From 638441bed666619b4275f68bbca9d1cd731a2063 Mon Sep 17 00:00:00 2001 From: Dan Carpenter Date: Sat, 16 Mar 2024 12:30:09 +0300 Subject: [PATCH 01/11] serial: 8250_lpc18xx: disable clks on error in probe() Goto the clean up path to clean up a couple clocks before returning on this error path. Fixes: 0087b9e694ee ("serial: 8250_lpc18xx: Switch to use uart_read_port_properties()") Signed-off-by: Dan Carpenter Reviewed-by: Andy Shevchenko Link: https://lore.kernel.org/r/92646c10-e0b5-4117-a9ac-ce9987d33ce3@moroto.mountain Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/8250/8250_lpc18xx.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/tty/serial/8250/8250_lpc18xx.c b/drivers/tty/serial/8250/8250_lpc18xx.c index 7984ee05af1d..47e1a056a60c 100644 --- a/drivers/tty/serial/8250/8250_lpc18xx.c +++ b/drivers/tty/serial/8250/8250_lpc18xx.c @@ -151,7 +151,7 @@ static int lpc18xx_serial_probe(struct platform_device *pdev) ret = uart_read_port_properties(&uart.port); if (ret) - return ret; + goto dis_uart_clk; uart.port.iotype = UPIO_MEM32; uart.port.regshift = 2; From 7dfae6cbadc1ac99e38ad19fb08810b31ff167be Mon Sep 17 00:00:00 2001 From: Hans de Goede Date: Sun, 17 Mar 2024 22:41:23 +0100 Subject: [PATCH 02/11] serial: 8250_dw: Revert: Do not reclock if already at correct rate Commit e5d6bd25f93d ("serial: 8250_dw: Do not reclock if already at correct rate") breaks the dw UARTs on Intel Bay Trail (BYT) and Cherry Trail (CHT) SoCs. Before this change the RTL8732BS Bluetooth HCI which is found connected over the dw UART on both BYT and CHT boards works properly: Bluetooth: hci0: RTL: examining hci_ver=06 hci_rev=000b lmp_ver=06 lmp_subver=8723 Bluetooth: hci0: RTL: rom_version status=0 version=1 Bluetooth: hci0: RTL: loading rtl_bt/rtl8723bs_fw.bin Bluetooth: hci0: RTL: loading rtl_bt/rtl8723bs_config-OBDA8723.bin Bluetooth: hci0: RTL: cfg_sz 64, total sz 24508 Bluetooth: hci0: RTL: fw version 0x365d462e where as after this change probing it fails: Bluetooth: hci0: RTL: examining hci_ver=06 hci_rev=000b lmp_ver=06 lmp_subver=8723 Bluetooth: hci0: RTL: rom_version status=0 version=1 Bluetooth: hci0: RTL: loading rtl_bt/rtl8723bs_fw.bin Bluetooth: hci0: RTL: loading rtl_bt/rtl8723bs_config-OBDA8723.bin Bluetooth: hci0: RTL: cfg_sz 64, total sz 24508 Bluetooth: hci0: command 0xfc20 tx timeout Bluetooth: hci0: RTL: download fw command failed (-110) Revert the changes to fix this regression. Fixes: e5d6bd25f93d ("serial: 8250_dw: Do not reclock if already at correct rate") Cc: stable@vger.kernel.org Cc: Peter Collingbourne Signed-off-by: Hans de Goede Reviewed-by: Andy Shevchenko Acked-by: Peter Collingbourne Link: https://lore.kernel.org/r/20240317214123.34482-1-hdegoede@redhat.com Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/8250/8250_dw.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/drivers/tty/serial/8250/8250_dw.c b/drivers/tty/serial/8250/8250_dw.c index a3acbf0f5da1..1300c92b8702 100644 --- a/drivers/tty/serial/8250/8250_dw.c +++ b/drivers/tty/serial/8250/8250_dw.c @@ -356,9 +356,9 @@ static void dw8250_set_termios(struct uart_port *p, struct ktermios *termios, long rate; int ret; + clk_disable_unprepare(d->clk); rate = clk_round_rate(d->clk, newrate); - if (rate > 0 && p->uartclk != rate) { - clk_disable_unprepare(d->clk); + if (rate > 0) { /* * Note that any clock-notifer worker will block in * serial8250_update_uartclk() until we are done. @@ -366,8 +366,8 @@ static void dw8250_set_termios(struct uart_port *p, struct ktermios *termios, ret = clk_set_rate(d->clk, newrate); if (!ret) p->uartclk = rate; - clk_prepare_enable(d->clk); } + clk_prepare_enable(d->clk); dw8250_do_set_termios(p, termios, old); } From 54c4ec5f8c471b7c1137a1f769648549c423c026 Mon Sep 17 00:00:00 2001 From: Emil Kronborg Date: Wed, 20 Mar 2024 12:15:36 +0000 Subject: [PATCH 03/11] serial: mxs-auart: add spinlock around changing cts state The uart_handle_cts_change() function in serial_core expects the caller to hold uport->lock. For example, I have seen the below kernel splat, when the Bluetooth driver is loaded on an i.MX28 board. [ 85.119255] ------------[ cut here ]------------ [ 85.124413] WARNING: CPU: 0 PID: 27 at /drivers/tty/serial/serial_core.c:3453 uart_handle_cts_change+0xb4/0xec [ 85.134694] Modules linked in: hci_uart bluetooth ecdh_generic ecc wlcore_sdio configfs [ 85.143314] CPU: 0 PID: 27 Comm: kworker/u3:0 Not tainted 6.6.3-00021-gd62a2f068f92 #1 [ 85.151396] Hardware name: Freescale MXS (Device Tree) [ 85.156679] Workqueue: hci0 hci_power_on [bluetooth] (...) [ 85.191765] uart_handle_cts_change from mxs_auart_irq_handle+0x380/0x3f4 [ 85.198787] mxs_auart_irq_handle from __handle_irq_event_percpu+0x88/0x210 (...) Cc: stable@vger.kernel.org Fixes: 4d90bb147ef6 ("serial: core: Document and assert lock requirements for irq helpers") Reviewed-by: Frank Li Signed-off-by: Emil Kronborg Link: https://lore.kernel.org/r/20240320121530.11348-1-emil.kronborg@protonmail.com Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/mxs-auart.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/drivers/tty/serial/mxs-auart.c b/drivers/tty/serial/mxs-auart.c index 4749331fe618..1e8853eae504 100644 --- a/drivers/tty/serial/mxs-auart.c +++ b/drivers/tty/serial/mxs-auart.c @@ -1086,11 +1086,13 @@ static void mxs_auart_set_ldisc(struct uart_port *port, static irqreturn_t mxs_auart_irq_handle(int irq, void *context) { - u32 istat; + u32 istat, stat; struct mxs_auart_port *s = context; u32 mctrl_temp = s->mctrl_prev; - u32 stat = mxs_read(s, REG_STAT); + uart_port_lock(&s->port); + + stat = mxs_read(s, REG_STAT); istat = mxs_read(s, REG_INTR); /* ack irq */ @@ -1126,6 +1128,8 @@ static irqreturn_t mxs_auart_irq_handle(int irq, void *context) istat &= ~AUART_INTR_TXIS; } + uart_port_unlock(&s->port); + return IRQ_HANDLED; } From 5555980571cc744cd99b6455e3e388b54519db8f Mon Sep 17 00:00:00 2001 From: Tony Lindgren Date: Mon, 25 Mar 2024 09:16:47 +0200 Subject: [PATCH 04/11] serial: core: Fix regression when runtime PM is not enabled Commit 45a3a8ef8129 ("serial: core: Revert checks for tx runtime PM state") caused a regression for Sun Ultra 60 for the sunsab driver as reported by Nick Bowler . We need to add back the check runtime PM enabled state for serial port controller device, I wrongly assumed earlier we could just remove it. Fixes: 45a3a8ef8129 ("serial: core: Revert checks for tx runtime PM state") Cc: stable Reported-by: Nick Bowler Signed-off-by: Tony Lindgren Link: https://lore.kernel.org/r/20240325071649.27040-1-tony@atomide.com Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/serial_core.