[PATCH 4/4] spi: aspeed: Add ASPEED FMC/SPI memory controller driver

[Chin-Ting Kuo <chin-ting_kuo@xxxxxxxxxxxxxx>]

Add driver for ASPEED BMC FMC/SPI memory controller which
supports spi-mem interface.

There are three SPI memory controllers embedded in an ASPEED SoC.
Each of them can connect to two or three SPI NOR flashes. The first
SPI memory controller is also named as Firmware Memory Controller (FMC),
which is similar to SPI memory controller. After device AC on, MCU ROM
can fetch device boot code from FMC CS 0. Thus, there exists additional
registers for boot process control in FMC.

ASPEED SPI memory controller supports single, dual and quad mode for
SPI NOR flash. It also supports two types of command mode, user mode
and command read/write mode. User mode is traditional pure SPI operations
where all transmission is controlled by CPU. Contrarily, with command
read/write mode, SPI controller can send command and address automatically
when CPU read/write related remapped address.

Besides, different wafer processes of SPI NOR flash result in different
signal response time. This phenomenon will be enlarged when SPI clock
frequency increases. ASPEED SPI memory controller provides a mechanism
for timing compensation in order to satisfy various SPI NOR flash parts
and PCB layout.

Signed-off-by: Chin-Ting Kuo <chin-ting_kuo@xxxxxxxxxxxxxx>
---
 drivers/spi/Kconfig      |  10 +
 drivers/spi/Makefile     |   1 +
 drivers/spi/spi-aspeed.c | 967 +++++++++++++++++++++++++++++++++++++++
 3 files changed, 978 insertions(+)
 create mode 100644 drivers/spi/spi-aspeed.c

diff --git a/drivers/spi/Kconfig b/drivers/spi/Kconfig
index 5cff60de8e83..caadf8647183 100644
--- a/drivers/spi/Kconfig
+++ b/drivers/spi/Kconfig
@@ -70,6 +70,16 @@ config SPI_AR934X
 	  This enables support for the SPI controller present on the
 	  Qualcomm Atheros AR934X/QCA95XX SoCs.
 
+config SPI_ASPEED
+	tristate "ASPEED FMC/SPI Memory Controller"
+	depends on OF && HAS_IOMEM
+	help
+	  Enable driver for ASPEED FMC/SPI Memory Controller.
+
+	  This driver is not a generic pure SPI driver, which
+	  is especially designed for spi-mem framework with
+	  SPI NOR flash direct read and write features.
+
 config SPI_ATH79
 	tristate "Atheros AR71XX/AR724X/AR913X SPI controller driver"
 	depends on ATH79 || COMPILE_TEST
diff --git a/drivers/spi/Makefile b/drivers/spi/Makefile
index 6fea5821662e..9e62c650fca0 100644
--- a/drivers/spi/Makefile
+++ b/drivers/spi/Makefile
@@ -17,6 +17,7 @@ obj-$(CONFIG_SPI_LOOPBACK_TEST)		+= spi-loopback-test.o
 obj-$(CONFIG_SPI_ALTERA)		+= spi-altera.o
 obj-$(CONFIG_SPI_AR934X)		+= spi-ar934x.o
 obj-$(CONFIG_SPI_ARMADA_3700)		+= spi-armada-3700.o
+obj-$(CONFIG_SPI_ASPEED)		+= spi-aspeed.o
 obj-$(CONFIG_SPI_ATMEL)			+= spi-atmel.o
 obj-$(CONFIG_SPI_ATMEL_QUADSPI)		+= atmel-quadspi.o
 obj-$(CONFIG_SPI_AT91_USART)		+= spi-at91-usart.o
diff --git a/drivers/spi/spi-aspeed.c b/drivers/spi/spi-aspeed.c
new file mode 100644
index 000000000000..795f67c9ca6a
--- /dev/null
+++ b/drivers/spi/spi-aspeed.c
@@ -0,0 +1,967 @@
+// SPDX-License-Identifier: GPL-2.0+
+
+/*
+ * ASPEED FMC/SPI Memory Controller Driver
+ *
+ * Copyright (c) 2020, ASPEED Corporation.
+ * Copyright (c) 2015-2016, IBM Corporation.
