mmc: core: Remove MMC_CAP2_HC_ERASE_SZ

The MMC_CAP2_HC_ERASE_SZ is used only by a few mmc host drivers. Its intent
is to enable eMMC's high-capacity erase size, as to improve the behaviour
of the erase operations.

We should strive to avoid software configuration options that aren't
necessary, but instead deploy common behaviours. For these reasons, let's
remove the capability bit for MMC_CAP2_HC_ERASE_SZ and make it the default
behaviour.

Note that this change doesn't affect eMMCs supporting trim/discard, because
these commands operates on sectors and takes precedence over erase
commands.

Signed-off-by: Ulf Hansson <[e-mail]>
Acked-by: Adrian Hunter <[e-mail]>
Reviewed-by: Linus Walleij <[e-mail]>
Reviewed-by: Shawn Lin <[e-mail]>
Tested-by: Shawn Lin <[e-mail]>

drivers/mmc/core/mmc.c

···
 		mmc_set_erase_size(card);
 	}
 
-	/*
-	 * 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.partition_setting_completed ||
-	    (card->ext_csd.rev >= 3 && (host->caps2 & MMC_CAP2_HC_ERASE_SZ))) {
+	/* Enable ERASE_GRP_DEF. This bit is lost after a reset or power off. */
+	if (card->ext_csd.rev >= 3) {
 		err = mmc_switch(card, EXT_CSD_CMD_SET_NORMAL,
 				 EXT_CSD_ERASE_GROUP_DEF, 1,
 				 card->ext_csd.generic_cmd6_time);

drivers/mmc/host/sdhci-acpi.c

···
 	.caps    = MMC_CAP_8_BIT_DATA | MMC_CAP_NONREMOVABLE |
 		   MMC_CAP_HW_RESET | MMC_CAP_1_8V_DDR |
 		   MMC_CAP_CMD_DURING_TFR | MMC_CAP_WAIT_WHILE_BUSY,
-	.caps2   = MMC_CAP2_HC_ERASE_SZ,
 	.flags   = SDHCI_ACPI_RUNTIME_PM,
 	.quirks  = SDHCI_QUIRK_NO_ENDATTR_IN_NOPDESC,
 	.quirks2 = SDHCI_QUIRK2_PRESET_VALUE_BROKEN |

drivers/mmc/host/sdhci-brcmstb.c

···
 		goto err_clk;
 	}
 
-	/* Enable MMC_CAP2_HC_ERASE_SZ for better max discard calculations */
-	host->mmc->caps2 |= MMC_CAP2_HC_ERASE_SZ;
-
 	sdhci_get_of_property(pdev);
 	mmc_of_parse(host->mmc);
 

drivers/mmc/host/sdhci-pci-core.c

···
 static int mfd_emmc_probe_slot(struct sdhci_pci_slot *slot)
 {
 	slot->host->mmc->caps |= MMC_CAP_8_BIT_DATA | MMC_CAP_NONREMOVABLE;
-	slot->host->mmc->caps2 |= MMC_CAP2_BOOTPART_NOACC |
-				  MMC_CAP2_HC_ERASE_SZ;
+	slot->host->mmc->caps2 |= MMC_CAP2_BOOTPART_NOACC;
 	return 0;
 }
 
···
 				 MMC_CAP_HW_RESET | MMC_CAP_1_8V_DDR |
 				 MMC_CAP_CMD_DURING_TFR |
 				 MMC_CAP_WAIT_WHILE_BUSY;
-	slot->host->mmc->caps2 |= MMC_CAP2_HC_ERASE_SZ;
 	slot->hw_reset = sdhci_pci_int_hw_reset;
 	if (slot->chip->pdev->device == PCI_DEVICE_ID_INTEL_BSW_EMMC)
 		slot->host->timeout_clk = 1000; /* 1000 kHz i.e. 1 MHz */

include/linux/mmc/host.h

···
 #define MMC_CAP2_HS200_1_2V_SDR	(1 << 6)        /* can support */
 #define MMC_CAP2_HS200		(MMC_CAP2_HS200_1_8V_SDR | \
 				 MMC_CAP2_HS200_1_2V_SDR)
-#define MMC_CAP2_HC_ERASE_SZ	(1 << 9)	/* High-capacity erase size */
 #define MMC_CAP2_CD_ACTIVE_HIGH	(1 << 10)	/* Card-detect signal active high */
 #define MMC_CAP2_RO_ACTIVE_HIGH	(1 << 11)	/* Write-protect signal active high */
 #define MMC_CAP2_PACKED_RD	(1 << 12)	/* Allow packed read */