From: Doug Anderson <dianders@chromium.org>
To: Alim Akhtar <alim.akhtar@gmail.com>
Cc: "Eddie Cai(蔡枫)" <eddie.cai@rock-chips.com>,
"Ulf Hansson" <ulf.hansson@linaro.org>,
"linux-mmc@vger.kernel.org" <linux-mmc@vger.kernel.org>,
"Heiko Stuebner" <heiko@sntech.de>,
"Sonny Rao" <sonnyrao@chromium.org>,
"Seungwon Jeon" <tgih.jun@samsung.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"Addy Ke" <addy.ke@rock-chips.com>,
"Jaehoon Chung" <jh80.chung@samsung.com>,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>
Subject: Re: [PATCH] mmc: dw_mmc: Reset DMA before enabling IDMAC
Date: Tue, 14 Oct 2014 09:51:26 -0700 [thread overview]
Message-ID: <CAD=FV=W57417Jdp8d-=yZgjUdTJyMKnzSvwg6YuXz3eTvTZZuQ@mail.gmail.com> (raw)
In-Reply-To: <CAD=FV=VQe-9c+QOYEmsuHwY+9qF1tkTgiakdSUWhUoWw6zuHSA@mail.gmail.com>
Hi,
On Thu, Oct 9, 2014 at 5:36 PM, Doug Anderson <dianders@chromium.org> wrote:
> Alim,
>
> On Thu, Oct 9, 2014 at 3:19 PM, Alim Akhtar <alim.akhtar@gmail.com> wrote:
>> Thats fine, I think every vendor (most of them) has a custom
>> implementation of dw_mmc, but they do have VERID register to check the
>> dw_mmc version.
>> The reason why I asked is, I have seen inconsistency in card
>> enumeration on few controller version, and this patch alone does not
>> help, and adding a call to dw_mci_idmac_reset() after DMA reset is
>> needed. And this is what is recommended in the synopsys's data book
>> also.
>> Do you see any issue/side effect after adding dw_mci_idmac_reset()?
>
> A quick test shows no problem with adding this to Sonny's patch:
>
> diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c
> index 66dc8fe..588b5b8 100644
> --- a/drivers/mmc/host/dw_mmc.c
> +++ b/drivers/mmc/host/dw_mmc.c
> @@ -481,6 +481,7 @@ static void dw_mci_idmac_start_dma(struct dw_mci
> *host, unsigned int sg_len)
>
> /* Make sure to reset DMA in case we did PIO before this */
> dw_mci_ctrl_reset(host, SDMMC_CTRL_DMA_RESET);
> + dw_mci_idmac_reset(host);
>
> /* Select IDMAC interface */
> temp = mci_readl(host, CTRL);
>
> I'll start reboot tests now to see how it behaves... I think Sonny is
> out of the office for a few days so we might need to wait for a spin,
> but I'll run with that change in the meantime and see how it behaves
> for me.
>
> Thanks!
Just FYI that I've been running with Alim's proposed change for
several days and it seems solid. I think Sonny may be able to spin
his patch this week. :)
-Doug
next prev parent reply other threads:[~2014-10-14 16:51 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-10-06 17:53 [PATCH] mmc: dw_mmc: Reset DMA before enabling IDMAC Sonny Rao
2014-10-06 18:11 ` Doug Anderson
2014-10-07 23:59 ` Jaehoon Chung
2014-10-08 11:28 ` Alim Akhtar
[not found] ` <CAO3aYcqi0g=eJta33s5oM-tAAmAhe86VvHd43p5RJ7qMPZzfrg@mail.gmail.com>
2014-10-09 22:19 ` Alim Akhtar
2014-10-10 0:36 ` Doug Anderson
2014-10-14 16:51 ` Doug Anderson [this message]
2014-10-14 19:58 ` Alim Akhtar
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