From: Sujit Reddy Thumma <sthumma@codeaurora.org>
To: James Bottomley <James.Bottomley@HansenPartnership.com>
Cc: Akinobu Mita <mita@fixstars.com>,
linux-scsi@vger.kernel.org,
Vinayak Holikatti <vinholikatti@gmail.com>,
Santosh Y <santoshsy@gmail.com>,
devicetree@vger.kernel.org
Subject: Re: [PATCH 1/2] ufs-pltfrm: initialize DMA mask for device-tree probed device
Date: Tue, 20 Aug 2013 12:56:21 +0530 [thread overview]
Message-ID: <52131A1D.2060907@codeaurora.org> (raw)
In-Reply-To: <1376922720.2069.10.camel@dabdike.int.hansenpartnership.com>
On 8/19/2013 8:02 PM, James Bottomley wrote:
> On Mon, 2013-08-19 at 22:56 +0900, Akinobu Mita wrote:
>> The device-tree probed device for ARM doesn't have dev->dma_mask.
>> So dma_set_mask() for the device doesn't succeed. The popular trick
>> for this is - dev->dma_mask = &dev->coherent_dma_mask;
>>
>> Currently there is no dma_set_mask() call in ufs-pltfrm, but the
>> forthcoming fix needs proper DMA mask setting in ufs core driver. So
>> initializing dev->dma_mask as described above is required.
>>
>> Signed-off-by: Akinobu Mita <mita@fixstars.com>
>> Cc: Sujit Reddy Thumma <sthumma@codeaurora.org>
>> Cc: Vinayak Holikatti <vinholikatti@gmail.com>
>> Cc: Santosh Y <santoshsy@gmail.com>
>> Cc: "James E.J. Bottomley" <JBottomley@parallels.com>
>> Cc: linux-scsi@vger.kernel.org
>> ---
>> drivers/scsi/ufs/ufshcd-pltfrm.c | 3 +++
>> 1 file changed, 3 insertions(+)
>>
>> diff --git a/drivers/scsi/ufs/ufshcd-pltfrm.c b/drivers/scsi/ufs/ufshcd-pltfrm.c
>> index 94ba40c..c780840 100644
>> --- a/drivers/scsi/ufs/ufshcd-pltfrm.c
>> +++ b/drivers/scsi/ufs/ufshcd-pltfrm.c
>> @@ -122,6 +122,9 @@ static int ufshcd_pltfrm_probe(struct platform_device *pdev)
>> goto out;
>> }
>>
>> + if (!dev->dma_mask)
>> + dev->dma_mask = &dev->coherent_dma_mask;
>> +
>
> If the DMA mask is NULL, it means there's buggy platform code somewhere;
> I'm not sure we should be hacking a fix in a SCSI driver.
Yes, ideally DT core should do this, there are patches lying around but
are not converged. Adding devicetree@vger.kernel.org to see if someone
has better suggestions.
Recent additions to kernel with similar hacks -
https://patchwork.kernel.org/patch/2537021/
--
Regards,
Sujit
next parent reply other threads:[~2013-08-20 7:26 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <1376920566-20325-1-git-send-email-mita@fixstars.com>
[not found] ` <1376922720.2069.10.camel@dabdike.int.hansenpartnership.com>
2013-08-20 7:26 ` Sujit Reddy Thumma [this message]
2013-08-20 15:03 ` [PATCH 1/2] ufs-pltfrm: initialize DMA mask for device-tree probed device Akinobu Mita
2013-08-20 20:54 ` Russell King - ARM Linux
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