kernel/drivers/tty, branch linux-6.2.y

serial: 8250: Add missing wakeup event reporting

2023-05-11T14:11:24Z

[ Upstream commit 0ba9e3a13c6adfa99e32b2576d20820ab10ad48a ] An 8250 UART configured as a wake-up source would not have reported itself through sysfs as being the source of wake-up, correct that. Fixes: b3b708fa2780 ("wake up from a serial port") Signed-off-by: Florian Fainelli Link: https://lore.kernel.org/r/20230414170241.2016255-1-f.fainelli@gmail.com Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin

tty: serial: fsl_lpuart: adjust buffer length to the intended size

2023-05-11T14:11:24Z

[ Upstream commit f73fd750552524b06b5d77ebfdd106ccc8fcac61 ] Based on the fls function definition provided below, we should not subtract 1 to obtain the correct buffer length: fls(0) = 0, fls(1) = 1, fls(0x80000000) = 32. Fixes: 5887ad43ee02 ("tty: serial: fsl_lpuart: Use cyclic DMA for Rx") Signed-off-by: Shenwei Wang Link: https://lore.kernel.org/r/20230410195555.1003900-1-shenwei.wang@nxp.com Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin

serial: 8250_bcm7271: Fix arbitration handling

2023-05-11T14:11:20Z

[ Upstream commit 15ac1122fd6d4bf408a03e6f23c7ad4f60b22f9e ] The arbitration of the UART DMA is mishandled for a few exceptional cases when probing and releasing the driver. It is possible that the DMA register spaces are not defined in device tree for an instance of the driver, so attempts to access the registers in brcmuart_arbitration() would use NULL pointers. It is also possible for the probe function to return an error while still holding the UART DMA. This would prevent the UART DMA from being claimed by an instance that could use it. These errors are addressed by only releasing the UART DMA if it is held by this instance (i.e. priv->dma_enabled == 1) and directing early error paths in probe to this common release_dma handling. Fixes: 41a469482de2 ("serial: 8250: Add new 8250-core based Broadcom STB driver") Signed-off-by: Doug Berger Acked-by: Florian Fainelli Link: https://lore.kernel.org/r/20230309190224.687380-1-opendmb@gmail.com Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin

serial: stm32: Re-assert RTS/DE GPIO in RS485 mode only if more data are transmitted

2023-05-11T14:11:20Z

[ Upstream commit c47527cbcc3c50800f34b8c684f29721f75de246 ] The stm32_usart_transmit_chars() may be called with empty or stopped transmit queue, and no XON/OFF character pending. This can happen at the end of transmission, where this last call is used to either handle the XON/XOFF x_char, or disable TX interrupt if queue is empty or stopped. If that occurs, do not assert the RS485 RTS/DE GPIO anymore, as the GPIO would remain asserted past the end of transmission and that would block the RS485 bus after the transmission. Only assert the RS485 RTS/DE GPIO if there is either pending XON/XOFF x_char, or at least one character in running transmit queue. Fixes: d7c76716169d ("serial: stm32: Use TC interrupt to deassert GPIO RTS in RS485 mode") Signed-off-by: Marek Vasut Link: https://lore.kernel.org/r/20230223042252.95480-2-marex@denx.de Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin

serial: max310x: fix IO data corruption in batched operations

2023-05-11T14:10:50Z

commit 3f42b142ea1171967e40e10e4b0241c0d6d28d41 upstream. After upgrading from 5.16 to 6.1, our board with a MAX14830 started producing lots of garbage data over UART. Bisection pointed out commit 285e76fc049c as the culprit. That patch tried to replace hand-written code which I added in 2b4bac48c1084 ("serial: max310x: Use batched reads when reasonably safe") with the generic regmap infrastructure for batched operations. Unfortunately, the `regmap_raw_read` and `regmap_raw_write` which were used are actually functions which perform IO over *multiple* registers. That's not what is needed for accessing these Tx/Rx FIFOs; the appropriate functions are the `_noinc_` versions, not the `_raw_` ones. Fix this regression by using `regmap_noinc_read()` and `regmap_noinc_write()` along with the necessary `regmap_config` setup; with this patch in place, our board communicates happily again. Since our board uses SPI for talking to this chip, the I2C part is completely untested. Fixes: 285e76fc049c ("serial: max310x: use regmap methods for SPI batch operations") Cc: stable@vger.kernel.org Reviewed-by: Andy Shevchenko Signed-off-by: Jan Kundrát Link: https://lore.kernel.org/r/79db8e82aadb0e174bc82b9996423c3503c8fb37.1680732084.git.jan.kundrat@cesnet.cz Signed-off-by: Greg Kroah-Hartman

serial: 8250: Fix serial8250_tx_empty() race with DMA Tx

2023-05-11T14:10:50Z

commit 146a37e05d620cef4ad430e5d1c9c077fe6fa76f upstream. There's a potential race before THRE/TEMT deasserts when DMA Tx is starting up (or the next batch of continuous Tx is being submitted). This can lead to misdetecting Tx empty condition. It is entirely normal for THRE/TEMT to be set for some time after the DMA Tx had been setup in serial8250_tx_dma(). As Tx side is definitely not empty at that point, it seems incorrect for serial8250_tx_empty() claim Tx is empty. Fix the race by also checking in serial8250_tx_empty() whether there's DMA Tx active. Note: This fix only addresses in-kernel race mainly to make using TCSADRAIN/FLUSH robust. Userspace can still cause other races but they seem userspace concurrency control problems. Fixes: 9ee4b83e51f74 ("serial: 8250: Add support for dmaengine") Cc: stable@vger.kernel.org Signed-off-by: Ilpo Järvinen Link: https://lore.kernel.org/r/20230317113318.31327-3-ilpo.jarvinen@linux.intel.com Signed-off-by: Greg Kroah-Hartman

