06.02.2019 22:16, Sowjanya Komatineni пишет:
> This patch adds DMA support for Tegra I2C.
>
> Tegra I2C TX and RX FIFO depth is 8 words. PIO mode is used for
> transfer size of the max FIFO depth and DMA mode is used for
> transfer size higher than max FIFO depth to save CPU overhead.
>
> PIO mode needs full intervention of CPU to fill or empty FIFO's
> and also need to service multiple data requests interrupt for the
> same transaction. This adds delay between data bytes of the same
> transfer when CPU is fully loaded and some slave devices has
> internal timeout for no bus activity and stops transaction to
> avoid bus hang. DMA mode is helpful in such cases.
>
> DMA mode is also helpful for Large transfers during downloading or
> uploading FW over I2C to some external devices.
>
> Signed-off-by: Sowjanya Komatineni <skomatineni@xxxxxxxxxx>
> ---
[snip]
> @@ -1124,6 +1453,10 @@ static int tegra_i2c_probe(struct platform_device *pdev)
> }
> }
>
> + ret = tegra_i2c_init_dma(i2c_dev);
> + if (ret < 0)
> + goto disable_div_clk;
> +
> ret = tegra_i2c_init(i2c_dev);
> if (ret) {
> dev_err(&pdev->dev, "Failed to initialize i2c controller\n");
Missing DMA resourcing release on probe failure.
diff --git a/drivers/i2c/busses/i2c-tegra.c b/drivers/i2c/busses/i2c-tegra.c
index 7921d3e6237d..11f25357b843 100644
--- a/drivers/i2c/busses/i2c-tegra.c
+++ b/drivers/i2c/busses/i2c-tegra.c
@@ -1612,14 +1612,14 @@ static int tegra_i2c_probe(struct platform_device *pdev)
ret = tegra_i2c_init(i2c_dev, false);
if (ret) {
dev_err(&pdev->dev, "Failed to initialize i2c controller\n");
- goto disable_div_clk;
+ goto release_dma;
}
ret = devm_request_irq(&pdev->dev, i2c_dev->irq,
tegra_i2c_isr, 0, dev_name(&pdev->dev), i2c_dev);
if (ret) {
dev_err(&pdev->dev, "Failed to request irq %i\n", i2c_dev->irq);
- goto disable_div_clk;
+ goto release_dma;
}
i2c_set_adapdata(&i2c_dev->adapter, i2c_dev);
@@ -1633,10 +1633,13 @@ static int tegra_i2c_probe(struct platform_device *pdev)
ret = i2c_add_numbered_adapter(&i2c_dev->adapter);
if (ret)
- goto disable_div_clk;
+ goto release_dma;
return 0;
+release_dma:
+ tegra_i2c_release_dma(i2c_dev);
+
disable_div_clk:
if (i2c_dev->is_multimaster_mode)
clk_disable(i2c_dev->div_clk);
