linux-block.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Shawn Lin <shawn.lin@rock-chips.com>
To: Ulf Hansson <ulf.hansson@linaro.org>,
	linux-mmc@vger.kernel.org,
	Adrian Hunter <adrian.hunter@intel.com>
Cc: shawn.lin@rock-chips.com,
	Linus Walleij <linus.walleij@linaro.org>,
	Wolfram Sang <wsa+renesas@sang-engineering.com>,
	Avri Altman <avri.altman@wdc.com>,
	Masami Hiramatsu <masami.hiramatsu@linaro.org>,
	linux-block@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 05/11] mmc: core: Enable eMMC sleep commands to use HW busy polling
Date: Fri, 7 May 2021 09:52:43 +0800	[thread overview]
Message-ID: <dcea3e14-4669-60ad-992f-a588a3c8c20f@rock-chips.com> (raw)
In-Reply-To: <20210504161222.101536-6-ulf.hansson@linaro.org>


On 2021/5/5 0:12, Ulf Hansson wrote:
> After the eMMC sleep command (CMD5) has been sent, the card start signals
> busy on the DAT0 line, which can be monitored to understand when it's
> allowed to proceed to power off the VCC regulator.
> 
> When MMC_CAP_WAIT_WHILE_BUSY isn't supported by the host the DAT0 line
> isn't being monitored for busy completion, but instead we are waiting a
> fixed period of time. The time corresponds to the sleep timeout that is
> specified in the EXT_CSD register of the eMMC card. This is many cases
> suboptimal, as the timeout corresponds to the worst case scenario.
> 
> To improve the situation add support for HW busy polling through the
> ->card_busy() host ops, when the host supports this.

Reviewed-by: Shawn Lin <shawn.lin@rock-chips.com>

> 
> Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
> ---
>   drivers/mmc/core/mmc.c | 25 ++++++++++++++++++++-----
>   1 file changed, 20 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c
> index 63a7bd0b239c..13074aa1f605 100644
> --- a/drivers/mmc/core/mmc.c
> +++ b/drivers/mmc/core/mmc.c
> @@ -1905,6 +1905,14 @@ static int mmc_can_sleep(struct mmc_card *card)
>   	return card->ext_csd.rev >= 3;
>   }
>   
> +static int mmc_sleep_busy_cb(void *cb_data, bool *busy)
> +{
> +	struct mmc_host *host = cb_data;
> +
> +	*busy = host->ops->card_busy(host);
> +	return 0;
> +}
> +
>   static int mmc_sleep(struct mmc_host *host)
>   {
>   	struct mmc_command cmd = {};
> @@ -1930,13 +1938,20 @@ static int mmc_sleep(struct mmc_host *host)
>   		goto out_release;
>   
>   	/*
> -	 * If the host does not wait while the card signals busy, then we will
> -	 * will have to wait the sleep/awake timeout.  Note, we cannot use the
> -	 * SEND_STATUS command to poll the status because that command (and most
> -	 * others) is invalid while the card sleeps.
> +	 * If the host does not wait while the card signals busy, then we can
> +	 * try to poll, but only if the host supports HW polling, as the
> +	 * SEND_STATUS cmd is not allowed. If we can't poll, then we simply need
> +	 * to wait the sleep/awake timeout.
>   	 */
> -	if (!use_r1b_resp || !(host->caps & MMC_CAP_WAIT_WHILE_BUSY))
> +	if (host->caps & MMC_CAP_WAIT_WHILE_BUSY && use_r1b_resp)
> +		goto out_release;
> +
> +	if (!host->ops->card_busy) {
>   		mmc_delay(timeout_ms);
> +		goto out_release;
> +	}
> +
> +	err = __mmc_poll_for_busy(card, timeout_ms, &mmc_sleep_busy_cb, host);
>   
>   out_release:
>   	mmc_retune_release(host);
> 



  parent reply	other threads:[~2021-05-07  1:52 UTC|newest]

