Merge remote-tracking branches 'spi/topic/armada', 'spi/topic/ath79', 'spi/topic/atmel' and 'spi/topic/axi' into spi-next

Documentation/devicetree/bindings/spi/spi-armada-3700.txt

···
+* Marvell Armada 3700 SPI Controller
+
+Required Properties:
+
+- compatible: should be "marvell,armada-3700-spi"
+- reg: physical base address of the controller and length of memory mapped
+       region.
+- interrupts: The interrupt number. The interrupt specifier format depends on
+	      the interrupt controller and of its driver.
+- clocks: Must contain the clock source, usually from the North Bridge clocks.
+- num-cs: The number of chip selects that is supported by this SPI Controller
+- #address-cells: should be 1.
+- #size-cells: should be 0.
+
+Example:
+
+	spi0: spi@10600 {
+		compatible = "marvell,armada-3700-spi";
+		#address-cells = <1>;
+		#size-cells = <0>;
+		reg = <0x10600 0x5d>;
+		clocks = <&nb_perih_clk 7>;
+		interrupts = <GIC_SPI 0 IRQ_TYPE_LEVEL_HIGH>;
+		num-cs = <4>;
+	};

drivers/spi/Kconfig

···
 	  This enables support for the SPI controller present on the
 	  Atheros AR71XX/AR724X/AR913X SoCs.
 
+config SPI_ARMADA_3700
+	tristate "Marvell Armada 3700 SPI Controller"
+	depends on (ARCH_MVEBU && OF) || COMPILE_TEST
+	help
+	  This enables support for the SPI controller present on the
+	  Marvell Armada 3700 SoCs.
+
 config SPI_ATMEL
 	tristate "Atmel SPI Controller"
 	depends on HAS_DMA

drivers/spi/Makefile

···
 
 # SPI master controller drivers (bus)
 obj-$(CONFIG_SPI_ALTERA)		+= spi-altera.o
+obj-$(CONFIG_SPI_ARMADA_3700)		+= spi-armada-3700.o
 obj-$(CONFIG_SPI_ATMEL)			+= spi-atmel.o
 obj-$(CONFIG_SPI_ATH79)			+= spi-ath79.o
 obj-$(CONFIG_SPI_AU1550)		+= spi-au1550.o

