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Commit ad909b3f authored by Jon Hunter's avatar Jon Hunter Committed by Greg Kroah-Hartman
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serial: tegra: Correct error handling on DMA setup 



Function tegra_uart_dma_channel_allocate() does not check that
dma_map_single() mapped the DMA buffer correctly. Add a check for this
and appropriate error handling.

Furthermore, if dmaengine_slave_config() (called by
tegra_uart_dma_channel_allocate()) fails, then memory allocated/mapped
is not freed/unmapped. Therefore, call tegra_uart_dma_channel_free()
instead of just dma_release_channel() if  dmaengine_slave_config() fails.

Signed-off-by: default avatarJon Hunter <jonathanh@nvidia.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent d92aca3a

drivers/tty/serial/serial-tegra.c

+28 −23
Original line number Diff line number Diff line
@@ -949,6 +949,28 @@ static int tegra_uart_hw_init(struct tegra_uart_port *tup) 
	return 0;

}



static void tegra_uart_dma_channel_free(struct tegra_uart_port *tup,

		bool dma_to_memory)

{

	if (dma_to_memory) {

		dmaengine_terminate_all(tup->rx_dma_chan);

		dma_release_channel(tup->rx_dma_chan);

		dma_free_coherent(tup->uport.dev, TEGRA_UART_RX_DMA_BUFFER_SIZE,

				tup->rx_dma_buf_virt, tup->rx_dma_buf_phys);

		tup->rx_dma_chan = NULL;

		tup->rx_dma_buf_phys = 0;

		tup->rx_dma_buf_virt = NULL;

	} else {

		dmaengine_terminate_all(tup->tx_dma_chan);

		dma_release_channel(tup->tx_dma_chan);

		dma_unmap_single(tup->uport.dev, tup->tx_dma_buf_phys,

			UART_XMIT_SIZE, DMA_TO_DEVICE);

		tup->tx_dma_chan = NULL;

		tup->tx_dma_buf_phys = 0;

		tup->tx_dma_buf_virt = NULL;

	}

}



static int tegra_uart_dma_channel_allocate(struct tegra_uart_port *tup,

			bool dma_to_memory)

{
@@ -981,6 +1003,11 @@ static int tegra_uart_dma_channel_allocate(struct tegra_uart_port *tup, 
		dma_phys = dma_map_single(tup->uport.dev,

			tup->uport.state->xmit.buf, UART_XMIT_SIZE,

			DMA_TO_DEVICE);

		if (dma_mapping_error(tup->uport.dev, dma_phys)) {

			dev_err(tup->uport.dev, "dma_map_single tx failed\n");

			dma_release_channel(dma_chan);

			return -ENOMEM;

		}

		dma_buf = tup->uport.state->xmit.buf;

	}
@@ -1013,32 +1040,10 @@ static int tegra_uart_dma_channel_allocate(struct tegra_uart_port *tup, 
	return 0;



scrub:

	dma_release_channel(dma_chan);

	tegra_uart_dma_channel_free(tup, dma_to_memory);

	return ret;

}



static void tegra_uart_dma_channel_free(struct tegra_uart_port *tup,

		bool dma_to_memory)

{

	if (dma_to_memory) {

		dmaengine_terminate_all(tup->rx_dma_chan);

		dma_release_channel(tup->rx_dma_chan);

		dma_free_coherent(tup->uport.dev, TEGRA_UART_RX_DMA_BUFFER_SIZE,

				tup->rx_dma_buf_virt, tup->rx_dma_buf_phys);

		tup->rx_dma_chan = NULL;

		tup->rx_dma_buf_phys = 0;

		tup->rx_dma_buf_virt = NULL;

	} else {

		dmaengine_terminate_all(tup->tx_dma_chan);

		dma_release_channel(tup->tx_dma_chan);

		dma_unmap_single(tup->uport.dev, tup->tx_dma_buf_phys,

			UART_XMIT_SIZE, DMA_TO_DEVICE);

		tup->tx_dma_chan = NULL;

		tup->tx_dma_buf_phys = 0;

		tup->tx_dma_buf_virt = NULL;

	}

}



static int tegra_uart_startup(struct uart_port *u)

{

	struct tegra_uart_port *tup = to_tegra_uport(u);