From: Adrian Hunter <adrian.hunter@intel.com>
To: Chunyan Zhang <zhang.lyra@gmail.com>
Cc: Chunyan Zhang <zhang.chunyan@linaro.org>,
Ulf Hansson <ulf.hansson@linaro.org>,
linux-mmc@vger.kernel.org,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Arnd Bergmann <arnd@arndb.de>, Mark Brown <broonie@kernel.org>,
kishon@ti.com, nsekhar@ti.com
Subject: Re: [PATCH v2 1/3] mmc: sdhci: add support for using external DMA devices
Date: Thu, 29 Nov 2018 12:48:13 +0200 [thread overview]
Message-ID: <d9091e09-da8d-5fd2-0957-30d34c2a0e21@intel.com> (raw)
In-Reply-To: <CAAfSe-sfe5A7b_8iBiUmvi_mo1zRZ_Oh0yu-uwXo8Hv+WBftWQ@mail.gmail.com>
On 29/11/18 11:59 AM, Chunyan Zhang wrote:
> Hi Adrian,
>
> On Thu, 29 Nov 2018 at 15:36, Adrian Hunter <adrian.hunter@intel.com> wrote:
>>
>> On 29/11/18 8:22 AM, Chunyan Zhang wrote:
>>> On Tue, 20 Nov 2018 at 21:41, Adrian Hunter <adrian.hunter@intel.com> wrote:
>>>>
>>>> On 12/11/18 9:26 AM, Chunyan Zhang wrote:
>>>>> Some standard SD host controllers can support both external dma
>>>>> controllers as well as ADMA/SDMA in which the SD host controller
>>>>> acts as DMA master. TI's omap controller is the case as an example.
>>>>>
>>>>> Currently the generic SDHCI code supports ADMA/SDMA integrated in
>>>>> the host controller but does not have any support for external DMA
>>>>> controllers implemented using dmaengine, meaning that custom code is
>>>>> needed for any systems that use an external DMA controller with SDHCI.
>>>>
>>>> I still think you probably need to reset the DMA if there are transfer
>>>> errors - perhaps you could comment on that. Also there are some comments below.
>>>
>>> With regard to "transfer error", do you mean if
>>> sdhci_external_dma_setup() failed?
>>
>> No, I mean any error interrupt that can leave the DMA uncompleted. For
>> SDHCI, resetting the data circuit cleans that up, but presumably something
>> is needed for external DMA?
>
> Yes, it should need a dmaengine_terminate_all().
>
> How about adding that at here (I will wrap it up of course):
> https://elixir.bootlin.com/linux/v4.19.5/source/drivers/mmc/host/sdhci.c#L2553
Yes except we really need to reverse
if (host->flags & SDHCI_REQ_USE_DMA) {
}
if (sdhci_needs_reset(host, mrq)) {
}
so that we do not unmap before killing the dma
Perhaps you could send that as a separate patch.
> Is there somewhere else I'm missing?
Testing ;-)
next prev parent reply other threads:[~2018-11-29 10:49 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-11-12 7:26 [PATCH v2 0/3] Add support for using external dma in SDHCI Chunyan Zhang
2018-11-12 7:26 ` [PATCH v2 1/3] mmc: sdhci: add support for using external DMA devices Chunyan Zhang
2018-11-20 13:39 ` Adrian Hunter
2018-11-29 6:22 ` Chunyan Zhang
2018-11-29 7:35 ` Adrian Hunter
2018-11-29 9:59 ` Chunyan Zhang
2018-11-29 10:48 ` Adrian Hunter [this message]
2018-11-30 1:15 ` Shawn Lin
2018-12-03 10:47 ` Chunyan Zhang
2018-11-29 6:07 ` [PATCH V3 " Chunyan Zhang
2018-11-29 9:23 ` Adrian Hunter
2018-11-29 9:44 ` Chunyan Zhang
2018-11-29 10:39 ` Adrian Hunter
2018-11-29 10:46 ` Chunyan Zhang
2018-12-03 9:03 ` Faiz Abbas
2018-12-03 10:46 ` Chunyan Zhang
2018-12-03 12:15 ` Faiz Abbas
2018-12-03 13:58 ` Faiz Abbas
2018-12-04 3:11 ` Chunyan Zhang
2018-11-12 7:26 ` [PATCH v2 2/3] mmc: sdhci-omap: Add using external dma Chunyan Zhang
2018-12-03 13:50 ` Faiz Abbas
2018-12-04 3:01 ` Chunyan Zhang
2018-11-12 7:26 ` [PATCH v2 3/3] dt-bindings: sdhci-omap: Add example for " Chunyan Zhang
2018-11-21 11:47 ` [PATCH v2 0/3] Add support for using external dma in SDHCI Faiz Abbas
2018-11-28 16:58 ` Rizvi, Mohammad Faiz Abbas
2018-11-29 6:14 ` Chunyan Zhang
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