Thread overview: 40+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-05-04 16:12 [PATCH 00/11] Initital support for new power/perf features for SD cards Ulf Hansson
2021-05-04 16:12 ` [PATCH 01/11] mmc: core: Drop open coding when preparing commands with busy signaling Ulf Hansson
2021-05-06 12:50   ` Linus Walleij
2021-05-07  1:42   ` Shawn Lin
2021-05-04 16:12 ` [PATCH 02/11] mmc: core: Take into account MMC_CAP_NEED_RSP_BUSY for eMMC HPI commands Ulf Hansson
2021-05-06 12:51   ` Linus Walleij
2021-05-07  1:44   ` Shawn Lin
2021-05-04 16:12 ` [PATCH 03/11] mmc: core: Re-structure some code in __mmc_poll_for_busy() Ulf Hansson
2021-05-06 12:52   ` Linus Walleij
2021-05-07  1:48   ` Shawn Lin
2021-05-04 16:12 ` [PATCH 04/11] mmc: core: Extend re-use of __mmc_poll_for_busy() Ulf Hansson
2021-05-06 12:53   ` Linus Walleij
2021-05-07  1:51   ` Shawn Lin
2021-05-04 16:12 ` [PATCH 05/11] mmc: core: Enable eMMC sleep commands to use HW busy polling Ulf Hansson
2021-05-06 12:55   ` Linus Walleij
2021-05-07  1:52   ` Shawn Lin [this message]
2021-05-04 16:12 ` [PATCH 06/11] mmc: core: Prepare mmc_send_cxd_data() to be re-used for additional cmds Ulf Hansson
2021-05-06 12:56   ` Linus Walleij
2021-05-06 13:00   ` Linus Walleij
2021-05-07  7:30     ` Ulf Hansson
2021-05-07  1:53   ` Shawn Lin
2021-05-04 16:12 ` [PATCH 07/11] mmc: core: Drop open coding in mmc_sd_switch() Ulf Hansson
2021-05-06 12:57   ` Linus Walleij
2021-05-07  1:54   ` Shawn Lin
2021-05-04 16:12 ` [PATCH 08/11] mmc: core: Parse the SD SCR register for support of CMD48/49 and CMD58/59 Ulf Hansson
2021-05-06 13:01   ` Linus Walleij
2021-05-07  1:58   ` Shawn Lin
2021-05-04 16:12 ` [PATCH 09/11] mmc: core: Read the SD function extension registers for power management Ulf Hansson
2021-05-06 13:04   ` Linus Walleij
2021-05-07  2:06   ` Shawn Lin
2021-05-07  7:27     ` Ulf Hansson
2021-05-07  7:48       ` Shawn Lin
2021-05-07 11:36         ` Ulf Hansson
2021-05-04 16:12 ` [PATCH 10/11] mmc: core: Read performance enhancements registers for SD cards Ulf Hansson
2021-05-06 13:05   ` Linus Walleij
2021-05-04 16:12 ` [PATCH 11/11] mmc: core: Add support for Power Off Notification " Ulf Hansson
2021-05-06 13:07   ` Linus Walleij
2021-05-07  6:44 ` [PATCH 00/11] Initital support for new power/perf features " Avri Altman
2021-05-07  7:31   ` Ulf Hansson
2021-05-11 10:56 ` Ulf Hansson

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=dcea3e14-4669-60ad-992f-a588a3c8c20f@rock-chips.com \
    --to=shawn.lin@rock-chips.com \
    --cc=adrian.hunter@intel.com \
    --cc=avri.altman@wdc.com \
    --cc=linus.walleij@linaro.org \
    --cc=linux-block@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-mmc@vger.kernel.org \
    --cc=masami.hiramatsu@linaro.org \
    --cc=ulf.hansson@linaro.org \
    --cc=wsa+renesas@sang-engineering.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).