mtd: spi-nor: fix spansion quad enable

commit 807c16253319ee6ccf8873ae64f070f7eb532cd5 upstream.

With the S25FL127S nor flash part, each writing to the configuration
register takes hundreds of ms. During that  time, no more accesses to
the flash should be done (even reads).

This commit adds a wait loop after the register writing until the flash
finishes its work.

This issue could make rootfs mounting fail when the latter was done too
much closely to this quad enable bit setting step. And in this case, a
driver as UBIFS may try to recover the filesystem and may broke it
completely.

Signed-off-by: Joël Esponde <joel.esponde@honeywell.com>
Signed-off-by: Cyrille Pitchen <cyrille.pitchen@atmel.com>
Signed-off-by: Amit Pundir <amit.pundir@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/mtd/spi-nor/spi-nor.c b/drivers/mtd/spi-nor/spi-nor.c
index c51ee52386a71d9166dd178d57663f8da4636bfd..f17cee64e862c7319cfad1d83155b6358af6a20b 100644 (file)
--- a/drivers/mtd/spi-nor/spi-nor.c
+++ b/drivers/mtd/spi-nor/spi-nor.c
@@ -864,6 +864,13 @@ static int spansion_quad_enable(struct spi_nor *nor)
                return -EINVAL;
        }
 
+       ret = spi_nor_wait_till_ready(nor);
+       if (ret) {
+               dev_err(nor->dev,
+                       "timeout while writing configuration register\n");
+               return ret;
+       }
+
        /* read back and check it */
        ret = read_cr(nor);
        if (!(ret > 0 && (ret & CR_QUAD_EN_SPAN))) {