Commit b086a46d authored by Maciej Andrzejewski's avatar Maciej Andrzejewski Committed by Miquel Raynal
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mtd: rawnand: arasan: Fix double assertion of chip-select 



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: acbd3d09 ("mtd: rawnand: arasan: Leverage additional GPIO CS")
Cc: stable@vger.kernel.org
Signed-off-by: default avatarMaciej Andrzejewski <maciej.andrzejewski@m-works.net>
Signed-off-by: default avatarMiquel Raynal <miquel.raynal@bootlin.com>
parent 9b458e8b

drivers/mtd/nand/raw/arasan-nand-controller.c

+2 −2
Original line number Diff line number Diff line
@@ -1409,8 +1409,8 @@ static int anfc_parse_cs(struct arasan_nfc *nfc) 
	 * 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;