From 0e5ec4140c4a8a38c4ff7293c018eb7da69a30db Mon Sep 17 00:00:00 2001 From: Russell Enderby Date: Tue, 5 Sep 2017 12:16:47 -0500 Subject: serial: bcm63xx: fix timing issue. MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Issue where unprintable characters can occur or output is cut off over the serial uart / linux console depending on timing. Problem occurs when changing the serial baud rate when setting up the new console.The bcm63xx driver does a disable and flush of the uart tx fifo while there is data still in the tx fifo. If the tx fifo still has data it is trying to send out, we need to wait until it is empty before disabling and flushing the uart. When we now go to change the uart parameters including speed we check if there is data currently in the tx fifo.If there is was mdelay(10) and check again.If it tries 3 times and still has data in it we just continue and sacrifice the tx fifo buffer. A cleaner and more preferred approach would be to remove : - spin_lock_irqsave() - bcm_uart_disable() - bcm_uart_flush() However it is not clear if the author put those in to fix another underlying issue.As a result this solution is a safer approach. Output before the fix: [0.306000] 14e00520.serial: ttyS0 at MMIO 0x14e00520 (irq = 9, base_baud = 1687500) is a° 0.315000] console[ttyS0] enabled Output verified after the fix: [0.315000] 14e00520.serial: ttyS0 at MMIO 0x14e00520 (irq = 9, base_baud = 1687500) is a bcm63xx_uart [0.334000] console[ttyS0] enabled Signed-off-by: Russell Enderby Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/bcm63xx_uart.c | 5 +++++ 1 file changed, 5 insertions(+) (limited to 'drivers/tty/serial') diff --git a/drivers/tty/serial/bcm63xx_uart.c b/drivers/tty/serial/bcm63xx_uart.c index 583c9a0c7ecc..8c48c3784831 100644 --- a/drivers/tty/serial/bcm63xx_uart.c +++ b/drivers/tty/serial/bcm63xx_uart.c @@ -507,9 +507,14 @@ static void bcm_uart_set_termios(struct uart_port *port, { unsigned int ctl, baud, quot, ier; unsigned long flags; + int tries; spin_lock_irqsave(&port->lock, flags); + /* Drain the hot tub fully before we power it off for the winter. */ + for (tries = 3; !bcm_uart_tx_empty(port) && tries; tries--) + mdelay(10); + /* disable uart while changing speed */ bcm_uart_disable(port); bcm_uart_flush(port); -- cgit v1.2.3 From 9d7ee0e28da59b05647c3d2a7ad4076c16b1a6ef Mon Sep 17 00:00:00 2001 From: Fugang Duan Date: Mon, 4 Sep 2017 19:20:24 +0800 Subject: tty: serial: lpuart: avoid report NULL interrupt The current driver register irq in .startup() and free the irq in .shutdown(), then user will see the NULL interrupt output from 'cat /proc/interrupts' after the uart port test completed: ... 41: 515 0 0 0 GICv3 257 Level fsl-lpuart 42: 2 0 0 0 GICv3 258 Level ... It is better to register all the irqs during probe function via devm_request_irq() to avoid to call free_irq(). Signed-off-by: Fugang Duan Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/fsl_lpuart.c | 40 +++++++++++++++++----------------------- 1 file changed, 17 insertions(+), 23 deletions(-) (limited to 'drivers/tty/serial') diff --git a/drivers/tty/serial/fsl_lpuart.c b/drivers/tty/serial/fsl_lpuart.c index 849c1f9991ce..f0252184291e 100644 --- a/drivers/tty/serial/fsl_lpuart.c +++ b/drivers/tty/serial/fsl_lpuart.c @@ -1276,7 +1276,6 @@ static void rx_dma_timer_init(struct lpuart_port *sport) static int lpuart_startup(struct uart_port *port) { struct lpuart_port *sport = container_of(port, struct lpuart_port, port); - int ret; unsigned long flags; unsigned char temp; @@ -1291,11 +1290,6 @@ static int lpuart_startup(struct uart_port *port) sport->rxfifo_size = 0x1 << (((temp >> UARTPFIFO_RXSIZE_OFF) & UARTPFIFO_FIFOSIZE_MASK) + 1); - ret = devm_request_irq(port->dev, port->irq, lpuart_int, 0, - DRIVER_NAME, sport); - if (ret) - return