brcm63xx: backport upstream solution for SPI message size limits

[openwrt/staging/noltari.git] / target / linux / brcm63xx / patches-4.4 / 000-4.8-09-mtd-spi-nor-add-read-loop.patch

diff --git a/target/linux/brcm63xx/patches-4.4/000-4.8-09-mtd-spi-nor-add-read-loop.patch b/target/linux/brcm63xx/patches-4.4/000-4.8-09-mtd-spi-nor-add-read-loop.patch
new file mode 100644 (file)
index 0000000..662c73a
--- /dev/null
+++ b/target/linux/brcm63xx/patches-4.4/000-4.8-09-mtd-spi-nor-add-read-loop.patch
@@ -0,0 +1,54 @@
+From 26f9bcad29a6c240881bd4efc90f16a9990dd6c2 Mon Sep 17 00:00:00 2001
+From: Michal Suchanek <hramrach@gmail.com>
+Date: Thu, 5 May 2016 17:31:55 -0700
+Subject: [PATCH 09/10] 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>
+---
+ drivers/mtd/spi-nor/spi-nor.c | 25 +++++++++++++++++++------
+ 1 file changed, 19 insertions(+), 6 deletions(-)
+
+--- a/drivers/mtd/spi-nor/spi-nor.c
++++ b/drivers/mtd/spi-nor/spi-nor.c
+@@ -890,14 +890,27 @@ static int spi_nor_read(struct mtd_info
+       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,