kernel/linux.git/drivers/tty/serial, branch linux-5.11.y

serial: omap: fix rs485 half-duplex filtering

2021-05-14T08:49:51+00:00

[ Upstream commit e2a5e8448e7393e96ccde346c68764b40a52cc10 ] Data received during half-duplex transmission must be filtered. If the target device responds quickly, emptying the FIFO at the end of the transmission can erase not only the echo characters but also part of the response message. By keeping the receive interrupt enabled even during transmission, it allows you to filter each echo character and only in a number equal to those transmitted. The issue was generated by a target device that started responding 240us later having received a request in communication at 115200bps. Sometimes, some messages received by the target were missing some of the first bytes. Fixes: 3a13884abea0 ("tty/serial: omap: empty the RX FIFO at the end of half-duplex TX") Signed-off-by: Dario Binacchi Link: https://lore.kernel.org/r/20210418094705.27014-1-dariobin@libero.it Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin

serial: omap: don't disable rs485 if rts gpio is missing

2021-05-14T08:49:51+00:00

[ Upstream commit 45f6b6db53c80787b79044629b062dfcf2da71ec ] There are rs485 transceivers (e.g. MAX13487E/MAX13488E) which automatically disable or enable the driver and receiver to keep the bus in the correct state. In these cases we don't need a GPIO for flow control. Fixes: 4a0ac0f55b18 ("OMAP: add RS485 support") Signed-off-by: Dario Binacchi Link: https://lore.kernel.org/r/20210415210945.25863-1-dariobin@libero.it Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin

serial: core: return early on unsupported ioctls

2021-05-14T08:49:48+00:00

[ Upstream commit 79c5966cec7b148199386ef9933c31b999379065 ] Drivers can return -ENOIOCTLCMD when an ioctl is not recognised to tell the upper layers to continue looking for a handler. This is not the case for the RS485 and ISO7816 ioctls whose handlers should return -ENOTTY directly in case a serial driver does not implement the corresponding methods. Fixes: a5f276f10ff7 ("serial_core: Handle TIOC[GS]RS485 ioctls.") Fixes: ad8c0eaa0a41 ("tty/serial_core: add ISO7816 infrastructure") Signed-off-by: Johan Hovold Link: https://lore.kernel.org/r/20210407095208.31838-9-johan@kernel.org Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin

serial: stm32: fix tx_empty condition

2021-05-14T08:49:36+00:00

[ Upstream commit 3db1d52466dc11dca4e47ef12a6e6e97f846af62 ] In "tx_empty", we should poll TC bit in both DMA and PIO modes (instead of TXE) to check transmission data register has been transmitted independently of the FIFO mode. TC indicates that both transmit register and shift register are empty. When shift register is empty, tx_empty should return TIOCSER_TEMT instead of TC value. Cleans the USART_CR_TC TCCF register define (transmission complete clear flag) as it is duplicate of USART_ICR_TCCF. Fixes: 48a6092fb41f ("serial: stm32-usart: Add STM32 USART Driver") Signed-off-by: Erwan Le Ray Link: https://lore.kernel.org/r/20210304162308.8984-13-erwan.leray@foss.st.com Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin

serial: stm32: add FIFO flush when port is closed

2021-05-14T08:49:36+00:00

[ Upstream commit 9f77d19207a0e8ba814c8ceb22e90ce7cb2aef64 ] Transmission complete error is sent when ISR_TC is not set. If port closure is requested despite data in TDR / TX FIFO has not been sent (because of flow control), ISR_TC is not set and error message is sent on port closure but also when a new port is opened. Flush the data when port is closed, so the error isn't printed twice upon next port opening. Fixes: 64c32eab6603 ("serial: stm32: Add support of TC bit status check") Signed-off-by: Erwan Le Ray Link: https://lore.kernel.org/r/20210304162308.8984-12-erwan.leray@foss.st.com Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin

serial: stm32: fix FIFO flush in startup and set_termios

2021-05-14T08:49:36+00:00

[ Upstream commit 315e2d8a125ad77a1bc28f621162713f3e7aef48 ] Fifo flush set USART_RQR register by calling stm32_usart_set_bits routine (Read/Modify/Write). USART_RQR register is a write only register. So, read before write isn't correct / relevant to flush the FIFOs. Replace stm32_usart_set_bits call by writel_relaxed. Fixes: 84872dc448fe ("serial: stm32: add RX and TX FIFO flush") Signed-off-by: Erwan Le Ray Link: https://lore.kernel.org/r/20210304162308.8984-11-erwan.leray@foss.st.com Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin

serial: stm32: call stm32_transmit_chars locked

2021-05-14T08:49:36+00:00

[ Upstream commit f16b90c2d9db3e6ac719d1946b9d335ca4ab33f3 ] stm32_transmit_chars should be called under lock also in tx DMA callback. Fixes: 3489187204eb ("serial: stm32: adding dma support") Signed-off-by: Erwan Le Ray Signed-off-by: Fabrice Gasnier Link: https://lore.kernel.org/r/20210304162308.8984-10-erwan.leray@foss.st.com Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin

serial: stm32: fix tx dma completion, release channel

2021-05-14T08:49:36+00:00

[ Upstream commit fb4f2e04ac13e7c400e6b86afbbd314a5a2a7e8d ] This patch add a proper release of dma channels when completing dma tx. Fixes: 3489187204eb ("serial: stm32: adding dma support") Signed-off-by: Erwan Le Ray Link: https://lore.kernel.org/r/20210304162308.8984-9-erwan.leray@foss.st.com Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin

serial: liteuart: fix return value check in liteuart_probe()

2021-05-14T08:49:36+00:00

[ Upstream commit cebeddd6d0d9f839b9df2930b6a768b54913a763 ] In case of error, the function devm_platform_get_and_ioremap_resource() returns ERR_PTR() and never returns NULL. The NULL test in the return value check should be replaced with IS_ERR(). Fixes: 1da81e5562fa ("drivers/tty/serial: add LiteUART driver") Reported-by: Hulk Robot Signed-off-by: Wei Yongjun Link: https://lore.kernel.org/r/20210305034929.3234352-1-weiyongjun1@huawei.com Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin

serial: stm32: fix a deadlock in set_termios

2021-05-14T08:49:36+00:00

[ Upstream commit 436c97936001776f16153771ee887f125443e974 ] CTS/RTS GPIOs support that has been added recently to STM32 UART driver has introduced scheduled code in a set_termios part protected by a spin lock. This generates a potential deadlock scenario: Chain exists of: &irq_desc_lock_class --> console_owner --> &port_lock_key Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&port_lock_key); lock(console_owner); lock(&port_lock_key); lock(&irq_desc_lock_class); *** DEADLOCK *** 4 locks held by stty/766: Move the scheduled code after the spinlock. Fixes: 6cf61b9bd7cc ("tty: serial: Add modem control gpio support for STM32 UART") Signed-off-by: Erwan Le Ray Link: https://lore.kernel.org/r/20210304162308.8984-8-erwan.leray@foss.st.com Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin