linux-kernel - Re: [PATCH 1/4] dmaengine: qcom: bam

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:   Tue, 23 Jan 2018 09:20:30 +0000
From:   Srinivas Kandagatla <srinivas.kandagatla@...aro.org>
To:     Vinod Koul <vinod.koul@...el.com>
Cc:     Andy Gross <andy.gross@...aro.org>, dmaengine@...r.kernel.org,
        Rob Herring <robh+dt@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        David Brown <david.brown@...aro.org>,
        Dan Williams <dan.j.williams@...el.com>,
        devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-arm-msm@...r.kernel.org, linux-soc@...r.kernel.org,
        yanhe@...cinc.com, ramkri@....qualcomm.com, sdharia@...cinc.com
Subject: Re: [PATCH 1/4] dmaengine: qcom: bam_dma: make bam clk optional



On 23/01/18 09:19, Vinod Koul wrote:
> On Mon, Jan 22, 2018 at 09:55:01AM +0000, Srinivas Kandagatla wrote:
> 
>>>> @@ -1180,13 +1180,14 @@ static int bam_dma_probe(struct platform_device *pdev)
>>>>   						"qcom,controlled-remotely");
>>>>   	bdev->bamclk = devm_clk_get(bdev->dev, "bam_clk");
>>>
>>> but you still do clk_get unconditionally?
>>
>> Only reason to do this way is to not break existing users in the mainline.
>>
>> remotely controlled BAM is already supported in upstream driver, there are
>> users of this who pass clk from device tree, If I make this conditional then
>> subsequent reads to the BAM registers for those instances might crash the
>> system.
> 
> But these instances are remote controlled, so if we stop representing them
> in Linux, why would we read them?

Plan is that we would transition those users once we get these 
bindings/changes in. Currently I don't have access to any of those 
devices so I made the changes safe, such that it does not break devices 
on mainline.

--srini

>