drivers/spi/spi-armada-3700.c

···
+/*
+ * Marvell Armada-3700 SPI controller driver
+ *
+ * Copyright (C) 2016 Marvell Ltd.
+ *
+ * Author: Wilson Ding <[e-mail]>
+ * Author: Romain Perier <[e-mail]>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/clk.h>
+#include <linux/completion.h>
+#include <linux/delay.h>
+#include <linux/err.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_irq.h>
+#include <linux/of_device.h>
+#include <linux/pinctrl/consumer.h>
+#include <linux/spi/spi.h>
+
+#define DRIVER_NAME			"armada_3700_spi"
+
+#define A3700_SPI_TIMEOUT		10
+
+/* SPI Register Offest */
+#define A3700_SPI_IF_CTRL_REG		0x00
+#define A3700_SPI_IF_CFG_REG		0x04
+#define A3700_SPI_DATA_OUT_REG		0x08
+#define A3700_SPI_DATA_IN_REG		0x0C
+#define A3700_SPI_IF_INST_REG		0x10
+#define A3700_SPI_IF_ADDR_REG		0x14
+#define A3700_SPI_IF_RMODE_REG		0x18
+#define A3700_SPI_IF_HDR_CNT_REG	0x1C
+#define A3700_SPI_IF_DIN_CNT_REG	0x20
+#define A3700_SPI_IF_TIME_REG		0x24
+#define A3700_SPI_INT_STAT_REG		0x28
+#define A3700_SPI_INT_MASK_REG		0x2C
+
+/* A3700_SPI_IF_CTRL_REG */
+#define A3700_SPI_EN			BIT(16)
+#define A3700_SPI_ADDR_NOT_CONFIG	BIT(12)
+#define A3700_SPI_WFIFO_OVERFLOW	BIT(11)
+#define A3700_SPI_WFIFO_UNDERFLOW	BIT(10)
+#define A3700_SPI_RFIFO_OVERFLOW	BIT(9)
+#define A3700_SPI_RFIFO_UNDERFLOW	BIT(8)
+#define A3700_SPI_WFIFO_FULL		BIT(7)
+#define A3700_SPI_WFIFO_EMPTY		BIT(6)
+#define A3700_SPI_RFIFO_FULL		BIT(5)
+#define A3700_SPI_RFIFO_EMPTY		BIT(4)
+#define A3700_SPI_WFIFO_RDY		BIT(3)
+#define A3700_SPI_RFIFO_RDY		BIT(2)
+#define A3700_SPI_XFER_RDY		BIT(1)
+#define A3700_SPI_XFER_DONE		BIT(0)
+
+/* A3700_SPI_IF_CFG_REG */
+#define A3700_SPI_WFIFO_THRS		BIT(28)
+#define A3700_SPI_RFIFO_THRS		BIT(24)
+#define A3700_SPI_AUTO_CS		BIT(20)
+#define A3700_SPI_DMA_RD_EN		BIT(18)
+#define A3700_SPI_FIFO_MODE		BIT(17)
+#define A3700_SPI_SRST			BIT(16)
+#define A3700_SPI_XFER_START		BIT(15)
+#define A3700_SPI_XFER_STOP		BIT(14)
+#define A3700_SPI_INST_PIN		BIT(13)
+#define A3700_SPI_ADDR_PIN		BIT(12)
+#define A3700_SPI_DATA_PIN1		BIT(11)
+#define A3700_SPI_DATA_PIN0		BIT(10)
+#define A3700_SPI_FIFO_FLUSH		BIT(9)
+#define A3700_SPI_RW_EN			BIT(8)
+#define A3700_SPI_CLK_POL		BIT(7)
+#define A3700_SPI_CLK_PHA		BIT(6)
+#define A3700_SPI_BYTE_LEN		BIT(5)
+#define A3700_SPI_CLK_PRESCALE		BIT(0)
+#define A3700_SPI_CLK_PRESCALE_MASK	(0x1f)
+
+#define A3700_SPI_WFIFO_THRS_BIT	28
+#define A3700_SPI_RFIFO_THRS_BIT	24
+#define A3700_SPI_FIFO_THRS_MASK	0x7
+
+#define A3700_SPI_DATA_PIN_MASK		0x3
+
+/* A3700_SPI_IF_HDR_CNT_REG */
+#define A3700_SPI_DUMMY_CNT_BIT		12
+#define A3700_SPI_DUMMY_CNT_MASK	0x7
+#define A3700_SPI_RMODE_CNT_BIT		8
+#define A3700_SPI_RMODE_CNT_MASK	0x3
+#define A3700_SPI_ADDR_CNT_BIT		4
+#define A3700_SPI_ADDR_CNT_MASK		0x7
+#define A3700_SPI_INSTR_CNT_BIT		0
+#define A3700_SPI_INSTR_CNT_MASK	0x3
+
+/* A3700_SPI_IF_TIME_REG */
+#define A3700_SPI_CLK_CAPT_EDGE		BIT(7)
+
+/* Flags and macros for struct a3700_spi */
+#define A3700_INSTR_CNT			1
+#define A3700_ADDR_CNT			3
+#define A3700_DUMMY_CNT			1
+
+struct a3700_spi {
+	struct spi_master *master;
+	void __iomem *base;
+	struct clk *clk;
+	unsigned int irq;
+	unsigned int flags;
+	bool xmit_data;
+	const u8 *tx_buf;
+	u8 *rx_buf;
+	size_t buf_len;
+	u8 byte_len;
+	u32 wait_mask;
+	struct completion done;
+	u32 addr_cnt;
+	u32 instr_cnt;
+	size_t hdr_cnt;
+};
+
+static u32 spireg_read(struct a3700_spi *a3700_spi, u32 offset)
+{
+	return readl(a3700_spi->base + offset);
+}
+
+static void spireg_write(struct a3700_spi *a3700_spi, u32 offset, u32 data)
+{
+	writel(data, a3700_spi->base + offset);
+}
+
+static void a3700_spi_auto_cs_unset(struct a3700_spi *a3700_spi)
+{
+	u32 val;
+
+	val = spireg_read(a3700_spi, A3700_SPI_IF_CFG_REG);
+	val &= ~A3700_SPI_AUTO_CS;
+	spireg_write(a3700_spi, A3700_SPI_IF_CFG_REG, val);
+}
+
+static void a3700_spi_activate_cs(struct a3700_spi *a3700_spi, unsigned int cs)
+{
+	u32 val;
+
+	val = spireg_read(a3700_spi, A3700_SPI_IF_CTRL_REG);
+	val |= (A3700_SPI_EN << cs);
+	spireg_write(a3700_spi, A3700_SPI_IF_CTRL_REG, val);
+}
+
+static void a3700_spi_deactivate_cs(struct a3700_spi *a3700_spi,
+				    unsigned int cs)
+{
+	u32 val;
+
+	val = spireg_read(a3700_spi, A3700_SPI_IF_CTRL_REG);
+	val &= ~(A3700_SPI_EN << cs);
+	spireg_write(a3700_spi, A3700_SPI_IF_CTRL_REG, val);
+}
+
+static int a3700_spi_pin_mode_set(struct a3700_spi *a3700_spi,
+				  unsigned int pin_mode)
+{
+	u32 val;
+
+	val = spireg_read(a3700_spi, A3700_SPI_IF_CFG_REG);
+	val &= ~(A3700_SPI_INST_PIN | A3700_SPI_ADDR_PIN);
+	val &= ~(A3700_SPI_DATA_PIN0 | A3700_SPI_DATA_PIN1);
+
+	switch (pin_mode) {
+	case 1:
+		break;
+	case 2:
+		val |= A3700_SPI_DATA_PIN0;
+		break;
+	case 4:
+		val |= A3700_SPI_DATA_PIN1;
+		break;
+	default:
+		dev_err(&a3700_spi->master->dev, "wrong pin mode %u", pin_mode);
+		return -EINVAL;
+	}
+
+	spireg_write(a3700_spi, A3700_SPI_IF_CFG_REG, val);
+
+	return 0;
+}
+
+static void a3700_spi_fifo_mode_set(struct a3700_spi *a3700_spi)
+{
+	u32 val;
+
+	val = spireg_read(a3700_spi, A3700_SPI_IF_CFG_REG);
+	val |= A3700_SPI_FIFO_MODE;
+	spireg_write(a3700_spi, A3700_SPI_IF_CFG_REG, val);
+}
+
+static void a3700_spi_mode_set(struct a3700_spi *a3700_spi,
+			       unsigned int mode_bits)
+{
+	u32 val;
+
+	val = spireg_read(a3700_spi, A3700_SPI_IF_CFG_REG);
+
+	if (mode_bits & SPI_CPOL)
+		val |= A3700_SPI_CLK_POL;
+	else
+		val &= ~A3700_SPI_CLK_POL;
+
+	if (mode_bits & SPI_CPHA)
+		val |= A3700_SPI_CLK_PHA;
+	else
+		val &= ~A3700_SPI_CLK_PHA;
+
+	spireg_write(a3700_spi, A3700_SPI_IF_CFG_REG, val);
+}
+
+static void a3700_spi_clock_set(struct a3700_spi *a3700_spi,
+				unsigned int speed_hz, u16 mode)
+{
+	u32 val;
+	u32 prescale;
+
+	prescale = DIV_ROUND_UP(clk_get_rate(a3700_spi->clk), speed_hz);
+
+	val = spireg_read(a3700_spi, A3700_SPI_IF_CFG_REG);
+	val = val & ~A3700_SPI_CLK_PRESCALE_MASK;
+
+	val = val | (prescale & A3700_SPI_CLK_PRESCALE_MASK);
+	spireg_write(a3700_spi, A3700_SPI_IF_CFG_REG, val);
+
+	if (prescale <= 2) {
+		val = spireg_read(a3700_spi, A3700_SPI_IF_TIME_REG);
