Message-ID:
 <SE1P216MB130326E2C4BA7E723A8955C9ED512@SE1P216MB1303.KORP216.PROD.OUTLOOK.COM>
Date: Mon, 19 Feb 2024 04:04:23 +0000
From: jackson.lee <jackson.lee@...psnmedia.com>
To: Nicolas Dufresne <nicolas@...fresne.ca>, "mchehab@...nel.org"
	<mchehab@...nel.org>, "linux-media@...r.kernel.org"
	<linux-media@...r.kernel.org>, "linux-kernel@...r.kernel.org"
	<linux-kernel@...r.kernel.org>, Nas Chung <nas.chung@...psnmedia.com>
CC: lafley.kim <lafley.kim@...psnmedia.com>, "b-brnich@...com"
	<b-brnich@...com>
Subject: RE: [RESEND PATCH v0 3/5] wave5 : Support runtime suspend/resume.


Hi Nicolas


> This seems very unnatural. We do the get() in "start_streaming()", but the
> put() is only done when the device is closed, or when the driver is
> removed. As this is not balanced, you seem to have to check the suspended
> condition all over the place.
> 
> I think we could aim for start_streaming()/stop_streaming() for your
> get/put placement. At least they will be bound to an entirely balanced API.
> But then, a media player in paused sate will prevent that device from
> being suspended.
> 
> If the HW is capable of preserving enough state, and From the short doc I
> have it gives me the impression it can preserve that, I'd suggest to
> follow what hantro driver is doing. What is does is that it will do get()
> in device_run(), and put() whenever the job completes. This driver has
> been designed so when there is no job, it means the firmware is currently
> idle and looking for more work. So it seems like the perfect moment to do
> suspend it.
>

Thanks your comment,

Currently they are not balanced, 
If we puts "the put functon" into the stop_streaming, our hw is stalled until doing wake-up command, so our v4l2 device become block.
so I'd like to update the below instead of calling get at the start_streaming function.


@@ -1867,6 +1868,13 @@ static int wave5_vpu_open_dec(struct file *filp)

        wave5_vdi_allocate_sram(inst->dev);

+       err = pm_runtime_resume_and_get(inst->dev->dev);
+       if (err) {
+               dev_err(inst->dev->dev, "decoder runtime resume failed %d\n", err);
+               ret = -EINVAL;
+               goto cleanup_inst;
+       }
+
        return 0;




