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path: root/drivers/mmc/core
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Diffstat (limited to 'drivers/mmc/core')
-rw-r--r--drivers/mmc/core/sd.c49
1 files changed, 41 insertions, 8 deletions
diff --git a/drivers/mmc/core/sd.c b/drivers/mmc/core/sd.c
index fb18b301502..ae54e8eb7fe 100644
--- a/drivers/mmc/core/sd.c
+++ b/drivers/mmc/core/sd.c
@@ -183,16 +183,13 @@ static void mmc_decode_scr(struct mmc_card *card)
}
/*
- * Test if the card supports high-speed mode and, if so, switch to it.
+ * Fetches and decodes switch information
*/
-static int mmc_switch_hs(struct mmc_card *card)
+static int mmc_read_switch(struct mmc_card *card)
{
int err;
u8 *status;
- if (!(card->host->caps & MMC_CAP_SD_HIGHSPEED))
- return MMC_ERR_NONE;
-
err = MMC_ERR_FAILED;
status = kmalloc(64, GFP_KERNEL);
@@ -209,14 +206,43 @@ static int mmc_switch_hs(struct mmc_card *card)
* Card not supporting high-speed will ignore the
* command.
*/
- if (err == MMC_ERR_TIMEOUT)
- err = MMC_ERR_NONE;
+ err = MMC_ERR_NONE;
goto out;
}
if (status[13] & 0x02)
card->sw_caps.hs_max_dtr = 50000000;
+out:
+ kfree(status);
+
+ return err;
+}
+
+/*
+ * Test if the card supports high-speed mode and, if so, switch to it.
+ */
+static int mmc_switch_hs(struct mmc_card *card)
+{
+ int err;
+ u8 *status;
+
+ if (!(card->host->caps & MMC_CAP_SD_HIGHSPEED))
+ return MMC_ERR_NONE;
+
+ if (card->sw_caps.hs_max_dtr == 0)
+ return MMC_ERR_NONE;
+
+ err = MMC_ERR_FAILED;
+
+ status = kmalloc(64, GFP_KERNEL);
+ if (!status) {
+ printk("%s: could not allocate a buffer for switch "
+ "capabilities.\n",
+ mmc_hostname(card->host));
+ return err;
+ }
+
err = mmc_sd_switch(card, 1, 0, 1, status);
if (err != MMC_ERR_NONE)
goto out;
@@ -393,7 +419,14 @@ int mmc_attach_sd(struct mmc_host *host, u32 ocr)
mmc_decode_scr(card);
/*
- * Check if card can be switched into high-speed mode.
+ * Fetch switch information from card.
+ */
+ err = mmc_read_switch(card);
+ if (err != MMC_ERR_NONE)
+ goto free_card;
+
+ /*
+ * Attempt to change to high-speed (if supported)
*/
err = mmc_switch_hs(card);
if (err != MMC_ERR_NONE)