sf: Simplify fastest read cmd code

Fastest read command code look for fastest read command
taking inputs from spi->mode_rx and flags from param table
and controller mode_rx is always been a priority.

Since mode_rx is always set from controller side this optimized
code doesn't require much and this code required exctra overhead like
1) Maintain e_rx_cmd in param table
2) Maintain mode_rx in spi_slave {}

Hence removed this code, and look for read command from normal
spi->mode from spi_slave{} and params->flags

Cc: Simon Glass <sjg@chromium.org>
Cc: Bin Meng <bmeng.cn@gmail.com>
Cc: Michal Simek <michal.simek@xilinx.com>
Cc: Siva Durga Prasad Paladugu <sivadur@xilinx.com>
Cc: Vignesh R <vigneshr@ti.com>
Cc: Mugunthan V N <mugunthanvnm@ti.com>
Signed-off-by: Jagan Teki <jteki@openedev.com>

drivers/mtd/spi/sf_internal.h

@@ -46,6 +46,10 @@ enum {
 	E_FSR		= BIT(2),
 	SST_WR		= BIT(3),
 	WR_QPP		= BIT(4),
+	RD_QUAD		= BIT(5),
+	RD_DUAL		= BIT(6),
+	RD_QUADIO	= BIT(7),
+	RD_DUALIO	= BIT(8),
 };
 
 enum spi_nor_option_flags {

drivers/mtd/spi/spi_flash.c

@@ -1013,15 +1013,8 @@ int spi_flash_scan(struct spi_flash *flash)
 	struct spi_slave *spi = flash->spi;
 	const struct spi_flash_params *params;
 	u16 jedec, ext_jedec;
-	u8 cmd, idcode[5];
+	u8 idcode[5];
 	int ret;
-	static u8 spi_read_cmds_array[] = {
-		CMD_READ_ARRAY_SLOW,
-		CMD_READ_ARRAY_FAST,
-		CMD_READ_DUAL_OUTPUT_FAST,
-		CMD_READ_QUAD_OUTPUT_FAST,
-		CMD_READ_DUAL_IO_FAST,
-		CMD_READ_QUAD_IO_FAST };
 
 	/* Read the ID codes */
 	ret = spi_flash_cmd(spi, CMD_READ_ID, idcode, sizeof(idcode));
@@ -1177,17 +1170,16 @@ int spi_flash_scan(struct spi_flash *flash)
 	/* Now erase size becomes valid sector size */
 	flash->sector_size = flash->erase_size;
 
-	/* Look for the fastest read cmd */
-	cmd = fls(params->e_rd_cmd & spi->mode_rx);
-	if (cmd) {
-		cmd = spi_read_cmds_array[cmd - 1];
-		flash->read_cmd = cmd;
-	} else {
-		/* Go for default supported read cmd */
-		flash->read_cmd = CMD_READ_ARRAY_FAST;
-	}
+	/* Look for read commands */
+	flash->read_cmd = CMD_READ_ARRAY_FAST;
+	if (spi->mode_rx & SPI_RX_SLOW)
+		flash->read_cmd = CMD_READ_ARRAY_SLOW;
+	else if (spi->mode_rx & SPI_RX_QUAD && params->flags & RD_QUAD)
+		flash->read_cmd = CMD_READ_QUAD_OUTPUT_FAST;
+	else if (spi->mode_rx & SPI_RX_DUAL && params->flags & RD_DUAL)
+		flash->read_cmd = CMD_READ_DUAL_OUTPUT_FAST;
 
-	/* Not require to look for fastest only two write cmds yet */
+	/* Look for write commands */
 	if (params->flags & WR_QPP && spi->mode & SPI_TX_QUAD)
 		flash->write_cmd = CMD_QUAD_PAGE_PROGRAM;
 	else