[U-Boot] [PATCH] mtd: sf: Add CONFIG_SPI_N25Q256A_RESET for software-reset

[Pavel Machek]

This is needed for the SoCFPGA booting from SPI NOR flash
e.g. (N25Q256A) as long as u-boot-spl 2013 is used (newer one is not
available).

Signed-off-by: Stefan Roese <sr at denx.de>
Signed-off-by: Pavel Machek <pavel at denx.de>

---

Ported to today's u-boot version.

diff --git a/drivers/mtd/spi/sf_probe.c b/drivers/mtd/spi/sf_probe.c
index 201471c..f7cfbd9 100644
--- a/drivers/mtd/spi/sf_probe.c
+++ b/drivers/mtd/spi/sf_probe.c
@@ -347,6 +348,36 @@ int spi_flash_probe_slave(struct spi_slave *spi, struct spi_flash *flash)
 		}
 	}
 
+#ifdef CONFIG_SPI_N25Q256A_RESET
+#define CMD_RESET_ENABLE 0x66
+#define CMD_RESET_MEMORY 0x99
+	/*
+	 * This is needed for the SoCFPGA booting from SPI NOR flash
+	 * e.g. (N25Q256A), as U-Boot SPL 2013-socfpga (only version
+	 * working on that board) sets 4-byt addressing mode.
+	 *
+	 * Additionally it may be good idea to change
+	 * this line in the Linux SPI NOR flash driver:
+	 *
+	 * { "n25q256a", INFO(0x20ba19, 0, 64 * 1024,  512,
+	 *    SECT_4K | SHUTDOWN_3BYTE) },
+	 *
+	 * Add SHUTDOWN_3BYTE here.
+	 */
+	ret = spi_flash_cmd(spi, CMD_RESET_ENABLE, NULL, 0);
+	if (ret) {
+		printf("SF: Failed issue reset command\n");
+		goto err_read_id;
+	}
+
+	ret = spi_flash_cmd(spi, CMD_RESET_MEMORY, NULL, 0);
+	if (ret) {
+		printf("SF: Failed issue reset command\n");
+		goto err_read_id;
+	}
+
+	printf("SF: Device software reset\n");
+#endif
 #ifdef CONFIG_OF_CONTROL
 	if (spi_flash_decode_fdt(gd->fdt_blob, flash)) {
 		debug("SF: FDT decode error\n");

-- 
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