> Le mercredi 31 janvier 2024 à 10:30 +0900, jackson.lee a écrit :
> > There are two device run-time PM callbacks defined in 'struct
> dev_pm_ops'
> > int (*runtime_suspend)(struct device *dev); int
> > (*runtime_resume)(struct device *dev);
> 
> I wonder how useful is it to teach everyone what the generic 'struct
> dev_pm_ops'
> contains. Perhaps you simply wanted that this patch implement both suspend
> and resume ops ?
> 
> >
> > Signed-off-by: Jackson Lee <jackson.lee@...psnmedia.com>
> > Signed-off-by: Nas Chung <nas.chung@...psnmedia.com>
> > ---
> >  .../platform/chips-media/wave5/wave5-hw.c     |  5 +-
> >  .../chips-media/wave5/wave5-vpu-dec.c         |  9 +++
> >  .../chips-media/wave5/wave5-vpu-enc.c         |  9 +++
> >  .../platform/chips-media/wave5/wave5-vpu.c    | 68 +++++++++++++++++++
> >  .../platform/chips-media/wave5/wave5-vpuapi.c |  7 ++
> > .../media/platform/chips-media/wave5/wave5.h  |  3 +
> >  6 files changed, 99 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/media/platform/chips-media/wave5/wave5-hw.c
> > b/drivers/media/platform/chips-media/wave5/wave5-hw.c
> > index 8ad7f3a28ae1..8aade5a38439 100644
> > --- a/drivers/media/platform/chips-media/wave5/wave5-hw.c
> > +++ b/drivers/media/platform/chips-media/wave5/wave5-hw.c
> > @@ -503,6 +503,7 @@ int wave5_vpu_build_up_dec_param(struct vpu_instance
> *inst,
> >  	/* This register must be reset explicitly */
> >  	vpu_write_reg(inst->dev, W5_CMD_EXT_ADDR, 0);
> >  	vpu_write_reg(inst->dev, W5_CMD_NUM_CQ_DEPTH_M1,
> > (COMMAND_QUEUE_DEPTH - 1));
> > +	vpu_write_reg(inst->dev, W5_CMD_ERR_CONCEAL, 0);
> 
> In some way, the relation between suspend and this register write is not
> obvious. If its not related, please do this in its own patch. Otherwise
> you want to explain why you needed this (possibly just in the commit
> message).
> 
> >
> >  	ret = send_firmware_command(inst, W5_CREATE_INSTANCE, true, NULL,
> NULL);
> >  	if (ret) {
> > @@ -1075,8 +1076,8 @@ int wave5_vpu_re_init(struct device *dev, u8 *fw,
> size_t size)
> >  	return setup_wave5_properties(dev);
> >  }
> >
> > -static int wave5_vpu_sleep_wake(struct device *dev, bool i_sleep_wake,
> const uint16_t *code,
> > -				size_t size)
> > +int wave5_vpu_sleep_wake(struct device *dev, bool i_sleep_wake, const
> uint16_t *code,
> > +			 size_t size)
> >  {
> >  	u32 reg_val;
> >  	struct vpu_buf *common_vb;
> > diff --git a/drivers/media/platform/chips-media/wave5/wave5-vpu-dec.c
> > b/drivers/media/platform/chips-media/wave5/wave5-vpu-dec.c
> > index ef227af72348..328a7a8f26c5 100644
> > --- a/drivers/media/platform/chips-media/wave5/wave5-vpu-dec.c
> > +++ b/drivers/media/platform/chips-media/wave5/wave5-vpu-dec.c
> > @@ -5,6 +5,7 @@
> >   * Copyright (C) 2021-2023 CHIPS&MEDIA INC
> >   */
> >
> > +#include <linux/pm_runtime.h>
> >  #include "wave5-helper.h"
> >
> >  #define VPU_DEC_DEV_NAME "C&M Wave5 VPU decoder"
> > @@ -1387,9 +1388,17 @@ static int wave5_vpu_dec_start_streaming(struct
> > vb2_queue *q, unsigned int count
> >
> >  	if (q->type == V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE && inst->state ==
> VPU_INST_STATE_NONE) {
> >  		struct dec_open_param open_param;
> > +		int err = 0;
> >
> >  		memset(&open_param, 0, sizeof(struct dec_open_param));
> >
> > +		err = pm_runtime_resume_and_get(inst->dev->dev);
> > +		if (err) {
> > +			dev_err(inst->dev->dev, "decoder runtime resume
> failed %d\n", err);
> > +			ret = -EINVAL;
> > +			goto return_buffers;
> > +		}
> > +
> >  		ret = wave5_vpu_dec_allocate_ring_buffer(inst);
> >  		if (ret)
> >  			goto return_buffers;
> > diff --git a/drivers/media/platform/chips-media/wave5/wave5-vpu-enc.c
> > b/drivers/media/platform/chips-media/wave5/wave5-vpu-enc.c
> > index 761775216cd4..ff73d69de41c 100644
> > --- a/drivers/media/platform/chips-media/wave5/wave5-vpu-enc.c
