06.02.2019 22:16, Sowjanya Komatineni пишет:
> +static void tegra_i2c_config_fifo_trig(struct tegra_i2c_dev *i2c_dev,
> + size_t len)
> +{
> + u32 val = 0, reg;
> + u8 dma_burst = 0;
> + struct dma_slave_config slv_config = {0};
> + struct dma_chan *chan;
> + int ret;
> + unsigned long reg_offset;
> +
> + if (i2c_dev->hw->has_mst_fifo)
> + reg = I2C_MST_FIFO_CONTROL;
> + else
> + reg = I2C_FIFO_CONTROL;
> +
> + if (i2c_dev->is_curr_dma_xfer) {
> + if (len & 0xF)
> + dma_burst = 1;
> + else if (len & 0x10)
> + dma_burst = 4;
> + else
> + dma_burst = 8;
> +
> + if (i2c_dev->msg_read) {
> + chan = i2c_dev->rx_dma_chan;
> + reg_offset = tegra_i2c_reg_addr(i2c_dev, I2C_RX_FIFO);
> + slv_config.src_addr = i2c_dev->base_phys + reg_offset;
> + slv_config.src_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
> + slv_config.src_maxburst = dma_burst;
> +
> + if (i2c_dev->hw->has_mst_fifo)
> + val |= I2C_MST_FIFO_CONTROL_RX_TRIG(dma_burst);
> + else
> + val |= I2C_FIFO_CONTROL_RX_TRIG(dma_burst);
> + } else {
> + chan = i2c_dev->tx_dma_chan;
> + reg_offset = tegra_i2c_reg_addr(i2c_dev, I2C_TX_FIFO);
> + slv_config.dst_addr = i2c_dev->base_phys + reg_offset;
> + slv_config.dst_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
> + slv_config.dst_maxburst = dma_burst;
> +
> + if (i2c_dev->hw->has_mst_fifo)
> + val |= I2C_MST_FIFO_CONTROL_TX_TRIG(dma_burst);
> + else
> + val |= I2C_FIFO_CONTROL_TX_TRIG(dma_burst);
> + }
Minor nit: let's replace "|=" with "=" for consistency, and then "u32 val = 0," to just "u32 val,".
> +
> + slv_config.device_fc = true;
> + ret = dmaengine_slave_config(chan, &slv_config);
> + if (ret < 0) {
> + dev_err(i2c_dev->dev, "DMA slave config failed: %d\n",
> + ret);
> + dev_err(i2c_dev->dev, "fallbacking to PIO\n");
> + tegra_i2c_release_dma(i2c_dev);
> + i2c_dev->is_curr_dma_xfer = false;
> + } else {
> + goto out;
> + }
> + }
> +
> + if (i2c_dev->hw->has_mst_fifo)
> + val = I2C_MST_FIFO_CONTROL_TX_TRIG(8) |
> + I2C_MST_FIFO_CONTROL_RX_TRIG(1);
> + else
> + val = I2C_FIFO_CONTROL_TX_TRIG(8) |
> + I2C_FIFO_CONTROL_RX_TRIG(1);
> +out:
> + i2c_writel(i2c_dev, val, reg);
> +}