+ */
+
+#include <linux/bitops.h>
+#include <linux/clk.h>
+#include <linux/device.h>
+#include <linux/err.h>
+#include <linux/errno.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+#include <linux/sizes.h>
+#include <linux/spi/spi.h>
+#include <linux/spi/spi-mem.h>
+
+/* ASPEED FMC/SPI memory control register related */
+#define OFFSET_CE_TYPE_SETTING		0x00
+#define OFFSET_CE_ADDR_MODE_CTRL	0x04
+#define OFFSET_INTR_CTRL_STATUS		0x08
+#define OFFSET_ADDR_DATA_MASK		0x0c
+#define OFFSET_CE0_CTRL_REG		0x10
+#define OFFSET_CE0_DECODE_RANGE_REG	0x30
+#define OFFSET_DMA_CTRL			0x80
+#define OFFSET_DMA_FLASH_ADDR_REG	0x84
+#define OFFSET_DMA_RAM_ADDR_REG		0x88
+#define OFFSET_DMA_LEN_REG		0x8c
+#define OFFSET_DMA_CHECKSUM_RESULT	0x90
+#define OFFSET_CE0_TIMING_COMPENSATION	0x94
+
+#define CTRL_IO_SINGLE_DATA	0
+#define CTRL_IO_DUAL_DATA	BIT(29)
+#define CTRL_IO_QUAD_DATA	BIT(30)
+
+#define CTRL_IO_MODE_USER	GENMASK(1, 0)
+#define CTRL_IO_MODE_CMD_READ	BIT(0)
+#define CTRL_IO_MODE_CMD_WRITE	BIT(1)
+#define CTRL_STOP_ACTIVE	BIT(2)
+
+#define CALIBRATION_LEN		0x400
+#define SPI_DAM_REQUEST		BIT(31)
+#define SPI_DAM_GRANT		BIT(30)
+#define SPI_DMA_CALIB_MODE	BIT(3)
+#define SPI_DMA_CALC_CKSUM	BIT(2)
+#define SPI_DMA_ENABLE		BIT(0)
+#define SPI_DMA_STATUS		BIT(11)
+
+enum aspeed_spi_ctl_reg_value {
+	ASPEED_SPI_BASE,
+	ASPEED_SPI_READ,
+	ASPEED_SPI_WRITE,
+	ASPEED_SPI_MAX,
+};
+
+#define ASPEED_SPI_MAX_CS 5
+
+struct aspeed_spi_controller;
+struct aspeed_spi_chip;
+
+struct aspeed_spi_info {
+	uint32_t cmd_io_ctrl_mask;
+	uint32_t max_data_bus_width;
+	uint32_t min_decode_sz;
+	void (*set_4byte)(struct aspeed_spi_controller *ast_ctrl, uint32_t cs);
+	int (*calibrate)(struct aspeed_spi_controller *ast_ctrl, uint32_t cs);
+	void (*adjust_decode_sz)(uint32_t decode_sz_arr[], int len);
+	uint32_t (*segment_start)(struct aspeed_spi_controller *ast_ctrl,
+				  uint32_t reg);
+	uint32_t (*segment_end)(struct aspeed_spi_controller *ast_ctrl,
+				uint32_t reg);
+	uint32_t (*segment_reg)(struct aspeed_spi_controller *ast_ctrl,
+				uint32_t start, uint32_t end);
+};
+
+struct aspeed_spi_chip {
+	void __iomem *ahb_base;
+	void __iomem *ahb_base_phy;
+	uint32_t ahb_window_sz;
+	uint32_t ctrl_val[ASPEED_SPI_MAX];
+	uint32_t max_clk_freq;
+};
+
+struct aspeed_spi_controller {
+	struct device *dev;
+	const struct aspeed_spi_info *info; /* controller info */
+	void __iomem *regs; /* controller registers */
+	void __iomem *ahb_base;
+	uint32_t ahb_base_phy; /* physical addr of AHB window  */
+	uint32_t ahb_window_sz; /* AHB window size */
+	uint32_t num_cs;
+	uint64_t ahb_clk;
+	struct aspeed_spi_chip *chips; /* pointers to attached chips */
+};
+
+static uint32_t
+aspeed_2600_spi_segment_start(struct aspeed_spi_controller *ast_ctrl,
+			      uint32_t reg)
+{
+	uint32_t start_offset = (reg << 16) & 0x0ff00000;
+
+	return ast_ctrl->ahb_base_phy + start_offset;
+}
+
+static uint32_t
+aspeed_2600_spi_segment_end(struct aspeed_spi_controller *ast_ctrl,
+			    uint32_t reg)
+{
+	uint32_t end_offset = reg & 0x0ff00000;
+
+	/* no decode range, set to physical ahb base */
+	if (end_offset == 0)
+		return ast_ctrl->ahb_base_phy;
+
+	return ast_ctrl->ahb_base_phy + end_offset + 0x100000;
+}
+
+static uint32_t
+aspeed_2600_spi_segment_reg(struct aspeed_spi_controller *ast_ctrl,
+			    uint32_t start, uint32_t end)
+{
+	/* no decode range, assign zero value */
+	if (start == end)
+		return 0;
+
+	return ((start & 0x0ff00000) >> 16) | ((end - 0x100000) & 0x0ff00000);
+}
+
+static void aspeed_spi_chip_set_4byte(struct aspeed_spi_controller *ast_ctrl,
+				      uint32_t cs)
+{
+	uint32_t reg_val;
+
+	reg_val = readl(ast_ctrl->regs + OFFSET_CE_ADDR_MODE_CTRL);
+	reg_val |= 0x11 << cs;
+	writel(reg_val, ast_ctrl->regs + OFFSET_CE_ADDR_MODE_CTRL);
+}
+
+uint32_t aspeed_spi_get_io_mode(uint32_t bus_width)
+{
+	switch (bus_width) {
+	case 1:
+		return CTRL_IO_SINGLE_DATA;
+	case 2:
+		return CTRL_IO_DUAL_DATA;
+	case 4:
+		return CTRL_IO_QUAD_DATA;
+	default:
+		return CTRL_IO_SINGLE_DATA;
+	}
+}
+
+/*
+ * Check whether the data is not all 0 or 1 in order to
+ * avoid calibriate umount spi-flash.
