From 46c6975a1fd9794ed979565235d24b2f5004e014 Mon Sep 17 00:00:00 2001 From: Marc Zyngier Date: Sun, 22 Apr 2018 13:33:46 +0100 Subject: serial: mvebu-uart: Fix local flags handling on termios update Commit 68a0db1d7da2 reworked the baud rate selection, but also added a (not so) subtle change in the way the local flags (c_lflag in the termios structure) are handled, forcing the new flags to always be the same as the old ones. The reason for that particular change is both obscure and undocumented. It also completely breaks userspace. Something as trivial as getty is unusable: Debian GNU/Linux 9 sy-borg ttyMV0 sy-borg login: root root [timeout] Debian GNU/Linux 9 sy-borg ttyMV0 which is quite obvious in retrospect: getty cannot get in control of the echo mode, is stuck in canonical mode, and times out without ever seeing anything valid. It also begs the question of how this change was ever tested. The fix is pretty obvious: stop messing with c_lflag, and the world will be a happier place. Cc: stable@vger.kernel.org # 4.15+ Fixes: 68a0db1d7da2 ("serial: mvebu-uart: add function to change baudrate") Signed-off-by: Marc Zyngier Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/mvebu-uart.c | 1 - 1 file changed, 1 deletion(-) (limited to 'drivers/tty/serial') diff --git a/drivers/tty/serial/mvebu-uart.c b/drivers/tty/serial/mvebu-uart.c index 750e5645dc85..f503fab1e268 100644 --- a/drivers/tty/serial/mvebu-uart.c +++ b/drivers/tty/serial/mvebu-uart.c @@ -495,7 +495,6 @@ static void mvebu_uart_set_termios(struct uart_port *port, termios->c_iflag |= old->c_iflag & ~(INPCK | IGNPAR); termios->c_cflag &= CREAD | CBAUD; termios->c_cflag |= old->c_cflag & ~(CREAD | CBAUD); - termios->c_lflag = old->c_lflag; } spin_unlock_irqrestore(&port->lock, flags); -- cgit v1.2.1 From 6d215f83e5fccb3dd023e97fef1bd0029bfedde9 Mon Sep 17 00:00:00 2001 From: Stefan Agner Date: Thu, 19 Apr 2018 17:39:16 +0200 Subject: serial: imx: warn user when using unsupported configuration MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit When using half-duplex mode (which disables receiver during txing) the RTS signal cannot be driven low during transmission when using i.MX UART RTS/CTS control. This seems to be a limitation of the i.MX UART IP: The RTS (CTS_B) signal is controlled by the receiver. When the receiver is disabled, the signal stays in UART logic idle state which is high... If SER_RS485_RTS_ON_SEND is used, RTS needs to be high active during transmission. Since this is the default state of the RTS (CTS_B) signal when the receiver is off, half-duplex mode in this configuration works fine. However, a low-active RTS signal (flag SER_RS485_RTS_ON_SEND not set) cannot be generated when the receiver is turned off. Print an error if the user selects this unsupported configuration (both SER_RS485_RTS_ON_SEND and SER_RS485_RX_DURING_TX unset) and configure the closest working configuration (set the SER_RS485_RX_DURING_TX flag). Signed-off-by: Stefan Agner Acked-by: Uwe Kleine-König Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/imx.c | 17 +++++++++++++++++ 1 file changed, 17 insertions(+) (limited to 'drivers/tty/serial') diff --git a/drivers/tty/serial/imx.c b/drivers/tty/serial/imx.c index 91f3a1a5cb7f..65d7a2bfb6d2 100644 --- a/drivers/tty/serial/imx.c +++ b/drivers/tty/serial/imx.c @@ -1833,6 +1833,11 @@ static int imx_uart_rs485_config(struct uart_port *port, rs485conf->flags &= ~SER_RS485_ENABLED; if (rs485conf->flags & SER_RS485_ENABLED) { + /* Enable receiver if low-active RTS signal is requested */ + if (sport->have_rtscts && !sport->have_rtsgpio && + !