> > +++ b/drivers/media/platform/chips-media/wave5/wave5-vpu-enc.c
> > @@ -5,6 +5,7 @@
> >   * Copyright (C) 2021-2023 CHIPS&MEDIA INC
> >   */
> >
> > +#include <linux/pm_runtime.h>
> >  #include "wave5-helper.h"
> >
> >  #define VPU_ENC_DEV_NAME "C&M Wave5 VPU encoder"
> > @@ -1387,9 +1388,17 @@ static int wave5_vpu_enc_start_streaming(struct
> > vb2_queue *q, unsigned int count
> >
> >  	if (inst->state == VPU_INST_STATE_NONE && q->type ==
> V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE) {
> >  		struct enc_open_param open_param;
> > +		int err = 0;
> >
> >  		memset(&open_param, 0, sizeof(struct enc_open_param));
> >
> > +		err = pm_runtime_resume_and_get(inst->dev->dev);
> > +		if (err) {
> > +			dev_err(inst->dev->dev, "encoder runtime resume
> failed %d\n", err);
> > +			ret = -EINVAL;
> > +			goto return_buffers;
> > +		}
> > +
> >  		wave5_set_enc_openparam(&open_param, inst);
> >
> >  		ret = wave5_vpu_enc_open(inst, &open_param); diff --git
> > a/drivers/media/platform/chips-media/wave5/wave5-vpu.c
> > b/drivers/media/platform/chips-media/wave5/wave5-vpu.c
> > index 0d90b5820bef..f81409740a56 100644
> > --- a/drivers/media/platform/chips-media/wave5/wave5-vpu.c
> > +++ b/drivers/media/platform/chips-media/wave5/wave5-vpu.c
> > @@ -10,6 +10,7 @@
> >  #include <linux/clk.h>
> >  #include <linux/firmware.h>
> >  #include <linux/interrupt.h>
> > +#include <linux/pm_runtime.h>
> >  #include "wave5-vpu.h"
> >  #include "wave5-regdefine.h"
> >  #include "wave5-vpuconfig.h"
> > @@ -117,6 +118,65 @@ static int wave5_vpu_load_firmware(struct device
> *dev, const char *fw_name,
> >  	return 0;
> >  }
> >
> > +static __maybe_unused int wave5_pm_suspend(struct device *dev) {
> > +	struct vpu_device *vpu = dev_get_drvdata(dev);
> > +
> > +	if (pm_runtime_suspended(dev))
> > +		return 0;
> > +
> > +	wave5_vpu_sleep_wake(dev, true, NULL, 0);
> > +	clk_bulk_disable_unprepare(vpu->num_clks, vpu->clks);
> > +
> > +	return 0;
> > +}
> > +
> > +static __maybe_unused int wave5_pm_resume(struct device *dev) {
> > +	struct vpu_device *vpu = dev_get_drvdata(dev);
> > +	int ret = 0;
> > +
> > +	wave5_vpu_sleep_wake(dev, false, NULL, 0);
> > +	ret = clk_bulk_prepare_enable(vpu->num_clks, vpu->clks);
> > +	if (ret) {
> > +		dev_err(dev, "Enabling clocks, fail: %d\n", ret);
> > +		return ret;
> > +	}
> > +
> > +	return ret;
> > +}
> > +
> > +static __maybe_unused int wave5_suspend(struct device *dev) {
> > +	struct vpu_device *vpu = dev_get_drvdata(dev);
> > +	struct vpu_instance *inst;
> > +
> > +	list_for_each_entry(inst, &vpu->instances, list)
> > +		v4l2_m2m_suspend(inst->v4l2_m2m_dev);
> > +
> > +	return pm_runtime_force_suspend(dev); }
> > +
> > +static __maybe_unused int wave5_resume(struct device *dev) {
> > +	struct vpu_device *vpu = dev_get_drvdata(dev);
> > +	struct vpu_instance *inst;
> > +	int ret = 0;
> > +
> > +	ret = pm_runtime_force_resume(dev);
> > +	if (ret < 0)
> > +		return ret;
> > +
> > +	list_for_each_entry(inst, &vpu->instances, list)
> > +		v4l2_m2m_resume(inst->v4l2_m2m_dev);
> > +
> > +	return ret;
> > +}
> 
> The functions wave5_suspend() and wave5_resume() are not just
> "maybe_unsued" but actually never used. What was the intention ?
> Considering the usage of __maybe_unused has been such a bad friend for
> this one, could you instead bracket the functions with an explicit ?
> 
> #ifdef CONFIG_PM
> #endif
> 
> This way the compiler will have a word if you implement something that you
> forgot to actually use.
> 
> > +
> > +static const struct dev_pm_ops wave5_pm_ops = {
> > +	SET_RUNTIME_PM_OPS(wave5_pm_suspend, wave5_pm_resume, NULL) };
> > +
> >  static int wave5_vpu_probe(struct platform_device *pdev)  {
> >  	int ret;
> > @@ -232,6 +292,10 @@ static int wave5_vpu_probe(struct platform_device
> *pdev)
> >  		 (match_data->flags & WAVE5_IS_DEC) ? "'DECODE'" : "");
