mediatek: backport spi-mem based mtk spinor driver

This new driver has full quadspi and DMA support, providing way better
reading performance.

Signed-off-by: Chuanhong Guo <[email protected]>

target/linux/mediatek/mt7629/config-5.4

@@ -336,6 +336,7 @@ CONFIG_SPI=y
 CONFIG_SPI_MASTER=y
 CONFIG_SPI_MEM=y
 # CONFIG_SPI_MT65XX is not set
+CONFIG_SPI_MTK_NOR=y
 CONFIG_SRCU=y
 CONFIG_STACKTRACE=y
 # CONFIG_SWAP is not set

target/linux/mediatek/patches-5.4/0001-v5.7-spi-make-spi-max-frequency-optional.patch

@@ -0,0 +1,38 @@
+From 671c3bf50ae498dc12aef6c70abe5cfa066b1348 Mon Sep 17 00:00:00 2001
+From: Chuanhong Guo <[email protected]>
+Date: Fri, 6 Mar 2020 16:50:49 +0800
+Subject: [PATCH 1/2] spi: make spi-max-frequency optional
+
+We only need a spi-max-frequency when we specifically request a
+spi frequency lower than the max speed of spi host.
+This property is already documented as optional property and current
+host drivers are implemented to operate at highest speed possible
+when spi->max_speed_hz is 0.
+This patch makes spi-max-frequency an optional property so that
+we could just omit it to use max controller speed.
+
+Signed-off-by: Chuanhong Guo <[email protected]>
+Link: https://lore.kernel.org/r/[email protected]
+Signed-off-by: Mark Brown <[email protected]>
+---
+ drivers/spi/spi.c | 9 ++-------
+ 1 file changed, 2 insertions(+), 7 deletions(-)
+
+--- a/drivers/spi/spi.c
++++ b/drivers/spi/spi.c
+@@ -1785,13 +1785,8 @@ static int of_spi_parse_dt(struct spi_co
+ 		spi->mode |= SPI_CS_HIGH;
+ 
+ 	/* Device speed */
+-	rc = of_property_read_u32(nc, "spi-max-frequency", &value);
+-	if (rc) {
+-		dev_err(&ctlr->dev,
+-			"%pOF has no valid 'spi-max-frequency' property (%d)\n", nc, rc);
+-		return rc;
+-	}
+-	spi->max_speed_hz = value;
++	if (!of_property_read_u32(nc, "spi-max-frequency", &value))
++		spi->max_speed_hz = value;
+ 
+ 	return 0;
+ }

target/linux/mediatek/patches-5.4/0002-v5.7-spi-add-support-for-mediatek-spi-nor-controller.patch

@@ -0,0 +1,761 @@
+From 881d1ee9fe81ff2be1b90809a07621be97404a57 Mon Sep 17 00:00:00 2001
+From: Chuanhong Guo <[email protected]>
+Date: Fri, 6 Mar 2020 16:50:50 +0800
+Subject: [PATCH 2/2] spi: add support for mediatek spi-nor controller
+
+This is a driver for mtk spi-nor controller using spi-mem interface.
+The same controller already has limited support provided by mtk-quadspi
+driver under spi-nor framework and this new driver is a replacement
+for the old one.
+
+Comparing to the old driver, this driver has following advantages:
+1. It can handle any full-duplex spi transfer up to 6 bytes, and
+   this is implemented using generic spi interface.
+2. It take account into command opcode properly. The reading routine
+   in this controller can only use 0x03 or 0x0b as opcode on 1-1-1
+   transfers, but old driver doesn't implement this properly. This
+   driver checks supported opcode explicitly and use (1) to perform
+   unmatched operations.
+3. It properly handles SFDP reading. Old driver can't read SFDP
+   due to the bug mentioned in (2).
+4. It can do 1-2-2 and 1-4-4 fast reading on spi-nor. These two ops
+   requires parsing SFDP, which isn't possible in old driver. And
+   the old driver is only flagged to support 1-1-2 mode.
+5. It takes advantage of the DMA feature in this controller for
+   long reads and supports IRQ on DMA requests to free cpu cycles
+   from polling status registers on long DMA reading. It achieves
+   up to 17.5MB/s reading speed (1-4-4 mode) which is way faster
+   than the old one. IRQ is implemented as optional to maintain
+   backward compatibility.
