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| author | Lars-Peter Clausen <lars@metafoo.de> | 2015-05-06 20:31:19 +0200 |
|---|---|---|
| committer | Ulf Hansson <ulf.hansson@linaro.org> | 2015-06-01 09:06:59 +0200 |
| commit | 9f6e0bff2afb52a4c29f5ca8a4db01810357974e (patch) | |
| tree | 427a344078d58843f9d5a7fcc1f303c54ff26dc6 | |
| parent | 0250fdf257b1e5febba19b7cc536a3c9431e50bf (diff) | |
| download | op-kernel-dev-9f6e0bff2afb52a4c29f5ca8a4db01810357974e.zip op-kernel-dev-9f6e0bff2afb52a4c29f5ca8a4db01810357974e.tar.gz | |
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>
| -rw-r--r-- | drivers/mmc/core/sd.c | 30 | ||||
| -rw-r--r-- | include/linux/mmc/host.h | 1 |
2 files changed, 24 insertions, 7 deletions
diff --git a/drivers/mmc/core/sd.c b/drivers/mmc/core/sd.c index 31a9ef2..8f6864a 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", diff --git a/include/linux/mmc/host.h b/include/linux/mmc/host.h index f471193..433eccb 100644 --- a/include/linux/mmc/host.h +++ b/include/linux/mmc/host.h @@ -286,6 +286,7 @@ struct mmc_host { MMC_CAP2_HS400_1_2V) #define MMC_CAP2_HSX00_1_2V (MMC_CAP2_HS200_1_2V_SDR | MMC_CAP2_HS400_1_2V) #define MMC_CAP2_SDIO_IRQ_NOTHREAD (1 << 17) +#define MMC_CAP2_NO_WRITE_PROTECT (1 << 18) /* No physical write protect pin, assume that card is always read-write */ mmc_pm_flag_t pm_caps; /* supported pm features */ |
