Re: [linux-sunxi] [PATCH v2 2/2] media: cedrus: Implement runtime PM

From: Ezequiel Garcia
Date: Tue May 05 2020 - 08:53:23 EST

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On Wed, 22 Apr 2020 at 01:00, Samuel Holland <samuel@xxxxxxxxxxxx> wrote:
>
> This allows the VE clocks and PLL_VE to be disabled most of the time.
> A runtime PM reference is held while streaming.
>
> Originally-by: Jernej Åkrabec <jernej.skrabec@xxxxxxxxx>

Originally-by is not documented, perhaps just go with Signed-off-by,
as Jernej suggested.

> Signed-off-by: Samuel Holland <samuel@xxxxxxxxxxxx>
> ---
>
> v2: moved PM reference to cedrus_{start,stop}_streaming, based on an
> earlier patch by Jernej Skrabec. Removes the need for autosuspend.
> I tested this with running 2x v4l2-request-test in parallel.
>
> ---
> drivers/staging/media/sunxi/cedrus/cedrus.c | 7 ++
> .../staging/media/sunxi/cedrus/cedrus_hw.c | 106 ++++++++++++------
> .../staging/media/sunxi/cedrus/cedrus_hw.h | 3 +
> .../staging/media/sunxi/cedrus/cedrus_video.c | 33 ++++--
> 4 files changed, 104 insertions(+), 45 deletions(-)
>
> diff --git a/drivers/staging/media/sunxi/cedrus/cedrus.c b/drivers/staging/media/sunxi/cedrus/cedrus.c
> index 05a85517ff60..bc27f9430eeb 100644
> --- a/drivers/staging/media/sunxi/cedrus/cedrus.c
> +++ b/drivers/staging/media/sunxi/cedrus/cedrus.c
> @@ -16,6 +16,7 @@
> #include <linux/platform_device.h>
> #include <linux/module.h>
> #include <linux/of.h>
> +#include <linux/pm.h>
>
> #include <media/v4l2-device.h>
> #include <media/v4l2-ioctl.h>
> @@ -551,12 +552,18 @@ static const struct of_device_id cedrus_dt_match[] = {
> };
> MODULE_DEVICE_TABLE(of, cedrus_dt_match);
>
> +static const struct dev_pm_ops cedrus_dev_pm_ops = {
> + SET_RUNTIME_PM_OPS(cedrus_hw_suspend,
> + cedrus_hw_resume, NULL)
> +};
> +
> static struct platform_driver cedrus_driver = {
> .probe = cedrus_probe,
> .remove = cedrus_remove,
> .driver = {
> .name = CEDRUS_NAME,
> .of_match_table = of_match_ptr(cedrus_dt_match),
> + .pm = &cedrus_dev_pm_ops,
> },
> };
> module_platform_driver(cedrus_driver);
> diff --git a/drivers/staging/media/sunxi/cedrus/cedrus_hw.c b/drivers/staging/media/sunxi/cedrus/cedrus_hw.c
> index daf5f244f93b..1744e6fcc999 100644
> --- a/drivers/staging/media/sunxi/cedrus/cedrus_hw.c
> +++ b/drivers/staging/media/sunxi/cedrus/cedrus_hw.c
> @@ -19,6 +19,7 @@
> #include <linux/dma-mapping.h>
> #include <linux/interrupt.h>
> #include <linux/clk.h>
> +#include <linux/pm_runtime.h>
> #include <linux/regmap.h>
> #include <linux/reset.h>
> #include <linux/soc/sunxi/sunxi_sram.h>
> @@ -140,6 +141,64 @@ static irqreturn_t cedrus_irq(int irq, void *data)
> return IRQ_HANDLED;
> }
>
> +int cedrus_hw_suspend(struct device *device)
> +{
> + struct cedrus_dev *dev = dev_get_drvdata(device);
> +
> + reset_control_assert(dev->rstc);
> +
> + clk_disable_unprepare(dev->ram_clk);
> + clk_disable_unprepare(dev->mod_clk);
> + clk_disable_unprepare(dev->ahb_clk);
> +

You can use clk_bulk API here.

