From 74c2cee4e82bb71953267e87900e279ab5aa1dc3 Mon Sep 17 00:00:00 2001
From: Bin Meng <bmeng.cn@gmail.com>
Date: Fri, 12 Dec 2014 19:36:13 +0530
Subject: [PATCH] spi: sf: Support byte program for sst spi flash

Currently if SST flash advertises SST_WP flag in the params table
the word program command (ADh) with auto address increment will be
used for the flash write op. However some SPI controllers do not
support the word program command (like the Intel ICH 7), the byte
programm command (02h) has to be used.

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Acked-by: Simon Glass <sjg@chromium.org>
Tested-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Jagannadha Sutradharudu Teki <jagannadh.teki@gmail.com>
---
 drivers/mtd/spi/sf_internal.h |  2 ++
 drivers/mtd/spi/sf_ops.c      | 31 +++++++++++++++++++++++++++++++
 2 files changed, 33 insertions(+)

diff --git a/drivers/mtd/spi/sf_internal.h b/drivers/mtd/spi/sf_internal.h
index 7218e697a0..fb53cb0834 100644
--- a/drivers/mtd/spi/sf_internal.h
+++ b/drivers/mtd/spi/sf_internal.h
@@ -110,6 +110,8 @@ enum {
 
 int sst_write_wp(struct spi_flash *flash, u32 offset, size_t len,
 		const void *buf);
+int sst_write_bp(struct spi_flash *flash, u32 offset, size_t len,
+		const void *buf);
 #endif
 
 /**
diff --git a/drivers/mtd/spi/sf_ops.c b/drivers/mtd/spi/sf_ops.c
index 759231f2e3..34bc54e73e 100644
--- a/drivers/mtd/spi/sf_ops.c
+++ b/drivers/mtd/spi/sf_ops.c
@@ -517,4 +517,35 @@ int sst_write_wp(struct spi_flash *flash, u32 offset, size_t len,
 	spi_release_bus(flash->spi);
 	return ret;
 }
+
+int sst_write_bp(struct spi_flash *flash, u32 offset, size_t len,
+		const void *buf)
+{
+	size_t actual;
+	int ret;
+
+	ret = spi_claim_bus(flash->spi);
+	if (ret) {
+		debug("SF: Unable to claim SPI bus\n");
+		return ret;
+	}
+
+	for (actual = 0; actual < len; actual++) {
+		ret = sst_byte_write(flash, offset, buf + actual);
+		if (ret) {
+			debug("SF: sst byte program failed\n");
+			break;
+		}
+		offset++;
+	}
+
+	if (!ret)
+		ret = spi_flash_cmd_write_disable(flash);
+
+	debug("SF: sst: program %s %zu bytes @ 0x%zx\n",
+	      ret ? "failure" : "success", len, offset - actual);
+
+	spi_release_bus(flash->spi);
+	return ret;
+}
 #endif