+
+Signed-off-by: Chuanhong Guo <[email protected]>
+Link: https://lore.kernel.org/r/[email protected]
+Signed-off-by: Mark Brown <[email protected]>
+---
+ drivers/spi/Kconfig       |  10 +
+ drivers/spi/Makefile      |   1 +
+ drivers/spi/spi-mtk-nor.c | 689 ++++++++++++++++++++++++++++++++++++++
+ 3 files changed, 700 insertions(+)
+ create mode 100644 drivers/spi/spi-mtk-nor.c
+
+--- a/drivers/spi/Kconfig
++++ b/drivers/spi/Kconfig
+@@ -433,6 +433,16 @@ config SPI_MT7621
+ 	help
+ 	  This selects a driver for the MediaTek MT7621 SPI Controller.
+ 
++config SPI_MTK_NOR
++	tristate "MediaTek SPI NOR controller"
++	depends on ARCH_MEDIATEK || COMPILE_TEST
++	help
++	  This enables support for SPI NOR controller found on MediaTek
++	  ARM SoCs. This is a controller specifically for SPI-NOR flash.
++	  It can perform generic SPI transfers up to 6 bytes via generic
++	  SPI interface as well as several SPI-NOR specific instructions
++	  via SPI MEM interface.
++
+ config SPI_NPCM_FIU
+ 	tristate "Nuvoton NPCM FLASH Interface Unit"
+ 	depends on ARCH_NPCM || COMPILE_TEST
+--- a/drivers/spi/Makefile
++++ b/drivers/spi/Makefile
+@@ -61,6 +61,7 @@ obj-$(CONFIG_SPI_MPC52xx_PSC)		+= spi-mp
+ obj-$(CONFIG_SPI_MPC52xx)		+= spi-mpc52xx.o
+ obj-$(CONFIG_SPI_MT65XX)                += spi-mt65xx.o
+ obj-$(CONFIG_SPI_MT7621)		+= spi-mt7621.o
++obj-$(CONFIG_SPI_MTK_NOR)		+= spi-mtk-nor.o
+ obj-$(CONFIG_SPI_MXIC)			+= spi-mxic.o
+ obj-$(CONFIG_SPI_MXS)			+= spi-mxs.o
+ obj-$(CONFIG_SPI_NPCM_FIU)		+= spi-npcm-fiu.o
+--- /dev/null
++++ b/drivers/spi/spi-mtk-nor.c
+@@ -0,0 +1,689 @@
++// SPDX-License-Identifier: GPL-2.0
++//
++// Mediatek SPI NOR controller driver
++//
++// Copyright (C) 2020 Chuanhong Guo <[email protected]>
++
++#include <linux/bits.h>
++#include <linux/clk.h>
++#include <linux/completion.h>
++#include <linux/dma-mapping.h>
++#include <linux/interrupt.h>
++#include <linux/io.h>
++#include <linux/iopoll.h>
++#include <linux/kernel.h>
++#include <linux/module.h>
++#include <linux/of_device.h>
++#include <linux/spi/spi.h>
++#include <linux/spi/spi-mem.h>
++#include <linux/string.h>
++
++#define DRIVER_NAME "mtk-spi-nor"
++
++#define MTK_NOR_REG_CMD			0x00
++#define MTK_NOR_CMD_WRITE		BIT(4)
++#define MTK_NOR_CMD_PROGRAM		BIT(2)
++#define MTK_NOR_CMD_READ		BIT(0)
++#define MTK_NOR_CMD_MASK		GENMASK(5, 0)
++
++#define MTK_NOR_REG_PRG_CNT		0x04
++#define MTK_NOR_REG_RDATA		0x0c
++
++#define MTK_NOR_REG_RADR0		0x10
++#define MTK_NOR_REG_RADR(n)		(MTK_NOR_REG_RADR0 + 4 * (n))
++#define MTK_NOR_REG_RADR3		0xc8
++
++#define MTK_NOR_REG_WDATA		0x1c
++
++#define MTK_NOR_REG_PRGDATA0		0x20
++#define MTK_NOR_REG_PRGDATA(n)		(MTK_NOR_REG_PRGDATA0 + 4 * (n))
++#define MTK_NOR_REG_PRGDATA_MAX		5
++
++#define MTK_NOR_REG_SHIFT0		0x38
