linux-kernel - Re: [PATCH v1 15/16] ACPI / MMC: PM: Unify fixing up device power

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Date:   Thu, 9 Jun 2022 18:33:07 +0300
From:   Adrian Hunter <adrian.hunter@...el.com>
To:     "Rafael J. Wysocki" <rjw@...ysocki.net>,
        Linux ACPI <linux-acpi@...r.kernel.org>
Cc:     LKML <linux-kernel@...r.kernel.org>,
        Linux PM <linux-pm@...r.kernel.org>,
        Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
        Mika Westerberg <mika.westerberg@...ux.intel.com>,
        Hans de Goede <hdegoede@...hat.com>,
        Sakari Ailus <sakari.ailus@...ux.intel.com>,
        Ulf Hansson <ulf.hansson@...aro.org>, linux-mmc@...r.kernel.org
Subject: Re: [PATCH v1 15/16] ACPI / MMC: PM: Unify fixing up device power

On 9/06/22 17:18, Rafael J. Wysocki wrote:
> From: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
> 
> Introduce acpi_device_fix_up_power_extended() for fixing up power of
> a device having an ACPI companion in a manner that takes the device's
> children into account and make the MMC code use it in two places
> instead of walking the list of the device ACPI companion's children
> directly.
> 
> This will help to eliminate the children list head from struct
> acpi_device as it is redundant and it is used in questionable ways
> in some places (in particular, locking is needed for walking the
> list pointed to it safely, but it is often missing).
> 
> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@...el.com>

Acked-by: Adrian Hunter <adrian.hunter@...el.com>

> ---
>  drivers/acpi/device_pm.c          |   22 ++++++++++++++++++++++
>  drivers/mmc/host/sdhci-acpi.c     |    7 ++-----
>  drivers/mmc/host/sdhci-pci-core.c |   11 +++--------
>  include/acpi/acpi_bus.h           |    1 +
>  4 files changed, 28 insertions(+), 13 deletions(-)
> 
> Index: linux-pm/drivers/mmc/host/sdhci-acpi.c
> ===================================================================
> --- linux-pm.orig/drivers/mmc/host/sdhci-acpi.c
> +++ linux-pm/drivers/mmc/host/sdhci-acpi.c
> @@ -775,8 +775,8 @@ static int sdhci_acpi_probe(struct platf
>  {
>  	struct device *dev = &pdev->dev;
>  	const struct sdhci_acpi_slot *slot;
> -	struct acpi_device *device, *child;
>  	const struct dmi_system_id *id;
> +	struct acpi_device *device;
>  	struct sdhci_acpi_host *c;
>  	struct sdhci_host *host;
>  	struct resource *iomem;
> @@ -796,10 +796,7 @@ static int sdhci_acpi_probe(struct platf
>  	slot = sdhci_acpi_get_slot(device);
>  
>  	/* Power on the SDHCI controller and its children */
> -	acpi_device_fix_up_power(device);
> -	list_for_each_entry(child, &device->children, node)
> -		if (child->status.present && child->status.enabled)
> -			acpi_device_fix_up_power(child);
> +	acpi_device_fix_up_power_extended(device);
>  
>  	if (sdhci_acpi_byt_defer(dev))
>  		return -EPROBE_DEFER;
> Index: linux-pm/drivers/acpi/device_pm.c
> ===================================================================
> --- linux-pm.orig/drivers/acpi/device_pm.c
> +++ linux-pm/drivers/acpi/device_pm.c
> @@ -369,6 +369,28 @@ int acpi_device_fix_up_power(struct acpi
>  }
>  EXPORT_SYMBOL_GPL(acpi_device_fix_up_power);
>  
> +static int fix_up_power_if_applicable(struct acpi_device *adev, void *not_used)
> +{
> +	if (adev->status.present && adev->status.enabled)
> +		acpi_device_fix_up_power(adev);
> +
> +	return 0;
> +}
> +
> +/**
> + * acpi_device_fix_up_power_extended - Force device and its children into D0.
> + * @adev: Parent device object whose power state is to be fixed up.
> + *
> + * Call acpi_device_fix_up_power() for @adev and its children so long as they
> + * are reported as present and enabled.
> + */
> +void acpi_device_fix_up_power_extended(struct acpi_device *adev)
> +{
> +	acpi_device_fix_up_power(adev);
> +	acpi_dev_for_each_child(adev, fix_up_power_if_applicable, NULL);
> +}
> +EXPORT_SYMBOL_GPL(acpi_device_fix_up_power_extended);
> +
>  int acpi_device_update_power(struct acpi_device *device, int *state_p)
>  {
>  	int state;
> Index: linux-pm/include/acpi/acpi_bus.h
> ===================================================================
> --- linux-pm.orig/include/acpi/acpi_bus.h
> +++ linux-pm/include/acpi/acpi_bus.h
> @@ -524,6 +524,7 @@ const char *acpi_power_state_string(int
>  int acpi_device_set_power(struct acpi_device *device, int state);
>  int acpi_bus_init_power(struct acpi_device *device);
>  int acpi_device_fix_up_power(struct acpi_device *device);
> +void acpi_device_fix_up_power_extended(struct acpi_device *adev);
>  int acpi_bus_update_power(acpi_handle handle, int *state_p);
>  int acpi_device_update_power(struct acpi_device *device, int *state_p);
>  bool acpi_bus_power_manageable(acpi_handle handle);
> Index: linux-pm/drivers/mmc/host/sdhci-pci-core.c
> ===================================================================
> --- linux-pm.orig/drivers/mmc/host/sdhci-pci-core.c
> +++ linux-pm/drivers/mmc/host/sdhci-pci-core.c
> @@ -1240,16 +1240,11 @@ static const struct sdhci_pci_fixes sdhc
>  #ifdef CONFIG_ACPI
>  static void intel_mrfld_mmc_fix_up_power_slot(struct sdhci_pci_slot *slot)
>  {
> -	struct acpi_device *device, *child;
> +	struct acpi_device *device;
>  
>  	device = ACPI_COMPANION(&slot->chip->pdev->dev);
> -	if (!device)
> -		return;
> -
> -	acpi_device_fix_up_power(device);
> -	list_for_each_entry(child, &device->children, node)
> -		if (child->status.present && child->status.enabled)
> -			acpi_device_fix_up_power(child);
> +	if (device)
> +		acpi_device_fix_up_power_extended(device);
>  }
>  #else
>  static inline void intel_mrfld_mmc_fix_up_power_slot(struct sdhci_pci_slot *slot) {}
> 
> 
>