lkml.org 
[lkml]   [2019]   [Mar]   [20]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH] nvmem: core: fix read buffer in place
Date
When the bit_offset in the cell is zero, the pointer to the msb will
not be properly initialized (ie, will still be pointing to the first
byte in the buffer).

This being the case, if there are bits to clear in the msb, those will
be left untouched while the mask will incorrectly clear bit positions
on the first byte.

This commit also makes sure that any byte unused in the cell is
cleared.

Signed-off-by: Jorge Ramirez-Ortiz <jorge.ramirez-ortiz@linaro.org>
---
drivers/nvmem/core.c | 15 ++++++++++-----
1 file changed, 10 insertions(+), 5 deletions(-)

diff --git a/drivers/nvmem/core.c b/drivers/nvmem/core.c
index f24008b66826..53dc37574b5d 100644
--- a/drivers/nvmem/core.c
+++ b/drivers/nvmem/core.c
@@ -1166,7 +1166,7 @@ EXPORT_SYMBOL_GPL(nvmem_cell_put);
static void nvmem_shift_read_buffer_in_place(struct nvmem_cell *cell, void *buf)
{
u8 *p, *b;
- int i, bit_offset = cell->bit_offset;
+ int i, extra, bit_offset = cell->bit_offset;

p = b = buf;
if (bit_offset) {
@@ -1181,11 +1181,16 @@ static void nvmem_shift_read_buffer_in_place(struct nvmem_cell *cell, void *buf)
p = b;
*b++ >>= bit_offset;
}
-
- /* result fits in less bytes */
- if (cell->bytes != DIV_ROUND_UP(cell->nbits, BITS_PER_BYTE))
- *p-- = 0;
+ } else {
+ /* point to the msb */
+ p += cell->bytes - 1;
}
+
+ /* result fits in less bytes */
+ extra = cell->bytes - DIV_ROUND_UP(cell->nbits, BITS_PER_BYTE);
+ while (--extra >= 0)
+ *p-- = 0;
+
/* clear msb bits if any leftover in the last byte */
*p &= GENMASK((cell->nbits%BITS_PER_BYTE) - 1, 0);
}
--
2.20.1
\
 
 \ /
  Last update: 2019-03-20 20:33    [W:0.032 / U:0.016 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site