[PATCH 5.15 136/230] serial: 8250_mtk: Make sure to select the right FEATURE_SEL

Greg Kroah-Hartman
2022-07-11T09:59:48Z

From: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>

[ Upstream commit 6f81fdded0d024c7d4084d434764f30bca1cd6b1 ]

Set the FEATURE_SEL at probe time to make sure that BIT(0) is enabled:
this guarantees that when the port is configured as AP UART, the
right register layout is interpreted by the UART IP.

Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Cc: stable <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20220427132328.228297-3-angelogioacchino.delregno@collabora.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/tty/serial/8250/8250_mtk.c | 7 +++++++
1 file changed, 7 insertions(+)

diff --git a/drivers/tty/serial/8250/8250_mtk.c b/drivers/tty/serial/8250/8250_mtk.c
index de48a58460f4..de57f47635cd 100644
--- a/drivers/tty/serial/8250/8250_mtk.c
+++ b/drivers/tty/serial/8250/8250_mtk.c
@@ -57,6 +57,9 @@
#define MTK_UART_XON1 40 /* I/O: Xon character 1 */
#define MTK_UART_XOFF1 42 /* I/O: Xoff character 1 */

+#define MTK_UART_FEATURE_SEL 39 /* Feature Selection register */
+#define MTK_UART_FEAT_NEWRMAP BIT(0) /* Use new register map */
+
#ifdef CONFIG_SERIAL_8250_DMA
enum dma_rx_status {
DMA_RX_START = 0,
@@ -572,6 +575,10 @@ 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));
--
2.35.1