From: Michal Suchanek <hramrach@gmail.com>
Date: Fri, 6 May 2016 00:31:55 +0000 (-0700)
Subject: mtd: spi-nor: add read loop
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=26f9bcad29a6c240881bd4efc90f16a9990dd6c2;p=linux-beck.git

mtd: spi-nor: add read loop

mtdblock and ubi do not handle the situation when read returns less data
than requested. Loop in spi-nor until buffer is filled or an error is
returned.

Signed-off-by: Michal Suchanek <hramrach@gmail.com>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>
Tested-by Cyrille Pitchen <cyrille.pitchen@atmel.com>
Acked-by: Michal Suchanek <hramrach@gmail.com>
Tested-by: Michal Suchanek <hramrach@gmail.com>
---

diff --git a/drivers/mtd/spi-nor/spi-nor.c b/drivers/mtd/spi-nor/spi-nor.c
index fe55b48be5b3..a63922ed6385 100644
--- a/drivers/mtd/spi-nor/spi-nor.c
+++ b/drivers/mtd/spi-nor/spi-nor.c
@@ -1031,14 +1031,27 @@ static int spi_nor_read(struct mtd_info *mtd, loff_t from, size_t len,
 	if (ret)
 		return ret;
 
-	ret = nor->read(nor, from, len, buf);
+	while (len) {
+		ret = nor->read(nor, from, len, buf);
+		if (ret == 0) {
+			/* We shouldn't see 0-length reads */
+			ret = -EIO;
+			goto read_err;
+		}
+		if (ret < 0)
+			goto read_err;
 
-	spi_nor_unlock_and_unprep(nor, SPI_NOR_OPS_READ);
-	if (ret < 0)
-		return ret;
+		WARN_ON(ret > len);
+		*retlen += ret;
+		buf += ret;
+		from += ret;
+		len -= ret;
+	}
+	ret = 0;
 
-	*retlen += ret;
-	return 0;
+read_err:
+	spi_nor_unlock_and_unprep(nor, SPI_NOR_OPS_READ);
+	return ret;
 }
 
 static int sst_write(struct mtd_info *mtd, loff_t to, size_t len,