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: Karthikeyan Ramasubramanian <kramasub@codeaurora.org>
diff --git a/drivers/tty/serial/msm_geni_serial.c b/drivers/tty/serial/msm_geni_serial.c
index 67ed0e8..c5e2703 100644
--- a/drivers/tty/serial/msm_geni_serial.c
+++ b/drivers/tty/serial/msm_geni_serial.c
@@ -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 @@
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 @@
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) {