Patch "tty: serial: fsl_lpuart: make rx_watermark configurable for different platforms" has been added to the 5.15-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    tty: serial: fsl_lpuart: make rx_watermark configurable for different platforms

to the 5.15-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:
     tty-serial-fsl_lpuart-make-rx_watermark-configurable.patch
and it can be found in the queue-5.15 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit be1b5fa87112e48ee00e6feae3a7797a789d07f0
Author: Sherry Sun <sherry.sun@xxxxxxx>
Date:   Mon Jan 30 14:44:44 2023 +0800

    tty: serial: fsl_lpuart: make rx_watermark configurable for different platforms
    
    [ Upstream commit 34ebb26f12a84b744f43c5c4869516f122a2dfaa ]
    
    Add rx_watermark parameter for struct lpuart_port to make the receive
    watermark configurable for different platforms.
    No function changed.
    
    Signed-off-by: Sherry Sun <sherry.sun@xxxxxxx>
    Link: https://lore.kernel.org/r/20230130064449.9564-2-sherry.sun@xxxxxxx
    Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
    Stable-dep-of: a82c3df955f8 ("tty: serial: fsl_lpuart: reduce RX watermark to 0 on LS1028A")
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/drivers/tty/serial/fsl_lpuart.c b/drivers/tty/serial/fsl_lpuart.c
index bf709ea93ec97..380d9237989b2 100644
--- a/drivers/tty/serial/fsl_lpuart.c
+++ b/drivers/tty/serial/fsl_lpuart.c
@@ -257,6 +257,7 @@ struct lpuart_port {
 	unsigned int		txfifo_size;
 	unsigned int		rxfifo_size;
 
+	u8			rx_watermark;
 	bool			lpuart_dma_tx_use;
 	bool			lpuart_dma_rx_use;
 	struct dma_chan		*dma_tx_chan;
@@ -281,38 +282,45 @@ struct lpuart_soc_data {
 	enum lpuart_type devtype;
 	char iotype;
 	u8 reg_off;
+	u8 rx_watermark;
 };
 
 static const struct lpuart_soc_data vf_data = {
 	.devtype = VF610_LPUART,
 	.iotype = UPIO_MEM,
+	.rx_watermark = 1,
 };
 
 static const struct lpuart_soc_data ls1021a_data = {
 	.devtype = LS1021A_LPUART,
 	.iotype = UPIO_MEM32BE,
+	.rx_watermark = 1,
 };
 
 static const struct lpuart_soc_data ls1028a_data = {
 	.devtype = LS1028A_LPUART,
 	.iotype = UPIO_MEM32,
+	.rx_watermark = 1,
 };
 
 static struct lpuart_soc_data imx7ulp_data = {
 	.devtype = IMX7ULP_LPUART,
 	.iotype = UPIO_MEM32,
 	.reg_off = IMX_REG_OFF,
+	.rx_watermark = 1,
 };
 
 static struct lpuart_soc_data imx8qxp_data = {
 	.devtype = IMX8QXP_LPUART,
 	.iotype = UPIO_MEM32,
 	.reg_off = IMX_REG_OFF,
+	.rx_watermark = 1,
 };
 static struct lpuart_soc_data imxrt1050_data = {
 	.devtype = IMXRT1050_LPUART,
 	.iotype = UPIO_MEM32,
 	.reg_off = IMX_REG_OFF,
+	.rx_watermark = 1,
 };
 
 static const struct of_device_id lpuart_dt_ids[] = {
@@ -1556,7 +1564,7 @@ static void lpuart_setup_watermark(struct lpuart_port *sport)
 	}
 
 	writeb(0, sport->port.membase + UARTTWFIFO);
-	writeb(1, sport->port.membase + UARTRWFIFO);
+	writeb(sport->rx_watermark, sport->port.membase + UARTRWFIFO);
 
 	/* Restore cr2 */
 	writeb(cr2_saved, sport->port.membase + UARTCR2);
@@ -1591,7 +1599,8 @@ static void lpuart32_setup_watermark(struct lpuart_port *sport)
 	lpuart32_write(&sport->port, val, UARTFIFO);
 
 	/* set the watermark */
-	val = (0x1 << UARTWATER_RXWATER_OFF) | (0x0 << UARTWATER_TXWATER_OFF);
+	val = (sport->rx_watermark << UARTWATER_RXWATER_OFF) |
+	      (0x0 << UARTWATER_TXWATER_OFF);
 	lpuart32_write(&sport->port, val, UARTWATER);
 
 	/* Restore cr2 */
@@ -2736,6 +2745,7 @@ static int lpuart_probe(struct platform_device *pdev)
 	sport->port.dev = &pdev->dev;
 	sport->port.type = PORT_LPUART;
 	sport->devtype = sdata->devtype;
+	sport->rx_watermark = sdata->rx_watermark;
 	ret = platform_get_irq(pdev, 0);
 	if (ret < 0)
 		return ret;