chan_resources and
free_chan_resources.

Signed-off-by: Inderpal Singh <[email protected]>
---
This patch is based on slave-dma's next branch and on top
of the clean up patches at [1].

[1] https://lkml.org/lkml/2012/10/5/169

drivers/dma/pl330.c | 10 ++++++++++
1 file changed, 10 insertions(+)

diff --git a/drivers/dma/pl330.c b/drivers/dma/pl330.c
index 2ee1538..5ae19ea 100644
--- a/drivers/dma/pl330.c
+++ b/drivers/dma/pl330.c
@@ -25,6 +25,7 @@
#include <linux/amba/pl330.h>
#include <linux/scatterlist.h>
#include <linux/of.h>
+#include <linux/pm_runtime.h>

#include "dmaengine.h"
#define PL330_MAX_CHAN 8
@@ -2384,6 +2385,8 @@ static int pl330_alloc_chan_resources(struct dma_chan *chan)
struct dma_pl330_dmac *pdmac = pch->dmac;
unsigned long flags;

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

dma_cookie_init(chan);
@@ -2392,6 +2395,7 @@ static int pl330_alloc_chan_resources(struct dma_chan *chan)
pch->pl330_chid = pl330_request_channel(&pdmac->pif);
if (!pch->pl330_chid) {
spin_unlock_irqrestore(&pch->lock, flags);
+ pm_runtime_put(pdmac->ddma.dev);
return -ENOMEM;
}

@@ -2470,6 +2474,8 @@ 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);
+
+ pm_runtime_put(pch->dmac->ddma.dev);
}

static enum dma_status
@@ -2974,6 +2980,8 @@ pl330_probe(struct amba_device *adev, const struct amba_id *id)
pi->pcfg.data_bus_width / 8, pi->pcfg.num_chan,
pi->pcfg.num_peri, pi->pcfg.num_events);

+ pm_runtime_put(pd->dev);
+
return 0;

probe_err5:
@@ -3017,6 +3025,8 @@ static int __devexit pl330_remove(struct amba_device *adev)
return -EBUSY;
}

+ pm_runtime_get(pdmac->ddma.dev);
+
dma_async_device_unregister(&pdmac->ddma);

amba_set_drvdata(adev, NULL);
--
1.7.9.5

2012-10-24 11:15:22

by Vinod Koul

Subject: Re: [PATCH] DMA: PL330: Add runtime pm support

On Wed, 2012-10-17 at 09:42 +0530, Inderpal Singh wrote:
> At the pl330's probe point the device is already in runtime resume state.
> Hence to manage the device with runtime, the probe should do pm_runtime_put
> and remove should do pm_runtime_get to balance with probe.
>
> And in between, the device is being get/put at alloc_chan_resources and
> free_chan_resources.
>
> Signed-off-by: Inderpal Singh <[email protected]>
> ---
> This patch is based on slave-dma's next branch and on top
> of the clean up patches at [1].
>
> [1] https://lkml.org/lkml/2012/10/5/169
>
> drivers/dma/pl330.c | 10 ++++++++++
> 1 file changed, 10 insertions(+)
>
> diff --git a/drivers/dma/pl330.c b/drivers/dma/pl330.c
> index 2ee1538..5ae19ea 100644
> --- a/drivers/dma/pl330.c
> +++ b/drivers/dma/pl330.c
> @@ -25,6 +25,7 @@
> #include <linux/amba/pl330.h>
> #include <linux/scatterlist.h>
> #include <linux/of.h>
> +#include <linux/pm_runtime.h>
>
> #include "dmaengine.h"
> #define PL330_MAX_CHAN 8
> @@ -2384,6 +2385,8 @@ static int pl330_alloc_chan_resources(struct dma_chan *chan)
> struct dma_pl330_dmac *pdmac = pch->dmac;
> unsigned long flags;
>
> + pm_runtime_get_sync(pdmac->ddma.dev);
it would be really good if we move this to tx_submit. That way you
resume the dmaengine when actual transactions happen, not when someone
requests a channel.
Yes thats a little more work, though initially we can have this way.
> +
> spin_lock_irqsave(&pch->lock, flags);
>
> dma_cookie_init(chan);
> @@ -2392,6 +2395,7 @@ static int pl330_alloc_chan_resources(struct dma_chan *chan)
> pch->pl330_chid = pl330_request_channel(&pdmac->pif);
> if (!pch->pl330_chid) {
> spin_unlock_irqrestore(&pch->lock, flags);
> + pm_runtime_put(pdmac->ddma.dev);
> return -ENOMEM;
> }
>
> @@ -2470,6 +2474,8 @@ 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);
> +
> + pm_runtime_put(pch->dmac->ddma.dev);
> }
>
> static enum dma_status
> @@ -2974,6 +2980,8 @@ pl330_probe(struct amba_device *adev, const struct amba_id *id)
> pi->pcfg.data_bus_width / 8, pi->pcfg.num_chan,
> pi->pcfg.num_peri, pi->pcfg.num_events);
>
> + pm_runtime_put(pd->dev);
pm_runtime_put_noidle is better. Yous should also do pm_runtime_allow
here and pm_runtime_forbid in your remove.

> +
> return 0;
>
> probe_err5:
> @@ -3017,6 +3025,8 @@ static int __devexit pl330_remove(struct amba_device *adev)
> return -EBUSY;
> }
>
> + pm_runtime_get(pdmac->ddma.dev);
> +
> dma_async_device_unregister(&pdmac->ddma);
>
> amba_set_drvdata(adev, NULL);


--
Vinod Koul
Intel Corp.