[PATCH v3] mmc: Add Production State Awareness Support

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In this patch driver should recognize if eMMC device (Rev >=5.0)
was left in PRE_SOLDERING_POST_WRITES (0x02) state, and switch
it to NORMAL (0x00).
PRE_SOLDERING_POST_WRITES (0x02) state - represents a state
where the device is in production process and the
host (usually programmer) completed loading the content
to the device.
The host (usually programmer) sets the device to this state after
loading the content and just before soldering.
After soldering the device to the real host (not programmer),
the device should be switched to NORMAL (0x00) mode.
The NORMAL (0x00) mode of PSA register represents a state in
which the device is running in the field and uses regular operations.
Leaving device in PRE_SOLDERING_POST_WRITES (0x02) might cause
unexpected behaviour of eMMC device.

More details about PSA feature can be found in eMMC5.0 JEDEC spec (JESD84-B50.pdf):
http://www.jedec.org/standards-documents/technology-focus-areas/flash-memory-ssds-ufs-emmc/e-mmc

Signed-off-by: Alex Lemberg <alex.lemberg@xxxxxxxxxxx>
---
Changes in v2:
 - Remove typo in patch code
Changes in v3:
 - Move ext_csd revision check
---
 drivers/mmc/core/mmc.c   | 28 ++++++++++++++++++++++++++++
 include/linux/mmc/card.h |  2 ++
 include/linux/mmc/mmc.h  |  8 ++++++++
 3 files changed, 38 insertions(+)

diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c
index 02ad792..2c523ca 100644
--- a/drivers/mmc/core/mmc.c
+++ b/drivers/mmc/core/mmc.c
@@ -571,6 +571,16 @@ static int mmc_decode_ext_csd(struct mmc_card *card, u8 *ext_csd)
 		card->ext_csd.ffu_capable =
 			(ext_csd[EXT_CSD_SUPPORTED_MODE] & 0x1) &&
 			!(ext_csd[EXT_CSD_FW_CONFIG] & 0x1);
+		card->ext_csd.psa =
+			ext_csd[EXT_CSD_PSA];
+		if (ext_csd[EXT_CSD_PSA_TIMEOUT] > 0) {
+			card->ext_csd.psa_timeout =
+				100 *
+				(1 << ext_csd[EXT_CSD_PSA_TIMEOUT]);
+		} else {
+			pr_warn("%s: EXT_CSD PSA Timeout is zero\n",
+					mmc_hostname(card->host));
+		}
 	}
 out:
 	return err;
@@ -1358,6 +1368,24 @@ static int mmc_init_card(struct mmc_host *host, u32 ocr,
 	}
 
 	/*
+	 * eMMC v5.0 or later
+	 * and Production State Awareness state is
+	 * EXT_CSD_PSA_POST_SOLDERING_WRITES (0x02)
+	 * The host should set the device to NORMAL mode
+	 */
+	if ((card->ext_csd.rev >= 7) &&
+		(card->ext_csd.psa == EXT_CSD_PSA_POST_SOLDERING_WRITES)) {
+		unsigned int timeout;
+
+		timeout = DIV_ROUND_UP(card->ext_csd.psa_timeout, 1000);
+		card->ext_csd.psa = EXT_CSD_PSA_NORMAL;
+		err = mmc_switch(card, EXT_CSD_CMD_SET_NORMAL,
+			EXT_CSD_PSA, card->ext_csd.psa, timeout);
+		if (err && err != -EBADMSG)
+			goto free_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.
 	 */
diff --git a/include/linux/mmc/card.h b/include/linux/mmc/card.h
index 4d69c00..09ac3b0 100644
--- a/include/linux/mmc/card.h
+++ b/include/linux/mmc/card.h
@@ -60,9 +60,11 @@ struct mmc_ext_csd {
 	u8			packed_event_en;
 	unsigned int		part_time;		/* Units: ms */
 	unsigned int		sa_timeout;		/* Units: 100ns */
+	unsigned int		psa_timeout;		/* Units: 100us */
 	unsigned int		generic_cmd6_time;	/* Units: 10ms */
 	unsigned int            power_off_longtime;     /* Units: ms */
 	u8			power_off_notification;	/* state */
+	u8			psa; /* production state awareness */
 	unsigned int		hs_max_dtr;
 	unsigned int		hs200_max_dtr;
 #define MMC_HIGH_26_MAX_DTR	26000000
diff --git a/include/linux/mmc/mmc.h b/include/linux/mmc/mmc.h
index 49ad7a9..458814d 100644
--- a/include/linux/mmc/mmc.h
+++ b/include/linux/mmc/mmc.h
@@ -285,6 +285,7 @@ struct _mmc_csd {
 #define EXT_CSD_EXP_EVENTS_STATUS	54	/* RO, 2 bytes */
 #define EXT_CSD_EXP_EVENTS_CTRL		56	/* R/W, 2 bytes */
 #define EXT_CSD_DATA_SECTOR_SIZE	61	/* R */
+#define EXT_CSD_PSA			133	/* R/W/E */
 #define EXT_CSD_GP_SIZE_MULT		143	/* R/W */
 #define EXT_CSD_PARTITION_SETTING_COMPLETED 155	/* R/W */
 #define EXT_CSD_PARTITION_ATTRIBUTE	156	/* R/W */
@@ -315,6 +316,7 @@ struct _mmc_csd {
 #define EXT_CSD_PWR_CL_26_360		203	/* RO */
 #define EXT_CSD_SEC_CNT			212	/* RO, 4 bytes */
 #define EXT_CSD_S_A_TIMEOUT		217	/* RO */
+#define EXT_CSD_PSA_TIMEOUT		218	/* RO */
 #define EXT_CSD_REL_WR_SEC_C		222	/* RO */
 #define EXT_CSD_HC_WP_GRP_SIZE		221	/* RO */
 #define EXT_CSD_ERASE_TIMEOUT_MULT	223	/* RO */
@@ -433,6 +435,12 @@ struct _mmc_csd {
 #define EXT_CSD_BKOPS_LEVEL_2		0x2
 
 /*
+ * PRODUCTION STATE AWARENESS fields
+ */
+#define EXT_CSD_PSA_NORMAL		0x00
+#define EXT_CSD_PSA_POST_SOLDERING_WRITES	0x02
+
+/*
  * MMC_SWITCH access modes
  */
 
-- 
2.1.0

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