++#define MTK_NOR_REG_SHIFT(n)		(MTK_NOR_REG_SHIFT0 + 4 * (n))
++#define MTK_NOR_REG_SHIFT_MAX		9
++
++#define MTK_NOR_REG_CFG1		0x60
++#define MTK_NOR_FAST_READ		BIT(0)
++
++#define MTK_NOR_REG_CFG2		0x64
++#define MTK_NOR_WR_CUSTOM_OP_EN		BIT(4)
++#define MTK_NOR_WR_BUF_EN		BIT(0)
++
++#define MTK_NOR_REG_PP_DATA		0x98
++
++#define MTK_NOR_REG_IRQ_STAT		0xa8
++#define MTK_NOR_REG_IRQ_EN		0xac
++#define MTK_NOR_IRQ_DMA			BIT(7)
++#define MTK_NOR_IRQ_MASK		GENMASK(7, 0)
++
++#define MTK_NOR_REG_CFG3		0xb4
++#define MTK_NOR_DISABLE_WREN		BIT(7)
++#define MTK_NOR_DISABLE_SR_POLL		BIT(5)
++
++#define MTK_NOR_REG_WP			0xc4
++#define MTK_NOR_ENABLE_SF_CMD		0x30
++
++#define MTK_NOR_REG_BUSCFG		0xcc
++#define MTK_NOR_4B_ADDR			BIT(4)
++#define MTK_NOR_QUAD_ADDR		BIT(3)
++#define MTK_NOR_QUAD_READ		BIT(2)
++#define MTK_NOR_DUAL_ADDR		BIT(1)
++#define MTK_NOR_DUAL_READ		BIT(0)
++#define MTK_NOR_BUS_MODE_MASK		GENMASK(4, 0)
++
++#define MTK_NOR_REG_DMA_CTL		0x718
++#define MTK_NOR_DMA_START		BIT(0)
++
++#define MTK_NOR_REG_DMA_FADR		0x71c
++#define MTK_NOR_REG_DMA_DADR		0x720
++#define MTK_NOR_REG_DMA_END_DADR	0x724
++
++#define MTK_NOR_PRG_MAX_SIZE		6
++// Reading DMA src/dst addresses have to be 16-byte aligned
++#define MTK_NOR_DMA_ALIGN		16
++#define MTK_NOR_DMA_ALIGN_MASK		(MTK_NOR_DMA_ALIGN - 1)
++// and we allocate a bounce buffer if destination address isn't aligned.
++#define MTK_NOR_BOUNCE_BUF_SIZE		PAGE_SIZE
++
++// Buffered page program can do one 128-byte transfer
++#define MTK_NOR_PP_SIZE			128
++
++#define CLK_TO_US(sp, clkcnt)		((clkcnt) * 1000000 / sp->spi_freq)
++
++struct mtk_nor {
++	struct spi_controller *ctlr;
++	struct device *dev;
++	void __iomem *base;
++	u8 *buffer;
++	struct clk *spi_clk;
++	struct clk *ctlr_clk;
++	unsigned int spi_freq;
++	bool wbuf_en;
++	bool has_irq;
++	struct completion op_done;
++};
++
++static inline void mtk_nor_rmw(struct mtk_nor *sp, u32 reg, u32 set, u32 clr)
++{
++	u32 val = readl(sp->base + reg);
++
++	val &= ~clr;
++	val |= set;
++	writel(val, sp->base + reg);
++}
++
++static inline int mtk_nor_cmd_exec(struct mtk_nor *sp, u32 cmd, ulong clk)
++{
++	ulong delay = CLK_TO_US(sp, clk);
++	u32 reg;
++	int ret;
++
++	writel(cmd, sp->base + MTK_NOR_REG_CMD);
++	ret = readl_poll_timeout(sp->base + MTK_NOR_REG_CMD, reg, !(reg & cmd),
++				 delay / 3, (delay + 1) * 200);
++	if (ret < 0)
++		dev_err(sp->dev, "command %u timeout.\n", cmd);
++	return ret;
++}
++
++static void mtk_nor_set_addr(struct mtk_nor *sp, const struct spi_mem_op *op)
++{
++	u32 addr = op->addr.val;
++	int i;
++
++	for (i = 0; i < 3; i++) {
++		writeb(addr & 0xff, sp->base + MTK_NOR_REG_RADR(i));
++		addr >>= 8;
++	}
++	if (op->addr.nbytes == 4) {
