[U-Boot] [PATCH v2] mmc: implement mmc power on write protect function

[Lin Huang]

set the mmc specific addresss and range as power on
write protection, you can't earse and write this range
of data if you enable it after mmc power on.

Signed-off-by: Lin Huang <hl at rock-chips.com>
---
Changes in v2:
- Adviced by Simon:
- use standard way of doing function comments
Changes in v1:
- Adviced by Simon:
- use real error in errno.h to return
- add full function comments for new function

 drivers/mmc/mmc.c | 87 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
 include/mmc.h     | 36 +++++++++++++++++++++++
 2 files changed, 123 insertions(+)

diff --git a/drivers/mmc/mmc.c b/drivers/mmc/mmc.c
index 3a34028..1308ce9 100644
--- a/drivers/mmc/mmc.c
+++ b/drivers/mmc/mmc.c
@@ -1821,6 +1821,93 @@ int mmc_initialize(bd_t *bis)
 	return 0;
 }
 
+int mmc_get_wp_status(struct mmc *mmc, lbaint_t addr, char *status)
+{
+	struct mmc_cmd cmd;
+	struct mmc_data data;
+	int err;
+
+	cmd.cmdidx = MMC_CMD_WRITE_PROT_TYPE;
+	cmd.resp_type = MMC_RSP_R1;
+	cmd.cmdarg = addr;
+
+	data.dest = status;
+	data.blocksize = 8;
+	data.blocks = 1;
+	data.flags = MMC_DATA_READ;
+
+	err = mmc_send_cmd(mmc, &cmd, &data);
+
+	return err;
+}
+
+int mmc_usr_power_on_wp(struct mmc *mmc, lbaint_t addr, unsigned int size)
+{
+	int err;
+	unsigned int wp_group_size, wp_grp_num, i;
+	struct mmc_cmd cmd;
+	unsigned int timeout = 1000;
+	ALLOC_CACHE_ALIGN_BUFFER(u8, ext_csd, MMC_MAX_BLOCK_LEN);
+
+	size = size / MMC_MAX_BLOCK_LEN;
+
+	err = mmc_send_ext_csd(mmc, ext_csd);
+	if (err)
+		return err;
+
+	if ((ext_csd[EXT_CSD_USER_WP] & EXT_CSD_USER_PERM_WP_EN) ||
+	    (ext_csd[EXT_CSD_USER_WP] & EXT_CSD_USER_PWR_WP_DIS)) {
+		printf("Power on protection is disabled\n");
+		return -EINVAL;
+	}
+
+	if (ext_csd[EXT_CSD_ERASE_GROUP_DEF])
+		wp_group_size = ext_csd[EXT_CSD_HC_WP_GRP_SIZE] *
+				ext_csd[EXT_CSD_HC_ERASE_GRP_SIZE] * 1024;
+	else {
+		int erase_gsz, erase_gmul, wp_grp_size;
+
+		erase_gsz = (mmc->csd[2] & 0x00007c00) >> 10;
+		erase_gmul = (mmc->csd[2] & 0x000003e0) >> 5;
+		wp_grp_size = (mmc->csd[2] & 0x0000001f);
+		wp_group_size = (erase_gsz + 1) * (erase_gmul + 1) *
+				(wp_grp_size + 1);
+	}
+
+	if (size < wp_group_size) {
+		printf("wrong size, fail to set power on wp\n");
+		return -EINVAL;
+	}
+
+	err = mmc_switch(mmc, EXT_CSD_CMD_SET_NORMAL,
+				 EXT_CSD_USER_WP, EXT_CSD_USER_PWR_WP_EN);
+	if (err)
+		return err;
+
+	wp_grp_num = DIV_ROUND_UP(size, wp_group_size);
+	cmd.cmdidx = MMC_CMD_WRITE_PROT;
+	cmd.resp_type = MMC_RSP_R1b;
+
+	for (i = 0; i < wp_grp_num; i++) {
+		cmd.cmdarg = addr + i * wp_group_size;
+		err = mmc_send_cmd(mmc, &cmd, NULL);
+		if (err)
+			return err;
+
+		/* CMD28/CMD29 ON failure returns address out of range error */
+		if ((cmd.response[0] >> 31) & 0x01) {
+			printf("address for CMD28/29 out of range\n");
+			return -EINVAL;
+		}
+
+		err = mmc_send_status(mmc, timeout);
+		if (err)
+			return err;
+	}
+
+	return 0;
+}
+
 #ifdef CONFIG_SUPPORT_EMMC_BOOT
 /*
  * This function changes the size of boot partition and the size of rpmb
diff --git a/include/mmc.h b/include/mmc.h
index cda9a19..dd9e803 100644
--- a/include/mmc.h
+++ b/include/mmc.h
@@ -89,6 +89,8 @@
 #define MMC_CMD_SET_BLOCK_COUNT         23
 #define MMC_CMD_WRITE_SINGLE_BLOCK	24
 #define MMC_CMD_WRITE_MULTIPLE_BLOCK	25
+#define MMC_CMD_WRITE_PROT		28
+#define MMC_CMD_WRITE_PROT_TYPE		31
 #define MMC_CMD_ERASE_GROUP_START	35
 #define MMC_CMD_ERASE_GROUP_END		36
 #define MMC_CMD_ERASE			38
@@ -175,6 +177,7 @@
 #define EXT_CSD_WR_REL_PARAM		166	/* R */
 #define EXT_CSD_WR_REL_SET		167	/* R/W */
 #define EXT_CSD_RPMB_MULT		168	/* RO */
+#define EXT_CSD_USER_WP			171
 #define EXT_CSD_ERASE_GROUP_DEF		175	/* R/W */
 #define EXT_CSD_BOOT_BUS_WIDTH		177
 #define EXT_CSD_PART_CONF		179	/* R/W */
@@ -231,6 +234,10 @@
 #define EXT_CSD_WR_DATA_REL_USR		(1 << 0)	/* user data area WR_REL */
 #define EXT_CSD_WR_DATA_REL_GP(x)	(1 << ((x)+1))	/* GP part (x+1) WR_REL */
 