+		val |= A3700_SPI_CLK_CAPT_EDGE;
+		spireg_write(a3700_spi, A3700_SPI_IF_TIME_REG, val);
+	}
+
+	val = spireg_read(a3700_spi, A3700_SPI_IF_CFG_REG);
+	val &= ~(A3700_SPI_CLK_POL | A3700_SPI_CLK_PHA);
+
+	if (mode & SPI_CPOL)
+		val |= A3700_SPI_CLK_POL;
+
+	if (mode & SPI_CPHA)
+		val |= A3700_SPI_CLK_PHA;
+
+	spireg_write(a3700_spi, A3700_SPI_IF_CFG_REG, val);
+}
+
+static void a3700_spi_bytelen_set(struct a3700_spi *a3700_spi, unsigned int len)
+{
+	u32 val;
+
+	val = spireg_read(a3700_spi, A3700_SPI_IF_CFG_REG);
+	if (len == 4)
+		val |= A3700_SPI_BYTE_LEN;
+	else
+		val &= ~A3700_SPI_BYTE_LEN;
+	spireg_write(a3700_spi, A3700_SPI_IF_CFG_REG, val);
+
+	a3700_spi->byte_len = len;
+}
+
+static int a3700_spi_fifo_flush(struct a3700_spi *a3700_spi)
+{
+	int timeout = A3700_SPI_TIMEOUT;
+	u32 val;
+
+	val = spireg_read(a3700_spi, A3700_SPI_IF_CFG_REG);
+	val |= A3700_SPI_FIFO_FLUSH;
+	spireg_write(a3700_spi, A3700_SPI_IF_CFG_REG, val);
+
+	while (--timeout) {
+		val = spireg_read(a3700_spi, A3700_SPI_IF_CFG_REG);
+		if (!(val & A3700_SPI_FIFO_FLUSH))
+			return 0;
+		udelay(1);
+	}
+
+	return -ETIMEDOUT;
+}
+
+static int a3700_spi_init(struct a3700_spi *a3700_spi)
+{
+	struct spi_master *master = a3700_spi->master;
+	u32 val;
+	int i, ret = 0;
+
+	/* Reset SPI unit */
+	val = spireg_read(a3700_spi, A3700_SPI_IF_CFG_REG);
+	val |= A3700_SPI_SRST;
+	spireg_write(a3700_spi, A3700_SPI_IF_CFG_REG, val);
+
+	udelay(A3700_SPI_TIMEOUT);
+
+	val = spireg_read(a3700_spi, A3700_SPI_IF_CFG_REG);
+	val &= ~A3700_SPI_SRST;
+	spireg_write(a3700_spi, A3700_SPI_IF_CFG_REG, val);
+
+	/* Disable AUTO_CS and deactivate all chip-selects */
+	a3700_spi_auto_cs_unset(a3700_spi);
+	for (i = 0; i < master->num_chipselect; i++)
+		a3700_spi_deactivate_cs(a3700_spi, i);
+
+	/* Enable FIFO mode */
+	a3700_spi_fifo_mode_set(a3700_spi);
+
+	/* Set SPI mode */
+	a3700_spi_mode_set(a3700_spi, master->mode_bits);
+
+	/* Reset counters */
+	spireg_write(a3700_spi, A3700_SPI_IF_HDR_CNT_REG, 0);
+	spireg_write(a3700_spi, A3700_SPI_IF_DIN_CNT_REG, 0);
+
+	/* Mask the interrupts and clear cause bits */
+	spireg_write(a3700_spi, A3700_SPI_INT_MASK_REG, 0);
+	spireg_write(a3700_spi, A3700_SPI_INT_STAT_REG, ~0U);
+
+	return ret;
+}
+
+static irqreturn_t a3700_spi_interrupt(int irq, void *dev_id)
+{
+	struct spi_master *master = dev_id;
+	struct a3700_spi *a3700_spi;
+	u32 cause;
+
+	a3700_spi = spi_master_get_devdata(master);
+
+	/* Get interrupt causes */
+	cause = spireg_read(a3700_spi, A3700_SPI_INT_STAT_REG);
+
+	if (!cause || !(a3700_spi->wait_mask & cause))
+		return IRQ_NONE;
+
+	/* mask and acknowledge the SPI interrupts */
+	spireg_write(a3700_spi, A3700_SPI_INT_MASK_REG, 0);
+	spireg_write(a3700_spi, A3700_SPI_INT_STAT_REG, cause);
+
+	/* Wake up the transfer */
+	if (a3700_spi->wait_mask & cause)
+		complete(&a3700_spi->done);
+
+	return IRQ_HANDLED;
+}
+
+static bool a3700_spi_wait_completion(struct spi_device *spi)
+{
+	struct a3700_spi *a3700_spi;
+	unsigned int timeout;
+	unsigned int ctrl_reg;
+	unsigned long timeout_jiffies;
+
+	a3700_spi = spi_master_get_devdata(spi->master);
+
+	/* SPI interrupt is edge-triggered, which means an interrupt will
+	 * be generated only when detecting a specific status bit changed
+	 * from '0' to '1'. So when we start waiting for a interrupt, we
+	 * need to check status bit in control reg first, if it is already 1,
+	 * then we do not need to wait for interrupt
+	 */
+	ctrl_reg = spireg_read(a3700_spi, A3700_SPI_IF_CTRL_REG);
+	if (a3700_spi->wait_mask & ctrl_reg)
+		return true;
+
+	reinit_completion(&a3700_spi->done);
+
+	spireg_write(a3700_spi, A3700_SPI_INT_MASK_REG,
+		     a3700_spi->wait_mask);
+
+	timeout_jiffies = msecs_to_jiffies(A3700_SPI_TIMEOUT);
+	timeout = wait_for_completion_timeout(&a3700_spi->done,
+					      timeout_jiffies);
+
+	a3700_spi->wait_mask = 0;
+
+	if (timeout)
+		return true;
+
+	/* there might be the case that right after we checked the
+	 * status bits in this routine and before start to wait for
+	 * interrupt by wait_for_completion_timeout, the interrupt
+	 * happens, to avoid missing it we need to double check
+	 * status bits in control reg, if it is already 1, then
+	 * consider that we have the interrupt successfully and
+	 * return true.
+	 */
+	ctrl_reg = spireg_read(a3700_spi, A3700_SPI_IF_CTRL_REG);
+	if (a3700_spi->wait_mask & ctrl_reg)
+		return true;
+
+	spireg_write(a3700_spi, A3700_SPI_INT_MASK_REG, 0);
+
+	return true;
+}
+
+static bool a3700_spi_transfer_wait(struct spi_device *spi,
+				    unsigned int bit_mask)
+{
+	struct a3700_spi *a3700_spi;
+
+	a3700_spi = spi_master_get_devdata(spi->master);
+	a3700_spi->wait_mask = bit_mask;
+
+	return a3700_spi_wait_completion(spi);
+}
+
+static void a3700_spi_fifo_thres_set(struct a3700_spi *a3700_spi,
+				     unsigned int bytes)
+{
+	u32 val;
+
+	val = spireg_read(a3700_spi, A3700_SPI_IF_CFG_REG);
+	val &= ~(A3700_SPI_FIFO_THRS_MASK << A3700_SPI_RFIFO_THRS_BIT);
+	val |= (bytes - 1) << A3700_SPI_RFIFO_THRS_BIT;
+	val &= ~(A3700_SPI_FIFO_THRS_MASK << A3700_SPI_WFIFO_THRS_BIT);
+	val |= (7 - bytes) << A3700_SPI_WFIFO_THRS_BIT;
+	spireg_write(a3700_spi, A3700_SPI_IF_CFG_REG, val);
+}
+
+static void a3700_spi_transfer_setup(struct spi_device *spi,
+				    struct spi_transfer *xfer)
+{
+	struct a3700_spi *a3700_spi;
+	unsigned int byte_len;
+
+	a3700_spi = spi_master_get_devdata(spi->master);
+
+	a3700_spi_clock_set(a3700_spi, xfer->speed_hz, spi->mode);
+
+	byte_len = xfer->bits_per_word >> 3;
+
+	a3700_spi_fifo_thres_set(a3700_spi, byte_len);
+}
+
+static void a3700_spi_set_cs(struct spi_device *spi, bool enable)
+{
+	struct a3700_spi *a3700_spi = spi_master_get_devdata(spi->master);
+
+	if (!enable)
+		a3700_spi_activate_cs(a3700_spi, spi->chip_select);
+	else
+		a3700_spi_deactivate_cs(a3700_spi, spi->chip_select);
+}
+
+static void a3700_spi_header_set(struct a3700_spi *a3700_spi)
+{
+	u32 instr_cnt = 0, addr_cnt = 0, dummy_cnt = 0;
+	u32 val = 0;
+
+	/* Clear the header registers */
+	spireg_write(a3700_spi, A3700_SPI_IF_INST_REG, 0);