++		writeb(addr & 0xff, sp->base + MTK_NOR_REG_RADR3);
++		mtk_nor_rmw(sp, MTK_NOR_REG_BUSCFG, MTK_NOR_4B_ADDR, 0);
++	} else {
++		mtk_nor_rmw(sp, MTK_NOR_REG_BUSCFG, 0, MTK_NOR_4B_ADDR);
++	}
++}
++
++static bool mtk_nor_match_read(const struct spi_mem_op *op)
++{
++	int dummy = 0;
++
++	if (op->dummy.buswidth)
++		dummy = op->dummy.nbytes * BITS_PER_BYTE / op->dummy.buswidth;
++
++	if ((op->data.buswidth == 2) || (op->data.buswidth == 4)) {
++		if (op->addr.buswidth == 1)
++			return dummy == 8;
++		else if (op->addr.buswidth == 2)
++			return dummy == 4;
++		else if (op->addr.buswidth == 4)
++			return dummy == 6;
++	} else if ((op->addr.buswidth == 1) && (op->data.buswidth == 1)) {
++		if (op->cmd.opcode == 0x03)
++			return dummy == 0;
++		else if (op->cmd.opcode == 0x0b)
++			return dummy == 8;
++	}
++	return false;
++}
++
++static int mtk_nor_adjust_op_size(struct spi_mem *mem, struct spi_mem_op *op)
++{
++	size_t len;
++
++	if (!op->data.nbytes)
++		return 0;
++
++	if ((op->addr.nbytes == 3) || (op->addr.nbytes == 4)) {
++		if ((op->data.dir == SPI_MEM_DATA_IN) &&
++		    mtk_nor_match_read(op)) {
++			if ((op->addr.val & MTK_NOR_DMA_ALIGN_MASK) ||
++			    (op->data.nbytes < MTK_NOR_DMA_ALIGN))
++				op->data.nbytes = 1;
++			else if (!((ulong)(op->data.buf.in) &
++				   MTK_NOR_DMA_ALIGN_MASK))
++				op->data.nbytes &= ~MTK_NOR_DMA_ALIGN_MASK;
++			else if (op->data.nbytes > MTK_NOR_BOUNCE_BUF_SIZE)
++				op->data.nbytes = MTK_NOR_BOUNCE_BUF_SIZE;
++			return 0;
++		} else if (op->data.dir == SPI_MEM_DATA_OUT) {
++			if (op->data.nbytes >= MTK_NOR_PP_SIZE)
++				op->data.nbytes = MTK_NOR_PP_SIZE;
++			else
++				op->data.nbytes = 1;
++			return 0;
++		}
++	}
++
++	len = MTK_NOR_PRG_MAX_SIZE - sizeof(op->cmd.opcode) - op->addr.nbytes -
++	      op->dummy.nbytes;
++	if (op->data.nbytes > len)
++		op->data.nbytes = len;
++
++	return 0;
++}
++
++static bool mtk_nor_supports_op(struct spi_mem *mem,
++				const struct spi_mem_op *op)
++{
++	size_t len;
++
++	if (op->cmd.buswidth != 1)
++		return false;
++
++	if ((op->addr.nbytes == 3) || (op->addr.nbytes == 4)) {
++		if ((op->data.dir == SPI_MEM_DATA_IN) && mtk_nor_match_read(op))
++			return true;
++		else if (op->data.dir == SPI_MEM_DATA_OUT)
++			return (op->addr.buswidth == 1) &&
++			       (op->dummy.buswidth == 0) &&
++			       (op->data.buswidth == 1);
++	}
++	len = sizeof(op->cmd.opcode) + op->addr.nbytes + op->dummy.nbytes;
++	if ((len > MTK_NOR_PRG_MAX_SIZE) ||
++	    ((op->data.nbytes) && (len == MTK_NOR_PRG_MAX_SIZE)))
++		return false;
++	return true;
++}
++
++static void mtk_nor_setup_bus(struct mtk_nor *sp, const struct spi_mem_op *op)
++{
++	u32 reg = 0;
++
++	if (op->addr.nbytes == 4)
++		reg |= MTK_NOR_4B_ADDR;
++
++	if (op->data.buswidth == 4) {
