From 9706fc87b4cff0ac4f5d5d62327be83fe72e3108 Mon Sep 17 00:00:00 2001 From: Stefan Eichenberger Date: Wed, 3 Jul 2024 13:25:40 +0200 Subject: serial: imx: only set receiver level if it is zero With commit a81dbd0463ec ("serial: imx: set receiver level before starting uart") we set the receiver level to its default value. This caused a regression when using SDMA, where the receiver level is 9 instead of 8 (default). This change will first check if the receiver level is zero and only then set it to the default. This still avoids the interrupt storm when the receiver level is zero. Fixes: a81dbd0463ec ("serial: imx: set receiver level before starting uart") Cc: stable Signed-off-by: Stefan Eichenberger Link: https://lore.kernel.org/r/20240703112543.148304-1-eichest@gmail.com Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/imx.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/drivers/tty/serial/imx.c b/drivers/tty/serial/imx.c index f4f40c9373c2..e22be8f45c93 100644 --- a/drivers/tty/serial/imx.c +++ b/drivers/tty/serial/imx.c @@ -120,6 +120,7 @@ #define UCR4_OREN (1<<1) /* Receiver overrun interrupt enable */ #define UCR4_DREN (1<<0) /* Recv data ready interrupt enable */ #define UFCR_RXTL_SHF 0 /* Receiver trigger level shift */ +#define UFCR_RXTL_MASK 0x3F /* Receiver trigger 6 bits wide */ #define UFCR_DCEDTE (1<<6) /* DCE/DTE mode select */ #define UFCR_RFDIV (7<<7) /* Reference freq divider mask */ #define UFCR_RFDIV_REG(x) (((x) < 7 ? 6 - (x) : 6) << 7) @@ -1933,7 +1934,7 @@ static int imx_uart_rs485_config(struct uart_port *port, struct ktermios *termio struct serial_rs485 *rs485conf) { struct imx_port *sport = (struct imx_port *)port; - u32 ucr2; + u32 ucr2, ufcr; if (rs485conf->flags & SER_RS485_ENABLED) { /* Enable receiver if low-active RTS signal is requested */ @@ -1953,7 +1954,10 @@ static int imx_uart_rs485_config(struct uart_port *port, struct ktermios *termio /* Make sure Rx is enabled in case Tx is active with Rx disabled */ if (!(rs485conf->flags & SER_RS485_ENABLED) || rs485conf->flags & SER_RS485_RX_DURING_TX) { - imx_uart_setup_ufcr(sport, TXTL_DEFAULT, RXTL_DEFAULT); + /* If the receiver trigger is 0, set it to a default value */ + ufcr = imx_uart_readl(sport, UFCR); + if ((ufcr & UFCR_RXTL_MASK) == 0) + imx_uart_setup_ufcr(sport, TXTL_DEFAULT, RXTL_DEFAULT); imx_uart_start_rx(port); } -- cgit From c128a1b0523b685c8856ddc0ac0e1caef1fdeee5 Mon Sep 17 00:00:00 2001 From: Udit Kumar Date: Tue, 25 Jun 2024 21:37:25 +0530 Subject: serial: 8250_omap: Fix Errata i2310 with RX FIFO level check Errata i2310[0] says, Erroneous timeout can be triggered, if this Erroneous interrupt is not cleared then it may leads to storm of interrupts. Commit 9d141c1e6157 ("serial: 8250_omap: Implementation of Errata i2310") which added the workaround but missed ensuring RX FIFO is really empty before applying the errata workaround as recommended in the errata text. Fix this by adding back check for UART_OMAP_RX_LVL to be 0 for workaround to take effect. [0] https://www.ti.com/lit/pdf/sprz536 page 23 Fixes: 9d141c1e6157 ("serial: 8250_omap: Implementation of Errata i2310") Cc: stable@vger.kernel.org Reported-by: Vignesh Raghavendra Closes: https://lore.kernel.org/all/e96d0c55-0b12-4cbf-9d23-48963543de49@ti.com/ Signed-off-by: Udit Kumar Link: https://lore.kernel.org/r/20240625160725.2102194-1-u-kumar1@ti.com Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/8250/8250_omap.