3 files changed, 48 insertions, 9 deletions

diff --git a/drivers/mtd/devices/block2mtd.c b/drivers/mtd/devices/block2mtd.c
index e2c0057737e6..b468819bc436 100644
--- a/drivers/mtd/devices/block2mtd.c
+++ b/drivers/mtd/devices/block2mtd.c
@@ -431,7 +431,7 @@ static int block2mtd_setup2(const char *val)
 }
 
 
-static int block2mtd_setup(const char *val, struct kernel_param *kp)
+static int block2mtd_setup(const char *val, const struct kernel_param *kp)
 {
 #ifdef MODULE
 	return block2mtd_setup2(val);
diff --git a/drivers/mtd/devices/phram.c b/drivers/mtd/devices/phram.c
index 8b66e52ca3cc..d312c1b5a78e 100644
--- a/drivers/mtd/devices/phram.c
+++ b/drivers/mtd/devices/phram.c
@@ -247,26 +247,29 @@ static int phram_setup(const char *val)
 
 	ret = parse_num64(&start, token[1]);
 	if (ret) {
-		kfree(name);
 		parse_err("illegal start address\n");
+		goto error;
 	}
 
 	ret = parse_num64(&len, token[2]);
 	if (ret) {
-		kfree(name);
 		parse_err("illegal device length\n");
+		goto error;
 	}
 
 	ret = register_device(name, start, len);
-	if (!ret)
-		pr_info("%s device: %#llx at %#llx\n", name, len, start);
-	else
-		kfree(name);
+	if (ret)
+		goto error;
+
+	pr_info("%s device: %#llx at %#llx\n", name, len, start);
+	return 0;
 
+error:
+	kfree(name);
 	return ret;
 }
 
-static int phram_param_call(const char *val, struct kernel_param *kp)
+static int phram_param_call(const char *val, const struct kernel_param *kp)
 {
 #ifdef MODULE
 	return phram_setup(val);
diff --git a/drivers/mtd/devices/spear_smi.c b/drivers/mtd/devices/spear_smi.c
index 64c7458344d4..ddf296666fb1 100644
--- a/drivers/mtd/devices/spear_smi.c
+++ b/drivers/mtd/devices/spear_smi.c
@@ -595,6 +595,26 @@ static int spear_mtd_read(struct mtd_info *mtd, loff_t from, size_t len,
 	return 0;
 }
 
+/*
+ * The purpose of this function is to ensure a memcpy_toio() with byte writes
+ * only. Its structure is inspired from the ARM implementation of _memcpy_toio()
+ * which also does single byte writes but cannot be used here as this is just an
+ * implementation detail and not part of the API. Not mentioning the comment
+ * stating that _memcpy_toio() should be optimized.
+ */
+static void spear_smi_memcpy_toio_b(volatile void __iomem *dest,
+				    const void *src, size_t len)
+{
+	const unsigned char *from = src;
+
+	while (len) {
+		len--;
+		writeb(*from, dest);
+		from++;
+		dest++;
+	}
+}
+
 static inline int spear_smi_cpy_toio(struct spear_smi *dev, u32 bank,
 		void __iomem *dest, const void *src, size_t len)
 {
@@ -617,7 +637,23 @@ static inline int spear_smi_cpy_toio(struct spear_smi *dev, u32 bank,
 	ctrlreg1 = readl(dev->io_base + SMI_CR1);
 	writel((ctrlreg1 | WB_MODE) & ~SW_MODE, dev->io_base + SMI_CR1);
 
-	memcpy_toio(dest, src, len);
+	/*
+	 * In Write Burst mode (WB_MODE), the specs states that writes must be:
+	 * - incremental
+	 * - of the same size
+	 * The ARM implementation of memcpy_toio() will optimize the number of
+	 * I/O by using as much 4-byte writes as possible, surrounded by
+	 * 2-byte/1-byte access if:
+	 * - the destination is not 4-byte aligned
+	 * - the length is not a multiple of 4-byte.
+	 * Avoid this alternance of write access size by using our own 'byte
+	 * access' helper if at least one of the two conditions above is true.
+	 */
+	if (IS_ALIGNED(len, sizeof(u32)) &&
+	    IS_ALIGNED((uintptr_t)dest, sizeof(u32)))
+		memcpy_toio(dest, src, len);
+	else
+		spear_smi_memcpy_toio_b(dest, src, len);
 
 	writel(ctrlreg1, dev->io_base + SMI_CR1);