++		reg |= MTK_NOR_QUAD_READ;
++		writeb(op->cmd.opcode, sp->base + MTK_NOR_REG_PRGDATA(4));
++		if (op->addr.buswidth == 4)
++			reg |= MTK_NOR_QUAD_ADDR;
++	} else if (op->data.buswidth == 2) {
++		reg |= MTK_NOR_DUAL_READ;
++		writeb(op->cmd.opcode, sp->base + MTK_NOR_REG_PRGDATA(3));
++		if (op->addr.buswidth == 2)
++			reg |= MTK_NOR_DUAL_ADDR;
++	} else {
++		if (op->cmd.opcode == 0x0b)
++			mtk_nor_rmw(sp, MTK_NOR_REG_CFG1, MTK_NOR_FAST_READ, 0);
++		else
++			mtk_nor_rmw(sp, MTK_NOR_REG_CFG1, 0, MTK_NOR_FAST_READ);
++	}
++	mtk_nor_rmw(sp, MTK_NOR_REG_BUSCFG, reg, MTK_NOR_BUS_MODE_MASK);
++}
++
++static int mtk_nor_read_dma(struct mtk_nor *sp, u32 from, unsigned int length,
++			    u8 *buffer)
++{
++	int ret = 0;
++	ulong delay;
++	u32 reg;
++	dma_addr_t dma_addr;
++
++	dma_addr = dma_map_single(sp->dev, buffer, length, DMA_FROM_DEVICE);
++	if (dma_mapping_error(sp->dev, dma_addr)) {
++		dev_err(sp->dev, "failed to map dma buffer.\n");
++		return -EINVAL;
++	}
++
++	writel(from, sp->base + MTK_NOR_REG_DMA_FADR);
++	writel(dma_addr, sp->base + MTK_NOR_REG_DMA_DADR);
++	writel(dma_addr + length, sp->base + MTK_NOR_REG_DMA_END_DADR);
++
++	if (sp->has_irq) {
++		reinit_completion(&sp->op_done);
++		mtk_nor_rmw(sp, MTK_NOR_REG_IRQ_EN, MTK_NOR_IRQ_DMA, 0);
++	}
++
++	mtk_nor_rmw(sp, MTK_NOR_REG_DMA_CTL, MTK_NOR_DMA_START, 0);
++
++	delay = CLK_TO_US(sp, (length + 5) * BITS_PER_BYTE);
++
++	if (sp->has_irq) {
++		if (!wait_for_completion_timeout(&sp->op_done,
++						 (delay + 1) * 100))
++			ret = -ETIMEDOUT;
++	} else {
++		ret = readl_poll_timeout(sp->base + MTK_NOR_REG_DMA_CTL, reg,
++					 !(reg & MTK_NOR_DMA_START), delay / 3,
++					 (delay + 1) * 100);
++	}
++
++	dma_unmap_single(sp->dev, dma_addr, length, DMA_FROM_DEVICE);
++	if (ret < 0)
++		dev_err(sp->dev, "dma read timeout.\n");
++
++	return ret;
++}
++
++static int mtk_nor_read_bounce(struct mtk_nor *sp, u32 from,
++			       unsigned int length, u8 *buffer)
++{
++	unsigned int rdlen;
++	int ret;
++
++	if (length & MTK_NOR_DMA_ALIGN_MASK)
++		rdlen = (length + MTK_NOR_DMA_ALIGN) & ~MTK_NOR_DMA_ALIGN_MASK;
++	else
++		rdlen = length;
++
++	ret = mtk_nor_read_dma(sp, from, rdlen, sp->buffer);
++	if (ret)
++		return ret;
++
++	memcpy(buffer, sp->buffer, length);
++	return 0;
++}
++
++static int mtk_nor_read_pio(struct mtk_nor *sp, const struct spi_mem_op *op)
++{
++	u8 *buf = op->data.buf.in;
++	int ret;
++
++	ret = mtk_nor_cmd_exec(sp, MTK_NOR_CMD_READ, 6 * BITS_PER_BYTE);
++	if (!ret)
++		buf[0] = readb(sp->base + MTK_NOR_REG_RDATA);
++	return ret;
++}
++
++static int mtk_nor_write_buffer_enable(struct mtk_nor *sp)
++{
++	int ret;
++	u32 val;
++
++	if (sp->wbuf_en)
++		return 0;
++
++	val = readl(sp->base + MTK_NOR_REG_CFG2);
