[PATCH 3/4] mmc: Enabled HPI feature

[Chuanxiao Dong]

HPI feature is a new feature in eMMC4.41 standard. It will be
used to interrupt background operations and low priority
foreground operations

Signed-off-by: Chuanxiao Dong <chuanxiao.dong@xxxxxxxxx>
---
 drivers/mmc/core/mmc.c   |   31 +++++++++++++++++++++++++++++++
 include/linux/mmc/card.h |    2 ++
 include/linux/mmc/mmc.h  |    2 ++
 3 files changed, 35 insertions(+), 0 deletions(-)

diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c
index 471ed82..8d6c5cb 100644
--- a/drivers/mmc/core/mmc.c
+++ b/drivers/mmc/core/mmc.c
@@ -318,6 +318,18 @@ static int mmc_read_ext_csd(struct mmc_card *card)
 				ext_csd[EXT_CSD_BKOPS_EN];
 		}
 
+		/* check whether the eMMC card support HPI */
+		if (ext_csd[EXT_CSD_HPI_FEATURES] & 0x1) {
+			card->ext_csd.hpi = 1;
+			card->ext_csd.hpi_en =
+				ext_csd[EXT_CSD_HPI_MGMT];
+			if (ext_csd[EXT_CSD_HPI_FEATURES] & 0x2)
+				card->ext_csd.hpi_cmd =
+					MMC_STOP_TRANSMISSION;
+			else
+				card->ext_csd.hpi_cmd =
+					MMC_SEND_STATUS;
+		}
 	}
 
 	if (ext_csd[EXT_CSD_ERASED_MEM_CONT])
@@ -510,6 +522,25 @@ static int mmc_init_card(struct mmc_host *host, u32 ocr,
 	}
 
 	/*
+	 * enable HPI feature if eMMC card support
+	 */
+	if (card->ext_csd.hpi) {
+		if (!card->ext_csd.hpi_en) {
+			err = mmc_switch(card, EXT_CSD_CMD_SET_NORMAL,
+					EXT_CSD_HPI_MGMT, 1);
+			if (err && err != -EBADMSG)
+				goto free_card;
+
+			if (err) {
+				card->ext_csd.hpi_en = 0;
+				err = 0;
+			} else {
+				card->ext_csd.hpi_en = 1;
+			}
+		}
+	}
+
+	/*
 	 * Activate high speed (if supported)
 	 */
 	if ((card->ext_csd.hs_max_dtr != 0) &&
diff --git a/include/linux/mmc/card.h b/include/linux/mmc/card.h
index 4142ab5..efb2c56 100644
--- a/include/linux/mmc/card.h
+++ b/include/linux/mmc/card.h
@@ -57,6 +57,8 @@ struct mmc_ext_csd {
 	unsigned int		bkops:1; /* background support bit */
 	unsigned int		bkops_en:1; /* background enable bit */
 	unsigned int		hpi_en:1; /* HPI enable bit */
+	unsigned int		hpi:1; /* HPI support bit */
+	unsigned int		hpi_cmd; /* cmd used to for HPI */
 };
 
 struct sd_scr {
diff --git a/include/linux/mmc/mmc.h b/include/linux/mmc/mmc.h
index 2ba6a8b..34feaee 100644
--- a/include/linux/mmc/mmc.h
+++ b/include/linux/mmc/mmc.h
@@ -258,6 +258,7 @@ struct _mmc_csd {
  * EXT_CSD fields
  */
 
+#define EXT_CSD_HPI_MGMT		161	/* R/W */
 #define EXT_CSD_BKOPS_EN		163	/* R/W */
 #define EXT_CSD_BKOPS_START		164	/* W */
 #define EXT_CSD_ERASE_GROUP_DEF		175	/* R/W */
@@ -276,6 +277,7 @@ struct _mmc_csd {
 #define EXT_CSD_SEC_FEATURE_SUPPORT	231	/* RO */
 #define EXT_CSD_TRIM_MULT		232	/* RO */
 #define EXT_CSD_BKOPS_SUPPORT	502	/* RO */
+#define EXT_CSD_HPI_FEATURES	503	/* RO */
 
 /*
  * EXT_CSD field definitions
-- 
1.6.6.1

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