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c index ff85ebd3a007..25a83820927a 100644 --- a/drivers/tty/serial/serial_core.c +++ b/drivers/tty/serial/serial_core.c @@ -156,7 +156,7 @@ static void __uart_start(struct uart_state *state) * enabled, serial_port_runtime_resume() calls start_tx() again * after enabling the device. */ - if (pm_runtime_active(&port_dev->dev)) + if (!pm_runtime_enabled(port->dev) || pm_runtime_active(&port_dev->dev)) port->ops->start_tx(port); pm_runtime_mark_last_busy(&port_dev->dev); pm_runtime_put_autosuspend(&port_dev->dev); From 90452456eb69297fe7ae34e56e40d8e47dc9e019 Mon Sep 17 00:00:00 2001 From: Andy Shevchenko Date: Thu, 4 Apr 2024 01:41:52 +0300 Subject: [PATCH 05/11] serial: 8250_pci: Remove redundant PCI IDs Driver complains that PCI IDs are not needed for some of the LAVA cards: [ 0.297252] serial 0000:04:00.0: Redundant entry in serial pci_table. [ 0.297252] Please send the output of lspci -vv, this [ 0.297252] message (0x1407,0x0120,0x0000,0x0000), the [ 0.297252] manufacturer and name of serial board or [ 0.297252] modem board to . Do as suggested. Reported-by: Jimmy A Closes: https://lore.kernel.org/r/VI1P194MB052751BE157EFE9CEAB75725CE362@VI1P194MB0527.EURP194.PROD.OUTLOOK.COM Signed-off-by: Andy Shevchenko Link: https://lore.kernel.org/r/20240403224152.945099-1-andy.shevchenko@gmail.com Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/8250/8250_pci.c | 6 ------ 1 file changed, 6 deletions(-) diff --git a/drivers/tty/serial/8250/8250_pci.c b/drivers/tty/serial/8250/8250_pci.c index 0d35c77fad9e..e2e4f99f9d34 100644 --- a/drivers/tty/serial/8250/8250_pci.c +++ b/drivers/tty/serial/8250/8250_pci.c @@ -5010,12 +5010,6 @@ static const struct pci_device_id serial_pci_tbl[] = { { PCI_VENDOR_ID_LAVA, PCI_DEVICE_ID_LAVA_QUATRO_B, PCI_ANY_ID, PCI_ANY_ID, 0, 0, pbn_b0_bt_2_115200 }, - { PCI_VENDOR_ID_LAVA, PCI_DEVICE_ID_LAVA_QUATTRO_A, - PCI_ANY_ID, PCI_ANY_ID, 0, 0, - pbn_b0_bt_2_115200 }, - { PCI_VENDOR_ID_LAVA, PCI_DEVICE_ID_LAVA_QUATTRO_B, - PCI_ANY_ID, PCI_ANY_ID, 0, 0, - pbn_b0_bt_2_115200 }, { PCI_VENDOR_ID_LAVA, PCI_DEVICE_ID_LAVA_OCTO_A, PCI_ANY_ID, PCI_ANY_ID, 0, 0, pbn_b0_bt_4_460800 }, From 1be3226445362bfbf461c92a5bcdb1723f2e4907 Mon Sep 17 00:00:00 2001 From: Finn Thain Date: Mon, 8 Apr 2024 19:23:43 +1000 Subject: [PATCH 06/11] serial/pmac_zilog: Remove flawed mitigation for rx irq flood The mitigation was intended to stop the irq completely. That may be better than a hard lock-up but it turns out that you get a crash anyway if you're using pmac_zilog as a serial console: ttyPZ0: pmz: rx irq flood ! BUG: spinlock recursion on CPU#0, swapper/0 That's because the pr_err() call in pmz_receive_chars() results in pmz_console_write() attempting to lock a spinlock already locked in pmz_interrupt(). With CONFIG_DEBUG_SPINLOCK=y, this produces a fatal BUG splat. The spinlock in question is the one in struct uart_port. Even when it's not fatal, the serial port rx function ceases to work. Also, the iteration limit doesn't play nicely with QEMU, as can be seen in the bug report linked below. A web search for other reports of the error message "pmz: rx irq flood" didn't produce anything. So I don't think this code is needed any more. Remove it. Cc: Benjamin Herrenschmidt Cc: Michael Ellerman Cc: Nicholas Piggin Cc: Christophe Leroy Cc: Aneesh Kumar K.V Cc: Naveen N. Rao Cc: Andy Shevchenko Cc: stable@kernel.org Cc: linux-m68k@lists.linux-m68k.org Link: https://github.com/vivier/qemu-m68k/issues/44 Link: https://lore.kernel.org/all/1078874617.9746.36.camel@gaston/ Acked-by: Michael Ellerman Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Cc: stable Signed-off-by: Finn Thain Link: https://lore.kernel.org/r/e853cf2c762f23101cd2ddec0cc0c2be0e72685f.1712568223.git.fthain@linux-m68k.org Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/pmac_zilog.c | 14 -------------- 1 file changed, 14 deletions(-) diff --git a/drivers/tty/serial/pmac_zilog.c b/drivers/tty/serial/pmac_zilog.c index 05d97e89511e..92195f984de1 100644 --- a/drivers/tty/serial/pmac_zilog.c +++ b/drivers/tty/serial/pmac_zilog.c @@ -210,7 +210,6 @@ static bool pmz_receive_chars(struct uart_pmac_port *uap) { struct tty_port *port; unsigned char ch, r1, drop, flag; - int loops = 0; /* Sanity check, make sure the old bug is no longer happening */ if (uap->port.state == NULL) { @@ -291,24 +290,11 @@ static bool pmz_receive_chars(struct uart_pmac_port *uap) if (r1 & Rx_OVR) tty_insert_flip_char(port, 0, TTY_OVERRUN); next_char: - /* We can get stuck in an infinite loop getting char 0 when the - * line is in a wrong HW state, we break that here. - * When that happens, I disable the receive side of the driver. - * Note that what I've been experiencing is a real irq loop where - * I'm getting flooded regardless of the actual port speed. - * Something strange is going on with the HW - */ - if ((++loops) > 1000) - goto flood; ch = read_zsreg(uap, R0); if (!(ch & Rx_CH_AV)) break; } - return true; - flood: - pmz_interrupt_control(uap, 0); - pmz_error("pmz: rx irq flood !\n"); return true; } From d325a858a53b5816a60447887f7148eace999e00 Mon Sep 17 00:00:00 2001 From: Richard Genoud Date: Mon, 8 Apr 2024 12:13:29 +0200 Subject: [PATCH 07/11] MAINTAINERS: mailmap: update Richard Genoud's email address I'm working now at bootlin, so I'll use my bootlin address for kernel development from now on. Update also the yaml file for atmel-serial accordingly. Signed-off-by: Richard Genoud Reviewed-by: Nicolas Ferre Link: https://lore.kernel.org/r/20240408101329.9448-1-richard.genoud@bootlin.com Signed-off-by: Greg Kroah-Hartman --- .mailmap | 1 + Documentation/devicetree/bindings/serial/atmel,at91-usart.yaml | 2 +- MAINTAINERS | 2 +- 3 files changed, 3 insertions(+), 2 deletions(-) diff --git a/.mailmap b/.mailmap index 8284692f9610..71e28f4e0d4a 100644 --- a/.mailmap +++ b/.mailmap @@ -524,6 +524,7 @@ Rémi Denis-Courmont Ricardo Ribalda Ricardo Ribalda Ricardo Ribalda Delgado Ricardo Ribalda +Richard Genoud Richard Leitner Richard Leitner Richard Leitner diff --git a/Documentation/devicetree/bindings/serial/atmel,at91-usart.yaml b/Documentation/devicetree/bindings/serial/atmel,at91-usart.yaml index 65cb2e5c5eee..eb2992a447d7 100644 --- a/Documentation/devicetree/bindings/serial/atmel,at91-usart.yaml +++ b/Documentation/devicetree/bindings/serial/atmel,at91-usart.yaml @@ -8,7 +8,7 @@ $schema: http://devicetree.org/meta-schemas/core.yaml# title: Atmel Universal Synchronous Asynchronous Receiver/Transmitter (USART) maintainers: - - Richard Genoud + - Richard Genoud properties: compatible: diff --git a/MAINTAINERS b/MAINTAINERS index aea47e04c3a5..0dbdc81e46c6 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -14363,7 +14363,7 @@ F: drivers/dma/at_xdmac.c F: include/dt-bindings/dma/at91.h MICROCHIP AT91 SERIAL DRIVER -M: Richard Genoud +M: Richard Genoud S: Maintained F: Documentation/devicetree/bindings/serial/atmel,at91-usart.yaml F: drivers/tty/serial/atmel_serial.c From 9cf7ea2eeb745213dc2a04103e426b960e807940 Mon Sep 17 00:00:00 2001 From: Andy Shevchenko Date: Thu, 4 Apr 2024 17:59:26 +0300 Subject: [PATCH 08/11] serial: core: Clearing the circular buffer before NULLifying it The circular buffer is NULLified in uart_tty_port_shutdown() under the spin lock. However, the PM or other timer based callbacks may still trigger after this event without knowning that buffer pointer is not valid. Since the serial code is a bit inconsistent in checking the buffer state (some rely on the head-tail positions, some on the buffer pointer), it's better to have both aligned, i.e. buffer pointer to be NULL and