Re: [PATCH v6 07/12] spi: intel-dg: wake card on operations

[Rodrigo Vivi <rodrigo.vivi@intel.com>]

On Mon, Sep 16, 2024 at 04:49:23PM +0300, Alexander Usyskin wrote:
> Enable runtime PM in spi driver to notify graphics driver that
> whole card should be kept awake while spi operations are
> performed through this driver.
> 
> CC: Lucas De Marchi <lucas.demarchi@intel.com>
> Signed-off-by: Alexander Usyskin <alexander.usyskin@intel.com>
> ---
>  drivers/spi/spi-intel-dg.c | 44 ++++++++++++++++++++++++++++++++++++++
>  1 file changed, 44 insertions(+)
> 
> diff --git a/drivers/spi/spi-intel-dg.c b/drivers/spi/spi-intel-dg.c
> index c76b0a70f8d8..a14fc3190520 100644
> --- a/drivers/spi/spi-intel-dg.c
> +++ b/drivers/spi/spi-intel-dg.c
> @@ -12,11 +12,14 @@
>  #include <linux/module.h>
>  #include <linux/mtd/mtd.h>
>  #include <linux/mtd/partitions.h>
> +#include <linux/pm_runtime.h>
>  #include <linux/string.h>
>  #include <linux/slab.h>
>  #include <linux/sizes.h>
>  #include <linux/types.h>
>  
> +#define INTEL_DG_SPI_RPM_TIMEOUT 500
> +
>  struct intel_dg_spi {
>  	struct kref refcnt;
>  	struct mtd_info mtd;
> @@ -471,6 +474,12 @@ static int intel_dg_spi_erase(struct mtd_info *mtd, struct erase_info *info)
>  	total_len = info->len;
>  	addr = info->addr;
>  
> +	ret = pm_runtime_resume_and_get(mtd->dev.parent);
> +	if (ret < 0) {
> +		dev_err(&mtd->dev, "rpm: get failed %d\n", ret);

If I understood correctly,
this is the device = &aux_dev->dev;
which is the drm->pdev.dev
?

This is to ensure that the graphics driver is not going to runtime suspend,
right?

> +		return ret;
> +	}
> +
>  	mutex_lock(&spi->lock);
>  
>  	while (total_len > 0) {
> @@ -512,6 +521,8 @@ static int intel_dg_spi_erase(struct mtd_info *mtd, struct erase_info *info)
>  
>  out:
>  	mutex_unlock(&spi->lock);
> +	pm_runtime_mark_last_busy(mtd->dev.parent);
> +	pm_runtime_put_autosuspend(mtd->dev.parent);
>  	return ret;
>  }
>  
> @@ -545,6 +556,12 @@ static int intel_dg_spi_read(struct mtd_info *mtd, loff_t from, size_t len,
>  	if (len > spi->regions[idx].size - from)
>  		len = spi->regions[idx].size - from;
>  
> +	ret = pm_runtime_resume_and_get(mtd->dev.parent);
> +	if (ret < 0) {
> +		dev_err(&mtd->dev, "rpm: get failed %zd\n", ret);
> +		return ret;
> +	}
> +
>  	mutex_lock(&spi->lock);
>  
>  	ret = spi_read(spi, region, from, len, buf);
> @@ -557,6 +574,8 @@ static int intel_dg_spi_read(struct mtd_info *mtd, loff_t from, size_t len,
>  	*retlen = ret;
>  
>  	mutex_unlock(&spi->lock);
> +	pm_runtime_mark_last_busy(mtd->dev.parent);
> +	pm_runtime_put_autosuspend(mtd->dev.parent);
>  	return 0;
>  }
>  
> @@ -590,6 +609,12 @@ static int intel_dg_spi_write(struct mtd_info *mtd, loff_t to, size_t len,
>  	if (len > spi->regions[idx].size - to)
>  		len = spi->regions[idx].size - to;
>  
> +	ret = pm_runtime_resume_and_get(mtd->dev.parent);
> +	if (ret < 0) {
> +		dev_err(&mtd->dev, "rpm: get failed %zd\n", ret);
> +		return ret;
> +	}
> +
>  	mutex_lock(&spi->lock);
>  
>  	ret = spi_write(spi, region, to, len, buf);
> @@ -602,6 +627,8 @@ static int intel_dg_spi_write(struct mtd_info *mtd, loff_t to, size_t len,
>  	*retlen = ret;
>  
>  	mutex_unlock(&spi->lock);
> +	pm_runtime_mark_last_busy(mtd->dev.parent);
> +	pm_runtime_put_autosuspend(mtd->dev.parent);
>  	return 0;
>  }
>  
> @@ -747,6 +774,17 @@ static int intel_dg_spi_probe(struct auxiliary_device *aux_dev,
>  		}
>  	}
>  
> +	pm_runtime_enable(device);
> +
> +	pm_runtime_set_autosuspend_delay(device, INTEL_DG_SPI_RPM_TIMEOUT);
> +	pm_runtime_use_autosuspend(device);

If the above assumption is right, then I don't believe you
should change the device settings in here.

But if you tell me that this 'device' is the spi one, and not
the graphics dgfx, then I believe this code would be missing
the runtime pm suspend/resume functions.

> +
> +	ret = pm_runtime_resume_and_get(device);
> +	if (ret < 0) {
> +		dev_err(device, "rpm: get failed %d\n", ret);
> +		goto err_norpm;
> +	}
> +
>  	spi->base = devm_ioremap_resource(device, &ispi->bar);
>  	if (IS_ERR(spi->base)) {
>  		dev_err(device, "mmio not mapped\n");
> @@ -769,9 +807,13 @@ static int intel_dg_spi_probe(struct auxiliary_device *aux_dev,
>  
>  	dev_set_drvdata(&aux_dev->dev, spi);
>  
> +	pm_runtime_put(device);
>  	return 0;
>  
>  err:
> +	pm_runtime_put(device);
> +err_norpm:
> +	pm_runtime_disable(device);
>  	kref_put(&spi->refcnt, intel_dg_spi_release);
>  	return ret;
>  }
> @@ -783,6 +825,8 @@ static void intel_dg_spi_remove(struct auxiliary_device *aux_dev)
>  	if (!spi)
>  		return;
>  
> +	pm_runtime_disable(&aux_dev->dev);
> +
>  	mtd_device_unregister(&spi->mtd);
>  
>  	dev_set_drvdata(&aux_dev->dev, NULL);
> -- 
> 2.34.1
>