kernel/linux.git/drivers/tty/serial/atmel_serial.c, branch linux-4.4.y

tty: serial: atmel: Call dma_async_issue_pending()

2022-01-27T07:46:14+00:00

[ Upstream commit 4f4b9b5895614eb2e2b5f4cab7858f44bd113e1b ] The driver wrongly assummed that tx_submit() will start the transfer, which is not the case, now that the at_xdmac driver is fixed. tx_submit is supposed to push the current transaction descriptor to a pending queue, waiting for issue_pending to be called. issue_pending must start the transfer, not tx_submit. Fixes: 34df42f59a60 ("serial: at91: add rx dma support") Fixes: 08f738be88bb ("serial: at91: add tx dma support") Signed-off-by: Tudor Ambarus Link: https://lore.kernel.org/r/20211125090028.786832-4-tudor.ambarus@microchip.com Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin

tty: serial: atmel: Check return code of dmaengine_submit()

2022-01-27T07:46:14+00:00

[ Upstream commit 1e67bd2b8cb90b66e89562598e9c2046246832d3 ] The tx_submit() method of struct dma_async_tx_descriptor is entitled to do sanity checks and return errors if encountered. It's not the case for the DMA controller drivers that this client is using (at_h/xdmac), because they currently don't do sanity checks and always return a positive cookie at tx_submit() method. In case the controller drivers will implement sanity checks and return errors, print a message so that the client will be informed that something went wrong at tx_submit() level. Fixes: 08f738be88bb ("serial: at91: add tx dma support") Signed-off-by: Tudor Ambarus Acked-by: Richard Genoud Link: https://lore.kernel.org/r/20211125090028.786832-3-tudor.ambarus@microchip.com Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin

tty/serial: atmel: reschedule TX after RX was started

2019-09-21T05:12:48+00:00

commit d2ace81bf902a9f11d52e59e5d232d2255a0e353 upstream. When half-duplex RS485 communication is used, after RX is started, TX tasklet still needs to be scheduled tasklet. This avoids console freezing when more data is to be transmitted, if the serial communication is not closed. Fixes: 69646d7a3689 ("tty/serial: atmel: RS485 HD w/DMA: enable RX after TX is stopped") Signed-off-by: Razvan Stefanescu Cc: stable Link: https://lore.kernel.org/r/20190813074025.16218-1-razvan.stefanescu@microchip.com Signed-off-by: Greg Kroah-Hartman

tty/serial: atmel: RS485 HD w/DMA: enable RX after TX is stopped

2019-04-27T07:33:47+00:00

commit 69646d7a3689fbe1a65ae90397d22ac3f1b8d40f upstream. In half-duplex operation, RX should be started after TX completes. If DMA is used, there is a case when the DMA transfer completes but the TX FIFO is not emptied, so the RX cannot be restarted just yet. Use a boolean variable to store this state and rearm TX interrupt mask to be signaled again that the transfer finished. In interrupt transmit handler this variable is used to start RX. A warning message is generated if RX is activated before TX fifo is cleared. Fixes: b389f173aaa1 ("tty/serial: atmel: RS485 half duplex w/DMA: enable RX after TX is done") Signed-off-by: Razvan Stefanescu Acked-by: Richard Genoud Cc: stable Signed-off-by: Greg Kroah-Hartman

tty/serial: atmel: Add is_half_duplex helper

2019-04-27T07:33:47+00:00

commit f3040983132bf3477acd45d2452a906e67c2fec9 upstream. Use a helper function to check that a port needs to use half duplex communication, replacing several occurrences of multi-line bit checking. Fixes: b389f173aaa1 ("tty/serial: atmel: RS485 half duplex w/DMA: enable RX after TX is done") Cc: stable Signed-off-by: Razvan Stefanescu Acked-by: Richard Genoud Signed-off-by: Greg Kroah-Hartman

tty: atmel_serial: fix a potential NULL pointer dereference

2019-04-03T04:23:27+00:00

commit c85be041065c0be8bc48eda4c45e0319caf1d0e5 upstream. In case dmaengine_prep_dma_cyclic fails, the fix returns a proper error code to avoid NULL pointer dereference. Signed-off-by: Kangjie Lu Fixes: 34df42f59a60 ("serial: at91: add rx dma support") Acked-by: Richard Genoud Cc: stable Signed-off-by: Greg Kroah-Hartman

tty/serial: atmel: add new version check for usart

2018-03-18T10:17:53+00:00

commit fd63a8903a2c40425a9811c3371dd4d0f42c0ad3 upstream. On our at91sam9260 based board the usart0 and usart1 ports report their versions (ATMEL_US_VERSION) as 0x10302. This version is not included in the current checks in the driver. Signed-off-by: Jonas Danielsson Acked-by: Richard Genoud Acked-by: Nicolas Ferre Cc: stable Signed-off-by: Greg Kroah-Hartman

tty/serial: atmel: RS485 half duplex w/DMA: enable RX after TX is done

2017-04-21T07:30:08+00:00

commit b389f173aaa1204d6dc1f299082a162eb0491545 upstream. When using RS485 in half duplex, RX should be enabled when TX is finished, and stopped when TX starts. Before commit 0058f0871efe7b01c6 ("tty/serial: atmel: fix RS485 half duplex with DMA"), RX was not disabled in atmel_start_tx() if the DMA was used. So, collisions could happened. But disabling RX in atmel_start_tx() uncovered another bug: RX was enabled again in the wrong place (in atmel_tx_dma) instead of being enabled when TX is finished (in atmel_complete_tx_dma), so the transmission simply stopped. This bug was not triggered before commit 0058f0871efe7b01c6 ("tty/serial: atmel: fix RS485 half duplex with DMA") because RX was never disabled before. Moving atmel_start_rx() in atmel_complete_tx_dma() corrects the problem. Reported-by: Gil Weber Fixes: 0058f0871efe7b01c6 Tested-by: Gil Weber Signed-off-by: Richard Genoud Acked-by: Alexandre Belloni Signed-off-by: Alexandre Belloni Tested-by: Bryan Evenson Signed-off-by: Greg Kroah-Hartman

tty/serial: atmel: fix TX path in atmel_console_write()

2017-04-08T07:53:31+00:00

commit 497e1e16f45c70574dc9922c7f75c642c2162119 upstream. A side effect of 89d8232411a8 ("tty/serial: atmel_serial: BUG: stop DMA from transmitting in stop_tx") is that the console can be called with TX path disabled. Then the system would hang trying to push charecters out in atmel_console_putchar(). Signed-off-by: Nicolas Ferre Fixes: 89d8232411a8 ("tty/serial: atmel_serial: BUG: stop DMA from transmitting in stop_tx") Signed-off-by: Greg Kroah-Hartman Signed-off-by: Greg Kroah-Hartman

tty/serial: atmel: fix race condition (TX+DMA)

2017-04-08T07:53:31+00:00

commit 31ca2c63fdc0aee725cbd4f207c1256f5deaabde upstream. If uart_flush_buffer() is called between atmel_tx_dma() and atmel_complete_tx_dma(), the circular buffer has been cleared, but not atmel_port->tx_len. That leads to a circular buffer overflow (dumping (UART_XMIT_SIZE - atmel_port->tx_len) bytes). Tested-by: Nicolas Ferre Signed-off-by: Richard Genoud Signed-off-by: Greg Kroah-Hartman