kernel/linux.git/drivers/tty/serial, branch v5.4.113

serial: mvebu-uart: fix tx lost characters at power off

2021-01-27T10:47:50+00:00

commit 54ca955b5a4024e2ce0f206b03adb7109bc4da26 upstream. Commit c685af1108d7 ("serial: mvebu-uart: fix tx lost characters") fixed tx lost characters at low baud rates but started causing tx lost characters when kernel is going to power off or reboot. TX_EMP tells us when transmit queue is empty therefore all characters were transmitted. TX_RDY tells us when CPU can send a new character. Therefore we need to use different check prior transmitting new character and different check after all characters were sent. This patch splits polling code into two functions: wait_for_xmitr() which waits for TX_RDY and wait_for_xmite() which waits for TX_EMP. When rebooting A3720 platform without this patch on UART is print only: [ 42.699� And with this patch on UART is full output: [ 39.530216] reboot: Restarting system Fixes: c685af1108d7 ("serial: mvebu-uart: fix tx lost characters") Signed-off-by: Pali Rohár Cc: stable Link: https://lore.kernel.org/r/20201223191931.18343-1-pali@kernel.org Signed-off-by: Greg Kroah-Hartman

riscv: Fix sifive serial driver

2021-01-27T10:47:43+00:00

[ Upstream commit 1f1496a923b6ba16679074fe77100e1b53cdb880 ] Setup the port uartclk in sifive_serial_probe() so that the base baud rate is correctly printed during device probe instead of always showing "0". I.e. the probe message is changed from 38000000.serial: ttySIF0 at MMIO 0x38000000 (irq = 1, base_baud = 0) is a SiFive UART v0 to the correct: 38000000.serial: ttySIF0 at MMIO 0x38000000 (irq = 1, base_baud = 115200) is a SiFive UART v0 Signed-off-by: Damien Le Moal Reviewed-by: Palmer Dabbelt Acked-by: Palmer Dabbelt Signed-off-by: Palmer Dabbelt Signed-off-by: Sasha Levin

serial_core: Check for port state when tty is in error state

2020-12-30T10:51:00+00:00

commit 2f70e49ed860020f5abae4f7015018ebc10e1f0e upstream. At the moment opening a serial device node (such as /dev/ttyS3) succeeds even if there is no actual serial device behind it. Reading/writing/ioctls fail as expected because the uart port is not initialized (the type is PORT_UNKNOWN) and the TTY_IO_ERROR error state bit is set fot the tty. However setting line discipline does not have these checks 8250_port.c (8250 is the default choice made by univ8250_console_init()). As the result of PORT_UNKNOWN, uart_port::iobase is NULL which a platform translates onto some address accessing which produces a crash like below. This adds tty_port_initialized() to uart_set_ldisc() to prevent the crash. Found by syzkaller. Signed-off-by: Alexey Kardashevskiy Link: https://lore.kernel.org/r/20201203055834.45838-1-aik@ozlabs.ru Cc: stable Signed-off-by: Greg Kroah-Hartman

serial: 8250_omap: Avoid FIFO corruption caused by MDR1 access

2020-12-21T12:27:06+00:00

commit d96f04d347e4011977abdbb4da5d8f303ebd26f8 upstream. It has been observed that once per 300-1300 port openings the first transmitted byte is being corrupted on AM3352 ("v" written to FIFO appeared as "e" on the wire). It only happened if single byte has been transmitted right after port open, which means, DMA is not used for this transfer and the corruption never happened afterwards. Therefore I've carefully re-read the MDR1 errata (link below), which says "when accessing the MDR1 registers that causes a dummy under-run condition that will freeze the UART in IrDA transmission. In UART mode, this may corrupt the transferred data". Strictly speaking, omap_8250_mdr1_errataset() performs a read access and if the value is the same as should be written, exits without errata-recommended FIFO reset. A brief check of the serial_omap_mdr1_errataset() from the competing omap-serial driver showed it has no read access of MDR1. After removing the read access from omap_8250_mdr1_errataset() the data corruption never happened any more. Link: https://www.ti.com/lit/er/sprz360i/sprz360i.pdf Fixes: 61929cf0169d ("tty: serial: Add 8250-core based omap driver") Cc: stable@vger.kernel.org Signed-off-by: Alexander Sverdlin Link: https://lore.kernel.org/r/20201210055257.1053028-1-alexander.sverdlin@gmail.com Signed-off-by: Greg Kroah-Hartman

tty: serial: imx: keep console clocks always on

2020-11-24T12:29:20+00:00

commit e67c139c488e84e7eae6c333231e791f0e89b3fb upstream. For below code, there has chance to cause deadlock in SMP system: Thread 1: clk_enable_lock(); pr_info("debug message"); clk_enable_unlock(); Thread 2: imx_uart_console_write() clk_enable() clk_enable_lock(); Thread 1: Acuired clk enable_lock -> printk -> console_trylock_spinning Thread 2: console_unlock() -> imx_uart_console_write -> clk_disable -> Acquite clk enable_lock So the patch is to keep console port clocks always on like other console drivers. Fixes: 1cf93e0d5488 ("serial: imx: remove the uart_console() check") Acked-by: Uwe Kleine-König Signed-off-by: Fugang Duan Link: https://lore.kernel.org/r/20201111025136.29818-1-fugang.duan@nxp.com Cc: stable [fix up build warning - gregkh] Signed-off-by: Greg Kroah-Hartman

