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From: Md Sadre Alam <md.alam@oss.qualcomm.com>
To: Varadarajan Narayanan <varadarajan.narayanan@oss.qualcomm.com>,
	Vinod Koul <vkoul@kernel.org>
Cc: Frank Li <Frank.Li@kernel.org>,
	Abhishek Sahu <absahu@codeaurora.org>,
	mani@kernel.org, linux-arm-msm@vger.kernel.org,
	dmaengine@vger.kernel.org, linux-kernel@vger.kernel.org,
	lakshmi.d@oss.qualcomm.com
Subject: Re: [PATCH v5] dma: qcom: bam_dma: Fix command element mask field for BAM v1.6.0+
Date: Mon, 8 Jun 2026 11:20:01 +0530	[thread overview]
Message-ID: <5c24a3f3-a4c0-43ec-9653-bc374a9c5e22@oss.qualcomm.com> (raw)
In-Reply-To: <aiFXPPXtjCHj0Ged@hu-varada-blr.qualcomm.com>

Hi,

On 6/4/2026 4:15 PM, Varadarajan Narayanan wrote:
> On Tue, May 19, 2026 at 11:01:51PM +0530, Vinod Koul wrote:
>> On 14-05-26, 12:09, Varadarajan Narayanan wrote:
>>> From: Md Sadre Alam <md.alam@oss.qualcomm.com>
>>>
>>> BAM version 1.6.0 and later changed the behavior of the mask field in
>>> command elements for read operations. In newer BAM versions, the mask
>>> field for read commands contains the upper 4 bits of the destination
>>> address to support 36-bit addressing, while for write commands it
>>> continues to function as a traditional write mask.
>>
>> But this changes behaviour for all versions. What happens to folks on older
>> versions, wont this break for them, if not what am I missing

It will not have any impact on older version of BAM controller. Konrad 
also had a similar concern. Please refer to [1]

[1] 
https://lore.kernel.org/linux-arm-msm/2394e63f-1df7-764e-5489-3567065707a1@quicinc.com/

Thanks,
Alam.

  reply	other threads:[~2026-06-08  5:50 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-05-14  6:39 [PATCH v5] dma: qcom: bam_dma: Fix command element mask field for BAM v1.6.0+ Varadarajan Narayanan
2026-05-19 17:31 ` Vinod Koul
2026-06-04 10:45   ` Varadarajan Narayanan
2026-06-08  5:50     ` Md Sadre Alam [this message]
2026-06-08  6:03       ` Dmitry Baryshkov
2026-06-09 10:34         ` Md Sadre Alam

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