From: Adrian Hunter <adrian.hunter@intel.com>
To: Dmitry Antipov <dmitry.antipov@linaro.org>
Cc: Chris Ball <cjb@laptop.org>,
patches@linaro.org, linux-mmc@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] mmc: change mmc_delay() to use usleep_range()
Date: Tue, 17 Jan 2012 09:29:11 +0200 [thread overview]
Message-ID: <4F152347.1060703@intel.com> (raw)
In-Reply-To: <1326696200-514-1-git-send-email-dmitry.antipov@linaro.org>
On 16/01/12 08:43, Dmitry Antipov wrote:
> Use the usleep_range() to simplify mmc_delay() and give some more
> accuracy to it - but with an exception of mmc_card_sleepawake():
> for the hosts with very small (<100us) sleep/awake timeout, it's
> value is rounded up to 100us so usleep_range() always makes sense.
> ---
> drivers/mmc/core/core.h | 8 ++------
> drivers/mmc/core/mmc_ops.c | 9 ++++++---
> 2 files changed, 8 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/mmc/core/core.h b/drivers/mmc/core/core.h
> index 3bdafbc..fbd2cba 100644
> --- a/drivers/mmc/core/core.h
> +++ b/drivers/mmc/core/core.h
> @@ -48,12 +48,8 @@ void mmc_power_off(struct mmc_host *host);
>
> static inline void mmc_delay(unsigned int ms)
> {
> - if (ms < 1000 / HZ) {
> - cond_resched();
> - mdelay(ms);
> - } else {
> - msleep(ms);
> - }
> + unsigned long us = ms * USEC_PER_MSEC;
> + usleep_range(us, us + 1000);
> }
>
> void mmc_rescan(struct work_struct *work);
> diff --git a/drivers/mmc/core/mmc_ops.c b/drivers/mmc/core/mmc_ops.c
> index 4d41fa9..457443a 100644
> --- a/drivers/mmc/core/mmc_ops.c
> +++ b/drivers/mmc/core/mmc_ops.c
> @@ -82,9 +82,12 @@ int mmc_card_sleepawake(struct mmc_host *host, int sleep)
> * SEND_STATUS command to poll the status because that command (and most
> * others) is invalid while the card sleeps.
> */
> - if (!(host->caps & MMC_CAP_WAIT_WHILE_BUSY))
> - mmc_delay(DIV_ROUND_UP(card->ext_csd.sa_timeout, 10000));
> -
> + if (!(host->caps & MMC_CAP_WAIT_WHILE_BUSY)) {
> + /* JEDEC MMCA 4.41 specifies the timeout value is in 200ns..838.86ms
> + range, which is rounded it up to 100us here. */
> + unsigned long us = DIV_ROUND_UP(card->ext_csd.sa_timeout, 1000);
The divisor has changed from 10000 to 1000 but the change is from ms to us,
so it ought to be 3 zeros different - unless it is a bug fix (which should
be a separate patch)?
> + usleep_range(us, us + 100);
> + }
> if (!sleep)
> err = mmc_select_card(card);
>
next prev parent reply other threads:[~2012-01-17 7:29 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-01-16 6:43 [PATCH] mmc: change mmc_delay() to use usleep_range() Dmitry Antipov
2012-01-17 7:29 ` Adrian Hunter [this message]
2012-01-17 7:46 ` Adrian Hunter
-- strict thread matches above, loose matches on Subject: below --
2012-01-13 15:09 Dmitry Antipov
2012-01-13 21:38 ` Aaro Koskinen
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