mmc: core: add high-capacity erase size capability flag

Let drivers specify the use of high-capacity erase size.
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Chris Ball <cjb@laptop.org>

drivers/mmc/core/mmc.c

@@ -952,7 +952,8 @@ static int mmc_init_card(struct mmc_host *host, u32 ocr,
 	 * If enhanced_area_en is TRUE, host needs to enable ERASE_GRP_DEF
 	 * bit.  This bit will be lost every time after a reset or power off.
 	 */
-	if (card->ext_csd.enhanced_area_en) {
+	if (card->ext_csd.enhanced_area_en ||
+	    (card->ext_csd.rev >= 3 && (host->caps2 & MMC_CAP2_HC_ERASE_SZ))) {
 		err = mmc_switch(card, EXT_CSD_CMD_SET_NORMAL,
 				 EXT_CSD_ERASE_GROUP_DEF, 1,
 				 card->ext_csd.generic_cmd6_time);

include/linux/mmc/host.h

@@ -236,6 +236,7 @@ struct mmc_host {
 				 MMC_CAP2_HS200_1_2V_SDR)
 #define MMC_CAP2_BROKEN_VOLTAGE	(1 << 7)	/* Use the broken voltage */
 #define MMC_CAP2_DETECT_ON_ERR	(1 << 8)	/* On I/O err check card removal */
+#define MMC_CAP2_HC_ERASE_SZ	(1 << 9)	/* High-capacity erase size */
 
 	mmc_pm_flag_t		pm_caps;	/* supported pm features */
 	unsigned int        power_notify_type;