+#define EXT_CSD_USER_PWR_WP_DIS		(1 << 3) /* disable power-on write protect*/
+#define EXT_CSD_USER_PERM_WP_EN		(1 << 2) /* enable permanent write protect */
+#define EXT_CSD_USER_PWR_WP_EN		(1 << 0) /* enable power-on write protect */
+
 #define R1_ILLEGAL_COMMAND		(1 << 22)
 #define R1_APP_CMD			(1 << 5)
 
@@ -479,6 +486,35 @@ int mmc_get_env_addr(struct mmc *mmc, int copy, u32 *env_addr);
 struct pci_device_id;
 
 /**
+ * mmc_usr_power_on_wp() - Enable power-on write protect
+ *
+ * This function specific user area address enable power on write protect
+ *
+ * @mmc: pointer to the mmc device structure
+ * @addr: address of power-on write protect area, use block address
+ * @size: size of power on write protect area, in bytes
+ * @return 0 success, -ve on error
+ */
+int mmc_usr_power_on_wp(struct mmc *mmc, lbaint_t addr, unsigned int size);
+
+/**
+ * mmc_get_wp_status() - Get write protect status
+ *
+ * This function read specific user area address write protect status,
+ * the data bits represent:
+ * “00” Write protection group not protected
+ * “01” Write protection group is protected by temporary write protection
+ * “10” Write protection group is protected by power-on write protection
+ * “11” Write protection group is protected by permanent write protection
+ *
+ * @mmc: pointer for the mmc device strcuture
+ * @addr: address you want to read the status, use block address
+ * @status: write protect status you get:
+ * @return 0 on success, -ve on error
+ */
+int mmc_get_wp_status(struct mmc *mmc, lbaint_t addr, char *status);
+
+/**
  * pci_mmc_init() - set up PCI MMC devices
  *
  * This finds all the matching PCI IDs and sets them up as MMC devices.
-- 
1.9.1