From 720e78d7fa0f1df905a42ae68e7e3b0f95e53946 Mon Sep 17 00:00:00 2001 From: Dan Carpenter Date: Wed, 31 Jan 2024 11:24:59 +0300 Subject: serial: 8250_pci1xxxx: partially revert off by one patch I was reviewing this code again and I realized I made a mistake here. It should have been > instead of >=. The subtract ensures that we don't go out of bounds. My patch meant that we don't read the last chunk of the buffer. Fixes: 86ee55e9bc7f ("serial: 8250_pci1xxxx: fix off by one in pci1xxxx_process_read_data()") Signed-off-by: Dan Carpenter Link: https://lore.kernel.org/r/bd6fb361-bbb9-427d-90e8-a5df4de76221@moroto.mountain Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/8250/8250_pci1xxxx.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/tty/serial/8250/8250_pci1xxxx.c b/drivers/tty/serial/8250/8250_pci1xxxx.c index cd258922bd78..2dda737b1660 100644 --- a/drivers/tty/serial/8250/8250_pci1xxxx.c +++ b/drivers/tty/serial/8250/8250_pci1xxxx.c @@ -302,7 +302,7 @@ static void pci1xxxx_process_read_data(struct uart_port *port, * to read, the data is received one byte at a time. */ while (valid_burst_count--) { - if (*buff_index >= (RX_BUF_SIZE - UART_BURST_SIZE)) + if (*buff_index > (RX_BUF_SIZE - UART_BURST_SIZE)) break; burst_buf = (u32 *)&rx_buff[*buff_index]; *burst_buf = readl(port->membase + UART_RX_BURST_FIFO); -- cgit v1.2.3-70-g09d2 From 3ee07964d407411fd578a3bc998de44fd64d266a Mon Sep 17 00:00:00 2001 From: "Jiri Slaby (SUSE)" Date: Thu, 1 Feb 2024 11:55:56 +0100 Subject: serial: core: introduce uart_port_tx_flags() And an enum with a flag: UART_TX_NOSTOP. To NOT call __port->ops->stop_tx() when the circular buffer is empty. mxs-uart needs this (see the next patch). Signed-off-by: "Jiri Slaby (SUSE)" Cc: stable Tested-by: Emil Kronborg Link: https://lore.kernel.org/r/20240201105557.28043-1-jirislaby@kernel.org Signed-off-by: Greg Kroah-Hartman --- include/linux/serial_core.h | 32 +++++++++++++++++++++++++++----- 1 file changed, 27 insertions(+), 5 deletions(-) diff --git a/include/linux/serial_core.h b/include/linux/serial_core.h index 536b2581d3e2..55b1f3ba48ac 100644 --- a/include/linux/serial_core.h +++ b/include/linux/serial_core.h @@ -748,8 +748,17 @@ struct uart_driver { void uart_write_wakeup(struct uart_port *port); -#define __uart_port_tx(uport, ch, tx_ready, put_char, tx_done, for_test, \ - for_post) \ +/** + * enum UART_TX_FLAGS -- flags for uart_port_tx_flags() + * + * @UART_TX_NOSTOP: don't call port->ops->stop_tx() on empty buffer + */ +enum UART_TX_FLAGS { + UART_TX_NOSTOP = BIT(0), +}; + +#define __uart_port_tx(uport, ch, flags, tx_ready, put_char, tx_done, \ + for_test, for_post) \ ({ \ struct uart_port *__port = (uport); \ struct circ_buf *xmit = &__port->state->xmit; \ @@ -777,7 +786,7 @@ void uart_write_wakeup(struct uart_port *port); if (pending < WAKEUP_CHARS) { \ uart_write_wakeup(__port); \ \ - if (pending == 0) \ + if (!((flags) & UART_TX_NOSTOP) && pending == 0) \ __port->ops->stop_tx(__port); \ } \ \ @@ -812,7 +821,7 @@ void uart_write_wakeup(struct uart_port *port); */ #define uart_port_tx_limited(port, ch, count, tx_ready, put_char, tx_done) ({ \ unsigned int __count = (count); \ - __uart_port_tx(port, ch, tx_ready, put_char, tx_done, __count, \ + __uart_port_tx(port, ch, 0, tx_ready, put_char, tx_done, __count, \ __count--); \ }) @@ -826,8 +835,21 @@ void uart_write_wakeup(struct uart_port *port); * See uart_port_tx_limited() for more details. */ #define uart_port_tx(port, ch, tx_ready, put_char) \ - __uart_port_tx(port, ch, tx_ready, put_char, ({}), true, ({})) + __uart_port_tx(port, ch, 0, tx_ready, put_char, ({}), true, ({})) + +/** + * uart_port_tx_flags -- transmit helper for uart_port with flags + * @port: uart port + * @ch: variable to store a character to be written to the HW + * @flags: %UART_TX_NOSTOP or similar + * @tx_ready: can HW accept more data function + * @put_char: function to write a character + * + * See uart_port_tx_limited() for more details. + */ +#define uart_port_tx_flags(port, ch, flags, tx_ready, put_char) \ + __uart_port_tx(port, ch, flags, tx_ready, put_char, ({}), true, ({})) /* * Baud rate helpers. */ -- cgit v1.2.3-70-g09d2 From 7be50f2e8f20fc2299069b28dea59a28e3abe20a Mon Sep 17 00:00:00 2001 From: "Jiri Slaby (SUSE)" Date: Thu, 1 Feb 2024 11:55:57 +0100 Subject: serial: mxs-auart: fix tx Emil reports: After updating Linux on an i.MX28 board, serial communication over AUART broke. When I TX from the board and measure on the TX pin, it seems like the HW fifo is not emptied before the transmission is stopped. MXS performs weird things with stop_tx(). The driver makes it conditional on uart_tx_stopped(). So the driver needs special handling. Pass the brand new UART_TX_NOSTOP to uart_port_tx_flags() and handle the stop on its own. Signed-off-by: "Jiri Slaby (SUSE)" Reported-by: Emil Kronborg Cc: stable Fixes: 2d141e683e9a ("tty: serial: use uart_port_tx() helper") Closes: https://lore.kernel.org/all/miwgbnvy3hjpnricubg76ytpn7xoceehwahupy25bubbduu23s@om2lptpa26xw/ Tested-by: Stefan Wahren Tested-by: Emil Kronborg Link: https://lore.kernel.org/r/20240201105557.28043-2-jirislaby@kernel.org Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/mxs-auart.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/drivers/tty/serial/mxs-auart.c b/drivers/tty/serial/mxs-auart.c index 3ec725555bcc..4749331fe618 100644 --- a/drivers/tty/serial/mxs-auart.c +++ b/drivers/tty/serial/mxs-auart.c @@ -605,13 +605,16 @@ static void mxs_auart_tx_chars(struct mxs_auart_port *s) return; } - pending = uart_port_tx(&s->port, ch, + pending = uart_port_tx_flags(&s->port, ch, UART_TX_NOSTOP, !(mxs_read(s, REG_STAT) & AUART_STAT_TXFF), mxs_write(ch, s, REG_DATA)); if (pending) mxs_set(AUART_INTR_TXIEN, s, REG_INTR); else mxs_clr(AUART_INTR_TXIEN, s, REG_INTR); + + if (uart_tx_stopped(&s->port)) + mxs_auart_stop_tx(&s->port); } static void mxs_auart_rx_char(struct mxs_auart_port *s) -- cgit v1.2.3-70-g09d2