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/tty/serial/8250/8250_omap.c b/drivers/tty/serial/8250/8250_omap.c index ddac0a13cf84..1af9aed99c65 100644 --- a/drivers/tty/serial/8250/8250_omap.c +++ b/drivers/tty/serial/8250/8250_omap.c @@ -672,7 +672,8 @@ static irqreturn_t omap8250_irq(int irq, void *dev_id) * https://www.ti.com/lit/pdf/sprz536 */ if (priv->habit & UART_RX_TIMEOUT_QUIRK && - (iir & UART_IIR_RX_TIMEOUT) == UART_IIR_RX_TIMEOUT) { + (iir & UART_IIR_RX_TIMEOUT) == UART_IIR_RX_TIMEOUT && + serial_port_in(port, UART_OMAP_RX_LVL) == 0) { unsigned char efr2, timeout_h, timeout_l; efr2 = serial_in(up, UART_OMAP_EFR2); -- cgit From acd09ac253b5de8fd79fc61a482ee19154914c7a Mon Sep 17 00:00:00 2001 From: Jacky Huang Date: Tue, 25 Jun 2024 06:41:28 +0000 Subject: tty: serial: ma35d1: Add a NULL check for of_node The pdev->dev.of_node can be NULL if the "serial" node is absent. Add a NULL check to return an error in such cases. Fixes: 930cbf92db01 ("tty: serial: Add Nuvoton ma35d1 serial driver support") Reported-by: Dan Carpenter Closes: https://lore.kernel.org/all/8df7ce45-fd58-4235-88f7-43fe7cd67e8f@moroto.mountain/ Signed-off-by: Jacky Huang Reviewed-by: Dan Carpenter Cc: stable Link: https://lore.kernel.org/r/20240625064128.127-1-ychuang570808@gmail.com Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/ma35d1_serial.c | 13 +++++++------ 1 file changed, 7 insertions(+), 6 deletions(-) diff --git a/drivers/tty/serial/ma35d1_serial.c b/drivers/tty/serial/ma35d1_serial.c index 19f0a305cc43..3b4206e815fe 100644 --- a/drivers/tty/serial/ma35d1_serial.c +++ b/drivers/tty/serial/ma35d1_serial.c @@ -688,12 +688,13 @@ static int ma35d1serial_probe(struct platform_device *pdev) struct uart_ma35d1_port *up; int ret = 0; - if (pdev->dev.of_node) { - ret = of_alias_get_id(pdev->dev.of_node, "serial"); - if (ret < 0) { - dev_err(&pdev->dev, "failed to get alias/pdev id, errno %d\n", ret); - return ret; - } + if (!pdev->dev.of_node) + return -ENODEV; + + ret = of_alias_get_id(pdev->dev.of_node, "serial"); + if (ret < 0) { + dev_err(&pdev->dev, "failed to get alias/pdev id, errno %d\n", ret); + return ret; } up = &ma35d1serial_ports[ret]; up->port.line = ret; -- cgit From 1af2156e58f3af1216ce2f0456b3b8949faa5c7e Mon Sep 17 00:00:00 2001 From: Rasmus Villemoes Date: Tue, 25 Jun 2024 20:42:05 +0200 Subject: serial: imx: ensure RTS signal is not left active after shutdown If a process is killed while writing to a /dev/ttymxc* device in RS485 mode, we observe that the RTS signal is left high, thus making it impossible for other devices to transmit anything. Moreover, the ->tx_state variable is left in state SEND, which means that when one next opens the device and configures baud rate etc., the initialization code in imx_uart_set_termios dutifully ensures the RTS pin is pulled down, but since ->tx_state is already SEND, the logic in imx_uart_start_tx() does not in fact pull the pin high before transmitting, so nothing actually gets on the wire on the other side of the transceiver. Only when that transmission is allowed to complete is the state machine then back in a consistent state. This is completely reproducible by doing something as simple as seq 10000 > /dev/ttymxc0 and hitting ctrl-C, and watching with a logic analyzer. Signed-off-by: Rasmus Villemoes Cc: stable Reviewed-by: Marek Vasut Link: https://lore.kernel.org/r/20240625184206.508837-1-linux@rasmusvillemoes.dk Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/imx.c | 51 ++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 51 insertions(+) diff --git a/drivers/tty/serial/imx.c b/drivers/tty/serial/imx.c index