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Commit 7282cec9 authored by Qipan Li's avatar Qipan Li Committed by Greg Kroah-Hartman
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serial: sirf: transfer more bytes once to decrease interrupts 



the current codes send 1 bytes, then after getting TX done interrupt,
send subsequent bytes. it causes redundant interrupts.
for example, if we have 3 bytes in TX buffer, the TX flow is:
1. send 1 byte
2. get TX down interrupt
3. send the left 2 bytes
4. get TX down interrupt

this patch moves to send more bytes and decrease interrupts, the new
flow is:
1. send 3 bytes
2. get TX down interrupt

Signed-off-by: default avatarQipan Li <Qipan.Li@csr.com>
Signed-off-by: default avatarBarry Song <Baohua.Song@csr.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent a9977620

drivers/tty/serial/sirfsoc_uart.c

+2 −1
Original line number Diff line number Diff line
@@ -290,7 +290,8 @@ static void sirfsoc_uart_start_tx(struct uart_port *port) 
	if (sirfport->tx_dma_chan)

		sirfsoc_uart_tx_with_dma(sirfport);

	else {

		sirfsoc_uart_pio_tx_chars(sirfport, 1);

		sirfsoc_uart_pio_tx_chars(sirfport,

			SIRFSOC_UART_IO_TX_REASONABLE_CNT);

		wr_regl(port, ureg->sirfsoc_tx_fifo_op, SIRFUART_FIFO_START);

		if (!sirfport->is_marco)

			wr_regl(port, ureg->sirfsoc_int_en_reg,

drivers/tty/serial/sirfsoc_uart.h

+1 −1
Original line number Diff line number Diff line
@@ -449,4 +449,4 @@ struct sirfsoc_uart_port { 


/* I/O Mode */

#define SIRFSOC_UART_IO_RX_MAX_CNT		256

#define SIRFSOC_UART_IO_TX_REASONABLE_CNT	6
 
#define SIRFSOC_UART_IO_TX_REASONABLE_CNT	256