(rs485conf->flags & SER_RS485_RTS_ON_SEND)) + rs485conf->flags |= SER_RS485_RX_DURING_TX; + /* disable transmitter */ ucr2 = imx_uart_readl(sport, UCR2); if (rs485conf->flags & SER_RS485_RTS_AFTER_SEND) @@ -2265,6 +2270,18 @@ static int imx_uart_probe(struct platform_device *pdev) (!sport->have_rtscts && !sport->have_rtsgpio)) dev_err(&pdev->dev, "no RTS control, disabling rs485\n"); + /* + * If using the i.MX UART RTS/CTS control then the RTS (CTS_B) + * signal cannot be set low during transmission in case the + * receiver is off (limitation of the i.MX UART IP). + */ + if (sport->port.rs485.flags & SER_RS485_ENABLED && + sport->have_rtscts && !sport->have_rtsgpio && + (!(sport->port.rs485.flags & SER_RS485_RTS_ON_SEND) && + !(sport->port.rs485.flags & SER_RS485_RX_DURING_TX))) + dev_err(&pdev->dev, + "low-active RTS not possible when receiver is off, enabling receiver\n"); + imx_uart_rs485_config(&sport->port, &sport->port.rs485); /* Disable interrupts before requesting them */ -- cgit v1.2.1 From 0aa821d846c0590ad64a00af95a3dcc29263d70f Mon Sep 17 00:00:00 2001 From: Stefan Agner Date: Fri, 20 Apr 2018 14:44:07 +0200 Subject: serial: imx: fix cached UCR2 read on software reset MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit To reset the UART the SRST needs be cleared (low active). According to the documentation the bit will remain active for 4 module clocks until it is cleared (set to 1). Hence the real register need to be read in case the cached register indicates that the SRST bit is zero. This bug lead to wrong baudrate because the baud rate register got restored before reset completed in imx_flush_buffer. Fixes: 3a0ab62f43de ("serial: imx: implement shadow registers for UCRx and UFCR") Signed-off-by: Stefan Agner Reviewed-by: Fabio Estevam Reviewed-by: Uwe Kleine-König Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/imx.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'drivers/tty/serial') diff --git a/drivers/tty/serial/imx.c b/drivers/tty/serial/imx.c index 65d7a2bfb6d2..c2fc6bef7a6f 100644 --- a/drivers/tty/serial/imx.c +++ b/drivers/tty/serial/imx.c @@ -316,7 +316,7 @@ static u32 imx_uart_readl(struct imx_port *sport, u32 offset) * differ from the value that was last written. As it only * clears after being set, reread conditionally. */ - if (sport->ucr2 & UCR2_SRST) + if (!(sport->ucr2 & UCR2_SRST)) sport->ucr2 = readl(sport->port.membase + offset); return sport->ucr2; break; -- cgit v1.2.1 From dd709e72cb934eefd44de8d9969097173fbf45dc Mon Sep 17 00:00:00 2001 From: Daniel Kurtz Date: Fri, 6 Apr 2018 17:21:53 -0600 Subject: earlycon: Use a pointer table to fix __earlycon_table stride Commit 99492c39f39f ("earlycon: Fix __earlycon_table stride") tried to fix __earlycon_table stride by forcing the earlycon_id struct alignment to 32 and asking the linker to 32-byte align the __earlycon_table symbol. This fix was based on commit 07fca0e57fca92 ("tracing: Properly align linker defined symbols") which tried a similar fix for the tracing subsystem. However, this fix doesn't quite work because there is no guarantee that gcc will place structures packed into an array format. In fact, gcc 4.9 chooses to 64-byte align these structs by inserting additional padding between the entries because it has no clue that they are supposed to be in an array. If we are unlucky, the linker will assign symbol "__earlycon_table" to a 32-byte aligned address which does not correspond to the 64-byte aligned contents of section "__earlycon_table". To address this same problem, the fix to the tracing system was subsequently re-implemented using a more robust table of pointers approach by commits: 3d56e331b653 ("tracing: Replace syscall_meta_data struct array with pointer array") 654986462939 ("tracepoints: Fix section alignment using pointer array") e4a9ea5ee7c8 ("tracing: Replace trace_event struct array with pointer array") Let's use this same "array of pointers to structs" approach for EARLYCON_TABLE. Fixes: 99492c39f39f ("earlycon: Fix __earlycon_table stride") Signed-off-by: Daniel Kurtz Suggested-by: Aaron Durbin Reviewed-by: Rob Herring Tested-by: Guenter Roeck Reviewed-by: Guenter Roeck Cc: stable Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/earlycon.