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Commit 36c09910 authored by Qipan Li's avatar Qipan Li Committed by Greg Kroah-Hartman
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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: default avatarQipan Li <Qipan.Li@csr.com>
Signed-off-by: default avatarBarry Song <Baohua.Song@csr.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent eab192ae

drivers/tty/serial/sirfsoc_uart.c

+9 −0
Original line number Diff line number Diff line
@@ -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);