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Commit 17fae28e authored by Stephen Boyd's avatar Stephen Boyd Committed by Greg Kroah-Hartman
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msm_serial: Send more than 1 character at a time on UARTDM 



UARTDM cores have a TX fifo that can accept more than one
character per register write, but the msm_serial driver currently
only supports 1 character mode. Add support for this mode of operation
to speed up the transmit path on DM devices.

Signed-off-by: default avatarStephen Boyd <sboyd@codeaurora.org>
Acked-by: default avatarDavid Brown <davidb@codeaurora.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 6909dadd

drivers/tty/serial/msm_serial.c

+32 −19
Original line number Original line Diff line number Diff line
@@ -195,10 +195,10 @@ static void handle_rx(struct uart_port *port) 
	tty_flip_buffer_push(tport);

	tty_flip_buffer_push(tport);

}

}





static void reset_dm_count(struct uart_port *port)

static void reset_dm_count(struct uart_port *port, int count)

{

{

	wait_for_xmitr(port);

	wait_for_xmitr(port);

	msm_write(port, 1, UARTDM_NCF_TX);

	msm_write(port, count, UARTDM_NCF_TX);

	msm_read(port, UARTDM_NCF_TX);

	msm_read(port, UARTDM_NCF_TX);

}

}
@@ -206,39 +206,52 @@ static void handle_tx(struct uart_port *port) 
{

{

	struct circ_buf *xmit = &port->state->xmit;

	struct circ_buf *xmit = &port->state->xmit;

	struct msm_port *msm_port = UART_TO_MSM(port);

	struct msm_port *msm_port = UART_TO_MSM(port);

	int sent_tx;

	unsigned int tx_count, num_chars;

	unsigned int tf_pointer = 0;



	tx_count = uart_circ_chars_pending(xmit);

	tx_count = min3(tx_count, (unsigned int)UART_XMIT_SIZE - xmit->tail,

			port->fifosize);





	if (port->x_char) {

	if (port->x_char) {

		if (msm_port->is_uartdm)

		if (msm_port->is_uartdm)

			reset_dm_count(port);

			reset_dm_count(port, tx_count + 1);





		msm_write(port, port->x_char,

		msm_write(port, port->x_char,

			  msm_port->is_uartdm ? UARTDM_TF : UART_TF);

			  msm_port->is_uartdm ? UARTDM_TF : UART_TF);

		port->icount.tx++;

		port->icount.tx++;

		port->x_char = 0;

		port->x_char = 0;

	} else if (tx_count && msm_port->is_uartdm) {

		reset_dm_count(port, tx_count);

	}

	}





	if (msm_port->is_uartdm)

	while (tf_pointer < tx_count) {

		reset_dm_count(port);

		int i;

		char buf[4] = { 0 };

		unsigned int *bf = (unsigned int *)&buf;





	while (msm_read(port, UART_SR) & UART_SR_TX_READY) {

		if (!(msm_read(port, UART_SR) & UART_SR_TX_READY))

		if (uart_circ_empty(xmit)) {

			/* disable tx interrupts */

			msm_port->imr &= ~UART_IMR_TXLEV;

			msm_write(port, msm_port->imr, UART_IMR);

			break;

			break;

		}

		msm_write(port, xmit->buf[xmit->tail],

			  msm_port->is_uartdm ? UARTDM_TF : UART_TF);





		if (msm_port->is_uartdm)

		if (msm_port->is_uartdm)

			reset_dm_count(port);

			num_chars = min(tx_count - tf_pointer, sizeof(buf));

		else

			num_chars = 1;





		xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);

		for (i = 0; i < num_chars; i++) {

			buf[i] = xmit->buf[xmit->tail + i];

			port->icount.tx++;

			port->icount.tx++;

		sent_tx = 1;

		}

		}





		msm_write(port, *bf, msm_port->is_uartdm ? UARTDM_TF : UART_TF);

		xmit->tail = (xmit->tail + num_chars) & (UART_XMIT_SIZE - 1);

		tf_pointer += num_chars;

	}



	/* disable tx interrupts if nothing more to send */

	if (uart_circ_empty(xmit))

		msm_stop_tx(port);



	if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)

	if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)

		uart_write_wakeup(port);

		uart_write_wakeup(port);

}

}
@@ -759,7 +772,7 @@ static void msm_console_putchar(struct uart_port *port, int c) 
	struct msm_port *msm_port = UART_TO_MSM(port);

	struct msm_port *msm_port = UART_TO_MSM(port);





	if (msm_port->is_uartdm)

	if (msm_port->is_uartdm)

		reset_dm_count(port);

		reset_dm_count(port, 1);





	while (!(msm_read(port, UART_SR) & UART_SR_TX_READY))

	while (!(msm_read(port, UART_SR) & UART_SR_TX_READY))

		;

		;