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) (limited to 'drivers/tty/serial') diff --git a/drivers/tty/serial/earlycon.c b/drivers/tty/serial/earlycon.c index a24278380fec..22683393a0f2 100644 --- a/drivers/tty/serial/earlycon.c +++ b/drivers/tty/serial/earlycon.c @@ -169,7 +169,7 @@ static int __init register_earlycon(char *buf, const struct earlycon_id *match) */ int __init setup_earlycon(char *buf) { - const struct earlycon_id *match; + const struct earlycon_id **p_match; if (!buf || !buf[0]) return -EINVAL; @@ -177,7 +177,9 @@ int __init setup_earlycon(char *buf) if (early_con.flags & CON_ENABLED) return -EALREADY; - for (match = __earlycon_table; match < __earlycon_table_end; match++) { + for (p_match = __earlycon_table; p_match < __earlycon_table_end; + p_match++) { + const struct earlycon_id *match = *p_match; size_t len = strlen(match->name); if (strncmp(buf, match->name, len)) -- cgit v1.2.1 From 066cd1c4e4b9b43116f2bf0f4a84ac7235e7abec Mon Sep 17 00:00:00 2001 From: Karthikeyan Ramasubramanian Date: Fri, 6 Apr 2018 18:49:00 -0600 Subject: tty: serial: qcom_geni_serial: Use signed variable to get IRQ The platform_get_irq can return error. Assigning the return value to an unsigned variable and checking it for negative value will always return false. Use an intermediate signed variable to get IRQ information, check for any error and then assign it to 'irq' variable inside uart_port structure. Signed-off-by: Karthikeyan Ramasubramanian Reported-by: Dan Carpenter Reviewed-by: Stephen Boyd Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/qcom_geni_serial.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) (limited to 'drivers/tty/serial') diff --git a/drivers/tty/serial/qcom_geni_serial.c b/drivers/tty/serial/qcom_geni_serial.c index 65ff669373d4..a1b3eb04cb32 100644 --- a/drivers/tty/serial/qcom_geni_serial.c +++ b/drivers/tty/serial/qcom_geni_serial.c @@ -1022,6 +1022,7 @@ static int qcom_geni_serial_probe(struct platform_device *pdev) struct qcom_geni_serial_port *port; struct uart_port *uport; struct resource *res; + int irq; if (pdev->dev.of_node) line = of_alias_get_id(pdev->dev.of_node, "serial"); @@ -1061,11 +1062,12 @@ static int qcom_geni_serial_probe(struct platform_device *pdev) port->rx_fifo_depth = DEF_FIFO_DEPTH_WORDS; port->tx_fifo_width = DEF_FIFO_WIDTH_BITS; - uport->irq = platform_get_irq(pdev, 0); - if (uport->irq < 0) { - dev_err(&pdev->dev, "Failed to get IRQ %d\n", uport->irq); - return uport->irq; + irq = platform_get_irq(pdev, 0); + if (irq < 0) { + dev_err(&pdev->dev, "Failed to get IRQ %d\n", irq); + return irq; } + uport->irq = irq; uport->private_data = &qcom_geni_console_driver; platform_set_drvdata(pdev, port); -- cgit v1.2.1 From 66dd99c2033684169f04068f66c7f83f7da229b8 Mon Sep 17 00:00:00 2001 From: Michal Simek Date: Mon, 23 Apr 2018 10:55:21 +0200 Subject: tty: serial: xuartps: Setup early console when uartclk is also passed Baudrate calculation depends on requested baudrate and uart clock. This patch is checking that uartclk is also passed. The same logic is used 8250_early.c/init_port function. Signed-off-by: Michal Simek Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/xilinx_uartps.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'drivers/tty/serial') diff --git a/drivers/tty/serial/xilinx_uartps.c b/drivers/tty/serial/xilinx_uartps.c index abcb4d09a2d8..bd72dd843338 100644 --- a/drivers/tty/serial/xilinx_uartps.c +++ b/drivers/tty/serial/xilinx_uartps.c @@ -1181,7 +1181,7 @@ static int __init cdns_early_console_setup(struct earlycon_device *device, /* only set baud if specified on command line - otherwise * assume it has been initialized by a boot loader. */ - if (device->baud) { + if (port->uartclk && device->baud) { u32 cd = 0, bdiv = 0; u32 mr; int div8; -- cgit v1.2.1