head-tail possitions to be the same, meaning it's empty. This will prevent asynchronous calls to dereference NULL pointer as reported recently in 8250 case: BUG: kernel NULL pointer dereference, address: 00000cf5 Workqueue: pm pm_runtime_work EIP: serial8250_tx_chars (drivers/tty/serial/8250/8250_port.c:1809) ... ? serial8250_tx_chars (drivers/tty/serial/8250/8250_port.c:1809) __start_tx (drivers/tty/serial/8250/8250_port.c:1551) serial8250_start_tx (drivers/tty/serial/8250/8250_port.c:1654) serial_port_runtime_suspend (include/linux/serial_core.h:667 drivers/tty/serial/serial_port.c:63) __rpm_callback (drivers/base/power/runtime.c:393) ? serial_port_remove (drivers/tty/serial/serial_port.c:50) rpm_suspend (drivers/base/power/runtime.c:447) The proposed change will prevent ->start_tx() to be called during suspend on shut down port. Fixes: 43066e32227e ("serial: port: Don't suspend if the port is still busy") Cc: stable Reported-by: kernel test robot Closes: https://lore.kernel.org/oe-lkp/202404031607.2e92eebe-lkp@intel.com Signed-off-by: Andy Shevchenko Link: https://lore.kernel.org/r/20240404150034.41648-1-andriy.shevchenko@linux.intel.com Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/serial_core.c | 1 + 1 file changed, 1 insertion(+) diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c index 25a83820927a..2247efe97250 100644 --- a/drivers/tty/serial/serial_core.c +++ b/drivers/tty/serial/serial_core.c @@ -1788,6 +1788,7 @@ static void uart_tty_port_shutdown(struct tty_port *port) * Free the transmit buffer. */ uart_port_lock_irq(uport); + uart_circ_clear(&state->xmit); buf = state->xmit.buf; state->xmit.buf = NULL; uart_port_unlock_irq(uport); From 1aa4ad4eb695bac1b0a7ba542a16d6833c9c8dd8 Mon Sep 17 00:00:00 2001 From: Tony Lindgren Date: Thu, 11 Apr 2024 08:58:45 +0300 Subject: [PATCH 09/11] serial: core: Fix missing shutdown and startup for serial base port We are seeing start_tx being called after port shutdown as noted by Jiri. This happens because we are missing the startup and shutdown related functions for the serial base port. Let's fix the issue by adding startup and shutdown functions for the serial base port to block tx flushing for the serial base port when the port is not in use. Fixes: 84a9582fd203 ("serial: core: Start managing serial controllers to enable runtime PM") Cc: stable Reported-by: Jiri Slaby Signed-off-by: Tony Lindgren Link: https://lore.kernel.org/r/20240411055848.38190-1-tony@atomide.com Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/serial_base.h | 4 ++++ drivers/tty/serial/serial_core.c | 20 ++++++++++++++++--- drivers/tty/serial/serial_port.c | 34 ++++++++++++++++++++++++++++++++ 3 files changed, 55 insertions(+), 3 deletions(-) diff --git a/drivers/tty/serial/serial_base.h b/drivers/tty/serial/serial_base.h index c74c548f0db6..b6c38d2edfd4 100644 --- a/drivers/tty/serial/serial_base.h +++ b/drivers/tty/serial/serial_base.h @@ -22,6 +22,7 @@ struct serial_ctrl_device { struct serial_port_device { struct device dev; struct uart_port *port; + unsigned int tx_enabled:1; }; int serial_base_ctrl_init(void); @@ -30,6 +31,9 @@ void serial_base_ctrl_exit(void); int serial_base_port_init(void); void serial_base_port_exit(void); +void serial_base_port_startup(struct uart_port *port); +void serial_base_port_shutdown(struct uart_port *port); + int serial_base_driver_register(struct device_driver *driver); void serial_base_driver_unregister(struct device_driver *driver); diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c index 2247efe97250..c476d884356d 