serial: fix TIOCSRS485 locking

2023-05-11T14:10:50Z

commit 9e4f2a8004213339e9d837d891a59cc80e082966 upstream. The RS485 multipoint addressing support for some reason added a new ADDRB termios cflag which is (only!) updated from one of the RS485 ioctls. Make sure to take the termios rw semaphore for the right ioctl (i.e. set, not get). Fixes: ae50bb275283 ("serial: take termios_rwsem for ->rs485_config() & pass termios as param") Cc: stable@vger.kernel.org # 6.0 Cc: Ilpo Järvinen Reviewed-by: Ilpo Järvinen Signed-off-by: Johan Hovold Link: https://lore.kernel.org/r/20230412124811.11217-1-johan@kernel.org Signed-off-by: Greg Kroah-Hartman

tty: Prevent writing chars during tcsetattr TCSADRAIN/FLUSH

2023-05-11T14:10:50Z

commit 094fb49a2d0d6827c86d2e0840873e6db0c491d2 upstream. If userspace races tcsetattr() with a write, the drained condition might not be guaranteed by the kernel. There is a race window after checking Tx is empty before tty_set_termios() takes termios_rwsem for write. During that race window, more characters can be queued by a racing writer. Any ongoing transmission might produce garbage during HW's ->set_termios() call. The intent of TCSADRAIN/FLUSH seems to be preventing such a character corruption. If those flags are set, take tty's write lock to stop any writer before performing the lower layer Tx empty check and wait for the pending characters to be sent (if any). The initial wait for all-writers-done must be placed outside of tty's write lock to avoid deadlock which makes it impossible to use tty_wait_until_sent(). The write lock is retried if a racing write is detected. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Cc: stable@vger.kernel.org Signed-off-by: Ilpo Järvinen Link: https://lore.kernel.org/r/20230317113318.31327-2-ilpo.jarvinen@linux.intel.com Signed-off-by: Greg Kroah-Hartman

serial: 8250: Prevent starting up DMA Rx on THRI interrupt

2023-04-13T15:02:47Z

commit 90b8596ac46043e4a782d9111f5b285251b13756 upstream. Hans de Goede reported Bluetooth adapters (HCIs) connected over an UART connection failed due corrupted Rx payload. The problem was narrowed down to DMA Rx starting on UART_IIR_THRI interrupt. The problem occurs despite LSR having DR bit set, which is precondition for attempting to start DMA Rx in the first place. From a debug patch: [x.807834] 8250irq: iir=cc lsr+saved=60 received=0/15 ier=0f dma_t/rx/err=0/0/0 [x.808676] 8250irq: iir=c2 lsr+saved=61 received=0/0 ier=0f dma_t/rx/err=0/0/0 [x.808776] 8250irq: iir=cc lsr+saved=60 received=1/12 ier=0d dma_t/rx/err=0/1/0 [x.808870] Bluetooth: hci0: Frame reassembly failed (-84) In the debug snippet, received field indicates 1 byte was transferred over DMA and 12 bytes after that with the non-DMA Rx. The sole byte DMA handled was corrupted (gets zeroed) which leads to the HCI failure. This problem became apparent after commit e8ffbb71f783 ("serial: 8250: use THRE & __stop_tx also with DMA") changed Tx stop behavior. Tx stop is now triggered from a THRI interrupt. Despite that this problem looks like a HW bug, this fix is not adding UART_BUG_xx flag to the driver beucase it seems useful in general to avoid starting DMA when there are only a few bytes to transfer. Skipping DMA for small transfers avoids the extra overhead DMA incurs. Thus, don't setup DMA Rx on UART_IIR_THRI but leave it to a subsequent interrupt which has Rx a related IIR value. By returning false from handle_rx_dma(), the DMA vs non-DMA decision is postponed until either UART_IIR_RDI (FIFO threshold worth of bytes awaiting) or UART_IIR_TIMEOUT (inter-character timeout) triggers at a later time which allows better to discern whether the number of bytes warrants starting DMA or not. Reported-by: Hans de Goede Tested-by: Hans de Goede Fixes: e8ffbb71f783 ("serial: 8250: use THRE & __stop_tx also with DMA") Cc: stable@vger.kernel.org Signed-off-by: Ilpo Järvinen Acked-by: Hans de Goede Link: https://lore.kernel.org/r/20230317103034.12881-1-ilpo.jarvinen@linux.intel.com Signed-off-by: Greg Kroah-Hartman

tty: serial: fsl_lpuart: fix crash in lpuart_uport_is_active

2023-04-13T15:02:46Z

commit 178e00f36f934a88682d96aa046c1f90cb6f83a7 upstream. For serdev framework, tty->dev is a NULL pointer, lpuart_uport_is_active calling device_may_wakeup() may cause kernel NULL pointer crash, so here add the NULL pointer check before using it. Fixes: 4f5cb8c5e915 ("tty: serial: fsl_lpuart: enable wakeup source for lpuart") Cc: stable Signed-off-by: Sherry Sun Link: https://lore.kernel.org/r/20230323110923.24581-1-sherry.sun@nxp.com Signed-off-by: Greg Kroah-Hartman