linux-kernel - Re: [PATCH v3 06/23] ata: libahci_platform: Convert to using platform devm-ioremap methods

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Message-ID: <252c0b18-c640-f813-408f-6f8d2e4af1d4@suse.de>
Date:   Thu, 12 May 2022 08:31:13 +0200
From:   Hannes Reinecke <hare@...e.de>
To:     Serge Semin <Sergey.Semin@...kalelectronics.ru>,
        Damien Le Moal <damien.lemoal@...nsource.wdc.com>,
        Hans de Goede <hdegoede@...hat.com>,
        Jens Axboe <axboe@...nel.dk>
Cc:     Serge Semin <fancer.lancer@...il.com>,
        Alexey Malahov <Alexey.Malahov@...kalelectronics.ru>,
        Pavel Parkhomenko <Pavel.Parkhomenko@...kalelectronics.ru>,
        Rob Herring <robh+dt@...nel.org>, linux-ide@...r.kernel.org,
        linux-kernel@...r.kernel.org, devicetree@...r.kernel.org
Subject: Re: [PATCH v3 06/23] ata: libahci_platform: Convert to using platform
 devm-ioremap methods

On 5/12/22 01:17, Serge Semin wrote:
> Currently the IOMEM AHCI registers space is mapped by means of the
> two functions invocation: platform_get_resource() is used to get the very
> first memory resource and devm_ioremap_resource() is called to remap that
> resource. Device-managed kernel API provides a handy wrapper to perform
> the same in single function call: devm_platform_ioremap_resource().
> 
> While at it seeing many AHCI platform drivers rely on having the AHCI CSR
> space marked with "ahci" name let's first try to find and remap the CSR
> IO-mem with that name and only if it fails fallback to getting the very
> first registers space platform resource.
> 
> Signed-off-by: Serge Semin <Sergey.Semin@...kalelectronics.ru>
> 
> ---
> 
> Changelog v2:
> - Check whether there is "ahhi" reg resource before using the
>    devm_platform_ioremap_resource_byname() method in order to prevent a
>    false error message printed in the log (@Damien)
> - Slightly update the patch title due to the change above and to be more
>    specific that the platform device managed methods are utilized.
> ---
>   drivers/ata/libahci_platform.c | 10 ++++++++--
>   1 file changed, 8 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/ata/libahci_platform.c b/drivers/ata/libahci_platform.c
> index f7f9bfcfc164..8c9fbcc3043b 100644
> --- a/drivers/ata/libahci_platform.c
> +++ b/drivers/ata/libahci_platform.c
> @@ -404,8 +404,14 @@ struct ahci_host_priv *ahci_platform_get_resources(struct platform_device *pdev,
>   
>   	devres_add(dev, hpriv);
>   
> -	hpriv->mmio = devm_ioremap_resource(dev,
> -			      platform_get_resource(pdev, IORESOURCE_MEM, 0));
> +	/*
> +	 * If the DT provided an "ahci" named resource, use it. Otherwise,
> +	 * fallback to using the default first resource for the device node.
> +	 */
> +	if (platform_get_resource_byname(pdev, IORESOURCE_MEM, "ahci"))
> +		hpriv->mmio = devm_platform_ioremap_resource_byname(pdev, "ahci");
> +	else
> +		hpriv->mmio = devm_platform_ioremap_resource(pdev, 0);
>   	if (IS_ERR(hpriv->mmio)) {
>   		rc = PTR_ERR(hpriv->mmio);
>   		goto err_out;

Reviewed-by: Hannes Reinecke <hare@...e.de>

Cheers,

Hannes
-- 
Dr. Hannes Reinecke		           Kernel Storage Architect
hare@...e.de			                  +49 911 74053 688
SUSE Software Solutions Germany GmbH, Maxfeldstr. 5, 90409 Nürnberg
HRB 36809 (AG Nürnberg), GF: Felix Imendörffer