linux-kernel - [PATCH v4 06/16] spi: dw: Parameterize the DMA Rx/Tx burst length

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Message-ID: <20200522000806.7381-7-Sergey.Semin@baikalelectronics.ru>
Date:   Fri, 22 May 2020 03:07:55 +0300
From:   Serge Semin <Sergey.Semin@...kalelectronics.ru>
To:     Mark Brown <broonie@...nel.org>
CC:     Serge Semin <Sergey.Semin@...kalelectronics.ru>,
        Serge Semin <fancer.lancer@...il.com>,
        Georgy Vlasov <Georgy.Vlasov@...kalelectronics.ru>,
        Ramil Zaripov <Ramil.Zaripov@...kalelectronics.ru>,
        Alexey Malahov <Alexey.Malahov@...kalelectronics.ru>,
        Thomas Bogendoerfer <tsbogend@...ha.franken.de>,
        Paul Burton <paulburton@...nel.org>,
        Ralf Baechle <ralf@...ux-mips.org>,
        Arnd Bergmann <arnd@...db.de>,
        Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
        Rob Herring <robh+dt@...nel.org>, <linux-mips@...r.kernel.org>,
        <devicetree@...r.kernel.org>,
        Wan Ahmad Zainie <wan.ahmad.zainie.wan.mohamad@...el.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Jarkko Nikula <jarkko.nikula@...ux.intel.com>,
        <linux-spi@...r.kernel.org>, <linux-kernel@...r.kernel.org>
Subject: [PATCH v4 06/16] spi: dw: Parameterize the DMA Rx/Tx burst length

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@...kalelectronics.ru>
Signed-off-by: Georgy Vlasov <Georgy.Vlasov@...kalelectronics.ru>
Co-developed-by: Ramil Zaripov <Ramil.Zaripov@...kalelectronics.ru>
Signed-off-by: Ramil Zaripov <Ramil.Zaripov@...kalelectronics.ru>
Signed-off-by: Serge Semin <Sergey.Semin@...kalelectronics.ru>
Cc: Alexey Malahov <Alexey.Malahov@...kalelectronics.ru>
Cc: Thomas Bogendoerfer <tsbogend@...ha.franken.de>
Cc: Paul Burton <paulburton@...nel.org>
Cc: Ralf Baechle <ralf@...ux-mips.org>
Cc: Arnd Bergmann <arnd@...db.de>
Cc: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
Cc: Rob Herring <robh+dt@...nel.org>
Cc: linux-mips@...r.kernel.org
Cc: devicetree@...r.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 c39bc8758339..1598c36c905f 100644
--- a/drivers/spi/spi-dw-mid.c
+++ b/drivers/spi/spi-dw-mid.c
@@ -20,7 +20,9 @@
 
 #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)
 {
@@ -198,7 +200,7 @@ 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;
@@ -273,7 +275,7 @@ 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;
@@ -298,8 +300,8 @@ 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;
-- 
2.25.1