+ */
+static bool aspeed_spi_calibriation_enable(const uint8_t *buf, uint32_t sz)
+{
+	const uint32_t *buf_32 = (const uint32_t *)buf;
+	uint32_t i;
+	uint32_t valid_count = 0;
+
+	for (i = 0; i < (sz / 4); i++) {
+		if (buf_32[i] != 0 && buf_32[i] != 0xffffffff)
+			valid_count++;
+		if (valid_count > 100)
+			return true;
+	}
+
+	return false;
+}
+
+static uint32_t
+aspeed_2600_spi_dma_checksum(struct aspeed_spi_controller *ast_ctrl,
+			     uint32_t cs, uint32_t div, uint32_t delay)
+{
+	uint32_t ctrl_val;
+	uint32_t checksum;
+
+	writel(0xaeed0000, ast_ctrl->regs + OFFSET_DMA_CTRL);
+	if (readl(ast_ctrl->regs + OFFSET_DMA_CTRL) & SPI_DAM_REQUEST) {
+		while (!(readl(ast_ctrl->regs + OFFSET_DMA_CTRL) &
+			 SPI_DAM_GRANT))
+			;
+	}
+
+	writel((uint32_t)ast_ctrl->chips[cs].ahb_base_phy,
+	       ast_ctrl->regs + OFFSET_DMA_FLASH_ADDR_REG);
+	writel(CALIBRATION_LEN, ast_ctrl->regs + OFFSET_DMA_LEN_REG);
+
+	ctrl_val = SPI_DMA_ENABLE | SPI_DMA_CALC_CKSUM | SPI_DMA_CALIB_MODE |
+		   (delay << 8) | ((div & 0xf) << 16);
+	writel(ctrl_val, ast_ctrl->regs + OFFSET_DMA_CTRL);
+	while (!(readl(ast_ctrl->regs + OFFSET_INTR_CTRL_STATUS) &
+		 SPI_DMA_STATUS))
+		;
+
+	checksum = readl(ast_ctrl->regs + OFFSET_DMA_CHECKSUM_RESULT);
+
+	writel(0xdeea0000, ast_ctrl->regs + OFFSET_DMA_CTRL);
+	writel(0x0, ast_ctrl->regs + OFFSET_DMA_CTRL);
+
+	return checksum;
+}
+
+static int get_mid_point_of_longest_one(uint8_t *buf, uint32_t len)
+{
+	int i;
+	int start = 0, mid_point = 0;
+	int max_cnt = 0, cnt = 0;
+
+	for (i = 0; i < len; i++) {
+		if (buf[i] == 1) {
+			cnt++;
+		} else {
+			cnt = 0;
+			start = i;
+		}
+
+		if (max_cnt < cnt) {
+			max_cnt = cnt;
+			mid_point = start + (cnt / 2);
+		}
+	}
+
+	/*
+	 * In order to get a stable SPI read timing,
+	 * abandon the result if the length of longest
+	 * consecutive good points is too short.
+	 */
+	if (max_cnt < 4)
+		return -1;
+
+	return mid_point;
+}
+
+/* Transfer maximum clock frequency to register setting */
+static uint32_t
+aspeed_2600_spi_clk_basic_setting(struct aspeed_spi_controller *ast_ctrl,
+				  uint32_t *max_clk)
+{
+	struct device *dev = ast_ctrl->dev;
+	uint32_t hclk_clk = ast_ctrl->ahb_clk;
+	uint32_t hclk_div = 0x400; /* default value */
+	uint32_t i, j = 0;
+	bool found = false;
+	/* HCLK/1 ..	HCLK/16 */
+	uint32_t hclk_masks[] = { 15, 7, 14, 6, 13, 5, 12, 4,
+				  11, 3, 10, 2, 9,  1, 8,  0 };
+
+	/* FMC/SPIR10[27:24] */
+	for (j = 0; j < 0xf; i++) {
+		/* FMC/SPIR10[11:8] */
+		for (i = 0; i < ARRAY_SIZE(hclk_masks); i++) {
+			if (i == 0 && j == 0)
+				continue;
+
+			if (hclk_clk / (i + 1 + (j * 16)) <= *max_clk) {
+				found = 1;
+				*max_clk = hclk_clk / (i + 1 + (j * 16));
+				break;
+			}
+		}
+
+		if (found) {
+			hclk_div = ((j << 24) | hclk_masks[i] << 8);
+			break;
+		}
+	}
+
+	dev_dbg(dev, "found: %s, hclk: %d, max_clk: %d\n", found ? "yes" : "no",
+		hclk_clk, *max_clk);
+	dev_dbg(dev, "base_clk: %d, h_div: %d (mask %x), speed: %d\n", j, i + 1,
+		hclk_masks[i], hclk_clk / (i + 1 + j * 16));
+
+	return hclk_div;
+}
+
+/*
+ * If SPI frequency is too high, timing compensation is needed,
+ * otherwise, SPI controller will sample unready data. For AST2600
+ * SPI memory controller, only the first four frequency levels
+ * (HCLK/2, HCLK/3,..., HCKL/5) may need timing compensation.
+ * Here, for each frequency, we will get a sequence of reading
+ * result (pass or fail) compared to golden data. Then, getting the
+ * middle point of the maximum pass widow. Besides, if the flash's
+ * content is too monotonous, the frequency recorded in the device
+ * tree will be adopted.
+ */
+int aspeed_2600_spi_timing_calibration(struct aspeed_spi_controller *ast_ctrl,
+				       uint32_t cs)
+{
+	int ret = 0;
+	struct device *dev = ast_ctrl->dev;
+	struct aspeed_spi_chip *chip = &ast_ctrl->chips[cs];
+	uint32_t max_freq = chip->max_clk_freq;
+	/* HCLK/2, ..., HCKL/5 */
+	uint32_t hclk_masks[] = { 7, 14, 6, 13 };
+	uint8_t *calib_res = NULL;
+	uint8_t *check_buf = NULL;
+	uint32_t reg_val;
+	uint32_t checksum, gold_checksum;
+	uint32_t i, hcycle, delay_ns, final_delay = 0;
+	uint32_t hclk_div;
+	bool pass;
+	int calib_point;
+
+	reg_val =
+		readl(ast_ctrl->regs + OFFSET_CE0_TIMING_COMPENSATION + cs * 4);
+	if (reg_val != 0) {
+		dev_dbg(dev, "has executed calibration.\n");
+		goto no_calib;
+	}
+
+	dev_dbg(dev, "calculate timing compensation :\n");
+	/*
+	 * use the related low frequency to get check calibration data
+	 * and get golden data.