+	spireg_write(a3700_spi, A3700_SPI_IF_ADDR_REG, 0);
+	spireg_write(a3700_spi, A3700_SPI_IF_RMODE_REG, 0);
+
+	/* Set header counters */
+	if (a3700_spi->tx_buf) {
+		if (a3700_spi->buf_len <= a3700_spi->instr_cnt) {
+			instr_cnt = a3700_spi->buf_len;
+		} else if (a3700_spi->buf_len <= (a3700_spi->instr_cnt +
+						  a3700_spi->addr_cnt)) {
+			instr_cnt = a3700_spi->instr_cnt;
+			addr_cnt = a3700_spi->buf_len - instr_cnt;
+		} else if (a3700_spi->buf_len <= a3700_spi->hdr_cnt) {
+			instr_cnt = a3700_spi->instr_cnt;
+			addr_cnt = a3700_spi->addr_cnt;
+			/* Need to handle the normal write case with 1 byte
+			 * data
+			 */
+			if (!a3700_spi->tx_buf[instr_cnt + addr_cnt])
+				dummy_cnt = a3700_spi->buf_len - instr_cnt -
+					    addr_cnt;
+		}
+		val |= ((instr_cnt & A3700_SPI_INSTR_CNT_MASK)
+			<< A3700_SPI_INSTR_CNT_BIT);
+		val |= ((addr_cnt & A3700_SPI_ADDR_CNT_MASK)
+			<< A3700_SPI_ADDR_CNT_BIT);
+		val |= ((dummy_cnt & A3700_SPI_DUMMY_CNT_MASK)
+			<< A3700_SPI_DUMMY_CNT_BIT);
+	}
+	spireg_write(a3700_spi, A3700_SPI_IF_HDR_CNT_REG, val);
+
+	/* Update the buffer length to be transferred */
+	a3700_spi->buf_len -= (instr_cnt + addr_cnt + dummy_cnt);
+
+	/* Set Instruction */
+	val = 0;
+	while (instr_cnt--) {
+		val = (val << 8) | a3700_spi->tx_buf[0];
+		a3700_spi->tx_buf++;
+	}
+	spireg_write(a3700_spi, A3700_SPI_IF_INST_REG, val);
+
+	/* Set Address */
+	val = 0;
+	while (addr_cnt--) {
+		val = (val << 8) | a3700_spi->tx_buf[0];
+		a3700_spi->tx_buf++;
+	}
+	spireg_write(a3700_spi, A3700_SPI_IF_ADDR_REG, val);
+}
+
+static int a3700_is_wfifo_full(struct a3700_spi *a3700_spi)
+{
+	u32 val;
+
+	val = spireg_read(a3700_spi, A3700_SPI_IF_CTRL_REG);
+	return (val & A3700_SPI_WFIFO_FULL);
+}
+
+static int a3700_spi_fifo_write(struct a3700_spi *a3700_spi)
+{
+	u32 val;
+	int i = 0;
+
+	while (!a3700_is_wfifo_full(a3700_spi) && a3700_spi->buf_len) {
+		val = 0;
+		if (a3700_spi->buf_len >= 4) {
+			val = cpu_to_le32(*(u32 *)a3700_spi->tx_buf);
+			spireg_write(a3700_spi, A3700_SPI_DATA_OUT_REG, val);
+
+			a3700_spi->buf_len -= 4;
+			a3700_spi->tx_buf += 4;
+		} else {
+			/*
+			 * If the remained buffer length is less than 4-bytes,
+			 * we should pad the write buffer with all ones. So that
+			 * it avoids overwrite the unexpected bytes following
+			 * the last one.
+			 */
+			val = GENMASK(31, 0);
+			while (a3700_spi->buf_len) {
+				val &= ~(0xff << (8 * i));
+				val |= *a3700_spi->tx_buf++ << (8 * i);
+				i++;
+				a3700_spi->buf_len--;
+
+				spireg_write(a3700_spi, A3700_SPI_DATA_OUT_REG,
+					     val);
+			}
+			break;
+		}
+	}
+
+	return 0;
+}
+
+static int a3700_is_rfifo_empty(struct a3700_spi *a3700_spi)
+{
+	u32 val = spireg_read(a3700_spi, A3700_SPI_IF_CTRL_REG);
+
+	return (val & A3700_SPI_RFIFO_EMPTY);
+}
+
+static int a3700_spi_fifo_read(struct a3700_spi *a3700_spi)
+{
+	u32 val;
+
+	while (!a3700_is_rfifo_empty(a3700_spi) && a3700_spi->buf_len) {
+		val = spireg_read(a3700_spi, A3700_SPI_DATA_IN_REG);
+		if (a3700_spi->buf_len >= 4) {
+			u32 data = le32_to_cpu(val);
+			memcpy(a3700_spi->rx_buf, &data, 4);
+
+			a3700_spi->buf_len -= 4;
+			a3700_spi->rx_buf += 4;
+		} else {
+			/*
+			 * When remain bytes is not larger than 4, we should
+			 * avoid memory overwriting and just write the left rx
+			 * buffer bytes.
+			 */
+			while (a3700_spi->buf_len) {
+				*a3700_spi->rx_buf = val & 0xff;
+				val >>= 8;
+
+				a3700_spi->buf_len--;
+				a3700_spi->rx_buf++;
+			}
+		}
+	}
+
+	return 0;
+}
+
+static void a3700_spi_transfer_abort_fifo(struct a3700_spi *a3700_spi)
+{
+	int timeout = A3700_SPI_TIMEOUT;
+	u32 val;
+
+	val = spireg_read(a3700_spi, A3700_SPI_IF_CFG_REG);
+	val |= A3700_SPI_XFER_STOP;
+	spireg_write(a3700_spi, A3700_SPI_IF_CFG_REG, val);
+
+	while (--timeout) {
+		val = spireg_read(a3700_spi, A3700_SPI_IF_CFG_REG);
+		if (!(val & A3700_SPI_XFER_START))
+			break;
+		udelay(1);
+	}
+
+	a3700_spi_fifo_flush(a3700_spi);
+
+	val &= ~A3700_SPI_XFER_STOP;
+	spireg_write(a3700_spi, A3700_SPI_IF_CFG_REG, val);
+}
+
+static int a3700_spi_prepare_message(struct spi_master *master,
+				     struct spi_message *message)
+{
+	struct a3700_spi *a3700_spi = spi_master_get_devdata(master);
+	struct spi_device *spi = message->spi;
+	int ret;
+
+	ret = clk_enable(a3700_spi->clk);
+	if (ret) {
+		dev_err(&spi->dev, "failed to enable clk with error %d\n", ret);
+		return ret;
+	}
+
+	/* Flush the FIFOs */
+	ret = a3700_spi_fifo_flush(a3700_spi);
+	if (ret)
+		return ret;
+
+	a3700_spi_bytelen_set(a3700_spi, 4);
+
+	return 0;
+}
+
+static int a3700_spi_transfer_one(struct spi_master *master,
+				  struct spi_device *spi,
+				  struct spi_transfer *xfer)
+{
+	struct a3700_spi *a3700_spi = spi_master_get_devdata(master);
+	int ret = 0, timeout = A3700_SPI_TIMEOUT;
+	unsigned int nbits = 0;
+	u32 val;
+
+	a3700_spi_transfer_setup(spi, xfer);
+
+	a3700_spi->tx_buf  = xfer->tx_buf;
+	a3700_spi->rx_buf  = xfer->rx_buf;
+	a3700_spi->buf_len = xfer->len;
+
+	/* SPI transfer headers */
+	a3700_spi_header_set(a3700_spi);
+
+	if (xfer->tx_buf)
+		nbits = xfer->tx_nbits;
+	else if (xfer->rx_buf)
+		nbits = xfer->rx_nbits;
+
+	a3700_spi_pin_mode_set(a3700_spi, nbits);
+
+	if (xfer->rx_buf) {
+		/* Set read data length */
+		spireg_write(a3700_spi, A3700_SPI_IF_DIN_CNT_REG,
+			     a3700_spi->buf_len);
+		/* Start READ transfer */
+		val = spireg_read(a3700_spi, A3700_SPI_IF_CFG_REG);
+		val &= ~A3700_SPI_RW_EN;
+		val |= A3700_SPI_XFER_START;
+		spireg_write(a3700_spi, A3700_SPI_IF_CFG_REG, val);
+	} else if (xfer->tx_buf) {
+		/* Start Write transfer */
+		val = spireg_read(a3700_spi, A3700_SPI_IF_CFG_REG);
+		val |= (A3700_SPI_XFER_START | A3700_SPI_RW_EN);
+		spireg_write(a3700_spi, A3700_SPI_IF_CFG_REG, val);
+
+		/*
+		 * If there are data to be written to the SPI device, xmit_data
+		 * flag is set true; otherwise the instruction in SPI_INSTR does
+		 * not require data to be written to the SPI device, then
+		 * xmit_data flag is set false.
+		 */
+		a3700_spi->xmit_data = (a3700_spi->buf_len != 0);
+	}
+