++	writel(val | MTK_NOR_WR_BUF_EN, sp->base + MTK_NOR_REG_CFG2);
++	ret = readl_poll_timeout(sp->base + MTK_NOR_REG_CFG2, val,
++				 val & MTK_NOR_WR_BUF_EN, 0, 10000);
++	if (!ret)
++		sp->wbuf_en = true;
++	return ret;
++}
++
++static int mtk_nor_write_buffer_disable(struct mtk_nor *sp)
++{
++	int ret;
++	u32 val;
++
++	if (!sp->wbuf_en)
++		return 0;
++	val = readl(sp->base + MTK_NOR_REG_CFG2);
++	writel(val & ~MTK_NOR_WR_BUF_EN, sp->base + MTK_NOR_REG_CFG2);
++	ret = readl_poll_timeout(sp->base + MTK_NOR_REG_CFG2, val,
++				 !(val & MTK_NOR_WR_BUF_EN), 0, 10000);
++	if (!ret)
++		sp->wbuf_en = false;
++	return ret;
++}
++
++static int mtk_nor_pp_buffered(struct mtk_nor *sp, const struct spi_mem_op *op)
++{
++	const u8 *buf = op->data.buf.out;
++	u32 val;
++	int ret, i;
++
++	ret = mtk_nor_write_buffer_enable(sp);
++	if (ret < 0)
++		return ret;
++
++	for (i = 0; i < op->data.nbytes; i += 4) {
++		val = buf[i + 3] << 24 | buf[i + 2] << 16 | buf[i + 1] << 8 |
++		      buf[i];
++		writel(val, sp->base + MTK_NOR_REG_PP_DATA);
++	}
++	return mtk_nor_cmd_exec(sp, MTK_NOR_CMD_WRITE,
++				(op->data.nbytes + 5) * BITS_PER_BYTE);
++}
++
++static int mtk_nor_pp_unbuffered(struct mtk_nor *sp,
++				 const struct spi_mem_op *op)
++{
++	const u8 *buf = op->data.buf.out;
++	int ret;
++
++	ret = mtk_nor_write_buffer_disable(sp);
++	if (ret < 0)
++		return ret;
++	writeb(buf[0], sp->base + MTK_NOR_REG_WDATA);
++	return mtk_nor_cmd_exec(sp, MTK_NOR_CMD_WRITE, 6 * BITS_PER_BYTE);
++}
++
++int mtk_nor_exec_op(struct spi_mem *mem, const struct spi_mem_op *op)
++{
++	struct mtk_nor *sp = spi_controller_get_devdata(mem->spi->master);
++	int ret;
++
++	if ((op->data.nbytes == 0) ||
++	    ((op->addr.nbytes != 3) && (op->addr.nbytes != 4)))
++		return -ENOTSUPP;
++
++	if (op->data.dir == SPI_MEM_DATA_OUT) {
++		mtk_nor_set_addr(sp, op);
++		writeb(op->cmd.opcode, sp->base + MTK_NOR_REG_PRGDATA0);
++		if (op->data.nbytes == MTK_NOR_PP_SIZE)
++			return mtk_nor_pp_buffered(sp, op);
++		return mtk_nor_pp_unbuffered(sp, op);
++	}
++
++	if ((op->data.dir == SPI_MEM_DATA_IN) && mtk_nor_match_read(op)) {
++		ret = mtk_nor_write_buffer_disable(sp);
++		if (ret < 0)
++			return ret;
++		mtk_nor_setup_bus(sp, op);
++		if (op->data.nbytes == 1) {
++			mtk_nor_set_addr(sp, op);
++			return mtk_nor_read_pio(sp, op);
++		} else if (((ulong)(op->data.buf.in) &
++			    MTK_NOR_DMA_ALIGN_MASK)) {
++			return mtk_nor_read_bounce(sp, op->addr.val,
++						   op->data.nbytes,
++						   op->data.buf.in);
++		} else {
++			return mtk_nor_read_dma(sp, op->addr.val,
++						op->data.nbytes,
++						op->data.buf.in);
++		}
++	}
++
++	return -ENOTSUPP;
++}
++
++static int mtk_nor_setup(struct spi_device *spi)
++{
++	struct mtk_nor *sp = spi_controller_get_devdata(spi->master);
