[PATCH AUTOSEL 4.14 153/371] spi: tegra114: configure dma burst size to fifo trig level

Sasha Levin
2020-01-16T18:27:49Z

From: Sowjanya Komatineni <skomatineni@nvidia.com>

[ Upstream commit f4ce428c41fb22e3ed55496dded94df44cb920fa ]

Fixes: Configure DMA burst size to be same as SPI TX/RX trigger levels
to avoid mismatch.

SPI FIFO trigger levels are calculated based on the transfer length.
So this patch moves DMA slave configuration to happen before start
of DMAs.

Signed-off-by: Sowjanya Komatineni <skomatineni@nvidia.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/spi/spi-tegra114.c | 52 ++++++++++++++++++++++----------------
1 file changed, 30 insertions(+), 22 deletions(-)

diff --git a/drivers/spi/spi-tegra114.c b/drivers/spi/spi-tegra114.c
index 18dfbd57c61f..84ff0c507f0b 100644
--- a/drivers/spi/spi-tegra114.c
+++ b/drivers/spi/spi-tegra114.c
@@ -529,6 +529,8 @@ static int tegra_spi_start_dma_based_transfer(
u32 val;
unsigned int len;
int ret = 0;
+ u8 dma_burst;
+ struct dma_slave_config dma_sconfig = {0};

val = SPI_DMA_BLK_SET(tspi->curr_dma_words - 1);
tegra_spi_writel(tspi, val, SPI_DMA_BLK);
@@ -540,12 +542,16 @@ static int tegra_spi_start_dma_based_transfer(
len = tspi->curr_dma_words * 4;

/* Set attention level based on length of transfer */
- if (len & 0xF)
+ if (len & 0xF) {
val |= SPI_TX_TRIG_1 | SPI_RX_TRIG_1;
- else if (((len) >> 4) & 0x1)
+ dma_burst = 1;
+ } else if (((len) >> 4) & 0x1) {
val |= SPI_TX_TRIG_4 | SPI_RX_TRIG_4;
- else
+ dma_burst = 4;
+ } else {
val |= SPI_TX_TRIG_8 | SPI_RX_TRIG_8;
+ dma_burst = 8;
+ }

if (tspi->cur_direction & DATA_DIR_TX)
val |= SPI_IE_TX;
@@ -556,7 +562,18 @@ static int tegra_spi_start_dma_based_transfer(
tegra_spi_writel(tspi, val, SPI_DMA_CTL);
tspi->dma_control_reg = val;

+ dma_sconfig.device_fc = true;
if (tspi->cur_direction & DATA_DIR_TX) {
+ dma_sconfig.dst_addr = tspi->phys + SPI_TX_FIFO;
+ dma_sconfig.dst_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
+ dma_sconfig.dst_maxburst = dma_burst;
+ ret = dmaengine_slave_config(tspi->tx_dma_chan, &dma_sconfig);
+ if (ret < 0) {
+ dev_err(tspi->dev,
+ "DMA slave config failed: %d\n", ret);
+ return ret;
+ }
+
tegra_spi_copy_client_txbuf_to_spi_txbuf(tspi, t);
ret = tegra_spi_start_tx_dma(tspi, len);
if (ret < 0) {
@@ -567,6 +584,16 @@ static int tegra_spi_start_dma_based_transfer(
}

if (tspi->cur_direction & DATA_DIR_RX) {
+ dma_sconfig.src_addr = tspi->phys + SPI_RX_FIFO;
+ dma_sconfig.src_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
+ dma_sconfig.src_maxburst = dma_burst;
+ ret = dmaengine_slave_config(tspi->rx_dma_chan, &dma_sconfig);
+ if (ret < 0) {
+ dev_err(tspi->dev,
+ "DMA slave config failed: %d\n", ret);
+ return ret;
+ }
+
/* Make the dma buffer to read by dma */
dma_sync_single_for_device(tspi->dev, tspi->rx_dma_phys,
tspi->dma_buf_size, DMA_FROM_DEVICE);
@@ -626,7 +653,6 @@ static int tegra_spi_init_dma_param(struct tegra_spi_data *tspi,
u32 *dma_buf;
dma_addr_t dma_phys;
int ret;
- struct dma_slave_config dma_sconfig;

dma_chan = dma_request_slave_channel_reason(tspi->dev,
dma_to_memory ? "rx" : "tx");
@@ -646,19 +672,6 @@ static int tegra_spi_init_dma_param(struct tegra_spi_data *tspi,
return -ENOMEM;
}

- if (dma_to_memory) {
- dma_sconfig.src_addr = tspi->phys + SPI_RX_FIFO;
- dma_sconfig.src_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
- dma_sconfig.src_maxburst = 0;
- } else {
- dma_sconfig.dst_addr = tspi->phys + SPI_TX_FIFO;
- dma_sconfig.dst_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
- dma_sconfig.dst_maxburst = 0;
- }
-
- ret = dmaengine_slave_config(dma_chan, &dma_sconfig);
- if (ret)
- goto scrub;
if (dma_to_memory) {
tspi->rx_dma_chan = dma_chan;
tspi->rx_dma_buf = dma_buf;
@@ -669,11 +682,6 @@ static int tegra_spi_init_dma_param(struct tegra_spi_data *tspi,
tspi->tx_dma_phys = dma_phys;
}
return 0;
-
-scrub:
- dma_free_coherent(tspi->dev, tspi->dma_buf_size, dma_buf, dma_phys);
- dma_release_channel(dma_chan);
- return ret;
}

static void tegra_spi_deinit_dma_param(struct tegra_spi_data *tspi,
--
2.20.1