+	while (a3700_spi->buf_len) {
+		if (a3700_spi->tx_buf) {
+			/* Wait wfifo ready */
+			if (!a3700_spi_transfer_wait(spi,
+						     A3700_SPI_WFIFO_RDY)) {
+				dev_err(&spi->dev,
+					"wait wfifo ready timed out\n");
+				ret = -ETIMEDOUT;
+				goto error;
+			}
+			/* Fill up the wfifo */
+			ret = a3700_spi_fifo_write(a3700_spi);
+			if (ret)
+				goto error;
+		} else if (a3700_spi->rx_buf) {
+			/* Wait rfifo ready */
+			if (!a3700_spi_transfer_wait(spi,
+						     A3700_SPI_RFIFO_RDY)) {
+				dev_err(&spi->dev,
+					"wait rfifo ready timed out\n");
+				ret = -ETIMEDOUT;
+				goto error;
+			}
+			/* Drain out the rfifo */
+			ret = a3700_spi_fifo_read(a3700_spi);
+			if (ret)
+				goto error;
+		}
+	}
+
+	/*
+	 * Stop a write transfer in fifo mode:
+	 *	- wait all the bytes in wfifo to be shifted out
+	 *	 - set XFER_STOP bit
+	 *	- wait XFER_START bit clear
+	 *	- clear XFER_STOP bit
+	 * Stop a read transfer in fifo mode:
+	 *	- the hardware is to reset the XFER_START bit
+	 *	   after the number of bytes indicated in DIN_CNT
+	 *	   register
+	 *	- just wait XFER_START bit clear
+	 */
+	if (a3700_spi->tx_buf) {
+		if (a3700_spi->xmit_data) {
+			/*
+			 * If there are data written to the SPI device, wait
+			 * until SPI_WFIFO_EMPTY is 1 to wait for all data to
+			 * transfer out of write FIFO.
+			 */
+			if (!a3700_spi_transfer_wait(spi,
+						     A3700_SPI_WFIFO_EMPTY)) {
+				dev_err(&spi->dev, "wait wfifo empty timed out\n");
+				return -ETIMEDOUT;
+			}
+		} else {
+			/*
+			 * If the instruction in SPI_INSTR does not require data
+			 * to be written to the SPI device, wait until SPI_RDY
+			 * is 1 for the SPI interface to be in idle.
+			 */
+			if (!a3700_spi_transfer_wait(spi, A3700_SPI_XFER_RDY)) {
+				dev_err(&spi->dev, "wait xfer ready timed out\n");
+				return -ETIMEDOUT;
+			}
+		}
+
+		val = spireg_read(a3700_spi, A3700_SPI_IF_CFG_REG);
+		val |= A3700_SPI_XFER_STOP;
+		spireg_write(a3700_spi, A3700_SPI_IF_CFG_REG, val);
+	}
+
+	while (--timeout) {
+		val = spireg_read(a3700_spi, A3700_SPI_IF_CFG_REG);
+		if (!(val & A3700_SPI_XFER_START))
+			break;
+		udelay(1);
+	}
+
+	if (timeout == 0) {
+		dev_err(&spi->dev, "wait transfer start clear timed out\n");
+		ret = -ETIMEDOUT;
+		goto error;
+	}
+
+	val &= ~A3700_SPI_XFER_STOP;
+	spireg_write(a3700_spi, A3700_SPI_IF_CFG_REG, val);
+	goto out;
+
+error:
+	a3700_spi_transfer_abort_fifo(a3700_spi);
+out:
+	spi_finalize_current_transfer(master);
+
+	return ret;
+}
+
+static int a3700_spi_unprepare_message(struct spi_master *master,
+				       struct spi_message *message)
+{
+	struct a3700_spi *a3700_spi = spi_master_get_devdata(master);
+
+	clk_disable(a3700_spi->clk);
+
+	return 0;
+}
+
+static const struct of_device_id a3700_spi_dt_ids[] = {
+	{ .compatible = "marvell,armada-3700-spi", .data = NULL },
+	{},
+};
+
+MODULE_DEVICE_TABLE(of, a3700_spi_dt_ids);
+
+static int a3700_spi_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct device_node *of_node = dev->of_node;
+	struct resource *res;
+	struct spi_master *master;
+	struct a3700_spi *spi;
+	u32 num_cs = 0;
+	int ret = 0;
+
+	master = spi_alloc_master(dev, sizeof(*spi));
+	if (!master) {
+		dev_err(dev, "master allocation failed\n");
+		ret = -ENOMEM;
+		goto out;
+	}
+
+	if (of_property_read_u32(of_node, "num-cs", &num_cs)) {
+		dev_err(dev, "could not find num-cs\n");
+		ret = -ENXIO;
+		goto error;
+	}
+
+	master->bus_num = pdev->id;
+	master->dev.of_node = of_node;
+	master->mode_bits = SPI_MODE_3;
+	master->num_chipselect = num_cs;
+	master->bits_per_word_mask = SPI_BPW_MASK(8) | SPI_BPW_MASK(32);
+	master->prepare_message =  a3700_spi_prepare_message;
+	master->transfer_one = a3700_spi_transfer_one;
+	master->unprepare_message = a3700_spi_unprepare_message;
+	master->set_cs = a3700_spi_set_cs;
+	master->flags = SPI_MASTER_HALF_DUPLEX;
+	master->mode_bits |= (SPI_RX_DUAL | SPI_RX_DUAL |
+			      SPI_RX_QUAD | SPI_TX_QUAD);
+
+	platform_set_drvdata(pdev, master);
+
+	spi = spi_master_get_devdata(master);
+	memset(spi, 0, sizeof(struct a3700_spi));
+
+	spi->master = master;
+	spi->instr_cnt = A3700_INSTR_CNT;
+	spi->addr_cnt = A3700_ADDR_CNT;
+	spi->hdr_cnt = A3700_INSTR_CNT + A3700_ADDR_CNT +
+		       A3700_DUMMY_CNT;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	spi->base = devm_ioremap_resource(dev, res);
+	if (IS_ERR(spi->base)) {
+		ret = PTR_ERR(spi->base);
+		goto error;
+	}
+
+	spi->irq = platform_get_irq(pdev, 0);
+	if (spi->irq < 0) {
+		dev_err(dev, "could not get irq: %d\n", spi->irq);
+		ret = -ENXIO;
+		goto error;
+	}
+
+	init_completion(&spi->done);
+
+	spi->clk = devm_clk_get(dev, NULL);
+	if (IS_ERR(spi->clk)) {
+		dev_err(dev, "could not find clk: %ld\n", PTR_ERR(spi->clk));
+		goto error;
+	}
+
+	ret = clk_prepare(spi->clk);
+	if (ret) {
+		dev_err(dev, "could not prepare clk: %d\n", ret);
+		goto error;
+	}
+
+	ret = a3700_spi_init(spi);
+	if (ret)
+		goto error_clk;
+
+	ret = devm_request_irq(dev, spi->irq, a3700_spi_interrupt, 0,
+			       dev_name(dev), master);
+	if (ret) {
+		dev_err(dev, "could not request IRQ: %d\n", ret);
+		goto error_clk;
+	}
+
+	ret = devm_spi_register_master(dev, master);
+	if (ret) {
+		dev_err(dev, "Failed to register master\n");
+		goto error_clk;
+	}
+
+	return 0;
+
+error_clk:
+	clk_disable_unprepare(spi->clk);
+error:
+	spi_master_put(master);
+out:
+	return ret;
+}
+
+static int a3700_spi_remove(struct platform_device *pdev)
+{
+	struct spi_master *master = platform_get_drvdata(pdev);
+	struct a3700_spi *spi = spi_master_get_devdata(master);
+
+	clk_unprepare(spi->clk);
+	spi_master_put(master);
+
+	return 0;
+}
+
+static struct platform_driver a3700_spi_driver = {
+	.driver = {
+		.name	= DRIVER_NAME,
+		.owner	= THIS_MODULE,
+		.of_match_table = of_match_ptr(a3700_spi_dt_ids),
+	},
+	.probe		= a3700_spi_probe,
+	.remove		= a3700_spi_remove,
+};
+
+module_platform_driver(a3700_spi_driver);
+
+MODULE_DESCRIPTION("Armada-3700 SPI driver");
+MODULE_AUTHOR("Wilson Ding <[e-mail]>");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:" DRIVER_NAME);

