linux-kernel - [PATCH v2 1/4] spi: mediatek: fix spi incorrect endian usage

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Date:	Thu, 20 Aug 2015 17:19:06 +0800
From:	Leilk Liu <leilk.liu@...iatek.com>
To:	Mark Brown <broonie@...nel.org>
CC:	Mark Rutland <mark.rutland@....com>,
	Matthias Brugger <matthias.bgg@...il.com>,
	Sascha Hauer <s.hauer@...gutronix.de>,
	<devicetree@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
	<linux-arm-kernel@...ts.infradead.org>,
	<linux-spi@...r.kernel.org>, <linux-mediatek@...ts.infradead.org>,
	Leilk Liu <leilk.liu@...iatek.com>
Subject: [PATCH v2 1/4] spi: mediatek: fix spi incorrect endian usage

TX_ENDIAN/RX_ENDIAN bits define whether to reverse the endian
order of the data DMA from/to memory. The endian order should
keep the same with cpu endian.

Signed-off-by: Leilk Liu <leilk.liu@...iatek.com>
---
 drivers/spi/spi-mt65xx.c                 | 38 ++++++++++++++------------------
 include/linux/platform_data/spi-mt65xx.h |  2 --
 2 files changed, 16 insertions(+), 24 deletions(-)

diff --git a/drivers/spi/spi-mt65xx.c b/drivers/spi/spi-mt65xx.c
index 321b820..79286c8 100644
--- a/drivers/spi/spi-mt65xx.c
+++ b/drivers/spi/spi-mt65xx.c
@@ -122,8 +122,6 @@ static const struct mtk_spi_compatible mt8173_compat = {
 static const struct mtk_chip_config mtk_default_chip_info = {
 	.rx_mlsb = 1,
 	.tx_mlsb = 1,
-	.tx_endian = 0,
-	.rx_endian = 0,
 };
 
 static const struct of_device_id mtk_spi_of_match[] = {
@@ -161,9 +159,13 @@ static void mtk_spi_config(struct mtk_spi *mdata,
 	reg_val |= (chip_config->rx_mlsb << SPI_CMD_RXMSBF_OFFSET);
 
 	/* set the tx/rx endian */
-	reg_val &= ~(SPI_CMD_TX_ENDIAN | SPI_CMD_RX_ENDIAN);
-	reg_val |= (chip_config->tx_endian << SPI_CMD_TX_ENDIAN_OFFSET);
-	reg_val |= (chip_config->rx_endian << SPI_CMD_RX_ENDIAN_OFFSET);
+#ifdef __LITTLE_ENDIAN
+	reg_val &= ~SPI_CMD_TX_ENDIAN;
+	reg_val &= ~SPI_CMD_RX_ENDIAN;
+#else
+	reg_val |= SPI_CMD_TX_ENDIAN;
+	reg_val |= SPI_CMD_RX_ENDIAN;
+#endif
 
 	/* set finish and pause interrupt always enable */
 	reg_val |= SPI_CMD_FINISH_IE | SPI_CMD_PAUSE_EN;
@@ -352,7 +354,7 @@ static int mtk_spi_fifo_transfer(struct spi_master *master,
 				 struct spi_device *spi,
 				 struct spi_transfer *xfer)
 {
-	int cnt, i;
+	int cnt;
 	struct mtk_spi *mdata = spi_master_get_devdata(master);
 
 	mdata->cur_transfer = xfer;
@@ -364,10 +366,7 @@ static int mtk_spi_fifo_transfer(struct spi_master *master,
 		cnt = xfer->len / 4 + 1;
 	else
 		cnt = xfer->len / 4;
-
-	for (i = 0; i < cnt; i++)
-		writel(*((u32 *)xfer->tx_buf + i),
-		       mdata->base + SPI_TX_DATA_REG);
+	iowrite32_rep(mdata->base + SPI_TX_DATA_REG, xfer->tx_buf, cnt);
 
 	mtk_spi_enable_transfer(master);
 
@@ -437,7 +436,7 @@ static bool mtk_spi_can_dma(struct spi_master *master,
 
 static irqreturn_t mtk_spi_interrupt(int irq, void *dev_id)
 {
-	u32 cmd, reg_val, i;
+	u32 cmd, reg_val, cnt;
 	struct spi_master *master = dev_id;
 	struct mtk_spi *mdata = spi_master_get_devdata(master);
 	struct spi_transfer *trans = mdata->cur_transfer;
@@ -449,18 +448,13 @@ static irqreturn_t mtk_spi_interrupt(int irq, void *dev_id)
 		mdata->state = MTK_SPI_IDLE;
 
 	if (!master->can_dma(master, master->cur_msg->spi, trans)) {
-		/* xfer len is not N*4 bytes every time in a transfer,
-		 * but SPI_RX_DATA_REG must reads 4 bytes once,
-		 * so rx buffer byte by byte.
-		 */
 		if (trans->rx_buf) {
-			for (i = 0; i < mdata->xfer_len; i++) {
-				if (i % 4 == 0)
-					reg_val =
-					readl(mdata->base + SPI_RX_DATA_REG);
-				*((u8 *)(trans->rx_buf + i)) =
-					(reg_val >> ((i % 4) * 8)) & 0xff;
-			}
+			if (mdata->xfer_len % 4)
+				cnt = mdata->xfer_len / 4 + 1;
+			else
+				cnt = mdata->xfer_len / 4;
+			ioread32_rep(mdata->base + SPI_RX_DATA_REG,
+				     trans->rx_buf, cnt);
 		}
 		spi_finalize_current_transfer(master);
 		return IRQ_HANDLED;
diff --git a/include/linux/platform_data/spi-mt65xx.h b/include/linux/platform_data/spi-mt65xx.h
index 7512255..54b0448 100644
--- a/include/linux/platform_data/spi-mt65xx.h
+++ b/include/linux/platform_data/spi-mt65xx.h
@@ -16,7 +16,5 @@
 struct mtk_chip_config {
 	u32 tx_mlsb;
 	u32 rx_mlsb;
-	u32 tx_endian;
-	u32 rx_endian;
 };
 #endif
-- 
1.8.1.1.dirty

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