This is a note to let you know that I've just added the patch titled
regmap: Account for register length when chunking
to the 4.19-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
regmap-account-for-register-length-when-chunking.patch
and it can be found in the queue-4.19 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 3981514180c987a79ea98f0ae06a7cbf58a9ac0f Mon Sep 17 00:00:00 2001
From: Jim Wylder <jwylder@xxxxxxxxxx>
Date: Wed, 17 May 2023 10:20:11 -0500
Subject: regmap: Account for register length when chunking
From: Jim Wylder <jwylder@xxxxxxxxxx>
commit 3981514180c987a79ea98f0ae06a7cbf58a9ac0f upstream.
Currently, when regmap_raw_write() splits the data, it uses the
max_raw_write value defined for the bus. For any bus that includes
the target register address in the max_raw_write value, the chunked
transmission will always exceed the maximum transmission length.
To avoid this problem, subtract the length of the register and the
padding from the maximum transmission.
Signed-off-by: Jim Wylder <jwylder@xxxxxxxxxx
Link: https://lore.kernel.org/r/20230517152444.3690870-2-jwylder@xxxxxxxxxx
Signed-off-by: Mark Brown <broonie@xxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/base/regmap/regmap.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
--- a/drivers/base/regmap/regmap.c
+++ b/drivers/base/regmap/regmap.c
@@ -1825,6 +1825,8 @@ int _regmap_raw_write(struct regmap *map
size_t val_count = val_len / val_bytes;
size_t chunk_count, chunk_bytes;
size_t chunk_regs = val_count;
+ size_t max_data = map->max_raw_write - map->format.reg_bytes -
+ map->format.pad_bytes;
int ret, i;
if (!val_count)
@@ -1832,8 +1834,8 @@ int _regmap_raw_write(struct regmap *map
if (map->use_single_write)
chunk_regs = 1;
- else if (map->max_raw_write && val_len > map->max_raw_write)
- chunk_regs = map->max_raw_write / val_bytes;
+ else if (map->max_raw_write && val_len > max_data)
+ chunk_regs = max_data / val_bytes;
chunk_count = val_count / chunk_regs;
chunk_bytes = chunk_regs * val_bytes;
Patches currently in stable-queue which might be from jwylder@xxxxxxxxxx are
queue-4.19/regmap-account-for-register-length-when-chunking.patch
