Commit 88ae8b86 authored by Hein Tibosch's avatar Hein Tibosch Committed by Chris Ball
Browse files

mmc: Make ID freq configurable 



In the latest releases of the mmc driver, the freq during initialization
is set to a fixed 400 Khz.  This was reportedly too fast for several
users.  As there doesn't seem to be an ideal frequency
which-works-for-all, Pierre suggested to let the driver try several
frequencies.

This patch implements that idea. It will try mmc-initialization using
several frequencies from an array 400, 300, 200 and 100.

In case SDIO is broken, it'll still try to detect SDMEM, also at different
freqs.

Signed-off-by: default avatarHein Tibosch <hein_tibosch@yahoo.es>
Cc: Pierre Ossman <pierre@ossman.eu>
Reviewed-by: default avatarChris Ball <cjb@laptop.org>
Tested-by: default avatarChris Ball <cjb@laptop.org>
Cc: Ben Nizette <bn@niasdigital.com>
Cc: Sascha Hauer <s.hauer@pengutronix.de>
Cc: Adrian Hunter <adrian.hunter@nokia.com>
Cc: Matt Fleming <matt@console-pimps.org>
Cc: <linux-mmc@vger.kernel.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarChris Ball <cjb@laptop.org>
parent 176d1ed4

drivers/mmc/core/core.c

+57 −45
Original line number Diff line number Diff line
@@ -908,12 +908,7 @@ static void mmc_power_up(struct mmc_host *host) 
	 */

	mmc_delay(10);



	if (host->f_min > 400000) {

		pr_warning("%s: Minimum clock frequency too high for "

				"identification mode\n", mmc_hostname(host));

		host->ios.clock = host->f_min;

	} else

		host->ios.clock = 400000;

	host->ios.clock = host->f_init;



	host->ios.power_mode = MMC_POWER_ON;

	mmc_set_ios(host);
@@ -1405,6 +1400,8 @@ void mmc_rescan(struct work_struct *work) 
	u32 ocr;

	int err;

	unsigned long flags;

	int i;

	const unsigned freqs[] = { 400000, 300000, 200000, 100000 };



	spin_lock_irqsave(&host->lock, flags);
@@ -1444,8 +1441,20 @@ void mmc_rescan(struct work_struct *work) 
	if (host->ops->get_cd && host->ops->get_cd(host) == 0)

		goto out;



	for (i = 0; i < ARRAY_SIZE(freqs); i++) {

		mmc_claim_host(host);



		if (freqs[i] >= host->f_min)

			host->f_init = freqs[i];

		else if (!i || freqs[i-1] > host->f_min)

			host->f_init = host->f_min;

		else {

			mmc_release_host(host);

			goto out;

		}

		pr_info("%s: %s: trying to init card at %u Hz\n",

			mmc_hostname(host), __func__, host->f_init);



		mmc_power_up(host);

		sdio_reset(host);

		mmc_go_idle(host);
@@ -1459,7 +1468,10 @@ void mmc_rescan(struct work_struct *work) 
		if (!err) {

			if (mmc_attach_sdio(host, ocr)) {

				mmc_claim_host(host);

			/* try SDMEM (but not MMC) even if SDIO is broken */

				/*

				 * Try SDMEM (but not MMC) even if SDIO

				 * is broken.

				 */

				if (mmc_send_app_op_cond(host, 0, &ocr))

					goto out_fail;
@@ -1492,7 +1504,7 @@ void mmc_rescan(struct work_struct *work) 
out_fail:

		mmc_release_host(host);

		mmc_power_off(host);



	}

out:

	if (host->caps & MMC_CAP_NEEDS_POLL)

		mmc_schedule_delayed_work(&host->detect, HZ);

include/linux/mmc/host.h

+1 −0
Original line number Diff line number Diff line
@@ -123,6 +123,7 @@ struct mmc_host { 
	const struct mmc_host_ops *ops;

	unsigned int		f_min;

	unsigned int		f_max;

	unsigned int		f_init;

	u32			ocr_avail;

	struct notifier_block	pm_notify;

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