[PATCH 05/19] drivers: mtd: nand: cadence: Add support for read status command

[dinesh.maniyam@intel.com]

From: Dinesh Maniyam <dinesh.maniyam@intel.com>

This patch will add support for read status command
in Cadence NAND driver. This status bit is important to check
whether the flash is write-protected.

Signed-off-by: Dinesh Maniyam <dinesh.maniyam@intel.com>
---
 drivers/mtd/nand/raw/cadence_nand.c | 46 ++++++++++++++++++++++++++++-
 include/cadence-nand.h              |  2 ++
 2 files changed, 47 insertions(+), 1 deletion(-)

diff --git a/drivers/mtd/nand/raw/cadence_nand.c b/drivers/mtd/nand/raw/cadence_nand.c
index f9f28c392b..670f5ca184 100644
--- a/drivers/mtd/nand/raw/cadence_nand.c
+++ b/drivers/mtd/nand/raw/cadence_nand.c
@@ -343,6 +343,7 @@ static int cadence_nand_generic_cmd_send(struct cadence_nand_info *cadence,
 
 	/* Issue command. */
 	writel_relaxed(reg, cadence->reg + CMD_REG0);
+	cadence->buf_index = 0;
 
 	return 0;
 }
@@ -1902,9 +1903,42 @@ static void cadence_nand_select_chip(struct mtd_info *mtd, int chipnr)
 	}
 }
 
+static int cadence_nand_status(struct mtd_info *mtd, unsigned int command)
+{
+	struct cadence_nand_info *cadence = mtd_to_cadence(mtd);
+	int ret = 0;
+
+	ret = cadence_nand_cmd_opcode(cadence, command);
+	if (ret)
+		return ret;
+
+	ret = cadence_nand_cmd_data(cadence, 1, GCMD_DIR_READ);
+	if (ret)
+		return ret;
+
+	return 0;
+}
+
 static void cadence_nand_cmdfunc(struct mtd_info *mtd, unsigned int command,
 				 int offset_in_page, int page)
 {
+	struct cadence_nand_info *cadence = mtd_to_cadence(mtd);
+	int ret = 0;
+
+	cadence->cmd = command;
+	switch (command) {
+	case NAND_CMD_STATUS:
+		ret = cadence_nand_status(mtd, command);
+		break;
+	/*
+	 * ecc will override other command for read, write and erase
+	 */
+	default:
+		break;
+	}
+
+	if (ret != 0)
+		printf("ERROR:%s:command:0x%x\n", __func__, cadence->cmd);
 }
 
 static int cadence_nand_dev_ready(struct mtd_info *mtd)
@@ -1921,7 +1955,17 @@ static int cadence_nand_dev_ready(struct mtd_info *mtd)
 
 static u8 cadence_nand_read_byte(struct mtd_info *mtd)
 {
-	return 0;
+	struct cadence_nand_info *cadence = mtd_to_cadence(mtd);
+	u32 size = 1;
+	u8 val;
+
+	if (cadence->buf_index == 0)
+		cadence_nand_read_buf(mtd, &cadence->buf[0], size);
+
+	val = *(&cadence->buf[0] + cadence->buf_index);
+	cadence->buf_index++;
+
+	return val;
 }
 
 static void cadence_nand_write_byte(struct mtd_info *mtd, u8 byte)
diff --git a/include/cadence-nand.h b/include/cadence-nand.h
index 101f60ce0e..5b9d6e0382 100644
--- a/include/cadence-nand.h
+++ b/include/cadence-nand.h
@@ -453,6 +453,8 @@ struct cadence_nand_info {
 	u8 *buf;
 	u32 buf_size;
 	u8 *stat;
+	u8 cmd;
+	u32 buf_index;
 
 	u8 curr_corr_str_idx;
 
-- 
2.26.2