> >  	dev_info(&pdev->dev, "Product Code:      0x%x\n", dev->product_code);
> >  	dev_info(&pdev->dev, "Firmware Revision: %u\n", fw_revision);
> > +
> > +	pm_runtime_enable(&pdev->dev);
> > +	wave5_vpu_sleep_wake(&pdev->dev, true, NULL, 0);
> > +
> >  	return 0;
> >
> >  err_enc_unreg:
> > @@ -254,6 +318,9 @@ static int wave5_vpu_remove(struct platform_device
> > *pdev)  {
> >  	struct vpu_device *dev = dev_get_drvdata(&pdev->dev);
> >
> > +	pm_runtime_put_sync(&pdev->dev);
> > +	pm_runtime_disable(&pdev->dev);
> > +
> >  	mutex_destroy(&dev->dev_lock);
> >  	mutex_destroy(&dev->hw_lock);
> >  	clk_bulk_disable_unprepare(dev->num_clks, dev->clks); @@ -281,6
> > +348,7 @@ static struct platform_driver wave5_vpu_driver = {
> >  	.driver = {
> >  		.name = VPU_PLATFORM_DEVICE_NAME,
> >  		.of_match_table = of_match_ptr(wave5_dt_ids),
> > +		.pm = &wave5_pm_ops,
> >  		},
> >  	.probe = wave5_vpu_probe,
> >  	.remove = wave5_vpu_remove,
> > diff --git a/drivers/media/platform/chips-media/wave5/wave5-vpuapi.c
> > b/drivers/media/platform/chips-media/wave5/wave5-vpuapi.c
> > index 1a3efb638dde..f1f8e4fc8474 100644
> > --- a/drivers/media/platform/chips-media/wave5/wave5-vpuapi.c
> > +++ b/drivers/media/platform/chips-media/wave5/wave5-vpuapi.c
> > @@ -6,6 +6,7 @@
> >   */
> >
> >  #include <linux/bug.h>
> > +#include <linux/pm_runtime.h>
> >  #include "wave5-vpuapi.h"
> >  #include "wave5-regdefine.h"
> >  #include "wave5.h"
> > @@ -232,6 +233,9 @@ int wave5_vpu_dec_close(struct vpu_instance *inst,
> > u32 *fail_res)
> >
> >  	wave5_vdi_free_dma_memory(vpu_dev, &p_dec_info->vb_task);
> >
> > +	if (!pm_runtime_suspended(inst->dev->dev))
> > +		pm_runtime_put_sync(inst->dev->dev);
> > +
> >  unlock_and_return:
> >  	mutex_unlock(&vpu_dev->hw_lock);
> >
> > @@ -734,6 +738,9 @@ int wave5_vpu_enc_close(struct vpu_instance *inst,
> > u32 *fail_res)
> >
> >  	wave5_vdi_free_dma_memory(vpu_dev, &p_enc_info->vb_task);
> >
> > +	if (!pm_runtime_suspended(inst->dev->dev))
> > +		pm_runtime_put_sync(inst->dev->dev);
> 
> This seems very unnatural. We do the get() in "start_streaming()", but the
> put() is only done when the device is closed, or when the driver is
> removed. As this is not balanced, you seem to have to check the suspended
> condition all over the place.
> 
> I think we could aim for start_streaming()/stop_streaming() for your
> get/put placement. At least they will be bound to an entirely balanced API.
> But then, a media player in paused sate will prevent that device from
> being suspended.
> 
> If the HW is capable of preserving enough state, and From the short doc I
> have it gives me the impression it can preserve that, I'd suggest to
> follow what hantro driver is doing. What is does is that it will do get()
> in device_run(), and put() whenever the job completes. This driver has
> been designed so when there is no job, it means the firmware is currently
> idle and looking for more work. So it seems like the perfect moment to do
> suspend it.
> 
> Nicolas
> 
> > +
> >  	mutex_unlock(&vpu_dev->hw_lock);
> >
> >  	return 0;
> > diff --git a/drivers/media/platform/chips-media/wave5/wave5.h
> > b/drivers/media/platform/chips-media/wave5/wave5.h
> > index 063028eccd3b..6125eff938a8 100644
> > --- a/drivers/media/platform/chips-media/wave5/wave5.h
> > +++ b/drivers/media/platform/chips-media/wave5/wave5.h
> > @@ -56,6 +56,9 @@ int wave5_vpu_get_version(struct vpu_device
> > *vpu_dev, u32 *revision);
> >
> >  int wave5_vpu_init(struct device *dev, u8 *fw, size_t size);
> >
> > +int wave5_vpu_sleep_wake(struct device *dev, bool i_sleep_wake, const
> uint16_t *code,
> > +			 size_t size);
> > +
> >  int wave5_vpu_reset(struct device *dev, enum sw_reset_mode
> > reset_mode);
> >
> >  int wave5_vpu_build_up_dec_param(struct vpu_instance *inst, struct
> > dec_open_param *param);

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