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authorQipan Li <Qipan.Li@csr.com>2015-05-14 06:45:23 +0000
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2015-05-24 12:50:41 -0700
commit36c0991089ef190ee5e3f72e1346c623b24a0e7d (patch)
treee7c0e097d16ac2bd72186c9dc5e1566ef6929f78 /drivers/tty/serial/sirfsoc_uart.c
parenteab192ae56fd52416af485e3d7ba2c6982200d71 (diff)
serial: sirf: fix endless loop bug in uart receive tasklet
In special condition, when cpu schedule into rx_tmo_process_tl or rx_dma_complete_tl and all the receive dma tasks have done, it will go into endless loop because no dma task cookie status be changed. Signed-off-by: Qipan Li <Qipan.Li@csr.com> Signed-off-by: Barry Song <Baohua.Song@csr.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/tty/serial/sirfsoc_uart.c')
-rw-r--r--drivers/tty/serial/sirfsoc_uart.c9
1 files changed, 9 insertions, 0 deletions
diff --git a/drivers/tty/serial/sirfsoc_uart.c b/drivers/tty/serial/sirfsoc_uart.c
index 48cceaf5338a..ffeb7663bd6e 100644
--- a/drivers/tty/serial/sirfsoc_uart.c
+++ b/drivers/tty/serial/sirfsoc_uart.c
@@ -488,6 +488,7 @@ static void sirfsoc_rx_tmo_process_tl(unsigned long param)
unsigned int count;
struct dma_tx_state tx_state;
unsigned long flags;
+ int i = 0;
spin_lock_irqsave(&port->lock, flags);
while (DMA_COMPLETE == dmaengine_tx_status(sirfport->rx_dma_chan,
@@ -497,6 +498,9 @@ static void sirfsoc_rx_tmo_process_tl(unsigned long param)
SIRFSOC_RX_DMA_BUF_SIZE);
sirfport->rx_completed++;
sirfport->rx_completed %= SIRFSOC_RX_LOOP_BUF_CNT;
+ i++;
+ if (i > SIRFSOC_RX_LOOP_BUF_CNT)
+ break;
}
count = CIRC_CNT(sirfport->rx_dma_items[sirfport->rx_issued].xmit.head,
sirfport->rx_dma_items[sirfport->rx_issued].xmit.tail,
@@ -713,6 +717,8 @@ static void sirfsoc_uart_rx_dma_complete_tl(unsigned long param)
struct sirfsoc_int_en *uint_en = &sirfport->uart_reg->uart_int_en;
struct dma_tx_state tx_state;
unsigned long flags;
+ int i = 0;
+
spin_lock_irqsave(&port->lock, flags);
while (DMA_COMPLETE == dmaengine_tx_status(sirfport->rx_dma_chan,
sirfport->rx_dma_items[sirfport->rx_completed].cookie,
@@ -726,6 +732,9 @@ static void sirfsoc_uart_rx_dma_complete_tl(unsigned long param)
else
sirfport->rx_completed++;
sirfport->rx_completed %= SIRFSOC_RX_LOOP_BUF_CNT;
+ i++;
+ if (i > SIRFSOC_RX_LOOP_BUF_CNT)
+ break;
}
spin_unlock_irqrestore(&port->lock, flags);
tty_flip_buffer_push(&port->state->port);