[U-Boot] [PATCH v2] mmc: add mmc partconf read capability

[Angelo Dureghello <angelo@sysam.it>]

This patch allows to read back the EXT_CSD[179] partition_config
register, just specifying the dev param:

U-Boot> mmc partconf 0
EXT_CSD[179], PARTITION_CONFIG register:
BOOT_ACK: 0
BOOT_PARTITION_ENABLE: 0
PARTITION_ACCESS: 0

Signed-off-by: Angelo Dureghello <angelo@sysam.it>
---
Changes for v2:
- fixed commit message
- added white lines in cmd/mmc.c
- fixed help in cmd/mmc.c
---
 cmd/mmc.c         | 35 +++++++++++++++++++++++++++++------
 drivers/mmc/mmc.c | 33 +++++++++++++++++++++++++++++++++
 include/mmc.h     |  6 ++++++
 3 files changed, 68 insertions(+), 6 deletions(-)

diff --git a/cmd/mmc.c b/cmd/mmc.c
index 39ef072..de28749 100644
--- a/cmd/mmc.c
+++ b/cmd/mmc.c
@@ -697,6 +697,24 @@ static int do_mmc_boot_resize(cmd_tbl_t *cmdtp, int flag,
 	printf("EMMC RPMB partition Size %d MB\n", rpmbsize);
 	return CMD_RET_SUCCESS;
 }
+
+static int do_mmc_partconf_read(struct mmc *mmc)
+{
+	int err;
+	u8 ack, part_num, access;
+
+	err = mmc_get_part_conf(mmc, &ack, &part_num, &access);
+	if (err)
+		return CMD_RET_FAILURE;
+
+	puts("EXT_CSD[179], PARTITION_CONFIG register:\n");
+	printf("BOOT_ACK: %d\n", ack);
+	printf("BOOT_PARTITION_ENABLE: %d\n", part_num);
+	printf("PARTITION_ACCESS: %d\n", access);
+
+	return 0;
+}
+
 static int do_mmc_partconf(cmd_tbl_t *cmdtp, int flag,
 			   int argc, char * const argv[])
 {
@@ -704,13 +722,10 @@ static int do_mmc_partconf(cmd_tbl_t *cmdtp, int flag,
 	struct mmc *mmc;
 	u8 ack, part_num, access;
 
-	if (argc != 5)
+	if (argc != 2 && argc != 5)
 		return CMD_RET_USAGE;
 
 	dev = simple_strtoul(argv[1], NULL, 10);
-	ack = simple_strtoul(argv[2], NULL, 10);
-	part_num = simple_strtoul(argv[3], NULL, 10);
-	access = simple_strtoul(argv[4], NULL, 10);
 
 	mmc = init_mmc_device(dev, false);
 	if (!mmc)
@@ -721,9 +736,17 @@ static int do_mmc_partconf(cmd_tbl_t *cmdtp, int flag,
 		return CMD_RET_FAILURE;
 	}
 
+	if (argc == 2)
+		return do_mmc_partconf_read(mmc);
+
+	ack = simple_strtoul(argv[2], NULL, 10);
+	part_num = simple_strtoul(argv[3], NULL, 10);
+	access = simple_strtoul(argv[4], NULL, 10);
+
 	/* acknowledge to be sent during boot operation */
 	return mmc_set_part_conf(mmc, ack, part_num, access);
 }
+
 static int do_mmc_rst_func(cmd_tbl_t *cmdtp, int flag,
 			   int argc, char * const argv[])
 {
@@ -858,8 +881,8 @@ U_BOOT_CMD(
 	" - Set the BOOT_BUS_WIDTH field of the specified device\n"
 	"mmc bootpart-resize <dev> <boot part size MB> <RPMB part size MB>\n"
 	" - Change sizes of boot and RPMB partitions of specified device\n"
-	"mmc partconf dev boot_ack boot_partition partition_access\n"
-	" - Change the bits of the PARTITION_CONFIG field of the specified device\n"
+	"mmc partconf dev [boot_ack boot_partition partition_access]\n"
+	" - Show or change the bits of the PARTITION_CONFIG field of the specified device\n"
 	"mmc rst-function dev value\n"
 	" - Change the RST_n_FUNCTION field of the specified device\n"
 	"   WARNING: This is a write-once field and 0 / 1 / 2 are the only valid values.\n"
diff --git a/drivers/mmc/mmc.c b/drivers/mmc/mmc.c
index d3c22ab..4cb3706 100644
--- a/drivers/mmc/mmc.c
+++ b/drivers/mmc/mmc.c
@@ -1954,6 +1954,39 @@ int mmc_set_part_conf(struct mmc *mmc, u8 ack, u8 part_num, u8 access)
 }
 