ret; - spin_lock_irqsave(&sport->port.lock, flags); lpuart_setup_watermark(sport); @@ -1333,7 +1327,6 @@ static int lpuart_startup(struct uart_port *port) static int lpuart32_startup(struct uart_port *port) { struct lpuart_port *sport = container_of(port, struct lpuart_port, port); - int ret; unsigned long flags; unsigned long temp; @@ -1346,11 +1339,6 @@ static int lpuart32_startup(struct uart_port *port) sport->rxfifo_size = 0x1 << (((temp >> UARTFIFO_RXSIZE_OFF) & UARTFIFO_FIFOSIZE_MASK) - 1); - ret = devm_request_irq(port->dev, port->irq, lpuart32_int, 0, - DRIVER_NAME, sport); - if (ret) - return ret; - spin_lock_irqsave(&sport->port.lock, flags); lpuart32_setup_watermark(sport); @@ -1380,8 +1368,6 @@ static void lpuart_shutdown(struct uart_port *port) spin_unlock_irqrestore(&port->lock, flags); - devm_free_irq(port->dev, port->irq, sport); - if (sport->lpuart_dma_rx_use) { del_timer_sync(&sport->lpuart_timer); lpuart_dma_rx_free(&sport->port); @@ -1400,7 +1386,6 @@ static void lpuart_shutdown(struct uart_port *port) static void lpuart32_shutdown(struct uart_port *port) { - struct lpuart_port *sport = container_of(port, struct lpuart_port, port); unsigned long temp; unsigned long flags; @@ -1413,8 +1398,6 @@ static void lpuart32_shutdown(struct uart_port *port) lpuart32_write(port, temp, UARTCTRL); spin_unlock_irqrestore(&port->lock, flags); - - devm_free_irq(port->dev, port->irq, sport); } static void @@ -2212,16 +2195,22 @@ static int lpuart_probe(struct platform_device *pdev) platform_set_drvdata(pdev, &sport->port); - if (lpuart_is_32(sport)) + if (lpuart_is_32(sport)) { lpuart_reg.cons = LPUART32_CONSOLE; - else + ret = devm_request_irq(&pdev->dev, sport->port.irq, lpuart32_int, 0, + DRIVER_NAME, sport); + } else { lpuart_reg.cons = LPUART_CONSOLE; + ret = devm_request_irq(&pdev->dev, sport->port.irq, lpuart_int, 0, + DRIVER_NAME, sport); + } + + if (ret) + goto failed_irq_request; ret = uart_add_one_port(&lpuart_reg, &sport->port); - if (ret) { - clk_disable_unprepare(sport->clk); - return ret; - } + if (ret) + goto failed_attach_port; sport->dma_tx_chan = dma_request_slave_channel(sport->port.dev, "tx"); if (!sport->dma_tx_chan) @@ -2240,6 +2229,11 @@ static int lpuart_probe(struct platform_device *pdev) } return 0; + +failed_attach_port: +failed_irq_request: + clk_disable_unprepare(sport->clk); + return ret; } static int lpuart_remove(struct platform_device *pdev) -- cgit v1.2.3 From c91261437985d481c472639d4397931d77f5d4e9 Mon Sep 17 00:00:00 2001 From: Alexey Khoroshilov Date: Sat, 2 Sep 2017 23:13:55 +0300 Subject: serial: sccnxp: Fix error handling in sccnxp_probe() sccnxp_probe() returns result of regulator_disable() that may lead to returning zero, while device is not properly initialized. Also the driver enables clocks, but it does not disable it. Found by Linux Driver Verification project (linuxtesting.org). Signed-off-by: Alexey Khoroshilov Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/sccnxp.c | 13 +++++++++++-- 1 file changed, 11 insertions(+), 2 deletions(-) (limited to 'drivers/tty/serial') diff --git a/drivers/tty/serial/sccnxp.c b/drivers/tty/serial/sccnxp.c index cdd2f942317c..b9c7a904c1ea 100644 --- a/drivers/tty/serial/sccnxp.c +++ b/drivers/tty/serial/sccnxp.c @@ -889,7 +889,16 @@ static int sccnxp_probe(struct platform_device *pdev) goto err_out; uartclk = 0; } else { - clk_prepare_enable(clk); + ret = clk_prepare_enable(clk); + if (ret) + goto err_out; + + ret = devm_add_action_or_reset(&pdev->dev, + (void(*)(void *))clk_disable_unprepare, + clk); + if (ret) + goto err_out; + uartclk = clk_get_rate(clk); } @@ -988,7 +997,7 @@ static int sccnxp_probe(struct platform_device *pdev) uart_unregister_driver(&s->uart); err_out: if (!IS_ERR(s->regulator)) - return regulator_disable(s->regulator); + regulator_disable(s->regulator); return ret; } -- cgit v1.2.3