From mboxrd@z Thu Jan  1 00:00:00 1970
From: u.kleine-koenig@pengutronix.de (Uwe =?iso-8859-1?Q?Kleine-K=F6nig?=)
Date: Mon, 27 Jan 2014 19:18:36 +0100
Subject: [PATCH] arm64: Add pdev_archdata for dmamask
In-Reply-To: <1390845177-2626-1-git-send-email-lauraa@codeaurora.org>
References: <y>
 <1390845177-2626-1-git-send-email-lauraa@codeaurora.org>
Message-ID: <20140127181836.GH26766@pengutronix.de>
To: linux-arm-kernel@lists.infradead.org
List-Id: linux-arm-kernel.lists.infradead.org

On Mon, Jan 27, 2014 at 09:52:57AM -0800, Laura Abbott wrote:
> The dma_mask for a device structure is a pointer. This pointer
> needs to be set up before the dma mask can actually be set. Most
> frameworks in the kernel take care of setting this up properly but
> platform devices that don't follow a regular bus structure may not
> ever have this set. As a result, checks such as dma_capable will
> always return false on a raw platform device and dma_set_mask will
> always return -EIO. Fix this by adding a dma_mask in the
> platform_device archdata and setting it to be the dma_mask. Devices
> used in other frameworks can change this as needed.
> 
> Cc: Will Deacon <will.deacon@arm.com>
> Cc: Catalin Marinas <catalin.marinas@arm.com>
> Suggested-by: Kumar Gala <galak@codeaurora.org>
> Signed-off-by: Laura Abbott <lauraa@codeaurora.org>
Hello,

there is another non-platform dependant approach available, that might
be worth to evaluate:

	http://mid.gmane.org/1390817152-30898-1-git-send-email-ydroneaud at opteya.com

> ---
>  arch/arm64/include/asm/device.h |    1 +
>  arch/arm64/kernel/setup.c       |    7 +++++++
>  2 files changed, 8 insertions(+), 0 deletions(-)
> 
> diff --git a/arch/arm64/include/asm/device.h b/arch/arm64/include/asm/device.h
> index cf98b36..209d40c 100644
> --- a/arch/arm64/include/asm/device.h
> +++ b/arch/arm64/include/asm/device.h
> @@ -24,6 +24,7 @@ struct dev_archdata {
>  };
>  
>  struct pdev_archdata {
> +	u64 dma_mask;
>  };
>  
>  #endif
> diff --git a/arch/arm64/kernel/setup.c b/arch/arm64/kernel/setup.c
> index bd9bbd0..f164347 100644
> --- a/arch/arm64/kernel/setup.c
> +++ b/arch/arm64/kernel/setup.c
> @@ -41,6 +41,7 @@
>  #include <linux/memblock.h>
>  #include <linux/of_fdt.h>
>  #include <linux/of_platform.h>
> +#include <linux/dma-mapping.h>
>  
>  #include <asm/cputype.h>
>  #include <asm/elf.h>
> @@ -337,3 +338,9 @@ const struct seq_operations cpuinfo_op = {
>  	.stop	= c_stop,
>  	.show	= c_show
>  };
> +
> +void arch_setup_pdev_archdata(struct platform_device *pdev)
> +{
> +	pdev->archdata.dma_mask = DMA_BIT_MASK(32);
> +	pdev->dev.dma_mask = &pdev->archdata.dma_mask;
> +}
Is it save to assume a default of DMA_BIT_MASK(32)?

Best regards
Uwe

-- 
Pengutronix e.K.                           | Uwe Kleine-K?nig            |
Industrial Linux Solutions                 | http://www.pengutronix.de/  |