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Commit d2697fc8 authored by Karthikeyan Ramasubramanian's avatar Karthikeyan Ramasubramanian
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tty: serial: msm_geni_serial: Update console port to yield the CPU 



With larger log buffer size, it takes longer duration to transmit the
entire contents of log buffer size. Since the transmit operation happens
in IRQ context, it leads to tasks getting starved.

Update the console to yield the CPU after it has transmitted a certain
threshold of data.

CRs-Fixed: 2110215
Change-Id: Ib9c6e9f6ba800029c4f06a50abaccdd5c863e344
Signed-off-by: default avatarKarthikeyan Ramasubramanian <kramasub@codeaurora.org>
parent 138d7bb7

drivers/tty/serial/msm_geni_serial.c

+10 −0
Original line number Diff line number Diff line
@@ -127,6 +127,7 @@ 
} while (0)



#define DMA_RX_BUF_SIZE		(2048)

#define CONSOLE_YIELD_LEN	(8 * 1024)

struct msm_geni_serial_port {

	struct uart_port uport;

	char name[20];
@@ -162,6 +163,7 @@ struct msm_geni_serial_port { 
	unsigned int cur_baud;

	int ioctl_count;

	int edge_count;

	unsigned int tx_yield_count;

};



static const struct uart_ops msm_geni_serial_pops;
@@ -1083,6 +1085,14 @@ static int msm_geni_serial_handle_tx(struct uart_port *uport) 


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

	msm_port->xmit_size = 0;

	if (uart_console(uport) &&

	    (uport->icount.tx - msm_port->tx_yield_count) > CONSOLE_YIELD_LEN) {

		msm_port->tx_yield_count = uport->icount.tx;

		msm_geni_serial_stop_tx(uport);

		uart_write_wakeup(uport);

		goto exit_handle_tx;

	}



	tx_fifo_status = geni_read_reg_nolog(uport->membase,

					SE_GENI_TX_FIFO_STATUS);

	if (uart_circ_empty(xmit) && !tx_fifo_status) {