drivers/spi/spi-ath79.c

···
 	{ .compatible = "qca,ar7100-spi", },
 	{ },
 };
+MODULE_DEVICE_TABLE(of, ath79_spi_of_match);
 
 static struct platform_driver ath79_spi_driver = {
 	.probe		= ath79_spi_probe,

drivers/spi/spi-atmel.c

···
 
 #define AUTOSUSPEND_TIMEOUT	2000
 
-struct atmel_spi_dma {
-	struct dma_chan			*chan_rx;
-	struct dma_chan			*chan_tx;
-	struct scatterlist		sgrx;
-	struct scatterlist		sgtx;
-	struct dma_async_tx_descriptor	*data_desc_rx;
-	struct dma_async_tx_descriptor	*data_desc_tx;
-
-	struct at_dma_slave	dma_slave;
-};
-
 struct atmel_spi_caps {
 	bool	is_spi2;
 	bool	has_wdrbt;
···
 
 	struct completion	xfer_completion;
 
-	/* scratch buffer */
-	void			*buffer;
-	dma_addr_t		buffer_dma;
-
 	struct atmel_spi_caps	caps;
 
 	bool			use_dma;
 	bool			use_pdc;
 	bool			use_cs_gpios;
-	/* dmaengine data */
-	struct atmel_spi_dma	dma;
 
 	bool			keep_cs;
 	bool			cs_active;
···
 	u32			csr;
 };
 
-#define BUFFER_SIZE		PAGE_SIZE
+#define SPI_MAX_DMA_XFER	65535 /* true for both PDC and DMA */
 #define INVALID_DMA_ADDRESS	0xffffffff
 
 /*
···
 	return as->use_dma && xfer->len >= DMA_MIN_BYTES;
 }
 
+static bool atmel_spi_can_dma(struct spi_master *master,
+			      struct spi_device *spi,
+			      struct spi_transfer *xfer)
+{
+	struct atmel_spi *as = spi_master_get_devdata(master);
+
+	return atmel_spi_use_dma(as, xfer);
+}
+
 static int atmel_spi_dma_slave_config(struct atmel_spi *as,
 				struct dma_slave_config *slave_config,
 				u8 bits_per_word)
 {
+	struct spi_master *master = platform_get_drvdata(as->pdev);
 	int err = 0;
 
 	if (bits_per_word > 8) {
···
 	 * path works the same whether FIFOs are available (and enabled) or not.
 	 */
 	slave_config->direction = DMA_MEM_TO_DEV;
-	if (dmaengine_slave_config(as->dma.chan_tx, slave_config)) {
+	if (dmaengine_slave_config(master->dma_tx, slave_config)) {
 		dev_err(&as->pdev->dev,
 			"failed to configure tx dma channel\n");
 		err = -EINVAL;
···
 	 * enabled) or not.
 	 */
 	slave_config->direction = DMA_DEV_TO_MEM;
-	if (dmaengine_slave_config(as->dma.chan_rx, slave_config)) {
+	if (dmaengine_slave_config(master->dma_rx, slave_config)) {
 		dev_err(&as->pdev->dev,
 			"failed to configure rx dma channel\n");
 		err = -EINVAL;
···
 	return err;
 }
 
-static int atmel_spi_configure_dma(struct atmel_spi *as)
+static int atmel_spi_configure_dma(struct spi_master *master,
+				   struct atmel_spi *as)
 {
 	struct dma_slave_config	slave_config;
 	struct device *dev = &as->pdev->dev;
···
 	dma_cap_zero(mask);
 	dma_cap_set(DMA_SLAVE, mask);
 
-	as->dma.chan_tx = dma_request_slave_channel_reason(dev, "tx");
-	if (IS_ERR(as->dma.chan_tx)) {
-		err = PTR_ERR(as->dma.chan_tx);
+	master->dma_tx = dma_request_slave_channel_reason(dev, "tx");
+	if (IS_ERR(master->dma_tx)) {
+		err = PTR_ERR(master->dma_tx);
 		if (err == -EPROBE_DEFER) {
 			dev_warn(dev, "no DMA channel available at the moment\n");
-			return err;
+			goto error_clear;
 		}
 		dev_err(dev,
 			"DMA TX channel not available, SPI unable to use DMA\n");
 		err = -EBUSY;
-		goto error;
+		goto error_clear;
 	}
 
 	/*
 	 * No reason to check EPROBE_DEFER here since we have already requested
 	 * tx channel. If it fails here, it's for another reason.
 	 */
-	as->dma.chan_rx = dma_request_slave_channel(dev, "rx");
+	master->dma_rx = dma_request_slave_channel(dev, "rx");
 
-	if (!as->dma.chan_rx) {
+	if (!master->dma_rx) {
 		dev_err(dev,
 			"DMA RX channel not available, SPI unable to use DMA\n");
 		err = -EBUSY;
···
 
 	dev_info(&as->pdev->dev,
 			"Using %s (tx) and %s (rx) for DMA transfers\n",
-			dma_chan_name(as->dma.chan_tx),
-			dma_chan_name(as->dma.chan_rx));
+			dma_chan_name(master->dma_tx),
+			dma_chan_name(master->dma_rx));
+
 	return 0;
 error:
-	if (as->dma.chan_rx)
-		dma_release_channel(as->dma.chan_rx);
-	if (!IS_ERR(as->dma.chan_tx))
-		dma_release_channel(as->dma.chan_tx);
+	if (master->dma_rx)
+		dma_release_channel(master->dma_rx);
+	if (!IS_ERR(master->dma_tx))
+		dma_release_channel(master->dma_tx);
+error_clear:
+	master->dma_tx = master->dma_rx = NULL;
 	return err;
 }
 
-static void atmel_spi_stop_dma(struct atmel_spi *as)
+static void atmel_spi_stop_dma(struct spi_master *master)
 {
-	if (as->dma.chan_rx)
-		dmaengine_terminate_all(as->dma.chan_rx);
-	if (as->dma.chan_tx)
-		dmaengine_terminate_all(as->dma.chan_tx);
+	if (master->dma_rx)
+		dmaengine_terminate_all(master->dma_rx);
+	if (master->dma_tx)
+		dmaengine_terminate_all(master->dma_tx);
 }
 