100644 --- a/drivers/tty/serial/serial_core.c +++ b/drivers/tty/serial/serial_core.c @@ -323,16 +323,26 @@ static int uart_startup(struct tty_struct *tty, struct uart_state *state, bool init_hw) { struct tty_port *port = &state->port; + struct uart_port *uport; int retval; if (tty_port_initialized(port)) - return 0; + goto out_base_port_startup; retval = uart_port_startup(tty, state, init_hw); - if (retval) + if (retval) { set_bit(TTY_IO_ERROR, &tty->flags); + return retval; + } - return retval; +out_base_port_startup: + uport = uart_port_check(state); + if (!uport) + return -EIO; + + serial_base_port_startup(uport); + + return 0; } /* @@ -355,6 +365,9 @@ static void uart_shutdown(struct tty_struct *tty, struct uart_state *state) if (tty) set_bit(TTY_IO_ERROR, &tty->flags); + if (uport) + serial_base_port_shutdown(uport); + if (tty_port_initialized(port)) { tty_port_set_initialized(port, false); @@ -1775,6 +1788,7 @@ static void uart_tty_port_shutdown(struct tty_port *port) uport->ops->stop_rx(uport); uart_port_unlock_irq(uport); + serial_base_port_shutdown(uport); uart_port_shutdown(port); /* diff --git a/drivers/tty/serial/serial_port.c b/drivers/tty/serial/serial_port.c index 22b9eeb23e68..7e3a1c7b097c 100644 --- a/drivers/tty/serial/serial_port.c +++ b/drivers/tty/serial/serial_port.c @@ -39,8 +39,12 @@ static int serial_port_runtime_resume(struct device *dev) /* Flush any pending TX for the port */ uart_port_lock_irqsave(port, &flags); + if (!port_dev->tx_enabled) + goto unlock; if (__serial_port_busy(port)) port->ops->start_tx(port); + +unlock: uart_port_unlock_irqrestore(port, flags); out: @@ -60,6 +64,11 @@ static int serial_port_runtime_suspend(struct device *dev) return 0; uart_port_lock_irqsave(port, &flags); + if (!port_dev->tx_enabled) { + uart_port_unlock_irqrestore(port, flags); + return 0; + } + busy = __serial_port_busy(port); if (busy) port->ops->start_tx(port); @@ -71,6 +80,31 @@ static int serial_port_runtime_suspend(struct device *dev) return busy ? -EBUSY : 0; } +static void serial_base_port_set_tx(struct uart_port *port, + struct serial_port_device *port_dev, + bool enabled) +{ + unsigned long flags; + + uart_port_lock_irqsave(port, &flags); + port_dev->tx_enabled = enabled; + uart_port_unlock_irqrestore(port, flags); +} + +void serial_base_port_startup(struct uart_port *port) +{ + struct serial_port_device *port_dev = port->port_dev; + + serial_base_port_set_tx(port, port_dev, true); +} + +void serial_base_port_shutdown(struct uart_port *port) +{ + struct serial_port_device *port_dev = port->port_dev; + + serial_base_port_set_tx(port, port_dev, false); +} + static DEFINE_RUNTIME_DEV_PM_OPS(serial_port_pm, serial_port_runtime_suspend, serial_port_runtime_resume, NULL); From 13c785323b36b845300b256d0e5963c3727667d7 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Uwe=20Kleine-K=C3=B6nig?= Date: Wed, 17 Apr 2024 11:03:27 +0200 Subject: [PATCH 10/11] serial: stm32: Return IRQ_NONE in the ISR if no handling happend MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit If there is a stuck irq that the handler doesn't address, returning IRQ_HANDLED unconditionally makes it impossible for the irq core to detect the problem and disable the irq. So only return IRQ_HANDLED if an event was handled. A stuck irq is still problematic, but with this change at least it only makes the UART nonfunctional instead of occupying the (usually only) CPU by 100% and so stall the whole machine. Fixes: 48a6092fb41f ("serial: stm32-usart: Add STM32 USART Driver") Cc: stable@vger.kernel.org Signed-off-by: Uwe Kleine-König Link: https://lore.kernel.org/r/5f92603d0dfd8a5b8014b2b10a902d91e0bb881f.1713344161.git.u.kleine-koenig@pengutronix.de Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/stm32-usart.