diff options
| author | Crescent Hsieh <crescentcy.hsieh@moxa.com> | 2026-07-31 15:48:14 +0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2026-08-03 16:51:57 +0200 |
| commit | 7df53c4d3364de240c94591aadb20737ddc970ea (patch) | |
| tree | e19e286313f06685ba3ea31228c967507e226afc | |
| parent | c016f2405cec3809c4be960ab6c3a9c3ee82ef71 (diff) | |
serial: 8250_mxpcie: speed up TX using memory-mapped FIFO window
The MUEx50 UART provides a memory-mapped TX FIFO data window along with
a TX FIFO level counter.
Fill the TX FIFO in bulk via the MMIO FIFO window based on available
FIFO space, using uart_port_tx_limited() for the common serial-core TX
handling.
Signed-off-by: Crescent Hsieh <crescentcy.hsieh@moxa.com>
Link: https://patch.msgid.link/20260731074820.735619-9-crescentcy.hsieh@moxa.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | drivers/tty/serial/8250/8250_mxpcie.c | 16 |
1 files changed, 15 insertions, 1 deletions
diff --git a/drivers/tty/serial/8250/8250_mxpcie.c b/drivers/tty/serial/8250/8250_mxpcie.c index 415468a02d0d..e864fb0624e5 100644 --- a/drivers/tty/serial/8250/8250_mxpcie.c +++ b/drivers/tty/serial/8250/8250_mxpcie.c @@ -81,8 +81,10 @@ #define MOXA_PUART_FCL 0x12 /* Flow Control Low Trigger Level */ #define MOXA_PUART_FCH 0x13 /* Flow Control High Trigger Level */ #define MOXA_PUART_RX_FIFO_CNT 0x15 /* Rx FIFO Data Counter */ +#define MOXA_PUART_TX_FIFO_CNT 0x16 /* Tx FIFO Data Counter */ #define MOXA_PUART_RX_FIFO_MEM 0x100 /* Memory Space to Rx FIFO Data Register */ +#define MOXA_PUART_TX_FIFO_MEM 0x100 /* Memory Space to Tx FIFO Data Register */ #define MOXA_GPIO_DIRECTION 0x09 #define MOXA_GPIO_OUTPUT 0x0A @@ -304,6 +306,18 @@ static bool mxpcie8250_should_rx(struct uart_8250_port *up, u16 lsr) return false; } +static void mxpcie8250_tx_chars(struct uart_8250_port *up) +{ + struct uart_port *port = &up->port; + unsigned int offset = 0; + unsigned char c; + + uart_port_tx_limited(port, c, port->fifosize - serial_in(up, MOXA_PUART_TX_FIFO_CNT), + true, + serial_out(up, MOXA_PUART_TX_FIFO_MEM + offset++, c), + ({})); +} + static int mxpcie8250_handle_irq(struct uart_port *port) { struct uart_8250_port *up = up_to_u8250p(port); @@ -327,7 +341,7 @@ static int mxpcie8250_handle_irq(struct uart_port *port) serial8250_modem_status(up); if ((lsr & UART_LSR_THRE) && (up->ier & UART_IER_THRI)) - serial8250_tx_chars(up); + mxpcie8250_tx_chars(up); return 1; } |