linux-kernel - Re: [PATCH v17 2/4] dmaengine: tegra: Add tegra gpcdma driver

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]

Message-ID: <45e1cbd1-d6dc-6341-399e-df53d5c48bd9@gmail.com>
Date:   Sun, 30 Jan 2022 13:17:25 +0300
From:   Dmitry Osipenko <digetx@...il.com>
To:     Akhil R <akhilrajeev@...dia.com>, devicetree@...r.kernel.org,
        dmaengine@...r.kernel.org, jonathanh@...dia.com,
        kyarlagadda@...dia.com, ldewangan@...dia.com,
        linux-kernel@...r.kernel.org, linux-tegra@...r.kernel.org,
        p.zabel@...gutronix.de, rgumasta@...dia.com, robh+dt@...nel.org,
        thierry.reding@...il.com, vkoul@...nel.org
Cc:     Pavan Kunapuli <pkunapuli@...dia.com>
Subject: Re: [PATCH v17 2/4] dmaengine: tegra: Add tegra gpcdma driver

30.01.2022 13:13, Dmitry Osipenko пишет:
> 30.01.2022 13:08, Dmitry Osipenko пишет:
>> 30.01.2022 13:05, Dmitry Osipenko пишет:
>>> static int tegra_dma_device_resume(struct dma_chan *dc)
>>> {
>>> 	struct tegra_dma_channel *tdc = to_tegra_dma_chan(dc);
>>> 	u32 val;
>>>
>>> 	if (!tdc->tdma->chip_data->hw_support_pause)
>>> 		return -ENOSYS;
>>>
>>> 	if (!tdc->dma_desc)
>>> 		return 0;
>>>
>>> 	val = tdc_read(tdc, TEGRA_GPCDMA_CHAN_CSRE);
>>> 	val &= ~TEGRA_GPCDMA_CHAN_CSRE_PAUSE;
>>> 	tdc_write(tdc, TEGRA_GPCDMA_CHAN_CSRE, val);
>>> 	
>>> 	enable_irq(tdc->irq);
>>
>> Correction:
>>
>> if (tdc->dma_desc) {
>> 	val = tdc_read(tdc, TEGRA_GPCDMA_CHAN_CSRE);
>> 	val &= ~TEGRA_GPCDMA_CHAN_CSRE_PAUSE;
>> 	tdc_write(tdc, TEGRA_GPCDMA_CHAN_CSRE, val);
>> }
>>
>> enable_irq(tdc->irq);
> 
> And apparently, tegra_dma_terminate_all() also needs to take care of
> removing the PAUSE bit. Otherwise it won't be possible to unpause
> channel after the termination.

Although, will be easier to just do this in the resume:

val = tdc_read(tdc, TEGRA_GPCDMA_CHAN_CSRE);

if (val & TEGRA_GPCDMA_CHAN_CSRE_PAUSE) {
	val &= ~TEGRA_GPCDMA_CHAN_CSRE_PAUSE;
	tdc_write(tdc, TEGRA_GPCDMA_CHAN_CSRE, val);
}