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serial: mfd: remove the TX full-empty interrupts workaround 

In A0 stepping, TX half-empty interrupt is not working, so have to
use the full-empty interrupts whose performance will be 15% lower.
Now re-enable the half-empty interrrupt after it is enabled in
silicon.

Signed-off-by: Feng Tang <feng.tang@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This commit is contained in:
Feng Tang 2011-02-22 15:28:10 +08:00 committed by Greg Kroah-Hartman
parent 10e82f6ce7
commit 085a4f758f
1 changed files with 5 additions and 21 deletions
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26
drivers/tty/serial/mfd.c
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@ -16,9 +16,7 @@
* 2/3 chan to port 1, 4/5 chan to port 3. Even number chans
* are used for RX, odd chans for TX
*
* 2. In A0 stepping, UART will not support TX half empty flag
*
* 3. The RI/DSR/DCD/DTR are not pinned out, DCD & DSR are always
* 2. The RI/DSR/DCD/DTR are not pinned out, DCD & DSR are always
* asserted, only when the HW is reset the DDCD and DDSR will
* be triggered
*/
@ -41,8 +39,6 @@
#include <linux/io.h>
#include <linux/debugfs.h>
#define MFD_HSU_A0_STEPPING 1
#define HSU_DMA_BUF_SIZE 2048
#define chan_readl(chan, offset) readl(chan->reg + offset)
@ -543,16 +539,9 @@ static void transmit_chars(struct uart_hsu_port *up)
return;
}
#ifndef MFD_HSU_A0_STEPPING
/* The IRQ is for TX FIFO half-empty */
count = up->port.fifosize / 2;
#else
/*
* A0 only supports fully empty IRQ, and the first char written
* into it won't clear the EMPT bit, so we may need be cautious
* by useing a shorter buffer
*/
count = up->port.fifosize - 4;
#endif
do {
serial_out(up, UART_TX, xmit->buf[xmit->tail]);
xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
@ -761,9 +750,8 @@ static void serial_hsu_break_ctl(struct uart_port *port, int break_state)
/*
* What special to do:
* 1. chose the 64B fifo mode
* 2. make sure not to select half empty mode for A0 stepping
* 3. start dma or pio depends on configuration
* 4. we only allocate dma memory when needed
* 2. start dma or pio depends on configuration
* 3. we only allocate dma memory when needed
*/
static int serial_hsu_startup(struct uart_port *port)
{
@ -967,10 +955,6 @@ serial_hsu_set_termios(struct uart_port *port, struct ktermios *termios,
fcr = UART_FCR_ENABLE_FIFO | UART_FCR_HSU_64_32B;
fcr |= UART_FCR_HSU_64B_FIFO;
#ifdef MFD_HSU_A0_STEPPING
/* A0 doesn't support half empty IRQ */
fcr |= UART_FCR_FULL_EMPT_TXI;
#endif
/*
* Ok, we're now changing the port state. Do it with