[PATCH v5 18/36] i2c: tegra: Don't fall back to PIO mode if DMA configuration fails

Dmitry Osipenko
2020-09-06T18:55:00Z

The DMA code path has been tested well enough and the DMA configuration
performed by tegra_i2c_config_fifo_trig() shouldn't ever fail in practice.
Hence let's remove the obscure transfer-mode switching in order to have a
cleaner and simpler code. Now I2C transfer will be failed if DMA
configuration fails.

Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
drivers/i2c/busses/i2c-tegra.c | 18 ++++++++++--------
1 file changed, 10 insertions(+), 8 deletions(-)

diff --git a/drivers/i2c/busses/i2c-tegra.c b/drivers/i2c/busses/i2c-tegra.c
index 20168e49dbb2..f38e0f3fe367 100644
--- a/drivers/i2c/busses/i2c-tegra.c
+++ b/drivers/i2c/busses/i2c-tegra.c
@@ -975,8 +975,7 @@ static irqreturn_t tegra_i2c_isr(int irq, void *dev_id)
return IRQ_HANDLED;
}

-static void tegra_i2c_config_fifo_trig(struct tegra_i2c_dev *i2c_dev,
- size_t len)
+static int tegra_i2c_config_fifo_trig(struct tegra_i2c_dev *i2c_dev, size_t len)
{
u32 val, reg;
u8 dma_burst;
@@ -1027,12 +1026,10 @@ static void tegra_i2c_config_fifo_trig(struct tegra_i2c_dev *i2c_dev,
if (ret < 0) {
dev_err(i2c_dev->dev, "DMA slave config failed: %d\n",
ret);
- dev_err(i2c_dev->dev, "falling back to PIO\n");
- tegra_i2c_release_dma(i2c_dev);
- i2c_dev->is_curr_dma_xfer = false;
- } else {
- goto out;
+ return ret;
}
+
+ goto out;
}

if (i2c_dev->hw->has_mst_fifo)
@@ -1043,6 +1040,8 @@ static void tegra_i2c_config_fifo_trig(struct tegra_i2c_dev *i2c_dev,
I2C_FIFO_CONTROL_RX_TRIG(1);
out:
i2c_writel(i2c_dev, val, reg);
+
+ return 0;
}

static unsigned long
@@ -1176,7 +1175,10 @@ static int tegra_i2c_xfer_msg(struct tegra_i2c_dev *i2c_dev,
i2c_dev->is_curr_dma_xfer = (xfer_size > I2C_PIO_MODE_PREFERRED_LEN) &&
i2c_dev->dma_buf &&
!i2c_dev->is_curr_atomic_xfer;
- tegra_i2c_config_fifo_trig(i2c_dev, xfer_size);
+
+ err = tegra_i2c_config_fifo_trig(i2c_dev, xfer_size);
+ if (err)
+ return err;

/*
* Transfer time in mSec = Total bits / transfer rate
--
2.27.0