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) diff --git a/drivers/tty/serial/stm32-usart.c b/drivers/tty/serial/stm32-usart.c index 58d169e5c1db..d60cbac69194 100644 --- a/drivers/tty/serial/stm32-usart.c +++ b/drivers/tty/serial/stm32-usart.c @@ -861,6 +861,7 @@ static irqreturn_t stm32_usart_interrupt(int irq, void *ptr) const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs; u32 sr; unsigned int size; + irqreturn_t ret = IRQ_NONE; sr = readl_relaxed(port->membase + ofs->isr); @@ -869,11 +870,14 @@ static irqreturn_t stm32_usart_interrupt(int irq, void *ptr) (sr & USART_SR_TC)) { stm32_usart_tc_interrupt_disable(port); stm32_usart_rs485_rts_disable(port); + ret = IRQ_HANDLED; } - if ((sr & USART_SR_RTOF) && ofs->icr != UNDEF_REG) + if ((sr & USART_SR_RTOF) && ofs->icr != UNDEF_REG) { writel_relaxed(USART_ICR_RTOCF, port->membase + ofs->icr); + ret = IRQ_HANDLED; + } if ((sr & USART_SR_WUF) && ofs->icr != UNDEF_REG) { /* Clear wake up flag and disable wake up interrupt */ @@ -882,6 +886,7 @@ static irqreturn_t stm32_usart_interrupt(int irq, void *ptr) stm32_usart_clr_bits(port, ofs->cr3, USART_CR3_WUFIE); if (irqd_is_wakeup_set(irq_get_irq_data(port->irq))) pm_wakeup_event(tport->tty->dev, 0); + ret = IRQ_HANDLED; } /* @@ -896,6 +901,7 @@ static irqreturn_t stm32_usart_interrupt(int irq, void *ptr) uart_unlock_and_check_sysrq(port); if (size) tty_flip_buffer_push(tport); + ret = IRQ_HANDLED; } } @@ -903,6 +909,7 @@ static irqreturn_t stm32_usart_interrupt(int irq, void *ptr) uart_port_lock(port); stm32_usart_transmit_chars(port); uart_port_unlock(port); + ret = IRQ_HANDLED; } /* Receiver timeout irq for DMA RX */ @@ -912,9 +919,10 @@ static irqreturn_t stm32_usart_interrupt(int irq, void *ptr) uart_unlock_and_check_sysrq(port); if (size) tty_flip_buffer_push(tport); + ret = IRQ_HANDLED; } - return IRQ_HANDLED; + return ret; } static void stm32_usart_set_mctrl(struct uart_port *port, unsigned int mctrl) From ea2624b5b829b8f93c0dce25721d835969b34faf Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Uwe=20Kleine-K=C3=B6nig?= Date: Wed, 17 Apr 2024 11:03:28 +0200 Subject: [PATCH 11/11] serial: stm32: Reset .throttled state in .startup() MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit When an UART is opened that still has .throttled set from a previous open, the RX interrupt is enabled but the irq handler doesn't consider it. This easily results in a stuck irq with the effect to occupy the CPU in a tight loop. So reset the throttle state in .startup() to ensure that RX irqs are handled. Fixes: d1ec8a2eabe9 ("serial: stm32: update throttle and unthrottle ops for dma mode") Cc: stable@vger.kernel.org Signed-off-by: Uwe Kleine-König Link: https://lore.kernel.org/r/a784f80d3414f7db723b2ec66efc56e1ad666cbf.1713344161.git.u.kleine-koenig@pengutronix.de Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/stm32-usart.c | 1 + 1 file changed, 1 insertion(+) diff --git a/drivers/tty/serial/stm32-usart.c b/drivers/tty/serial/stm32-usart.c index d60cbac69194..4fa5a03ebac0 100644 --- a/drivers/tty/serial/stm32-usart.c +++ b/drivers/tty/serial/stm32-usart.c @@ -1092,6 +1092,7 @@ static int stm32_usart_startup(struct uart_port *port) val |= USART_CR2_SWAP; writel_relaxed(val, port->membase + ofs->cr2); } + stm32_port->throttled = false; /* RX FIFO Flush */ if (ofs->rqr != UNDEF_REG)