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-rw-r--r--target/linux/layerscape/patches-4.4/1095-mtd-spi-nor-simplify-write-loop.patch100
1 files changed, 100 insertions, 0 deletions
diff --git a/target/linux/layerscape/patches-4.4/1095-mtd-spi-nor-simplify-write-loop.patch b/target/linux/layerscape/patches-4.4/1095-mtd-spi-nor-simplify-write-loop.patch
new file mode 100644
index 0000000000..8eb957db5d
--- /dev/null
+++ b/target/linux/layerscape/patches-4.4/1095-mtd-spi-nor-simplify-write-loop.patch
@@ -0,0 +1,100 @@
+From 93b40e12f7e580a41c4aee5597579cc539fd8544 Mon Sep 17 00:00:00 2001
+From: Michal Suchanek <hramrach@gmail.com>
+Date: Wed, 2 Dec 2015 10:38:20 +0000
+Subject: [PATCH 095/113] mtd: spi-nor: simplify write loop
+
+The spi-nor write loop assumes that what is passed to the hardware
+driver write() is what gets written.
+
+When write() writes less than page size at once data is dropped on the
+floor. Check the amount of data writen and exit if it does not match
+requested amount.
+
+Signed-off-by: Michal Suchanek <hramrach@gmail.com>
+Signed-off-by: Hou Zhiqiang <Zhiqiang.Hou@freescale.com>
+---
+ drivers/mtd/spi-nor/spi-nor.c | 58 ++++++++++++++++++-----------------------
+ 1 file changed, 25 insertions(+), 33 deletions(-)
+
+--- a/drivers/mtd/spi-nor/spi-nor.c
++++ b/drivers/mtd/spi-nor/spi-nor.c
+@@ -1017,8 +1017,8 @@ static int spi_nor_write(struct mtd_info
+ size_t *retlen, const u_char *buf)
+ {
+ struct spi_nor *nor = mtd_to_spi_nor(mtd);
+- u32 page_offset, page_size, i;
+- int ret;
++ size_t page_offset, page_remain, i;
++ ssize_t ret;
+
+ dev_dbg(nor->dev, "to 0x%08x, len %zd\n", (u32)to, len);
+
+@@ -1026,45 +1026,37 @@ static int spi_nor_write(struct mtd_info
+ if (ret)
+ return ret;
+
+- write_enable(nor);
++ for (i = 0; i < len; ) {
++ ssize_t written;
+
+- page_offset = to & (nor->page_size - 1);
+-
+- /* do all the bytes fit onto one page? */
+- if (page_offset + len <= nor->page_size) {
+- ret = nor->write(nor, to, len, buf);
+- if (ret < 0)
+- goto write_err;
+- *retlen += ret;
+- } else {
++ page_offset = to & (nor->page_size - 1);
++ WARN_ONCE(page_offset,
++ "Writing at offset %zu into a NOR page. Writing partial pages may decrease reliability and increase wear of NOR flash.",
++ page_offset);
+ /* the size of data remaining on the first page */
+- page_size = nor->page_size - page_offset;
+- ret = nor->write(nor, to, page_size, buf);
++ page_remain = min_t(size_t,
++ nor->page_size - page_offset, len - i);
++
++ write_enable(nor);
++ ret = nor->write(nor, to + i, page_remain, buf + i);
+ if (ret < 0)
+ goto write_err;
+- *retlen += ret;
++ written = ret;
+
+- /* write everything in nor->page_size chunks */
+- for (i = ret; i < len; ) {
+- page_size = len - i;
+- if (page_size > nor->page_size)
+- page_size = nor->page_size;
+-
+- ret = spi_nor_wait_till_ready(nor);
+- if (ret)
+- goto write_err;
+-
+- write_enable(nor);
+-
+- ret = nor->write(nor, to + i, page_size, buf + i);
+- if (ret < 0)
+- goto write_err;
+- *retlen += ret;
+- i += ret;
++ ret = spi_nor_wait_till_ready(nor);
++ if (ret)
++ goto write_err;
++ *retlen += written;
++ i += written;
++ if (written != page_remain) {
++ dev_err(nor->dev,
++ "While writing %zu bytes written %zd bytes\n",
++ page_remain, written);
++ ret = -EIO;
++ goto write_err;
+ }
+ }
+
+- ret = spi_nor_wait_till_ready(nor);
+ write_err:
+ spi_nor_unlock_and_unprep(nor, SPI_NOR_OPS_WRITE);
+ return ret;