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mmc: Make ID freq configurable

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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: Hein Tibosch <hein_tibosch@yahoo.es>
Cc: Pierre Ossman <pierre@ossman.eu>
Reviewed-by: Chris Ball <cjb@laptop.org>
Tested-by: Chris 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: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Chris Ball <cjb@laptop.org>
This commit is contained in:
Hein Tibosch 2010-09-06 09:37:19 +08:00 committed by Chris Ball
parent 176d1ed426
commit 88ae8b8664
2 changed files with 58 additions and 45 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

28
drivers/mmc/core/core.c
View file

@ -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);

1
include/linux/mmc/host.h
View file

@ -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;