e22be8f45c93..ff32cd2d2863 100644 --- a/drivers/tty/serial/imx.c +++ b/drivers/tty/serial/imx.c @@ -1552,6 +1552,7 @@ static void imx_uart_shutdown(struct uart_port *port) struct imx_port *sport = (struct imx_port *)port; unsigned long flags; u32 ucr1, ucr2, ucr4, uts; + int loops; if (sport->dma_is_enabled) { dmaengine_terminate_sync(sport->dma_chan_tx); @@ -1614,6 +1615,56 @@ static void imx_uart_shutdown(struct uart_port *port) ucr4 &= ~UCR4_TCEN; imx_uart_writel(sport, ucr4, UCR4); + /* + * We have to ensure the tx state machine ends up in OFF. This + * is especially important for rs485 where we must not leave + * the RTS signal high, blocking the bus indefinitely. + * + * All interrupts are now disabled, so imx_uart_stop_tx() will + * no longer be called from imx_uart_transmit_buffer(). It may + * still be called via the hrtimers, and if those are in play, + * we have to honour the delays. + */ + if (sport->tx_state == WAIT_AFTER_RTS || sport->tx_state == SEND) + imx_uart_stop_tx(port); + + /* + * In many cases (rs232 mode, or if tx_state was + * WAIT_AFTER_RTS, or if tx_state was SEND and there is no + * delay_rts_after_send), this will have moved directly to + * OFF. In rs485 mode, tx_state might already have been + * WAIT_AFTER_SEND and the hrtimer thus already started, or + * the above imx_uart_stop_tx() call could have started it. In + * those cases, we have to wait for the hrtimer to fire and + * complete the transition to OFF. + */ + loops = port->rs485.flags & SER_RS485_ENABLED ? + port->rs485.delay_rts_after_send : 0; + while (sport->tx_state != OFF && loops--) { + uart_port_unlock_irqrestore(&sport->port, flags); + msleep(1); + uart_port_lock_irqsave(&sport->port, &flags); + } + + if (sport->tx_state != OFF) { + dev_warn(sport->port.dev, "unexpected tx_state %d\n", + sport->tx_state); + /* + * This machine may be busted, but ensure the RTS + * signal is inactive in order not to block other + * devices. + */ + if (port->rs485.flags & SER_RS485_ENABLED) { + ucr2 = imx_uart_readl(sport, UCR2); + if (port->rs485.flags & SER_RS485_RTS_AFTER_SEND) + imx_uart_rts_active(sport, &ucr2); + else + imx_uart_rts_inactive(sport, &ucr2); + imx_uart_writel(sport, ucr2, UCR2); + } + sport->tx_state = OFF; + } + uart_port_unlock_irqrestore(&sport->port, flags); clk_disable_unprepare(sport->clk_per); -- cgit From 947cc4ecc06cb80a2aa2cebbbbf0e546fbaf0238 Mon Sep 17 00:00:00 2001 From: Johan Hovold Date: Thu, 4 Jul 2024 12:18:03 +0200 Subject: serial: qcom-geni: fix soft lockup on sw flow control and suspend The stop_tx() callback is used to implement software flow control and must not discard data as the Qualcomm GENI driver is currently doing when there is an active TX command. Cancelling an active command can also leave data in the hardware FIFO, which prevents the watermark interrupt from being enabled when TX is later restarted. This results in a soft lockup and is easily triggered by stopping TX using software flow control in a serial console but this can also happen after suspend. Fix this by only stopping any active command, and effectively clearing the hardware fifo, when shutting down the port. When TX is later restarted, a transfer command may need to be issued to discard any stale data that could prevent the watermark interrupt from firing. Fixes: c4f528795d1a ("tty: serial: msm_geni_serial: Add serial driver support for GENI based QUP") Cc: stable@vger.kernel.org # 4.17 Signed-off-by: Johan Hovold Link: https://lore.kernel.org/r/20240704101805.30612-2-johan+linaro@kernel.org Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/qcom_geni_serial.c | 33 ++++++++++++++++++++++++--------- 1 file changed, 24 insertions(+), 9 deletions(-) diff --git a/drivers/tty/serial/qcom_geni_serial.c b/drivers/tty/serial/qcom_geni_serial.c index 2bd25afe0d92..a41360d34790 100644 --- a/drivers/tty/serial/qcom_geni_serial.c +++ b/drivers/tty/serial/qcom_geni_serial.c @@ -649,15 +649,25 @@ static void qcom_geni_serial_start_tx_dma(struct uart_port *uport) static void qcom_geni_serial_start_tx_fifo(struct uart_port *uport) { + unsigned char c; u32 irq_en; - if (qcom_geni_serial_main_active(uport) || - !qcom_geni_serial_tx_empty(uport)) - return; + /* + * Start a new transfer in case the previous command was cancelled and + * left data in the FIFO which may prevent the watermark interrupt + * from triggering. Note that the stale data is discarded. + */ + if (!qcom_geni_serial_main_active(uport) && + !qcom_geni_serial_tx_empty(uport)) { + if (uart_fifo_out(uport, &c, 1) == 1) { + writel(M_CMD_DONE_EN, uport->membase + SE_GENI_M_IRQ_CLEAR); + qcom_geni_serial_setup_tx(uport, 1); + writel(c, uport->membase + SE_GENI_TX_FIFOn); + } + } irq_en = readl(uport->membase + SE_GENI_M_IRQ_EN); irq_en |= M_TX_FIFO_WATERMARK_EN | M_CMD_DONE_EN; - writel(DEF_TX_WM, uport->membase + SE_GENI_TX_WATERMARK_REG); writel(irq_en, uport->membase + SE_GENI_M_IRQ_EN); } @@ -665,13 +675,17 @@ static void qcom_geni_serial_start_tx_fifo(struct uart_port *uport) static void qcom_geni_serial_stop_tx_fifo(struct uart_port *uport) { u32 irq_en; - struct qcom_geni_serial_port *port = to_dev_port(uport); irq_en = readl(uport->membase + SE_GENI_M_IRQ_EN); irq_en &= ~(M_CMD_DONE_EN | M_TX_FIFO_WATERMARK_EN); writel(0, uport->membase + SE_GENI_TX_WATERMARK_REG); writel(irq_en, uport->membase + SE_GENI_M_IRQ_EN); - /* Possible stop tx is called multiple times. */ +} + +static void qcom_geni_serial_cancel_tx_cmd(struct uart_port *uport) +{ + struct qcom_geni_serial_port *port = to_dev_port(uport); + if (!qcom_geni_serial_main_active(uport)) return; @@ -684,6 +698,8 @@ static void qcom_geni_serial_stop_tx_fifo(struct uart_port *uport) writel(M_CMD_ABORT_EN, uport->membase + SE_GENI_M_IRQ_CLEAR); } writel(M_CMD_CANCEL_EN, uport->membase + SE_GENI_M_IRQ_CLEAR); + + port->tx_remaining = 0; } static void qcom_geni_serial_handle_rx_fifo(struct uart_port *uport, bool drop) @@ -1069,11 +1085,10 @@ static void qcom_geni_serial_shutdown(struct uart_port *uport) { disable_irq(uport->irq); - if (uart_console(uport)) - return; - qcom_geni_serial_stop_tx(uport); qcom_geni_serial_stop_rx(uport); + + qcom_geni_serial_cancel_tx_cmd(uport); } static int qcom_geni_serial_port_setup(struct uart_port *uport) -- cgit From 507786c51ccf8df726df804ae316a8c52537b407 Mon Sep 17 00:00:00 2001 From: Johan Hovold Date: Thu, 4 Jul 2024 12:18:04 +0200 Subject: serial: qcom-geni: fix hard lockup on buffer flush The Qualcomm GENI serial driver does not handle buffer flushing and used to continue printing discarded characters when the circular buffer was cleared. Since commit 1788cf6a91d9 ("tty: serial: switch from circ_buf to kfifo") this instead results in a hard lockup due to qcom_geni_serial_send_chunk_fifo() spinning indefinitely in the interrupt handler. This is easily triggered by interrupting a command such as dmesg in a serial console but can also happen when stopping a serial getty on reboot. Implement the flush_buffer() callback and use it to cancel any active TX command when the write buffer has been emptied. Reported-by: Douglas