++
++	if (spi->max_speed_hz && (spi->max_speed_hz < sp->spi_freq)) {
++		dev_err(&spi->dev, "spi clock should be %u Hz.\n",
++			sp->spi_freq);
++		return -EINVAL;
++	}
++	spi->max_speed_hz = sp->spi_freq;
++
++	return 0;
++}
++
++static int mtk_nor_transfer_one_message(struct spi_controller *master,
++					struct spi_message *m)
++{
++	struct mtk_nor *sp = spi_controller_get_devdata(master);
++	struct spi_transfer *t = NULL;
++	unsigned long trx_len = 0;
++	int stat = 0;
++	int reg_offset = MTK_NOR_REG_PRGDATA_MAX;
++	void __iomem *reg;
++	const u8 *txbuf;
++	u8 *rxbuf;
++	int i;
++
++	list_for_each_entry(t, &m->transfers, transfer_list) {
++		txbuf = t->tx_buf;
++		for (i = 0; i < t->len; i++, reg_offset--) {
++			reg = sp->base + MTK_NOR_REG_PRGDATA(reg_offset);
++			if (txbuf)
++				writeb(txbuf[i], reg);
++			else
++				writeb(0, reg);
++		}
++		trx_len += t->len;
++	}
++
++	writel(trx_len * BITS_PER_BYTE, sp->base + MTK_NOR_REG_PRG_CNT);
++
++	stat = mtk_nor_cmd_exec(sp, MTK_NOR_CMD_PROGRAM,
++				trx_len * BITS_PER_BYTE);
++	if (stat < 0)
++		goto msg_done;
++
++	reg_offset = trx_len - 1;
++	list_for_each_entry(t, &m->transfers, transfer_list) {
++		rxbuf = t->rx_buf;
++		for (i = 0; i < t->len; i++, reg_offset--) {
++			reg = sp->base + MTK_NOR_REG_SHIFT(reg_offset);
++			if (rxbuf)
++				rxbuf[i] = readb(reg);
++		}
++	}
++
++	m->actual_length = trx_len;
++msg_done:
++	m->status = stat;
++	spi_finalize_current_message(master);
++
++	return 0;
++}
++
++static void mtk_nor_disable_clk(struct mtk_nor *sp)
++{
++	clk_disable_unprepare(sp->spi_clk);
++	clk_disable_unprepare(sp->ctlr_clk);
++}
++
++static int mtk_nor_enable_clk(struct mtk_nor *sp)
++{
++	int ret;
++
++	ret = clk_prepare_enable(sp->spi_clk);
++	if (ret)
++		return ret;
++
++	ret = clk_prepare_enable(sp->ctlr_clk);
++	if (ret) {
++		clk_disable_unprepare(sp->spi_clk);
++		return ret;
++	}
++
++	return 0;
++}
++
++static int mtk_nor_init(struct mtk_nor *sp)
++{
++	int ret;
++
++	ret = mtk_nor_enable_clk(sp);
++	if (ret)
++		return ret;
++
++	sp->spi_freq = clk_get_rate(sp->spi_clk);
++
++	writel(MTK_NOR_ENABLE_SF_CMD, sp->base + MTK_NOR_REG_WP);
++	mtk_nor_rmw(sp, MTK_NOR_REG_CFG2, MTK_NOR_WR_CUSTOM_OP_EN, 0);
++	mtk_nor_rmw(sp, MTK_NOR_REG_CFG3,
++		    MTK_NOR_DISABLE_WREN | MTK_NOR_DISABLE_SR_POLL, 0);
++
++	return ret;
++}
++
++static irqreturn_t mtk_nor_irq_handler(int irq, void *data)
++{
++	struct mtk_nor *sp = data;
++	u32 irq_status, irq_enabled;
++
++	irq_status = readl(sp->base + MTK_NOR_REG_IRQ_STAT);
++	irq_enabled = readl(sp->base + MTK_NOR_REG_IRQ_EN);
++	// write status back to clear interrupt
++	writel(irq_status, sp->base + MTK_NOR_REG_IRQ_STAT);
++
++	if (!(irq_status & irq_enabled))