+	 */
+	reg_val = chip->ctrl_val[ASPEED_SPI_READ] & 0xf0fff0ff;
+	writel(reg_val, ast_ctrl->regs + OFFSET_CE0_CTRL_REG + cs * 4);
+
+	check_buf = kzalloc(CALIBRATION_LEN, GFP_KERNEL);
+	if (!check_buf)
+		return -ENOMEM;
+
+	memcpy_fromio(check_buf, chip->ahb_base, CALIBRATION_LEN);
+	if (!aspeed_spi_calibriation_enable(check_buf, CALIBRATION_LEN)) {
+		dev_info(dev, "flash data is monotonous, skip calibration.");
+		goto no_calib;
+	}
+
+	gold_checksum = aspeed_2600_spi_dma_checksum(ast_ctrl, cs, 0, 0);
+
+	/*
+	 * allocate a space to record calibration result for
+	 * different timing compensation with fixed
+	 * HCLK division.
+	 */
+	calib_res = kzalloc(6 * 17, GFP_KERNEL);
+	if (!calib_res) {
+		ret = -ENOMEM;
+		goto no_calib;
+	}
+
+	/* From HCLK/2 to HCLK/5 */
+	for (i = 0; i < ARRAY_SIZE(hclk_masks); i++) {
+		if (max_freq < (uint32_t)ast_ctrl->ahb_clk / (i + 2)) {
+			dev_dbg(dev, "skipping freq %d\n",
+				(uint32_t)ast_ctrl->ahb_clk / (i + 2));
+			continue;
+		}
+		max_freq = (uint32_t)ast_ctrl->ahb_clk / (i + 2);
+
+		checksum = aspeed_2600_spi_dma_checksum(ast_ctrl, cs,
+							hclk_masks[i], 0);
+		pass = (checksum == gold_checksum);
+		dev_dbg(dev, "HCLK/%d, no timing compensation: %s\n", i + 2,
+			pass ? "PASS" : "FAIL");
+
+		if (pass)
+			break;
+
+		memset(calib_res, 0x0, 6 * 17);
+
+		for (hcycle = 0; hcycle <= 5; hcycle++) {
+			/* increase DI delay by the step of 0.5ns */
+			dev_dbg(dev, "Delay Enable : hcycle %x\n", hcycle);
+			for (delay_ns = 0; delay_ns <= 0xf; delay_ns++) {
+				checksum = aspeed_2600_spi_dma_checksum(
+					ast_ctrl, cs, hclk_masks[i],
+					BIT(3) | hcycle | (delay_ns << 4));
+				pass = (checksum == gold_checksum);
+				calib_res[hcycle * 17 + delay_ns] = pass;
+				dev_dbg(dev,
+					"HCLK/%d, %d HCLK cycle, %d delay_ns : %s\n",
+					i + 2, hcycle, delay_ns,
+					pass ? "PASS" : "FAIL");
+			}
+		}
+
+		calib_point = get_mid_point_of_longest_one(calib_res, 6 * 17);
+		if (calib_point < 0) {
+			dev_info(dev, "cannot get good calibration point.\n");
+			continue;
+		}
+
+		hcycle = calib_point / 17;
+		delay_ns = calib_point % 17;
+		dev_dbg(dev, "final hcycle: %d, delay_ns: %d\n", hcycle,
+			delay_ns);
+
+		final_delay = (BIT(3) | hcycle | (delay_ns << 4)) << (i * 8);
+		writel(final_delay, ast_ctrl->regs +
+					    OFFSET_CE0_TIMING_COMPENSATION +
+					    cs * 4);
+		break;
+	}
+
+no_calib:
+
+	hclk_div = aspeed_2600_spi_clk_basic_setting(ast_ctrl, &max_freq);
+
+	/* configure SPI clock frequency */
+	reg_val = readl(ast_ctrl->regs + OFFSET_CE0_CTRL_REG + cs * 4);
+	reg_val = (reg_val & 0xf0fff0ff) | hclk_div;
+	writel(reg_val, ast_ctrl->regs + OFFSET_CE0_CTRL_REG + cs * 4);
+
+	/* add clock setting info for CE ctrl setting */
+	for (i = 0; i < ASPEED_SPI_MAX; i++)
+		chip->ctrl_val[i] = (chip->ctrl_val[i] & 0xf0fff0ff) | hclk_div;
+
+	dev_info(dev, "freq: %dMHz\n", max_freq / 1000000);
+
+	kfree(check_buf);
+	kfree(calib_res);
+
+	return ret;
+}
+
+/*
+ * AST2600 SPI memory controllers support multiple chip selects.
+ * The start address of a decode range should be multiple
+ * of its related flash size. Namely, the total decoded size
+ * from flash 0 to flash N should be multiple of flash (N + 1).