 /*
+ * Read EXT_CSD[179] which is PARTITION_CONFIG (formerly BOOT_CONFIG)
+ * and returning the extracted fields BOOT_ACK, BOOT_PARTITION_ENABLE and
+ * PARTITION_ACCESS.
+ *
+ * Returns 0 on success.
+ */
+int mmc_get_part_conf(struct mmc *mmc, u8 *ack, u8 *part_num, u8 *access)
+{
+	int err;
+	u8 part_conf;
+
+	ALLOC_CACHE_ALIGN_BUFFER(u8, ext_csd, MMC_MAX_BLOCK_LEN);
+
+	mmc->erase_grp_size = 1;
+	mmc->part_config = MMCPART_NOAVAILABLE;
+
+	if (IS_SD(mmc) || (mmc->version < MMC_VERSION_4))
+		return -1;
+
+	err = mmc_send_ext_csd(mmc, ext_csd);
+	if (err)
+		return err;
+
+	part_conf = ext_csd[EXT_CSD_PART_CONF];
+
+	*ack = EXT_CSD_EXTRACT_BOOT_ACK(part_conf);
+	*part_num = EXT_CSD_EXTRACT_BOOT_PART(part_conf);
+	*access = EXT_CSD_EXTRACT_PARTITION_ACCESS(part_conf);
+
+	return 0;
+}
+
+/*
  * Modify EXT_CSD[162] which is RST_n_FUNCTION based on the given value
  * for enable.  Note that this is a write-once field for non-zero values.
  *
diff --git a/include/mmc.h b/include/mmc.h
index cdb56e7..4b34b31 100644
--- a/include/mmc.h
+++ b/include/mmc.h
@@ -222,6 +222,10 @@
 #define EXT_CSD_BOOT_PART_NUM(x)	(x << 3)
 #define EXT_CSD_PARTITION_ACCESS(x)	(x << 0)
 
+#define EXT_CSD_EXTRACT_BOOT_ACK(x)		((x >> 6) & 1)
+#define EXT_CSD_EXTRACT_BOOT_PART(x)		((x >> 3) & 0x7)
+#define EXT_CSD_EXTRACT_PARTITION_ACCESS(x)	(x & 0x7)
+
 #define EXT_CSD_BOOT_BUS_WIDTH_MODE(x)	(x << 3)
 #define EXT_CSD_BOOT_BUS_WIDTH_RESET(x)	(x << 2)
 #define EXT_CSD_BOOT_BUS_WIDTH_WIDTH(x)	(x)
@@ -428,6 +432,8 @@ int mmc_boot_partition_size_change(struct mmc *mmc, unsigned long bootsize,
 					unsigned long rpmbsize);
 /* Function to modify the PARTITION_CONFIG field of EXT_CSD */
 int mmc_set_part_conf(struct mmc *mmc, u8 ack, u8 part_num, u8 access);
+/* Function to read back the PARTITION_CONFIG field of EXT_CSD */
+int mmc_get_part_conf(struct mmc *mmc, u8 *ack, u8 *part_num, u8 *access);
 /* Function to modify the BOOT_BUS_WIDTH field of EXT_CSD */
 int mmc_set_boot_bus_width(struct mmc *mmc, u8 width, u8 reset, u8 mode);
 /* Function to modify the RST_n_FUNCTION field of EXT_CSD */
-- 
2.8.0.rc3