-static void atmel_spi_release_dma(struct atmel_spi *as)
+static void atmel_spi_release_dma(struct spi_master *master)
 {
-	if (as->dma.chan_rx)
-		dma_release_channel(as->dma.chan_rx);
-	if (as->dma.chan_tx)
-		dma_release_channel(as->dma.chan_tx);
+	if (master->dma_rx) {
+		dma_release_channel(master->dma_rx);
+		master->dma_rx = NULL;
+	}
+	if (master->dma_tx) {
+		dma_release_channel(master->dma_tx);
+		master->dma_tx = NULL;
+	}
 }
 
 /* This function is called by the DMA driver from tasklet context */
···
 		cpu_relax();
 	}
 
-	if (xfer->tx_buf) {
-		if (xfer->bits_per_word > 8)
-			spi_writel(as, TDR, *(u16 *)(xfer->tx_buf + xfer_pos));
-		else
-			spi_writel(as, TDR, *(u8 *)(xfer->tx_buf + xfer_pos));
-	} else {
-		spi_writel(as, TDR, 0);
-	}
+	if (xfer->bits_per_word > 8)
+		spi_writel(as, TDR, *(u16 *)(xfer->tx_buf + xfer_pos));
+	else
+		spi_writel(as, TDR, *(u8 *)(xfer->tx_buf + xfer_pos));
 
 	dev_dbg(master->dev.parent,
 		"  start pio xfer %p: len %u tx %p rx %p bitpw %d\n",
···
 
 	/* Fill TX FIFO */
 	while (num_data >= 2) {
-		if (xfer->tx_buf) {
-			if (xfer->bits_per_word > 8) {
-				td0 = *words++;
-				td1 = *words++;
-			} else {
-				td0 = *bytes++;
-				td1 = *bytes++;
-			}
+		if (xfer->bits_per_word > 8) {
+			td0 = *words++;
+			td1 = *words++;
 		} else {
-			td0 = 0;
-			td1 = 0;
+			td0 = *bytes++;
+			td1 = *bytes++;
 		}
 
 		spi_writel(as, TDR, (td1 << 16) | td0);
···
 	}
 
 	if (num_data) {
-		if (xfer->tx_buf) {
-			if (xfer->bits_per_word > 8)
-				td0 = *words++;
-			else
-				td0 = *bytes++;
-		} else {
-			td0 = 0;
-		}
+		if (xfer->bits_per_word > 8)
+			td0 = *words++;
+		else
+			td0 = *bytes++;
 
 		spi_writew(as, TDR, td0);
 		num_data--;
···
 				u32 *plen)
 {
 	struct atmel_spi	*as = spi_master_get_devdata(master);
-	struct dma_chan		*rxchan = as->dma.chan_rx;
-	struct dma_chan		*txchan = as->dma.chan_tx;
+	struct dma_chan		*rxchan = master->dma_rx;
+	struct dma_chan		*txchan = master->dma_tx;
 	struct dma_async_tx_descriptor *rxdesc;
 	struct dma_async_tx_descriptor *txdesc;
 	struct dma_slave_config	slave_config;
 	dma_cookie_t		cookie;
-	u32	len = *plen;
 
 	dev_vdbg(master->dev.parent, "atmel_spi_next_xfer_dma_submit\n");
 
···
 	/* release lock for DMA operations */
 	atmel_spi_unlock(as);
 
-	/* prepare the RX dma transfer */
-	sg_init_table(&as->dma.sgrx, 1);
-	if (xfer->rx_buf) {
-		as->dma.sgrx.dma_address = xfer->rx_dma + xfer->len - *plen;
-	} else {
-		as->dma.sgrx.dma_address = as->buffer_dma;
-		if (len > BUFFER_SIZE)
-			len = BUFFER_SIZE;
-	}
-
-	/* prepare the TX dma transfer */
-	sg_init_table(&as->dma.sgtx, 1);
-	if (xfer->tx_buf) {
-		as->dma.sgtx.dma_address = xfer->tx_dma + xfer->len - *plen;
-	} else {
-		as->dma.sgtx.dma_address = as->buffer_dma;
-		if (len > BUFFER_SIZE)
-			len = BUFFER_SIZE;
-		memset(as->buffer, 0, len);
-	}
-
-	sg_dma_len(&as->dma.sgtx) = len;
-	sg_dma_len(&as->dma.sgrx) = len;
-
-	*plen = len;
+	*plen = xfer->len;
 
 	if (atmel_spi_dma_slave_config(as, &slave_config,
 				       xfer->bits_per_word))
 		goto err_exit;
 
 	/* Send both scatterlists */
-	rxdesc = dmaengine_prep_slave_sg(rxchan, &as->dma.sgrx, 1,
+	rxdesc = dmaengine_prep_slave_sg(rxchan,
+					 xfer->rx_sg.sgl, xfer->rx_sg.nents,
 					 DMA_FROM_DEVICE,
 					 DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
 	if (!rxdesc)
 		goto err_dma;
 
-	txdesc = dmaengine_prep_slave_sg(txchan, &as->dma.sgtx, 1,
+	txdesc = dmaengine_prep_slave_sg(txchan,
+					 xfer->tx_sg.sgl, xfer->tx_sg.nents,
 					 DMA_TO_DEVICE,
 					 DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
 	if (!txdesc)
···
 
 err_dma:
 	spi_writel(as, IDR, SPI_BIT(OVRES));
-	atmel_spi_stop_dma(as);
+	atmel_spi_stop_dma(master);
 err_exit:
 	atmel_spi_lock(as);
 	return -ENOMEM;
···
 				dma_addr_t *rx_dma,
 				u32 *plen)
 {
-	struct atmel_spi	*as = spi_master_get_devdata(master);
-	u32			len = *plen;
-
-	/* use scratch buffer only when rx or tx data is unspecified */
-	if (xfer->rx_buf)
-		*rx_dma = xfer->rx_dma + xfer->len - *plen;
-	else {
-		*rx_dma = as->buffer_dma;
-		if (len > BUFFER_SIZE)
-			len = BUFFER_SIZE;
-	}
-
-	if (xfer->tx_buf)
-		*tx_dma = xfer->tx_dma + xfer->len - *plen;
-	else {
-		*tx_dma = as->buffer_dma;
-		if (len > BUFFER_SIZE)
-			len = BUFFER_SIZE;
-		memset(as->buffer, 0, len);
-		dma_sync_single_for_device(&as->pdev->dev,
-				as->buffer_dma, len, DMA_TO_DEVICE);
-	}
-
-	*plen = len;
+	*rx_dma = xfer->rx_dma + xfer->len - *plen;
+	*tx_dma = xfer->tx_dma + xfer->len - *plen;
+	if (*plen > master->max_dma_len)
+		*plen = master->max_dma_len;
 }
 
 static int atmel_spi_set_xfer_speed(struct atmel_spi *as,
···
 	u16		*rxp16;
 	unsigned long	xfer_pos = xfer->len - as->current_remaining_bytes;
 