+ */
+void aspeed_2600_adjust_decode_sz(uint32_t decode_sz_arr[], int len)
+{
+	int cs, j;
+	uint32_t sz;
+
+	for (cs = len - 1; cs >= 0; cs--) {
+		sz = 0;
+		for (j = 0; j < cs; j++)
+			sz += decode_sz_arr[j];
+
+		if (sz % decode_sz_arr[cs] != 0)
+			decode_sz_arr[0] += (sz % decode_sz_arr[cs]);
+	}
+}
+
+static int
+aspeed_spi_decode_range_config(struct aspeed_spi_controller *ast_ctrl,
+			       uint32_t decode_sz_arr[])
+{
+	struct aspeed_spi_chip *chip = ast_ctrl->chips;
+	uint32_t i;
+	uint32_t cs;
+	uint32_t decode_reg_val;
+	uint32_t start_addr_phy, end_addr_phy, pre_end_addr_phy = 0;
+	uint32_t total_decode_sz = 0;
+
+	/* decode range sanity */
+	for (cs = 0; cs < ast_ctrl->num_cs; cs++) {
+		total_decode_sz += decode_sz_arr[cs];
+		if (ast_ctrl->ahb_window_sz < total_decode_sz) {
+			dev_err(ast_ctrl->dev, "insufficient decode size\n");
+			for (i = 0; i <= cs; i++)
+				dev_err(ast_ctrl->dev, "cs:%d %x\n", i,
+					decode_sz_arr[i]);
+			return -ENOSPC;
+		}
+	}
+
+	for (cs = 0; cs < ast_ctrl->num_cs; cs++) {
+		if (chip[cs].ahb_base)
+			devm_iounmap(ast_ctrl->dev, chip[cs].ahb_base);
+	}
+
+	/* configure each CE's decode range */
+	for (cs = 0; cs < ast_ctrl->num_cs; cs++) {
+		if (cs == 0)
+			start_addr_phy = ast_ctrl->ahb_base_phy;
+		else
+			start_addr_phy = pre_end_addr_phy;
+
+		chip[cs].ahb_base = devm_ioremap(ast_ctrl->dev, start_addr_phy,
+						 decode_sz_arr[cs]);
+		chip[cs].ahb_base_phy = (void __iomem *)start_addr_phy;
+
+		chip[cs].ahb_window_sz = decode_sz_arr[cs];
+		end_addr_phy = start_addr_phy + decode_sz_arr[cs];
+
+		decode_reg_val = ast_ctrl->info->segment_reg(
+			ast_ctrl, start_addr_phy, end_addr_phy);
+
+		writel(decode_reg_val,
+		       ast_ctrl->regs + OFFSET_CE0_DECODE_RANGE_REG + cs * 4);
+
+		pre_end_addr_phy = end_addr_phy;
+
+		dev_dbg(ast_ctrl->dev, "cs: %d, decode_reg: 0x%x\n", cs,
+			decode_reg_val);
+	}
+
+	return 0;
+}
+
+static const struct aspeed_spi_info ast2600_spi_info = {
+	.max_data_bus_width = 4,
+	.cmd_io_ctrl_mask = 0xf0ff40c3,
+	/* for ast2600, the minimum decode size for each CE is 2MB */
+	.min_decode_sz = 0x200000,
+	.set_4byte = aspeed_spi_chip_set_4byte,
+	.calibrate = aspeed_2600_spi_timing_calibration,
+	.adjust_decode_sz = aspeed_2600_adjust_decode_sz,
+	.segment_start = aspeed_2600_spi_segment_start,
+	.segment_end = aspeed_2600_spi_segment_end,
+	.segment_reg = aspeed_2600_spi_segment_reg,
+};
+
+/*
+ * If the slave device is SPI NOR flash, there are two types
+ * of command mode for ASPEED SPI memory controller used to
+ * transfer data. The first one is user mode and the other is
+ * command read/write mode. With user mode, SPI NOR flash
+ * command, address and data processes are all handled by CPU.
+ * But, when address filter is enabled to protect some flash
+ * regions from being written, user mode will be disabled.
+ * Thus, here, we use command read/write mode to issue SPI
+ * operations. After remapping flash space correctly, we can
+ * easily read/write data to flash by reading or writing
+ * related remapped address, then, SPI NOR flash command and
+ * address will be transferred to flash by controller
+ * automatically. Besides, ASPEED SPI memory controller can
+ * also block address or data bytes by configure FMC0C/SPIR0C
+ * address and data mask register in order to satisfy the
+ * following SPI flash operation sequences: (command) only,
+ * (command and address) only or (coommand and data) only.
+ */
+static int aspeed_spi_exec_op(struct spi_mem *mem, const struct spi_mem_op *op)
+{
+	struct aspeed_spi_controller *ast_ctrl =
+		spi_controller_get_devdata(mem->spi->master);
+	struct device *dev = ast_ctrl->dev;
+	uint32_t cs = mem->spi->chip_select;
+	struct aspeed_spi_chip *chip = &ast_ctrl->chips[cs];
+	uint32_t ctrl_val;
+	uint32_t addr_mode_reg, addr_mode_reg_backup;
+	uint32_t addr_data_mask = 0;
+	void __iomem *op_addr;
+	const void *data_buf;
+	uint32_t data_byte = 0;
+	uint32_t dummy_data = 0;
+
+	dev_dbg(dev, "cmd:%x(%d),addr:%llx(%d),dummy:%d(%d),data_len:%x(%d)\n",
+		op->cmd.opcode, op->cmd.buswidth, op->addr.val,