Anderson Link: https://lore.kernel.org/lkml/20240610222515.3023730-1-dianders@chromium.org/ Fixes: 1788cf6a91d9 ("tty: serial: switch from circ_buf to kfifo") Fixes: a1fee899e5be ("tty: serial: qcom_geni_serial: Fix softlock") Cc: stable@vger.kernel.org # 5.0 Signed-off-by: Johan Hovold Link: https://lore.kernel.org/r/20240704101805.30612-3-johan+linaro@kernel.org Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/qcom_geni_serial.c | 16 +++++++++++++--- 1 file changed, 13 insertions(+), 3 deletions(-) diff --git a/drivers/tty/serial/qcom_geni_serial.c b/drivers/tty/serial/qcom_geni_serial.c index a41360d34790..b2bbd2d79dbb 100644 --- a/drivers/tty/serial/qcom_geni_serial.c +++ b/drivers/tty/serial/qcom_geni_serial.c @@ -906,13 +906,17 @@ static void qcom_geni_serial_handle_tx_fifo(struct uart_port *uport, else pending = kfifo_len(&tport->xmit_fifo); - /* All data has been transmitted and acknowledged as received */ - if (!pending && !status && done) { + /* All data has been transmitted or command has been cancelled */ + if (!pending && done) { qcom_geni_serial_stop_tx_fifo(uport); goto out_write_wakeup; } - avail = port->tx_fifo_depth - (status & TX_FIFO_WC); + if (active) + avail = port->tx_fifo_depth - (status & TX_FIFO_WC); + else + avail = port->tx_fifo_depth; + avail *= BYTES_PER_FIFO_WORD; chunk = min(avail, pending); @@ -1091,6 +1095,11 @@ static void qcom_geni_serial_shutdown(struct uart_port *uport) qcom_geni_serial_cancel_tx_cmd(uport); } +static void qcom_geni_serial_flush_buffer(struct uart_port *uport) +{ + qcom_geni_serial_cancel_tx_cmd(uport); +} + static int qcom_geni_serial_port_setup(struct uart_port *uport) { struct qcom_geni_serial_port *port = to_dev_port(uport); @@ -1547,6 +1556,7 @@ static const struct uart_ops qcom_geni_console_pops = { .request_port = qcom_geni_serial_request_port, .config_port = qcom_geni_serial_config_port, .shutdown = qcom_geni_serial_shutdown, + .flush_buffer = qcom_geni_serial_flush_buffer, .type = qcom_geni_serial_get_type, .set_mctrl = qcom_geni_serial_set_mctrl, .get_mctrl = qcom_geni_serial_get_mctrl, -- cgit From 2ac33975abda6921896e52372aec2be2cf51ab37 Mon Sep 17 00:00:00 2001 From: Johan Hovold Date: Thu, 4 Jul 2024 12:18:05 +0200 Subject: serial: qcom-geni: do not kill the machine on fifo underrun The Qualcomm GENI serial driver did not handle buffer flushing and used to print discarded characters when the circular buffer was cleared. Since commit 1788cf6a91d9 ("tty: serial: switch from circ_buf to kfifo") this instead resulted in a hard lockup due to qcom_geni_serial_send_chunk_fifo() spinning indefinitely in the interrupt handler. The underlying bugs have now been fixed, but make sure to output NUL characters instead of killing the machine if a similar driver bug is ever reintroduced. Signed-off-by: Johan Hovold Link: https://lore.kernel.org/r/20240704101805.30612-4-johan+linaro@kernel.org Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/qcom_geni_serial.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/tty/serial/qcom_geni_serial.c b/drivers/tty/serial/qcom_geni_serial.c index b2bbd2d79dbb..69a632fefc41 100644 --- a/drivers/tty/serial/qcom_geni_serial.c +++ b/drivers/tty/serial/qcom_geni_serial.c @@ -878,7 +878,7 @@ static void qcom_geni_serial_send_chunk_fifo(struct uart_port *uport, memset(buf, 0, sizeof(buf)); tx_bytes = min(remaining, BYTES_PER_FIFO_WORD); - tx_bytes = uart_fifo_out(uport, buf, tx_bytes); + uart_fifo_out(uport, buf, tx_bytes); iowrite32_rep(uport->membase + SE_GENI_TX_FIFOn, buf, 1); -- cgit