tty: serial: fsl_lpuart: fix potential bug when using both of_alias_get_id and ida_si...

[ Upstream commit f398e0aa325c61fa20903833a5b534ecb8e6e418 ]

Now fsl_lpuart driver use both of_alias_get_id() and ida_simple_get() in
.probe(), which has the potential bug. For example, when remove the
lpuart7 alias in dts, of_alias_get_id() will return error, then call
ida_simple_get() to allocate the id 0 for lpuart7, this may confilct
with the lpuart4 which has alias 0.

    aliases {
	...
        serial0 = &lpuart4;
        serial1 = &lpuart5;
        serial2 = &lpuart6;
        serial3 = &lpuart7;
    }

So remove the ida_simple_get() in .probe(), return an error directly
when calling of_alias_get_id() fails, which is consistent with other
uart drivers behavior.

Fixes: 3bc3206e1c0f ("serial: fsl_lpuart: Remove the alias node dependence")
Signed-off-by: Sherry Sun <sherry.sun@nxp.com>
Link: https://lore.kernel.org/r/20220321112211.8895-1-sherry.sun@nxp.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/tty/serial/fsl_lpuart.c b/drivers/tty/serial/fsl_lpuart.c
index 33e5eba..481107f 100644 (file)
--- a/drivers/tty/serial/fsl_lpuart.c
+++ b/drivers/tty/serial/fsl_lpuart.c
@@ -239,8 +239,6 @@
 /* IMX lpuart has four extra unused regs located at the beginning */
 #define IMX_REG_OFF    0x10
 
-static DEFINE_IDA(fsl_lpuart_ida);
-
 enum lpuart_type {
        VF610_LPUART,
        LS1021A_LPUART,
@@ -275,7 +273,6 @@ struct lpuart_port {
        int                     rx_dma_rng_buf_len;
        unsigned int            dma_tx_nents;
        wait_queue_head_t       dma_wait;
-       bool                    id_allocated;
 };
 
 struct lpuart_soc_data {
@@ -2703,23 +2700,18 @@ static int lpuart_probe(struct platform_device *pdev)
 
        ret = of_alias_get_id(np, "serial");
        if (ret < 0) {
-               ret = ida_simple_get(&fsl_lpuart_ida, 0, UART_NR, GFP_KERNEL);
-               if (ret < 0) {
-                       dev_err(&pdev->dev, "port line is full, add device failed\n");
-                       return ret;
-               }
-               sport->id_allocated = true;
+               dev_err(&pdev->dev, "failed to get alias id, errno %d\n", ret);
+               return ret;
        }
        if (ret >= ARRAY_SIZE(lpuart_ports)) {
                dev_err(&pdev->dev, "serial%d out of range\n", ret);
-               ret = -EINVAL;
-               goto failed_out_of_range;
+               return -EINVAL;
        }
        sport->port.line = ret;
 
        ret = lpuart_enable_clks(sport);
        if (ret)
-               goto failed_clock_enable;
+               return ret;
        sport->port.uartclk = lpuart_get_baud_clk_rate(sport);
 
        lpuart_ports[sport->port.line] = sport;
@@ -2767,10 +2759,6 @@ failed_reset:
        uart_remove_one_port(&lpuart_reg, &sport->port);
 failed_attach_port:
        lpuart_disable_clks(sport);
-failed_clock_enable:
-failed_out_of_range:
-       if (sport->id_allocated)
-               ida_simple_remove(&fsl_lpuart_ida, sport->port.line);
        return ret;
 }
 
@@ -2780,9 +2768,6 @@ static int lpuart_remove(struct platform_device *pdev)
 
        uart_remove_one_port(&lpuart_reg, &sport->port);
 
-       if (sport->id_allocated)
-               ida_simple_remove(&fsl_lpuart_ida, sport->port.line);
-
        lpuart_disable_clks(sport);
 
        if (sport->dma_tx_chan)
@@ -2912,7 +2897,6 @@ static int __init lpuart_serial_init(void)
 
 static void __exit lpuart_serial_exit(void)
 {
-       ida_destroy(&fsl_lpuart_ida);
        platform_driver_unregister(&lpuart_driver);
        uart_unregister_driver(&lpuart_reg);
 }