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Since I2C supports only half duplex, there is no impact on perf with this. Signed-off-by: Akhil R Acked-by: Thierry Reding --- drivers/i2c/busses/i2c-tegra.c | 69 ++++++++++------------------------ 1 file changed, 20 insertions(+), 49 deletions(-) diff --git a/drivers/i2c/busses/i2c-tegra.c b/drivers/i2c/busses/i2c-tegra.c index c1e1e1c2b8d9..fe042232a181 100644 --- a/drivers/i2c/busses/i2c-tegra.c +++ b/drivers/i2c/busses/i2c-tegra.c @@ -249,8 +249,7 @@ struct tegra_i2c_hw_feature { * @msg_read: indicates that the transfer is a read access * @timings: i2c timings information like bus frequency * @multimaster_mode: indicates that I2C controller is in multi-master mode - * @tx_dma_chan: DMA transmit channel - * @rx_dma_chan: DMA receive channel + * @dma_chan: DMA channel * @dma_phys: handle to DMA resources * @dma_buf: pointer to allocated DMA buffer * @dma_buf_size: DMA buffer size @@ -283,8 +282,7 @@ struct tegra_i2c_dev { __u16 msg_len; struct completion dma_complete; - struct dma_chan *tx_dma_chan; - struct dma_chan *rx_dma_chan; + struct dma_chan *dma_chan; unsigned int dma_buf_size; struct device *dma_dev; dma_addr_t dma_phys; @@ -393,16 +391,14 @@ static int tegra_i2c_dma_submit(struct tegra_i2c_dev *i2c_dev, size_t len) { struct dma_async_tx_descriptor *dma_desc; enum dma_transfer_direction dir; - struct dma_chan *chan; dev_dbg(i2c_dev->dev, "starting DMA for length: %zu\n", len); reinit_completion(&i2c_dev->dma_complete); dir = i2c_dev->msg_read ? DMA_DEV_TO_MEM : DMA_MEM_TO_DEV; - chan = i2c_dev->msg_read ? i2c_dev->rx_dma_chan : i2c_dev->tx_dma_chan; - dma_desc = dmaengine_prep_slave_single(chan, i2c_dev->dma_phys, + dma_desc = dmaengine_prep_slave_single(i2c_dev->dma_chan, i2c_dev->dma_phys, len, dir, DMA_PREP_INTERRUPT | DMA_CTRL_ACK); if (!dma_desc) { @@ -415,7 +411,7 @@ static int tegra_i2c_dma_submit(struct tegra_i2c_dev *i2c_dev, size_t len) dma_desc->callback_param = i2c_dev; dmaengine_submit(dma_desc); - dma_async_issue_pending(chan); + dma_async_issue_pending(i2c_dev->dma_chan); return 0; } @@ -428,20 +424,14 @@ static void tegra_i2c_release_dma(struct tegra_i2c_dev *i2c_dev) i2c_dev->dma_buf = NULL; } - if (i2c_dev->tx_dma_chan) { - dma_release_channel(i2c_dev->tx_dma_chan); - i2c_dev->tx_dma_chan = NULL; - } - - if (i2c_dev->rx_dma_chan) { - dma_release_channel(i2c_dev->rx_dma_chan); - i2c_dev->rx_dma_chan = NULL; + if (i2c_dev->dma_chan) { + dma_release_channel(i2c_dev->dma_chan); + i2c_dev->dma_chan = NULL; } } static int tegra_i2c_init_dma(struct tegra_i2c_dev *i2c_dev) { - struct dma_chan *chan; dma_addr_t dma_phys; u32 *dma_buf; int err; @@ -459,25 +449,18 @@ static int tegra_i2c_init_dma(struct tegra_i2c_dev *i2c_dev) return 0; } - chan = dma_request_chan(i2c_dev->dev, "rx"); - if (IS_ERR(chan)) { - err = PTR_ERR(chan); - goto err_out; - } - - i2c_dev->rx_dma_chan = chan; - - chan = dma_request_chan(i2c_dev->dev, "tx"); - if (IS_ERR(chan)) { - err = PTR_ERR(chan); + /* + * The same channel will be used for both RX and TX. + * Keeping the name as "tx" for backward compatibility + * with existing devicetrees. + */ + i2c_dev->dma_chan = dma_request_chan(i2c_dev->dev, "tx"); + if (IS_ERR(i2c_dev->dma_chan)) { + err = PTR_ERR(i2c_dev->dma_chan); goto err_out; } - i2c_dev->tx_dma_chan = chan; - - WARN_ON(i2c_dev->tx_dma_chan->device != i2c_dev->rx_dma_chan->device); - i2c_dev->dma_dev = chan->device->dev; - + i2c_dev->dma_dev = i2c_dev->dma_chan->device->dev; i2c_dev->dma_buf_size = i2c_dev->hw->quirks->max_write_len + I2C_PACKET_HEADER_SIZE; @@ -976,11 +959,7 @@ static irqreturn_t tegra_i2c_isr(int irq, void *dev_id) dvc_writel(i2c_dev, DVC_STATUS_I2C_DONE_INTR, DVC_STATUS); if (i2c_dev->dma_mode) { - if (i2c_dev->msg_read) - dmaengine_terminate_async(i2c_dev->rx_dma_chan); - else - dmaengine_terminate_async(i2c_dev->tx_dma_chan); - + dmaengine_terminate_async(i2c_dev->dma_chan); complete(&i2c_dev->dma_complete); } @@ -994,7 +973,6 @@ static void tegra_i2c_config_fifo_trig(struct tegra_i2c_dev *i2c_dev, { struct dma_slave_config slv_config = {0}; u32 val, reg, dma_burst, reg_offset; - struct dma_chan *chan; int err; if (i2c_dev->hw->has_mst_fifo) @@ -1011,7 +989,6 @@ static void tegra_i2c_config_fifo_trig(struct tegra_i2c_dev *i2c_dev, 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; @@ -1023,7 +1000,6 @@ static void tegra_i2c_config_fifo_trig(struct tegra_i2c_dev *i2c_dev, 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; @@ -1037,7 +1013,7 @@ static void tegra_i2c_config_fifo_trig(struct tegra_i2c_dev *i2c_dev, } slv_config.device_fc = true; - err = dmaengine_slave_config(chan, &slv_config); + err = dmaengine_slave_config(i2c_dev->dma_chan, &slv_config); if (err) { dev_err(i2c_dev->dev, "DMA config failed: %d\n", err); dev_err(i2c_dev->dev, "falling back to PIO\n"); @@ -1347,13 +1323,8 @@ static int tegra_i2c_xfer_msg(struct tegra_i2c_dev *i2c_dev, * performs synchronization after the transfer's termination * and we want to get a completion if transfer succeeded. */ - dmaengine_synchronize(i2c_dev->msg_read ? - i2c_dev->rx_dma_chan : - i2c_dev->tx_dma_chan); - - dmaengine_terminate_sync(i2c_dev->msg_read ? - i2c_dev->rx_dma_chan : - i2c_dev->tx_dma_chan); + dmaengine_synchronize(i2c_dev->dma_chan); + dmaengine_terminate_sync(i2c_dev->dma_chan); if (!time_left && !completion_done(&i2c_dev->dma_complete)) { dev_err(i2c_dev->dev, "DMA transfer timed out\n");