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Subject[PATCH v5 06/16] spi: dw: Parameterize the DMA Rx/Tx burst length
Date
It isn't good to have numeric literals in the code especially if there
are multiple of them and they are related. Let's replace the Tx and Rx
burst level literals with the corresponding constants.

Co-developed-by: Georgy Vlasov <Georgy.Vlasov@baikalelectronics.ru>
Signed-off-by: Georgy Vlasov <Georgy.Vlasov@baikalelectronics.ru>
Co-developed-by: Ramil Zaripov <Ramil.Zaripov@baikalelectronics.ru>
Signed-off-by: Ramil Zaripov <Ramil.Zaripov@baikalelectronics.ru>
Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Alexey Malahov <Alexey.Malahov@baikalelectronics.ru>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Feng Tang <feng.tang@intel.com>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: linux-mips@vger.kernel.org
Cc: devicetree@vger.kernel.org

---

Changelog v3:
- Discard the dws->fifo_len utilization in the Tx FIFO DMA threshold
setting.
---
drivers/spi/spi-dw-mid.c | 10 ++++++----
1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/drivers/spi/spi-dw-mid.c b/drivers/spi/spi-dw-mid.c
index 4345881ebf66..93463bdba0f8 100644
--- a/drivers/spi/spi-dw-mid.c
+++ b/drivers/spi/spi-dw-mid.c
@@ -21,7 +21,9 @@

#define WAIT_RETRIES 5
#define RX_BUSY 0
+#define RX_BURST_LEVEL 16
#define TX_BUSY 1
+#define TX_BURST_LEVEL 16

static bool mid_spi_dma_chan_filter(struct dma_chan *chan, void *param)
{
@@ -227,7 +229,7 @@ static struct dma_async_tx_descriptor *dw_spi_dma_prepare_tx(struct dw_spi *dws,
memset(&txconf, 0, sizeof(txconf));
txconf.direction = DMA_MEM_TO_DEV;
txconf.dst_addr = dws->dma_addr;
- txconf.dst_maxburst = 16;
+ txconf.dst_maxburst = TX_BURST_LEVEL;
txconf.src_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
txconf.dst_addr_width = convert_dma_width(dws->n_bytes);
txconf.device_fc = false;
@@ -319,7 +321,7 @@ static struct dma_async_tx_descriptor *dw_spi_dma_prepare_rx(struct dw_spi *dws,
memset(&rxconf, 0, sizeof(rxconf));
rxconf.direction = DMA_DEV_TO_MEM;
rxconf.src_addr = dws->dma_addr;
- rxconf.src_maxburst = 16;
+ rxconf.src_maxburst = RX_BURST_LEVEL;
rxconf.dst_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
rxconf.src_addr_width = convert_dma_width(dws->n_bytes);
rxconf.device_fc = false;
@@ -344,8 +346,8 @@ static int mid_spi_dma_setup(struct dw_spi *dws, struct spi_transfer *xfer)
{
u16 imr = 0, dma_ctrl = 0;

- dw_writel(dws, DW_SPI_DMARDLR, 0xf);
- dw_writel(dws, DW_SPI_DMATDLR, 0x10);
+ dw_writel(dws, DW_SPI_DMARDLR, RX_BURST_LEVEL - 1);
+ dw_writel(dws, DW_SPI_DMATDLR, TX_BURST_LEVEL);

if (xfer->tx_buf) {
dma_ctrl |= SPI_DMA_TDMAE;
--
2.26.2
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