mmc: core: implement enhanced strobe support
Controllers use data strobe line to latch data from devices
under hs400 mode, but not for cmd line. So since emmc 5.1, JEDEC
introduces enhanced strobe mode for latching cmd response from
emmc devices to host controllers. This new feature is optional,
so it depends both on device's cap and host's cap to decide
whether to use it or not.
Signed-off-by: Shawn Lin <shawn.lin@rock-chips.com>
Reviewed-by: Jaehoon Chung <jh80.chung@samsung.com>
Tested-by: Douglas Anderson <dianders@chromium.org>
Tested-by: Jaehoon Chung <jh80.chung@samsung.com>
Acked-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
diff --git a/include/linux/mmc/host.h b/include/linux/mmc/host.h
index b836a27..d72c0c3 100644
--- a/include/linux/mmc/host.h
+++ b/include/linux/mmc/host.h
@@ -19,6 +19,7 @@
#include <linux/mmc/core.h>
#include <linux/mmc/card.h>
+#include <linux/mmc/mmc.h>
#include <linux/mmc/pm.h>
struct mmc_ios {
@@ -77,6 +78,8 @@
#define MMC_SET_DRIVER_TYPE_A 1
#define MMC_SET_DRIVER_TYPE_C 2
#define MMC_SET_DRIVER_TYPE_D 3
+
+ bool enhanced_strobe; /* hs400es selection */
};
struct mmc_host_ops {
@@ -143,6 +146,9 @@
/* Prepare HS400 target operating frequency depending host driver */
int (*prepare_hs400_tuning)(struct mmc_host *host, struct mmc_ios *ios);
+ /* Prepare enhanced strobe depending host driver */
+ void (*hs400_enhanced_strobe)(struct mmc_host *host,
+ struct mmc_ios *ios);
int (*select_drive_strength)(struct mmc_card *card,
unsigned int max_dtr, int host_drv,
int card_drv, int *drv_type);
@@ -514,6 +520,11 @@
return card->host->ios.timing == MMC_TIMING_MMC_HS400;
}
+static inline bool mmc_card_hs400es(struct mmc_card *card)
+{
+ return card->host->ios.enhanced_strobe;
+}
+
void mmc_retune_timer_stop(struct mmc_host *host);
static inline void mmc_retune_needed(struct mmc_host *host)