From: Vinod Koul <vinod.koul@intel.com>
To: Dmitry Osipenko <digetx@gmail.com>
Cc: Thierry Reding <thierry.reding@gmail.com>,
Jonathan Hunter <jonathanh@nvidia.com>,
Laxman Dewangan <ldewangan@nvidia.com>,
Peter De Schrijver <pdeschrijver@nvidia.com>,
Prashant Gaikwad <pgaikwad@nvidia.com>,
Michael Turquette <mturquette@baylibre.com>,
Stephen Boyd <sboyd@codeaurora.org>,
Rob Herring <robh+dt@kernel.org>,
linux-tegra@vger.kernel.org, devicetree@vger.kernel.org,
dmaengine@vger.kernel.org, linux-clk@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v1 4/5] dmaengine: Add driver for NVIDIA Tegra AHB DMA controller
Date: Thu, 28 Sep 2017 21:52:38 +0530 [thread overview]
Message-ID: <20170928162238.GF30097@localhost> (raw)
In-Reply-To: <260fa409-0d07-ec9e-9e3b-fb08255026d8@gmail.com>
On Thu, Sep 28, 2017 at 05:35:59PM +0300, Dmitry Osipenko wrote:
> On 28.09.2017 17:06, Dmitry Osipenko wrote:
> > On 28.09.2017 12:29, Vinod Koul wrote:
> >>> + default:
> >>> + return -EINVAL;
> >>> + }
> >>> +
> >>> + ahb_seq = burst << TEGRA_AHBDMA_CHANNEL_AHB_BURST_SHIFT;
> >>> + ahb_seq |= TEGRA_AHBDMA_CHANNEL_ADDR_WRAP;
> >>> + ahb_seq |= TEGRA_AHBDMA_CHANNEL_INTR_ENB;
> >>> +
> >>> + writel_relaxed(ahb_seq,
> >>> + ahbdma_chan->regs + TEGRA_AHBDMA_CHANNEL_AHB_SEQ);
> >>> +
> >>> + writel_relaxed(ahb_addr,
> >>> + ahbdma_chan->regs + TEGRA_AHBDMA_CHANNEL_AHB_PTR);
> >>
> >> oh no, you don't write to HW here. This can be called anytime when you have
> >> txn running! You should save these and use them in prep_ calls.
> >>
> >
> > BTW, some of the DMA drivers have exactly the same problem. I now see that it is
> > actually documented explicitly in provider.txt, but that's inconsistent across
> > the actual drivers.
> >
>
> Also, shouldn't prep_ and dma_slave_config be protected with locking? I don't
> see DMA core doing any locking and seems none of the drivers too.
In prep when you modify the list yes (with vchan I suspect that maybe taken
care), but in general yes driver needs to do that
--
~Vinod
next prev parent reply other threads:[~2017-09-28 16:19 UTC|newest]
Thread overview: 45+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-09-25 23:22 [PATCH v1 0/5] NVIDIA Tegra AHB DMA controller driver Dmitry Osipenko
2017-09-25 23:22 ` [PATCH v1 1/5] clk: tegra: Add AHB DMA clock entry Dmitry Osipenko
2017-09-26 9:56 ` Peter De Schrijver
2017-09-26 14:46 ` Dmitry Osipenko
2017-09-27 8:36 ` Peter De Schrijver
2017-09-27 9:41 ` Dmitry Osipenko
2017-09-25 23:22 ` [PATCH v1 2/5] clk: tegra: Bump SCLK clock rate to 216MHz on Tegra20 Dmitry Osipenko
2017-09-26 10:01 ` Peter De Schrijver
2017-09-25 23:22 ` [PATCH v1 3/5] dt-bindings: Add DT bindings for NVIDIA Tegra AHB DMA controller Dmitry Osipenko
2017-09-26 14:50 ` Jon Hunter
2017-09-26 15:16 ` Dmitry Osipenko
2017-09-27 1:57 ` Dmitry Osipenko
2017-09-27 8:34 ` Jon Hunter
2017-09-27 12:12 ` Dmitry Osipenko
2017-09-27 13:44 ` Jon Hunter
2017-09-27 13:46 ` Jon Hunter
2017-09-27 14:29 ` Dmitry Osipenko
2017-09-27 23:32 ` Stephen Boyd
2017-09-28 8:33 ` Jon Hunter
2017-09-29 19:30 ` Stephen Warren
2017-09-30 3:11 ` Dmitry Osipenko
2017-10-02 17:05 ` Stephen Warren
2017-10-02 23:02 ` Dmitry Osipenko
2017-10-03 10:32 ` Jon Hunter
2017-10-03 12:07 ` Dmitry Osipenko
2017-10-03 12:19 ` Jon Hunter
2017-10-03 15:38 ` Stephen Warren
2017-10-03 17:04 ` Dmitry Osipenko
2017-10-05 20:33 ` Rob Herring
2017-10-05 21:30 ` Dmitry Osipenko
2017-09-25 23:22 ` [PATCH v1 4/5] dmaengine: Add driver " Dmitry Osipenko
2017-09-26 14:45 ` Jon Hunter
2017-09-26 16:06 ` Dmitry Osipenko
2017-09-26 21:37 ` Jon Hunter
2017-09-26 23:00 ` Dmitry Osipenko
2017-09-28 9:29 ` Vinod Koul
2017-09-28 12:17 ` Dmitry Osipenko
2017-09-28 14:06 ` Dmitry Osipenko
2017-09-28 14:35 ` Dmitry Osipenko
2017-09-28 16:22 ` Vinod Koul [this message]
2017-09-28 16:37 ` Dmitry Osipenko
2017-09-28 16:21 ` Vinod Koul
2017-09-25 23:22 ` [PATCH v1 5/5] ARM: dts: tegra: Add AHB DMA controller nodes Dmitry Osipenko
2017-09-28 9:31 ` [PATCH v1 0/5] NVIDIA Tegra AHB DMA controller driver Vinod Koul
2017-09-28 12:24 ` Dmitry Osipenko
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