> + return 0;
> +}
> +
> +int cedrus_hw_resume(struct device *device)
> +{
> + struct cedrus_dev *dev = dev_get_drvdata(device);
> + int ret;
> +
> + ret = clk_prepare_enable(dev->ahb_clk);
> + if (ret) {
> + dev_err(dev->dev, "Failed to enable AHB clock\n");
> +
> + return ret;
> + }
> +
> + ret = clk_prepare_enable(dev->mod_clk);
> + if (ret) {
> + dev_err(dev->dev, "Failed to enable MOD clock\n");
> +
> + goto err_ahb_clk;
> + }
> +
> + ret = clk_prepare_enable(dev->ram_clk);
> + if (ret) {
> + dev_err(dev->dev, "Failed to enable RAM clock\n");
> +
> + goto err_mod_clk;
> + }
> +
> + ret = reset_control_reset(dev->rstc);
> + if (ret) {
> + dev_err(dev->dev, "Failed to apply reset\n");
> +
> + goto err_ram_clk;
> + }
> +
> + return 0;
> +
> +err_ram_clk:
> + clk_disable_unprepare(dev->ram_clk);
> +err_mod_clk:
> + clk_disable_unprepare(dev->mod_clk);
> +err_ahb_clk:
> + clk_disable_unprepare(dev->ahb_clk);
> +
> + return ret;
> +}
> +
> int cedrus_hw_probe(struct cedrus_dev *dev)
> {
> const struct cedrus_variant *variant;
> @@ -236,42 +295,17 @@ int cedrus_hw_probe(struct cedrus_dev *dev)
> goto err_sram;
> }
>
> - ret = clk_prepare_enable(dev->ahb_clk);
> - if (ret) {
> - dev_err(dev->dev, "Failed to enable AHB clock\n");
> -
> - goto err_sram;
> - }
> -
> - ret = clk_prepare_enable(dev->mod_clk);
> - if (ret) {
> - dev_err(dev->dev, "Failed to enable MOD clock\n");
> -
> - goto err_ahb_clk;
> - }
> -
> - ret = clk_prepare_enable(dev->ram_clk);
> - if (ret) {
> - dev_err(dev->dev, "Failed to enable RAM clock\n");
> -
> - goto err_mod_clk;
> - }
> -
> - ret = reset_control_reset(dev->rstc);
> - if (ret) {
> - dev_err(dev->dev, "Failed to apply reset\n");
> -
> - goto err_ram_clk;
> + pm_runtime_enable(dev->dev);
> + if (!pm_runtime_enabled(dev->dev)) {
> + ret = cedrus_hw_resume(dev->dev);
> + if (ret)
> + goto err_pm;
> }
>
> return 0;
>
> -err_ram_clk:
> - clk_disable_unprepare(dev->ram_clk);
> -err_mod_clk:
> - clk_disable_unprepare(dev->mod_clk);
> -err_ahb_clk:
> - clk_disable_unprepare(dev->ahb_clk);
> +err_pm:
> + pm_runtime_disable(dev->dev);
> err_sram:
> sunxi_sram_release(dev->dev);
> err_mem:
> @@ -282,11 +316,9 @@ int cedrus_hw_probe(struct cedrus_dev *dev)
>
> void cedrus_hw_remove(struct cedrus_dev *dev)
> {
> - reset_control_assert(dev->rstc);
> -
> - clk_disable_unprepare(dev->ram_clk);
> - clk_disable_unprepare(dev->mod_clk);
> - clk_disable_unprepare(dev->ahb_clk);
> + pm_runtime_disable(dev->dev);
> + if (!pm_runtime_status_suspended(dev->dev))
> + cedrus_hw_suspend(dev->dev);
>
> sunxi_sram_release(dev->dev);
>
> diff --git a/drivers/staging/media/sunxi/cedrus/cedrus_hw.h b/drivers/staging/media/sunxi/cedrus/cedrus_hw.h
> index 604ff932fbf5..45f641f0bfa2 100644
> --- a/drivers/staging/media/sunxi/cedrus/cedrus_hw.h
> +++ b/drivers/staging/media/sunxi/cedrus/cedrus_hw.h
> @@ -22,6 +22,9 @@ void cedrus_engine_disable(struct cedrus_dev *dev);
> void cedrus_dst_format_set(struct cedrus_dev *dev,
> struct v4l2_pix_format *fmt);
>
> +int cedrus_hw_suspend(struct device *device);
> +int cedrus_hw_resume(struct device *device);
> +
> int cedrus_hw_probe(struct cedrus_dev *dev);
> void cedrus_hw_remove(struct cedrus_dev *dev);
>
> diff --git a/drivers/staging/media/sunxi/cedrus/cedrus_video.c b/drivers/staging/media/sunxi/cedrus/cedrus_video.c
> index ed3f511f066f..16d82309e7b6 100644
> --- a/drivers/staging/media/sunxi/cedrus/cedrus_video.c
> +++ b/drivers/staging/media/sunxi/cedrus/cedrus_video.c
> @@ -13,6 +13,8 @@
> * Marek Szyprowski, <m.szyprowski@xxxxxxxxxxx>
> */
>
> +#include <linux/pm_runtime.h>
> +
> #include <media/videobuf2-dma-contig.h>
> #include <media/v4l2-device.h>
> #include <media/v4l2-ioctl.h>
> @@ -450,12 +452,24 @@ static int cedrus_start_streaming(struct vb2_queue *vq, unsigned int count)
> return -EINVAL;
> }
>
> - if (V4L2_TYPE_IS_OUTPUT(vq->type) &&
> - dev->dec_ops[ctx->current_codec]->start)
> - ret = dev->dec_ops[ctx->current_codec]->start(ctx);
> + if (V4L2_TYPE_IS_OUTPUT(vq->type)) {
> + ret = pm_runtime_get_sync(dev->dev);

It's entirely up to you, but you could do get_sync/put
between .device_run, as everything should happen
in the context of v4l2_m2m_ops.device_run.
(In that case, I believe you'd want to enable autosuspend.)

Not sure there's much to gain from an power consumption
pov, though.

With the Originally-by changed:

Reviewed-by: Ezequiel Garcia <ezequiel@xxxxxxxxxxxxx>

Thanks,
Ezequiel

Next message: Nicolas Saenz Julienne: "Re: [PATCH v2 2/2] usb: xhci: Load Raspberry Pi 4 VL805's firmware"
Previous message: Andy Shevchenko: "Re: [PATCH 4.19 28/37] dmaengine: dmatest: Fix iteration non-stop logic"
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