tty: serial: imx: fix potential deadlock

2020-11-24T12:29:20+00:00

commit 33f16855dcb973f745c51882d0e286601ff3be2b upstream. Enabling the lock dependency validator has revealed that the way spinlocks are used in the IMX serial port could result in a deadlock. Specifically, imx_uart_int() acquires a spinlock without disabling the interrupts, meaning that another interrupt could come along and try to acquire the same spinlock, potentially causing the two to wait for each other indefinitely. Use spin_lock_irqsave() instead to disable interrupts upon acquisition of the spinlock. Fixes: c974991d2620 ("tty:serial:imx: use spin_lock instead of spin_lock_irqsave in isr") Reviewed-by: Uwe Kleine-König Signed-off-by: Sam Nobs Link: https://lore.kernel.org/r/1604955006-9363-1-git-send-email-samuel.nobs@taitradio.com Cc: stable Signed-off-by: Greg Kroah-Hartman

tty: serial: fsl_lpuart: LS1021A has a FIFO size of 16 words, like LS1028A

2020-11-10T11:37:33+00:00

commit c97f2a6fb3dfbfbbc88edc8ea62ef2b944e18849 upstream. Prior to the commit that this one fixes, the FIFO size was derived from the read-only register LPUARTx_FIFO[TXFIFOSIZE] using the following formula: TX FIFO size = 2 ^ (LPUARTx_FIFO[TXFIFOSIZE] - 1) The documentation for LS1021A is a mess. Under chapter 26.1.3 LS1021A LPUART module special consideration, it mentions TXFIFO_SZ and RXFIFO_SZ being equal to 4, and in the register description for LPUARTx_FIFO, it shows the out-of-reset value of TXFIFOSIZE and RXFIFOSIZE fields as "011", even though these registers read as "101" in reality. And when LPUART on LS1021A was working, the "101" value did correspond to "16 datawords", by applying the formula above, even though the documentation is wrong again (!!!!) and says that "101" means 64 datawords (hint: it doesn't). So the "new" formula created by commit f77ebb241ce0 has all the premises of being wrong for LS1021A, because it relied only on false data and no actual experimentation. Interestingly, in commit c2f448cff22a ("tty: serial: fsl_lpuart: add LS1028A support"), Michael Walle applied a workaround to this by manually setting the FIFO widths for LS1028A. It looks like the same values are used by LS1021A as well, in fact. When the driver thinks that it has a deeper FIFO than it really has, getty (user space) output gets truncated. Many thanks to Michael for pointing out where to look. Fixes: f77ebb241ce0 ("tty: serial: fsl_lpuart: correct the FIFO depth size") Suggested-by: Michael Walle Signed-off-by: Vladimir Oltean Link: https://lore.kernel.org/r/20201023013429.3551026-1-vladimir.oltean@nxp.com Reviewed-by：Fugang Duan Cc: stable Signed-off-by: Greg Kroah-Hartman

tty: serial: fsl_lpuart: add LS1028A support

2020-11-10T11:37:33+00:00

commit c2f448cff22a7ed09281f02bde084b0ce3bc61ed upstream. The LS1028A uses little endian register access and has a different FIFO size encoding. Signed-off-by: Michael Walle Link: https://lore.kernel.org/r/20200306214433.23215-4-michael@walle.cc Signed-off-by: Greg Kroah-Hartman

serial: txx9: add missing platform_driver_unregister() on error in serial_txx9_init

2020-11-10T11:37:32+00:00

commit 0c5fc92622ed5531ff324b20f014e9e3092f0187 upstream. Add the missing platform_driver_unregister() before return from serial_txx9_init in the error handling case when failed to register serial_txx9_pci_driver with macro ENABLE_SERIAL_TXX9_PCI defined. Fixes: ab4382d27412 ("tty: move drivers/serial/ to drivers/tty/serial/") Signed-off-by: Qinglang Miao Link: https://lore.kernel.org/r/20201103084942.109076-1-miaoqinglang@huawei.com Cc: stable Signed-off-by: Greg Kroah-Hartman

serial: 8250_mtk: Fix uart_get_baud_rate warning

2020-11-10T11:37:32+00:00

commit 912ab37c798770f21b182d656937072b58553378 upstream. Mediatek 8250 port supports speed higher than uartclk / 16. If the baud rates in both the new and the old termios setting are higher than uartclk / 16, the WARN_ON in uart_get_baud_rate() will be triggered. Passing NULL as the old termios so uart_get_baud_rate() will use uartclk / 16 - 1 as the new baud rate which will be replaced by the original baud rate later by tty_termios_encode_baud_rate() in mtk8250_set_termios(). Fixes: 551e553f0d4a ("serial: 8250_mtk: Fix high-speed baud rates clamping") Signed-off-by: Claire Chang Link: https://lore.kernel.org/r/20201102120749.374458-1-tientzu@chromium.org Cc: stable Signed-off-by: Greg Kroah-Hartman