6.12-stable review patch. If anyone has any objections, please let me know.
------------------
From: Maciej Andrzejewski <maciej.andrzejewski@xxxxxxxxxxx>
commit b086a46dae48829e11c0c02580e30d920b76743c upstream.
When two chip-selects are configured in the device tree, and the second is
a non-native GPIO, both the GPIO-based chip-select and the first native
chip-select may be asserted simultaneously. This double assertion causes
incorrect read and write operations.
The issue occurs because when nfc->ncs <= 2, nfc->spare_cs is always
initialized to 0 due to static initialization. Consequently, when the
second chip-select (GPIO-based) is selected in anfc_assert_cs(), it is
detected by anfc_is_gpio_cs(), and nfc->native_cs is assigned the value 0.
This results in both the GPIO-based chip-select being asserted and the
NAND controller register receiving 0, erroneously selecting the native
chip-select.
This patch resolves the issue, as confirmed by oscilloscope testing with
configurations involving two or more chip-selects in the device tree.
Fixes: acbd3d0945f9 ("mtd: rawnand: arasan: Leverage additional GPIO CS")
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Maciej Andrzejewski <maciej.andrzejewski@xxxxxxxxxxx>
Signed-off-by: Miquel Raynal <miquel.raynal@xxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/mtd/nand/raw/arasan-nand-controller.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
--- a/drivers/mtd/nand/raw/arasan-nand-controller.c
+++ b/drivers/mtd/nand/raw/arasan-nand-controller.c
@@ -1409,8 +1409,8 @@ static int anfc_parse_cs(struct arasan_n
* case, the "not" chosen CS is assigned to nfc->spare_cs and selected
* whenever a GPIO CS must be asserted.
*/
- if (nfc->cs_array && nfc->ncs > 2) {
- if (!nfc->cs_array[0] && !nfc->cs_array[1]) {
+ if (nfc->cs_array) {
+ if (nfc->ncs > 2 && !nfc->cs_array[0] && !nfc->cs_array[1]) {
dev_err(nfc->dev,
"Assign a single native CS when using GPIOs\n");
return -EINVAL;
