From: Ulf Hansson <ulf.hansson@linaro.org>
To: Chaotian Jing <chaotian.jing@mediatek.com>
Cc: Matthias Brugger <matthias.bgg@gmail.com>,
Adrian Hunter <adrian.hunter@intel.com>,
Wolfram Sang <wsa+renesas@sang-engineering.com>,
Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>,
Masahiro Yamada <yamada.masahiro@socionext.com>,
linux-mmc <linux-mmc@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>,
linux-mediatek@lists.infradead.org,
srv_heupstream <srv_heupstream@mediatek.com>,
Sascha Hauer <kernel@pengutronix.de>
Subject: Re: [PATCH 2/3] mmc: mmc: do not use CMD13 to get status after speed mode switch
Date: Tue, 21 Jun 2016 15:16:03 +0200 [thread overview]
Message-ID: <CAPDyKFqaba9D4XtuDnPLcq2D4dpO6Cq9-RfhwoEu_vO=Pt9wEQ@mail.gmail.com> (raw)
In-Reply-To: <1463647662-27426-3-git-send-email-chaotian.jing@mediatek.com>
On 19 May 2016 at 10:47, Chaotian Jing <chaotian.jing@mediatek.com> wrote:
> Per JEDEC spec, it is not recommended to use CMD13 to get card status
> after speed mode switch. below are two reason about this:
> 1. CMD13 cannot be guaranteed due to the asynchronous operation.
> Therefore it is not recommended to use CMD13 to check busy completion
> of the timing change indication.
> 2. After switch to HS200, CMD13 will get response of 0x800, and even the
> busy signal gets de-asserted, the response of CMD13 is aslo 0x800.
>
> Signed-off-by: Chaotian Jing <chaotian.jing@mediatek.com>
Thanks, applied for next! (With a minor change, see below)
[...]
>
> /* Switch HS to HS200 */
> val = EXT_CSD_TIMING_HS200 |
> card->drive_strength << EXT_CSD_DRV_STR_SHIFT;
> err = __mmc_switch(card, EXT_CSD_CMD_SET_NORMAL, EXT_CSD_HS_TIMING,
> val, card->ext_csd.generic_cmd6_time, true,
> - send_status, true);
> + false, true);
To keep consistency with other calls to __mmc_switch(), I change these lines to:
err = __mmc_switch(card, EXT_CSD_CMD_SET_NORMAL, EXT_CSD_HS_TIMING,
val, card->ext_csd.generic_cmd6_time,
true, false, true);
> if (err)
> goto out_err;
>
> mmc_set_timing(host, MMC_TIMING_MMC_HS200);
>
> - if (!send_status) {
> - err = mmc_switch_status(card);
> - if (err)
> - goto out_err;
> - }
> + err = mmc_switch_status(card);
> + if (err)
> + goto out_err;
>
> mmc_set_bus_speed(card);
>
> @@ -1243,7 +1227,6 @@ static void mmc_select_driver_type(struct mmc_card *card)
> static int mmc_select_hs200(struct mmc_card *card)
> {
> struct mmc_host *host = card->host;
> - bool send_status = true;
> unsigned int old_timing;
> int err = -EINVAL;
> u8 val;
> @@ -1260,9 +1243,6 @@ static int mmc_select_hs200(struct mmc_card *card)
>
> mmc_select_driver_type(card);
>
> - if (host->caps & MMC_CAP_WAIT_WHILE_BUSY)
> - send_status = false;
> -
> /*
> * Set the bus width(4 or 8) with host's support and
> * switch to HS200 mode if bus width is set successfully.
> @@ -1274,20 +1254,18 @@ static int mmc_select_hs200(struct mmc_card *card)
> err = __mmc_switch(card, EXT_CSD_CMD_SET_NORMAL,
> EXT_CSD_HS_TIMING, val,
> card->ext_csd.generic_cmd6_time,
> - true, send_status, true);
> + true, false, true);
[...]
Kind regards
Uffe
next prev parent reply other threads:[~2016-06-21 13:16 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-05-19 8:47 [PATCH v2] mmc: mmc: do not use CMD13 to get status after speed mode Chaotian Jing
2016-05-19 8:47 ` [PATCH 1/3] mmc: mmc: use ops->card_busy() to check card status in __mmc_switch() Chaotian Jing
2016-06-21 13:15 ` Ulf Hansson
2016-05-19 8:47 ` [PATCH 2/3] mmc: mmc: do not use CMD13 to get status after speed mode switch Chaotian Jing
2016-06-21 13:16 ` Ulf Hansson [this message]
2016-07-15 22:10 ` Bjorn Andersson
2016-07-18 12:50 ` Ulf Hansson
2016-07-18 13:38 ` Georgi Djakov
2016-07-19 9:31 ` Ulf Hansson
2016-07-19 16:27 ` Georgi Djakov
2016-05-19 8:47 ` [PATCH 3/3] mmc: mmc: fix switch timeout issue caused by jiffies precision Chaotian Jing
2016-06-21 13:15 ` Ulf Hansson
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