+		op->addr.buswidth, op->dummy.nbytes, op->dummy.buswidth,
+		op->data.nbytes, op->data.buswidth);
+
+	addr_mode_reg = addr_mode_reg_backup =
+		readl(ast_ctrl->regs + OFFSET_CE_ADDR_MODE_CTRL);
+	addr_data_mask = readl(ast_ctrl->regs + OFFSET_ADDR_DATA_MASK);
+
+	ctrl_val = chip->ctrl_val[ASPEED_SPI_BASE];
+	ctrl_val &= ~ast_ctrl->info->cmd_io_ctrl_mask;
+
+	/* configure opcode */
+	ctrl_val |= op->cmd.opcode << 16;
+
+	/* configure operation address, address length and address mask */
+	if (op->addr.nbytes != 0) {
+		if (op->addr.nbytes == 3)
+			addr_mode_reg &= ~(0x11 << cs);
+		else
+			addr_mode_reg |= (0x11 << cs);
+
+		addr_data_mask &= 0x0f;
+		op_addr = chip->ahb_base + op->addr.val;
+	} else {
+		addr_data_mask |= 0xf0;
+		op_addr = chip->ahb_base;
+	}
+
+	if (op->dummy.nbytes != 0) {
+		ctrl_val |= ((op->dummy.nbytes & 0x3) << 6 |
+			     (op->dummy.nbytes & 0x4) << 14);
+	}
+
+	/* configure data io mode and data mask */
+	if (op->data.nbytes != 0) {
+		addr_data_mask &= 0xF0;
+		data_byte = op->data.nbytes;
+		if (op->data.dir == SPI_MEM_DATA_OUT)
+			data_buf = op->data.buf.out;
+		else
+			data_buf = op->data.buf.in;
+
+		if (op->data.buswidth)
+			ctrl_val |= aspeed_spi_get_io_mode(op->data.buswidth);
+
+	} else {
+		addr_data_mask |= 0x0f;
+		data_byte = 1;
+		data_buf = &dummy_data;
+	}
+
+	/* configure command mode */
+	if (op->data.dir == SPI_MEM_DATA_OUT)
+		ctrl_val |= CTRL_IO_MODE_CMD_WRITE;
+	else
+		ctrl_val |= CTRL_IO_MODE_CMD_READ;
+
+	/* set controller registers */
+	writel(ctrl_val, ast_ctrl->regs + OFFSET_CE0_CTRL_REG + cs * 4);
+	writel(addr_mode_reg, ast_ctrl->regs + OFFSET_CE_ADDR_MODE_CTRL);
+	writel(addr_data_mask, ast_ctrl->regs + OFFSET_ADDR_DATA_MASK);
+
+	dev_dbg(dev, "ctrl: 0x%08x, addr_mode: 0x%x, mask: 0x%x, addr:0x%08x\n",
+		ctrl_val, addr_mode_reg, addr_data_mask, (uint32_t)op_addr);
+
+	/* trigger spi transmission or reception sequence */
+	if (op->data.dir == SPI_MEM_DATA_OUT)
+		memcpy_toio(op_addr, data_buf, data_byte);
+	else
+		memcpy_fromio((void *)data_buf, op_addr, data_byte);
+
+	/* restore controller setting */
+	writel(chip->ctrl_val[ASPEED_SPI_READ],
+	       ast_ctrl->regs + OFFSET_CE0_CTRL_REG + cs * 4);
+	writel(addr_mode_reg_backup, ast_ctrl->regs + OFFSET_CE_ADDR_MODE_CTRL);
+	writel(0x0, ast_ctrl->regs + OFFSET_ADDR_DATA_MASK);
+
+	return 0;
+}
+
+static int aspeed_spi_dirmap_read(struct spi_mem_dirmap_desc *desc,
+				  uint64_t offs, size_t len, void *buf)
+{
+	struct aspeed_spi_controller *ast_ctrl =
+		spi_controller_get_devdata(desc->mem->spi->master);
+	struct aspeed_spi_chip *chip =
+		&ast_ctrl->chips[desc->mem->spi->chip_select];
+	struct spi_mem_op op_tmpl = desc->info.op_tmpl;
+
+	if (chip->ahb_window_sz < offs + len) {
+		dev_info(ast_ctrl->dev,
+			 "read range exceeds flash remapping size\n");
+		return 0;
+	}
+
+	dev_dbg(ast_ctrl->dev, "read op:0x%x, addr:0x%llx, len:0x%x\n",
+		op_tmpl.cmd.opcode, offs, len);
+
+	memcpy_fromio(buf, chip->ahb_base + offs, len);
+
+	return len;
+}
+
+static int aspeed_spi_dirmap_write(struct spi_mem_dirmap_desc *desc,
+				   uint64_t offs, size_t len, const void *buf)
+{
+	struct aspeed_spi_controller *ast_ctrl =
+		spi_controller_get_devdata(desc->mem->spi->master);
+	struct aspeed_spi_chip *chip =
+		&ast_ctrl->chips[desc->mem->spi->chip_select];
+	uint32_t reg_val;
+	uint32_t target_cs = desc->mem->spi->chip_select;
+	struct spi_mem_op op_tmpl = desc->info.op_tmpl;
+
+	if (chip->ahb_window_sz < offs + len) {
+		dev_info(ast_ctrl->dev,
+			 "write range exceeds flash remapping size\n");
+		return 0;
+	}
+
+	dev_dbg(ast_ctrl->dev, "write op:0x%x, addr:0x%llx, len:0x%x\n",
+		op_tmpl.cmd.opcode, offs, len);
+
+	reg_val = ast_ctrl->chips[target_cs].ctrl_val[ASPEED_SPI_WRITE];
+	writel(reg_val, ast_ctrl->regs + OFFSET_CE0_CTRL_REG + target_cs * 4);
+
+	memcpy_toio(chip->ahb_base + offs, buf, len);
+
+	reg_val = ast_ctrl->chips[target_cs].ctrl_val[ASPEED_SPI_READ];
+	writel(reg_val, ast_ctrl->regs + OFFSET_CE0_CTRL_REG + target_cs * 4);
+
+	return len;
+}
+
