From: Feng Tang <feng.tang@xxxxxxxxx>
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@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>
---
drivers/tty/serial/mfd.c | 26 +++++---------------------
1 files changed, 5 insertions(+), 21 deletions(-)
diff --git a/drivers/tty/serial/mfd.c b/drivers/tty/serial/mfd.c
index 7767774..53ff6af 100644
--- a/drivers/tty/serial/mfd.c
+++ b/drivers/tty/serial/mfd.c
@@ -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
--
1.7.4.1
--
To unsubscribe from this list: send the line "unsubscribe linux-serial" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
