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Groups > linux.kernel > #1741691
| From | Vinod Koul <vinod.koul@intel.com> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | Re: [PATCH v1 4/5] dmaengine: Add driver for NVIDIA Tegra AHB DMA controller |
| Date | 2017-09-28 18:20 +0200 |
| Message-ID | <uuJHA-2JP-21@gated-at.bofh.it> (permalink) |
| References | <utKZ3-4P8-5@gated-at.bofh.it> <utKZ3-4P8-3@gated-at.bofh.it> <uuDiO-7d1-5@gated-at.bofh.it> <uuHFM-1y2-15@gated-at.bofh.it> <uuI8N-1Hr-5@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
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
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Re: [PATCH v1 4/5] dmaengine: Add driver for NVIDIA Tegra AHB DMA controller Vinod Koul <vinod.koul@intel.com> - 2017-09-28 11:30 +0200
Re: [PATCH v1 4/5] dmaengine: Add driver for NVIDIA Tegra AHB DMA controller Dmitry Osipenko <digetx@gmail.com> - 2017-09-28 14:20 +0200
Re: [PATCH v1 4/5] dmaengine: Add driver for NVIDIA Tegra AHB DMA controller Dmitry Osipenko <digetx@gmail.com> - 2017-09-28 16:10 +0200
Re: [PATCH v1 4/5] dmaengine: Add driver for NVIDIA Tegra AHB DMA controller Dmitry Osipenko <digetx@gmail.com> - 2017-09-28 16:40 +0200
Re: [PATCH v1 4/5] dmaengine: Add driver for NVIDIA Tegra AHB DMA controller Vinod Koul <vinod.koul@intel.com> - 2017-09-28 18:20 +0200
Re: [PATCH v1 4/5] dmaengine: Add driver for NVIDIA Tegra AHB DMA controller Dmitry Osipenko <digetx@gmail.com> - 2017-09-28 18:40 +0200
Re: [PATCH v1 4/5] dmaengine: Add driver for NVIDIA Tegra AHB DMA controller Vinod Koul <vinod.koul@intel.com> - 2017-09-28 18:20 +0200
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