From af9a1f61ac331c2f910d9186767d02f8e982c38e Mon Sep 17 00:00:00 2001 From: Mikko Perttunen Date: Wed, 9 Jun 2021 18:56:55 +0300 Subject: [PATCH] serial: tegra-tcu: Reorder channel initialization Request the RX mailbox only after initializing the UART data structures. Otherwise it can rarely happen that the receive callback is called before the UART is ready. Fixes: 2d908b38d409 ("serial: Add Tegra Combined UART driver") Signed-off-by: Mikko Perttunen Link: https://lore.kernel.org/r/20210609155655.3567545-1-mperttunen@nvidia.com Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/tegra-tcu.c | 26 +++++++++++++++----------- 1 file changed, 15 insertions(+), 11 deletions(-) diff --git a/drivers/tty/serial/tegra-tcu.c b/drivers/tty/serial/tegra-tcu.c index 52687c65ad745..4877c54c613d1 100644 --- a/drivers/tty/serial/tegra-tcu.c +++ b/drivers/tty/serial/tegra-tcu.c @@ -195,13 +195,6 @@ static int tegra_tcu_probe(struct platform_device *pdev) return err; } - tcu->rx = mbox_request_channel_byname(&tcu->rx_client, "rx"); - if (IS_ERR(tcu->rx)) { - err = PTR_ERR(tcu->rx); - dev_err(&pdev->dev, "failed to get rx mailbox: %d\n", err); - goto free_tx; - } - #if IS_ENABLED(CONFIG_SERIAL_TEGRA_TCU_CONSOLE) /* setup the console */ strcpy(tcu->console.name, "ttyTCU"); @@ -226,7 +219,7 @@ static int tegra_tcu_probe(struct platform_device *pdev) if (err) { dev_err(&pdev->dev, "failed to register UART driver: %d\n", err); - goto free_rx; + goto free_tx; } /* setup the port */ @@ -246,6 +239,17 @@ static int tegra_tcu_probe(struct platform_device *pdev) goto unregister_uart; } + /* + * Request RX channel after creating port to ensure tcu->port + * is ready for any immediate incoming bytes. + */ + tcu->rx = mbox_request_channel_byname(&tcu->rx_client, "rx"); + if (IS_ERR(tcu->rx)) { + err = PTR_ERR(tcu->rx); + dev_err(&pdev->dev, "failed to get rx mailbox: %d\n", err); + goto remove_uart_port; + } + platform_set_drvdata(pdev, tcu); #if IS_ENABLED(CONFIG_SERIAL_TEGRA_TCU_CONSOLE) register_console(&tcu->console); @@ -253,10 +257,10 @@ static int tegra_tcu_probe(struct platform_device *pdev) return 0; +remove_uart_port: + uart_remove_one_port(&tcu->driver, &tcu->port); unregister_uart: uart_unregister_driver(&tcu->driver); -free_rx: - mbox_free_channel(tcu->rx); free_tx: mbox_free_channel(tcu->tx); @@ -270,9 +274,9 @@ static int tegra_tcu_remove(struct platform_device *pdev) #if IS_ENABLED(CONFIG_SERIAL_TEGRA_TCU_CONSOLE) unregister_console(&tcu->console); #endif + mbox_free_channel(tcu->rx); uart_remove_one_port(&tcu->driver, &tcu->port); uart_unregister_driver(&tcu->driver); - mbox_free_channel(tcu->rx); mbox_free_channel(tcu->tx); return 0; -- 2.30.2