This is a note to let you know that I've just added the patch titled
Revert "serial: 8250_mtk: Make sure to select the right FEATURE_SEL"
to the 5.18-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:
revert-serial-8250_mtk-make-sure-to-select-the-right.patch
and it can be found in the queue-5.18 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 7c05cb859a88b0fac8720c19bed12a733825c555
Author: AngeloGioacchino Del Regno <angelogioacchino.delregno@xxxxxxxxxxxxx>
Date: Tue May 10 14:26:20 2022 +0200
Revert "serial: 8250_mtk: Make sure to select the right FEATURE_SEL"
[ Upstream commit f0136f65285bcfb7e8f90d1013723076a35acd51 ]
It was found that some MediaTek SoCs are incompatible with this
change. Also, this register was mistakenly understood as it was
related to the 16550A register layout selection but, at least
on some IPs, if not all, it's related to something else unknown.
This reverts commit 6f81fdded0d024c7d4084d434764f30bca1cd6b1.
Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@xxxxxxxxxxxxx>
Fixes: 6f81fdded0d0 ("serial: 8250_mtk: Make sure to select the right FEATURE_SEL")
Reported-by: "kernelci.org bot" <bot@xxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20220510122620.150342-1-angelogioacchino.delregno@xxxxxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/tty/serial/8250/8250_mtk.c b/drivers/tty/serial/8250/8250_mtk.c
index 21053db93ff1..54051ec7b499 100644
--- a/drivers/tty/serial/8250/8250_mtk.c
+++ b/drivers/tty/serial/8250/8250_mtk.c
@@ -54,9 +54,6 @@
#define MTK_UART_TX_TRIGGER 1
#define MTK_UART_RX_TRIGGER MTK_UART_RX_SIZE
-#define MTK_UART_FEATURE_SEL 39 /* Feature Selection register */
-#define MTK_UART_FEAT_NEWRMAP BIT(0) /* Use new register map */
-
#define MTK_UART_XON1 40 /* I/O: Xon character 1 */
#define MTK_UART_XOFF1 42 /* I/O: Xoff character 1 */
@@ -575,10 +572,6 @@ static int mtk8250_probe(struct platform_device *pdev)
uart.dma = data->dma;
#endif
- /* Set AP UART new register map */
- writel(MTK_UART_FEAT_NEWRMAP, uart.port.membase +
- (MTK_UART_FEATURE_SEL << uart.port.regshift));
-
/* Disable Rate Fix function */
writel(0x0, uart.port.membase +
(MTK_UART_RATE_FIX << uart.port.regshift));
