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 fe55b48..a63922e 100644 (file)
--- 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,