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authorLars-Peter Clausen <lars@metafoo.de>2015-05-06 20:31:19 +0200
committerUlf Hansson <ulf.hansson@linaro.org>2015-06-01 09:06:59 +0200
commit9f6e0bff2afb52a4c29f5ca8a4db01810357974e (patch)
tree427a344078d58843f9d5a7fcc1f303c54ff26dc6 /drivers/mmc/core/sd.c
parent0250fdf257b1e5febba19b7cc536a3c9431e50bf (diff)
mmc: Add support for disabling write-protect detection
It is not uncommon to see systems where there is no physical write-protect signal (e.g. when using eMMC or microSD card slots). For some controllers, which have a dedicated write-protection detection logic (like SDHCI controllers), the get_ro() callback can return bogus data in such a case. Instead of handling this on a per controller basis this patch adds a new capability flag to the MMC core that can be set to specify that the result of get_ro() is invalid. When the flag is set the core will not call get_ro() and assume that the card is always read-write. Signed-off-by: Lars-Peter Clausen <lars@metafoo.de> Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Diffstat (limited to 'drivers/mmc/core/sd.c')
-rw-r--r--drivers/mmc/core/sd.c30
1 files changed, 23 insertions, 7 deletions
diff --git a/drivers/mmc/core/sd.c b/drivers/mmc/core/sd.c
index 31a9ef256d06..8f6864a2a055 100644
--- a/drivers/mmc/core/sd.c
+++ b/drivers/mmc/core/sd.c
@@ -804,6 +804,28 @@ int mmc_sd_get_csd(struct mmc_host *host, struct mmc_card *card)
return 0;
}
+static int mmc_sd_get_ro(struct mmc_host *host)
+{
+ int ro;
+
+ /*
+ * Some systems don't feature a write-protect pin and don't need one.
+ * E.g. because they only have micro-SD card slot. For those systems
+ * assume that the SD card is always read-write.
+ */
+ if (host->caps2 & MMC_CAP2_NO_WRITE_PROTECT)
+ return 0;
+
+ if (!host->ops->get_ro)
+ return -1;
+
+ mmc_host_clk_hold(host);
+ ro = host->ops->get_ro(host);
+ mmc_host_clk_release(host);
+
+ return ro;
+}
+
int mmc_sd_setup_card(struct mmc_host *host, struct mmc_card *card,
bool reinit)
{
@@ -855,13 +877,7 @@ int mmc_sd_setup_card(struct mmc_host *host, struct mmc_card *card,
* Check if read-only switch is active.
*/
if (!reinit) {
- int ro = -1;
-
- if (host->ops->get_ro) {
- mmc_host_clk_hold(card->host);
- ro = host->ops->get_ro(host);
- mmc_host_clk_release(card->host);
- }
+ int ro = mmc_sd_get_ro(host);
if (ro < 0) {
pr_warn("%s: host does not support reading read-only switch, assuming write-enable\n",