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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>
This commit is contained in:
Qipan Li 2015-05-14 06:45:23 +00:00 committed by Greg Kroah-Hartman
parent eab192ae56
commit 36c0991089
1 changed files with 9 additions and 0 deletions
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9
drivers/tty/serial/sirfsoc_uart.c
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@ -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);