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authorSonic Zhang <sonic.zhang@analog.com>2009-06-11 13:51:33 +0100
committerLinus Torvalds <torvalds@linux-foundation.org>2009-06-11 08:51:05 -0700
commit2860b7911137eabb01c159abefb506e538ff3cb7 (patch)
tree2bd65c78638a87dd7eb40bc477dc22a4fd9abab0
parent84507794a9d5d4decd6bc9c111480076dba0d301 (diff)
downloadvexpress-lsk-2860b7911137eabb01c159abefb506e538ff3cb7.tar.gz
Blackfin Serial Driver: disable dma rx interrupt only rather than all irqs
The UART RX handling code isn't exactly speeding, so don't go disabling all interrupts when processing the buffer. Just disable the relevant DMA interrupt. This greatly improves latency of the system when utilizing the UART. Signed-off-by: Sonic Zhang <sonic.zhang@analog.com> Signed-off-by: Mike Frysinger <vapier@gentoo.org> Signed-off-by: Alan Cox <alan@linux.intel.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--drivers/serial/bfin_5xx.c7
1 files changed, 4 insertions, 3 deletions
diff --git a/drivers/serial/bfin_5xx.c b/drivers/serial/bfin_5xx.c
index 64603f5bb70..e2f6b1bfac9 100644
--- a/drivers/serial/bfin_5xx.c
+++ b/drivers/serial/bfin_5xx.c
@@ -479,9 +479,9 @@ static void bfin_serial_dma_rx_chars(struct bfin_serial_port *uart)
void bfin_serial_rx_dma_timeout(struct bfin_serial_port *uart)
{
int x_pos, pos;
- unsigned long flags;
- spin_lock_irqsave(&uart->port.lock, flags);
+ dma_disable_irq(uart->rx_dma_channel);
+ spin_lock_bh(&uart->port.lock);
/* 2D DMA RX buffer ring is used. Because curr_y_count and
* curr_x_count can't be read as an atomic operation,
@@ -512,7 +512,8 @@ void bfin_serial_rx_dma_timeout(struct bfin_serial_port *uart)
uart->rx_dma_buf.tail = uart->rx_dma_buf.head;
}
- spin_unlock_irqrestore(&uart->port.lock, flags);
+ spin_unlock_bh(&uart->port.lock);
+ dma_enable_irq(uart->rx_dma_channel);
mod_timer(&(uart->rx_dma_timer), jiffies + DMA_RX_FLUSH_JIFFIES);
}