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: 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>
diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c
index ab4446c..222466d 100644
--- a/drivers/mmc/core/core.c
+++ b/drivers/mmc/core/core.c
@@ -908,12 +908,7 @@
*/
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 @@
u32 ocr;
int err;
unsigned long flags;
+ int i;
+ const unsigned freqs[] = { 400000, 300000, 200000, 100000 };
spin_lock_irqsave(&host->lock, flags);
@@ -1444,55 +1441,70 @@
if (host->ops->get_cd && host->ops->get_cd(host) == 0)
goto out;
- mmc_claim_host(host);
+ for (i = 0; i < ARRAY_SIZE(freqs); i++) {
+ mmc_claim_host(host);
- mmc_power_up(host);
- sdio_reset(host);
- mmc_go_idle(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_send_if_cond(host, host->ocr_avail);
+ mmc_power_up(host);
+ sdio_reset(host);
+ mmc_go_idle(host);
- /*
- * First we search for SDIO...
- */
- err = mmc_send_io_op_cond(host, 0, &ocr);
- if (!err) {
- if (mmc_attach_sdio(host, ocr)) {
- mmc_claim_host(host);
- /* try SDMEM (but not MMC) even if SDIO is broken */
- if (mmc_send_app_op_cond(host, 0, &ocr))
- goto out_fail;
+ mmc_send_if_cond(host, host->ocr_avail);
+ /*
+ * First we search for SDIO...
+ */
+ err = mmc_send_io_op_cond(host, 0, &ocr);
+ if (!err) {
+ if (mmc_attach_sdio(host, ocr)) {
+ mmc_claim_host(host);
+ /*
+ * Try SDMEM (but not MMC) even if SDIO
+ * is broken.
+ */
+ if (mmc_send_app_op_cond(host, 0, &ocr))
+ goto out_fail;
+
+ if (mmc_attach_sd(host, ocr))
+ mmc_power_off(host);
+ }
+ goto out;
+ }
+
+ /*
+ * ...then normal SD...
+ */
+ err = mmc_send_app_op_cond(host, 0, &ocr);
+ if (!err) {
if (mmc_attach_sd(host, ocr))
mmc_power_off(host);
+ goto out;
}
- goto out;
- }
- /*
- * ...then normal SD...
- */
- err = mmc_send_app_op_cond(host, 0, &ocr);
- if (!err) {
- if (mmc_attach_sd(host, ocr))
- mmc_power_off(host);
- goto out;
- }
-
- /*
- * ...and finally MMC.
- */
- err = mmc_send_op_cond(host, 0, &ocr);
- if (!err) {
- if (mmc_attach_mmc(host, ocr))
- mmc_power_off(host);
- goto out;
- }
+ /*
+ * ...and finally MMC.
+ */
+ err = mmc_send_op_cond(host, 0, &ocr);
+ if (!err) {
+ if (mmc_attach_mmc(host, ocr))
+ mmc_power_off(host);
+ goto out;
+ }
out_fail:
- mmc_release_host(host);
- mmc_power_off(host);
-
+ mmc_release_host(host);
+ mmc_power_off(host);
+ }
out:
if (host->caps & MMC_CAP_NEEDS_POLL)
mmc_schedule_delayed_work(&host->detect, HZ);
diff --git a/include/linux/mmc/host.h b/include/linux/mmc/host.h
index 2e0fe62..20be040 100644
--- a/include/linux/mmc/host.h
+++ b/include/linux/mmc/host.h
@@ -123,6 +123,7 @@
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;