-	if (xfer->rx_buf) {
-		if (xfer->bits_per_word > 8) {
-			rxp16 = (u16 *)(((u8 *)xfer->rx_buf) + xfer_pos);
-			*rxp16 = spi_readl(as, RDR);
-		} else {
-			rxp = ((u8 *)xfer->rx_buf) + xfer_pos;
-			*rxp = spi_readl(as, RDR);
-		}
+	if (xfer->bits_per_word > 8) {
+		rxp16 = (u16 *)(((u8 *)xfer->rx_buf) + xfer_pos);
+		*rxp16 = spi_readl(as, RDR);
 	} else {
-		spi_readl(as, RDR);
+		rxp = ((u8 *)xfer->rx_buf) + xfer_pos;
+		*rxp = spi_readl(as, RDR);
 	}
 	if (xfer->bits_per_word > 8) {
 		if (as->current_remaining_bytes > 2)
···
 	/* Read data */
 	while (num_data) {
 		rd = spi_readl(as, RDR);
-		if (xfer->rx_buf) {
-			if (xfer->bits_per_word > 8)
-				*words++ = rd;
-			else
-				*bytes++ = rd;
-		}
+		if (xfer->bits_per_word > 8)
+			*words++ = rd;
+		else
+			*bytes++ = rd;
 		num_data--;
 	}
 }
···
 	 * better fault reporting.
 	 */
 	if ((!msg->is_dma_mapped)
-		&& (atmel_spi_use_dma(as, xfer)	|| as->use_pdc)) {
+		&& as->use_pdc) {
 		if (atmel_spi_dma_map_xfer(as, xfer) < 0)
 			return -ENOMEM;
 	}
···
 			spi_readl(as, SR);
 
 		} else if (atmel_spi_use_dma(as, xfer)) {
-			atmel_spi_stop_dma(as);
+			atmel_spi_stop_dma(master);
 		}
 
 		if (!msg->is_dma_mapped
-			&& (atmel_spi_use_dma(as, xfer) || as->use_pdc))
+			&& as->use_pdc)
 			atmel_spi_dma_unmap_xfer(master, xfer);
 
 		return 0;
···
 	}
 
 	if (!msg->is_dma_mapped
-		&& (atmel_spi_use_dma(as, xfer) || as->use_pdc))
+		&& as->use_pdc)
 		atmel_spi_dma_unmap_xfer(master, xfer);
 
 	if (xfer->delay_usecs)
···
 		int cs_gpio = of_get_named_gpio(pdev->dev.of_node,
 						"cs-gpios", i);
 
-			if (cs_gpio == -EPROBE_DEFER)
-				return cs_gpio;
+		if (cs_gpio == -EPROBE_DEFER)
+			return cs_gpio;
 
-			if (gpio_is_valid(cs_gpio)) {
-				ret = devm_gpio_request(&pdev->dev, cs_gpio,
-							dev_name(&pdev->dev));
-				if (ret)
-					return ret;
-			}
+		if (gpio_is_valid(cs_gpio)) {
+			ret = devm_gpio_request(&pdev->dev, cs_gpio,
+						dev_name(&pdev->dev));
+			if (ret)
+				return ret;
+		}
 	}
 
 	return 0;
···
 	master->bus_num = pdev->id;
 	master->num_chipselect = master->dev.of_node ? 0 : 4;
 	master->setup = atmel_spi_setup;
+	master->flags = (SPI_MASTER_MUST_RX | SPI_MASTER_MUST_TX);
 	master->transfer_one_message = atmel_spi_transfer_one_message;
 	master->cleanup = atmel_spi_cleanup;
 	master->auto_runtime_pm = true;
+	master->max_dma_len = SPI_MAX_DMA_XFER;
+	master->can_dma = atmel_spi_can_dma;
 	platform_set_drvdata(pdev, master);
 
 	as = spi_master_get_devdata(master);
-
-	/*
-	 * Scratch buffer is used for throwaway rx and tx data.
-	 * It's coherent to minimize dcache pollution.
-	 */
-	as->buffer = dma_alloc_coherent(&pdev->dev, BUFFER_SIZE,
-					&as->buffer_dma, GFP_KERNEL);
-	if (!as->buffer)
-		goto out_free;
 
 	spin_lock_init(&as->lock);
 
···
 	as->regs = devm_ioremap_resource(&pdev->dev, regs);
 	if (IS_ERR(as->regs)) {
 		ret = PTR_ERR(as->regs);
-		goto out_free_buffer;
+		goto out_unmap_regs;
 	}
 	as->phybase = regs->start;
 	as->irq = irq;
···
 	as->use_dma = false;
 	as->use_pdc = false;
 	if (as->caps.has_dma_support) {
-		ret = atmel_spi_configure_dma(as);
-		if (ret == 0)
+		ret = atmel_spi_configure_dma(master, as);
+		if (ret == 0) {
 			as->use_dma = true;
-		else if (ret == -EPROBE_DEFER)
+		} else if (ret == -EPROBE_DEFER) {
 			return ret;
+		}
 	} else {
 		as->use_pdc = true;
 	}
···
 		spi_writel(as, CR, SPI_BIT(FIFOEN));
 	}
 
-	/* go! */
-	dev_info(&pdev->dev, "Atmel SPI Controller at 0x%08lx (irq %d)\n",
-			(unsigned long)regs->start, irq);
-
 	pm_runtime_set_autosuspend_delay(&pdev->dev, AUTOSUSPEND_TIMEOUT);
 	pm_runtime_use_autosuspend(&pdev->dev);
 	pm_runtime_set_active(&pdev->dev);
···
 	if (ret)
 		goto out_free_dma;
 
+	/* go! */
+	dev_info(&pdev->dev, "Atmel SPI Controller at 0x%08lx (irq %d)\n",
+			(unsigned long)regs->start, irq);
+
 	return 0;
 
 out_free_dma:
···
 	pm_runtime_set_suspended(&pdev->dev);
 
 	if (as->use_dma)
-		atmel_spi_release_dma(as);
+		atmel_spi_release_dma(master);
 
 	spi_writel(as, CR, SPI_BIT(SWRST));
 	spi_writel(as, CR, SPI_BIT(SWRST)); /* AT91SAM9263 Rev B workaround */
 	clk_disable_unprepare(clk);
 out_free_irq:
 out_unmap_regs:
-out_free_buffer:
-	dma_free_coherent(&pdev->dev, BUFFER_SIZE, as->buffer,
-			as->buffer_dma);
 out_free:
 	spi_master_put(master);
 	return ret;
···
 	/* reset the hardware and block queue progress */
 	spin_lock_irq(&as->lock);
 	if (as->use_dma) {
-		atmel_spi_stop_dma(as);
-		atmel_spi_release_dma(as);
+		atmel_spi_stop_dma(master);
+		atmel_spi_release_dma(master);
 	}
 
 	spi_writel(as, CR, SPI_BIT(SWRST));
 	spi_writel(as, CR, SPI_BIT(SWRST)); /* AT91SAM9263 Rev B workaround */
 	spi_readl(as, SR);
 	spin_unlock_irq(&as->lock);
-
-	dma_free_coherent(&pdev->dev, BUFFER_SIZE, as->buffer,
-			as->buffer_dma);
 
 	clk_disable_unprepare(as->clk);
 

drivers/spi/spi-axi-spi-engine.c

···
 	{ .compatible = "adi,axi-spi-engine-1.00.a" },
 	{ },
 };
+MODULE_DEVICE_TABLE(of, spi_engine_match_table);
 
 static struct platform_driver spi_engine_driver = {
 	.probe = spi_engine_probe,