Patch "serial: sprd: getting port index via serial aliases only" has been added to the 5.4-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

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

    serial: sprd: getting port index via serial aliases only

to the 5.4-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:
     serial-sprd-getting-port-index-via-serial-aliases-on.patch
and it can be found in the queue-5.4 subdirectory.

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



commit 9f24d2754195a7e0f8374a57ca3e5b08702c902a
Author: Chunyan Zhang <chunyan.zhang@xxxxxxxxxx>
Date:   Wed Mar 18 18:50:48 2020 +0800

    serial: sprd: getting port index via serial aliases only
    
    [ Upstream commit 4b7349cb4e26e79429ecd619eb588bf384f69fdb ]
    
    This patch simplifies the process of getting serial port number, with
    this patch, serial devices must have aliases configured in devicetree.
    
    The serial port searched out via sprd_port array maybe wrong if we don't
    have serial alias defined in devicetree, and specify console with command
    line, we would get the wrong port number if other serial ports probe
    failed before console's. So using aliases is mandatory.
    
    Reviewed-by: Baolin Wang <baolin.wang7@xxxxxxxxx>
    Signed-off-by: Chunyan Zhang <chunyan.zhang@xxxxxxxxxx>
    Link: https://lore.kernel.org/r/20200318105049.19623-2-zhang.lyra@xxxxxxxxx
    Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
    Stable-dep-of: f9608f188756 ("serial: sprd: Assign sprd_port after initialized to avoid wrong access")
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/drivers/tty/serial/sprd_serial.c b/drivers/tty/serial/sprd_serial.c
index 07573de70445c..e6acf2c848f39 100644
--- a/drivers/tty/serial/sprd_serial.c
+++ b/drivers/tty/serial/sprd_serial.c
@@ -1073,29 +1073,6 @@ static struct uart_driver sprd_uart_driver = {
 	.cons = SPRD_CONSOLE,
 };
 
-static int sprd_probe_dt_alias(int index, struct device *dev)
-{
-	struct device_node *np;
-	int ret = index;
-
-	if (!IS_ENABLED(CONFIG_OF))
-		return ret;
-
-	np = dev->of_node;
-	if (!np)
-		return ret;
-
-	ret = of_alias_get_id(np, "serial");
-	if (ret < 0)
-		ret = index;
-	else if (ret >= ARRAY_SIZE(sprd_port) || sprd_port[ret] != NULL) {
-		dev_warn(dev, "requested serial port %d not available.\n", ret);
-		ret = index;
-	}
-
-	return ret;
-}
-
 static int sprd_remove(struct platform_device *dev)
 {
 	struct sprd_uart_port *sup = platform_get_drvdata(dev);
@@ -1173,14 +1150,11 @@ static int sprd_probe(struct platform_device *pdev)
 	int index;
 	int ret;
 
-	for (index = 0; index < ARRAY_SIZE(sprd_port); index++)
-		if (sprd_port[index] == NULL)
-			break;
-
-	if (index == ARRAY_SIZE(sprd_port))
-		return -EBUSY;
-
-	index = sprd_probe_dt_alias(index, &pdev->dev);
+	index = of_alias_get_id(pdev->dev.of_node, "serial");
+	if (index < 0 || index >= ARRAY_SIZE(sprd_port)) {
+		dev_err(&pdev->dev, "got a wrong serial alias id %d\n", index);
+		return -EINVAL;
+	}
 
 	sprd_port[index] = devm_kzalloc(&pdev->dev, sizeof(*sprd_port[index]),
 					GFP_KERNEL);