+static int aspeed_spi_dirmap_create(struct spi_mem_dirmap_desc *desc)
+{
+	int ret = 0;
+	struct aspeed_spi_controller *ast_ctrl =
+		spi_controller_get_devdata(desc->mem->spi->master);
+	struct device *dev = ast_ctrl->dev;
+	const struct aspeed_spi_info *info = ast_ctrl->info;
+	struct spi_mem_op op_tmpl = desc->info.op_tmpl;
+	uint32_t decode_sz_arr[5];
+	uint32_t cs, target_cs = desc->mem->spi->chip_select;
+	uint32_t reg_val;
+
+	if (desc->info.op_tmpl.data.dir == SPI_MEM_DATA_IN) {
+		/* record original decode size */
+		for (cs = 0; cs < ast_ctrl->num_cs; cs++) {
+			reg_val = readl(ast_ctrl->regs +
+					OFFSET_CE0_DECODE_RANGE_REG + cs * 4);
+			decode_sz_arr[cs] =
+				info->segment_end(ast_ctrl, reg_val) -
+				info->segment_start(ast_ctrl, reg_val);
+		}
+
+		decode_sz_arr[target_cs] = desc->info.length;
+
+		if (info->adjust_decode_sz)
+			info->adjust_decode_sz(decode_sz_arr, ast_ctrl->num_cs);
+
+		for (cs = 0; cs < ast_ctrl->num_cs; cs++) {
+			dev_dbg(dev, "cs: %d, sz: 0x%x\n", cs,
+				decode_sz_arr[cs]);
+		}
+
+		ret = aspeed_spi_decode_range_config(ast_ctrl, decode_sz_arr);
+		if (ret)
+			return ret;
+
+		reg_val = readl(ast_ctrl->regs + OFFSET_CE0_CTRL_REG +
+				target_cs * 4) &
+			  (~info->cmd_io_ctrl_mask);
+		reg_val |= aspeed_spi_get_io_mode(op_tmpl.data.buswidth) |
+			   op_tmpl.cmd.opcode << 16 |
+			   ((op_tmpl.dummy.nbytes) & 0x3) << 6 |
+			   ((op_tmpl.dummy.nbytes) & 0x4) << 14 |
+			   CTRL_IO_MODE_CMD_READ;
+
+		writel(reg_val,
+		       ast_ctrl->regs + OFFSET_CE0_CTRL_REG + target_cs * 4);
+		ast_ctrl->chips[target_cs].ctrl_val[ASPEED_SPI_READ] = reg_val;
+		ast_ctrl->chips[target_cs].max_clk_freq =
+			desc->mem->spi->max_speed_hz;
+
+		ret = info->calibrate(ast_ctrl, target_cs);
+
+		dev_info(dev, "read bus width: %d [0x%08x]\n",
+			 op_tmpl.data.buswidth,
+			 ast_ctrl->chips[target_cs].ctrl_val[ASPEED_SPI_READ]);
+
+	} else if (desc->info.op_tmpl.data.dir == SPI_MEM_DATA_OUT) {
+		reg_val = readl(ast_ctrl->regs + OFFSET_CE0_CTRL_REG +
+				target_cs * 4) &
+			  (~info->cmd_io_ctrl_mask);
+		reg_val |= aspeed_spi_get_io_mode(op_tmpl.data.buswidth) |
+			   op_tmpl.cmd.opcode << 16 | CTRL_IO_MODE_CMD_WRITE;
+		ast_ctrl->chips[target_cs].ctrl_val[ASPEED_SPI_WRITE] = reg_val;
+
+		dev_info(dev, "write bus width: %d [0x%08x]\n",
+			 op_tmpl.data.buswidth,
+			 ast_ctrl->chips[target_cs].ctrl_val[ASPEED_SPI_WRITE]);
+	}
+
+	return ret;
+}
+
+static const char *aspeed_spi_get_name(struct spi_mem *mem)
+{
+	struct device *dev = &mem->spi->master->dev;
+	const char *name;
+
+	name = devm_kasprintf(dev, GFP_KERNEL, "%s-%d", dev_name(dev),
+			      mem->spi->chip_select);
+
+	if (!name) {
+		dev_err(dev, "cannot get spi name\n");
+		return ERR_PTR(-ENOMEM);
+	}
+
+	return name;
+}
+
+/*
+ * Currently, only support 1-1-1, 1-1-2 or 1-1-4
+ * SPI NOR flash operation format.
+ */
+static bool aspeed_spi_support_op(struct spi_mem *mem,
+				  const struct spi_mem_op *op)
+{
+	struct aspeed_spi_controller *ast_ctrl =
+		spi_controller_get_devdata(mem->spi->master);
+
+	if (op->cmd.buswidth > 1)
+		return false;
+
+	if (op->addr.nbytes != 0) {
+		if (op->addr.buswidth > 1 || op->addr.nbytes > 4)
+			return false;
+	}
+
+	if (op->dummy.nbytes != 0) {
+		if (op->dummy.buswidth > 1 || op->dummy.nbytes > 7)
+			return false;
+	}
+
+	if (op->data.nbytes != 0 &&
+	    ast_ctrl->info->max_data_bus_width < op->data.buswidth)
+		return false;
+
+	if (!spi_mem_default_supports_op(mem, op))
+		return false;
+
+	if (op->addr.nbytes == 4)
+		ast_ctrl->info->set_4byte(ast_ctrl, mem->spi->chip_select);
+
+	return true;
+}
+
+static const struct spi_controller_mem_ops aspeed_spi_mem_ops = {
+	.exec_op = aspeed_spi_exec_op,
+	.get_name = aspeed_spi_get_name,
+	.supports_op = aspeed_spi_support_op,
+	.dirmap_create = aspeed_spi_dirmap_create,
+	.dirmap_read = aspeed_spi_dirmap_read,
+	.dirmap_write = aspeed_spi_dirmap_write,
+};
+
+/*
+ * Initialize SPI controller for each chip select.
+ * Here, only the minimum decode range is configured
+ * in order to get device (SPI NOR flash) information
+ * at the early stage.
+ */
+static int aspeed_spi_ctrl_init(struct aspeed_spi_controller *ast_ctrl)
+{
+	int ret;
+	uint32_t cs;
+	uint32_t val;
+	uint32_t decode_sz_arr[ASPEED_SPI_MAX_CS];
+
+	/* enable write capability for all CEs */
+	val = readl(ast_ctrl->regs + OFFSET_CE_TYPE_SETTING);
+	writel(val | (GENMASK(ast_ctrl->num_cs, 0) << 16),
+	       ast_ctrl->regs + OFFSET_CE_TYPE_SETTING);
+
+	/* initial each CE's controller register */
+	for (cs = 0; cs < ast_ctrl->num_cs; cs++) {
+		val = CTRL_STOP_ACTIVE | CTRL_IO_MODE_USER;
+		writel(val, ast_ctrl->regs + OFFSET_CE0_CTRL_REG + cs * 4);
+		ast_ctrl->chips[cs].ctrl_val[ASPEED_SPI_BASE] = val;
+	}
+
+	for (cs = 0; cs < ast_ctrl->num_cs && cs < ASPEED_SPI_MAX_CS; cs++)
+		decode_sz_arr[cs] = ast_ctrl->info->min_decode_sz;
+
+	ret = aspeed_spi_decode_range_config(ast_ctrl, decode_sz_arr);
+
+	return ret;
+}
+
+static const struct of_device_id aspeed_spi_matches[] = {
+	{ .compatible = "aspeed,ast2600-fmc", .data = &ast2600_spi_info },
+	{ .compatible = "aspeed,ast2600-spi", .data = &ast2600_spi_info },
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, aspeed_spi_matches);
+
+static int aspeed_spi_probe(struct platform_device *pdev)
+{
+	int ret;
+	struct device *dev = &pdev->dev;
+	struct spi_controller *spi_ctrl;
+	struct aspeed_spi_controller *ast_ctrl;
+	const struct of_device_id *match;
+	struct clk *clk;
+	struct resource *res;
+
+	spi_ctrl = spi_alloc_master(dev, sizeof(struct aspeed_spi_controller));
+	if (!spi_ctrl)
+		return -ENOMEM;
+
+	ast_ctrl = spi_controller_get_devdata(spi_ctrl);
+
+	match = of_match_device(aspeed_spi_matches, dev);
+	if (!match || !match->data) {
+		dev_err(dev, "no compatible OF match\n");
+		return -ENODEV;
+	}
+
+	ast_ctrl->info = match->data;
+
+	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "spi_ctrl_reg");
+	ast_ctrl->regs = devm_ioremap_resource(dev, res);
+	if (IS_ERR(ast_ctrl->regs))
+		return PTR_ERR(ast_ctrl->regs);
+
+	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "spi_mmap");
+	ast_ctrl->ahb_base_phy = res->start;
+	ast_ctrl->ahb_window_sz = resource_size(res);
+
+	ast_ctrl->dev = dev;
+
+	clk = devm_clk_get(&pdev->dev, NULL);
+	if (IS_ERR(clk))
+		return PTR_ERR(clk);
+	ast_ctrl->ahb_clk = clk_get_rate(clk);
+	devm_clk_put(&pdev->dev, clk);
+
+	if (of_property_read_u32(dev->of_node, "num-cs", &ast_ctrl->num_cs)) {
+		dev_err(dev, "fail to get chip number.\n");
+		goto end;
+	}
+
+	if (ast_ctrl->num_cs > ASPEED_SPI_MAX_CS) {
+		dev_err(dev, "chip number, %d, exceeds %d.\n", ast_ctrl->num_cs,
+			ASPEED_SPI_MAX_CS);
+		goto end;
+	}
+
+	ast_ctrl->chips =
+		devm_kzalloc(dev,
+			     sizeof(struct aspeed_spi_chip) * ast_ctrl->num_cs,
+			     GFP_KERNEL);
+
+	platform_set_drvdata(pdev, ast_ctrl);
+
+	spi_ctrl->mode_bits =
+		SPI_RX_DUAL | SPI_RX_QUAD | SPI_TX_DUAL | SPI_TX_QUAD;
+
+	spi_ctrl->bus_num = -1;
+	spi_ctrl->mem_ops = &aspeed_spi_mem_ops;
+	spi_ctrl->dev.of_node = dev->of_node;
+	spi_ctrl->num_chipselect = ast_ctrl->num_cs;
+
+	ret = aspeed_spi_ctrl_init(ast_ctrl);
+	if (ret)
+		goto end;
+
+	ret = devm_spi_register_master(dev, spi_ctrl);
+
+end:
+	return ret;
+}
+
+static int aspeed_spi_remove(struct platform_device *pdev)
+{
+	struct aspeed_spi_controller *ast_ctrl = platform_get_drvdata(pdev);
+	uint32_t val;
+
+	/* disable write capability for all CEs */
+	val = readl(ast_ctrl->regs + OFFSET_CE_TYPE_SETTING);
+	writel(val & ~(GENMASK(ast_ctrl->num_cs, 0) << 16),
+	       ast_ctrl->regs + OFFSET_CE_TYPE_SETTING);
+
+	return 0;
+}
+
+static struct platform_driver aspeed_spi_driver = {
+	.driver = {
+		.name = "ASPEED_FMC_SPI",
+		.bus = &platform_bus_type,
+		.of_match_table = aspeed_spi_matches,
+	},
+	.probe = aspeed_spi_probe,
+	.remove = aspeed_spi_remove,
+};
+module_platform_driver(aspeed_spi_driver);
+
+MODULE_DESCRIPTION("ASPEED FMC/SPI Memory Controller Driver");
+MODULE_AUTHOR("Chin-Ting Kuo <chin-ting_kuo@xxxxxxxxxxxxxx>");
+MODULE_AUTHOR("Cedric Le Goater <clg@xxxxxxxx>");
+MODULE_LICENSE("GPL v2");
-- 
2.17.1