++		return IRQ_NONE;
++
++	if (irq_status & MTK_NOR_IRQ_DMA) {
++		complete(&sp->op_done);
++		writel(0, sp->base + MTK_NOR_REG_IRQ_EN);
++	}
++
++	return IRQ_HANDLED;
++}
++
++static size_t mtk_max_msg_size(struct spi_device *spi)
++{
++	return MTK_NOR_PRG_MAX_SIZE;
++}
++
++static const struct spi_controller_mem_ops mtk_nor_mem_ops = {
++	.adjust_op_size = mtk_nor_adjust_op_size,
++	.supports_op = mtk_nor_supports_op,
++	.exec_op = mtk_nor_exec_op
++};
++
++static const struct of_device_id mtk_nor_match[] = {
++	{ .compatible = "mediatek,mt8173-nor" },
++	{ /* sentinel */ }
++};
++MODULE_DEVICE_TABLE(of, mtk_nor_match);
++
++static int mtk_nor_probe(struct platform_device *pdev)
++{
++	struct spi_controller *ctlr;
++	struct mtk_nor *sp;
++	void __iomem *base;
++	u8 *buffer;
++	struct clk *spi_clk, *ctlr_clk;
++	int ret, irq;
++
++	base = devm_platform_ioremap_resource(pdev, 0);
++	if (IS_ERR(base))
++		return PTR_ERR(base);
++
++	spi_clk = devm_clk_get(&pdev->dev, "spi");
++	if (IS_ERR(spi_clk))
++		return PTR_ERR(spi_clk);
++
++	ctlr_clk = devm_clk_get(&pdev->dev, "sf");
++	if (IS_ERR(ctlr_clk))
++		return PTR_ERR(ctlr_clk);
++
++	buffer = devm_kmalloc(&pdev->dev,
++			      MTK_NOR_BOUNCE_BUF_SIZE + MTK_NOR_DMA_ALIGN,
++			      GFP_KERNEL);
++	if (!buffer)
++		return -ENOMEM;
++
++	if ((ulong)buffer & MTK_NOR_DMA_ALIGN_MASK)
++		buffer = (u8 *)(((ulong)buffer + MTK_NOR_DMA_ALIGN) &
++				~MTK_NOR_DMA_ALIGN_MASK);
++
++	ctlr = spi_alloc_master(&pdev->dev, sizeof(*sp));
++	if (!ctlr) {
++		dev_err(&pdev->dev, "failed to allocate spi controller\n");
++		return -ENOMEM;
++	}
++
++	ctlr->bits_per_word_mask = SPI_BPW_MASK(8);
++	ctlr->dev.of_node = pdev->dev.of_node;
++	ctlr->max_message_size = mtk_max_msg_size;
++	ctlr->mem_ops = &mtk_nor_mem_ops;
++	ctlr->mode_bits = SPI_RX_DUAL | SPI_RX_QUAD | SPI_TX_DUAL | SPI_TX_QUAD;
++	ctlr->num_chipselect = 1;
++	ctlr->setup = mtk_nor_setup;
++	ctlr->transfer_one_message = mtk_nor_transfer_one_message;
++
++	dev_set_drvdata(&pdev->dev, ctlr);
++
++	sp = spi_controller_get_devdata(ctlr);
++	sp->base = base;
++	sp->buffer = buffer;
++	sp->has_irq = false;
++	sp->wbuf_en = false;
++	sp->ctlr = ctlr;
++	sp->dev = &pdev->dev;
++	sp->spi_clk = spi_clk;
++	sp->ctlr_clk = ctlr_clk;
++
++	irq = platform_get_irq_optional(pdev, 0);
++	if (irq < 0) {
++		dev_warn(sp->dev, "IRQ not available.");
++	} else {
++		writel(MTK_NOR_IRQ_MASK, base + MTK_NOR_REG_IRQ_STAT);
++		writel(0, base + MTK_NOR_REG_IRQ_EN);
++		ret = devm_request_irq(sp->dev, irq, mtk_nor_irq_handler, 0,
++				       pdev->name, sp);
++		if (ret < 0) {
++			dev_warn(sp->dev, "failed to request IRQ.");
++		} else {
++			init_completion(&sp->op_done);
++			sp->has_irq = true;
++		}
++	}
++
++	ret = mtk_nor_init(sp);
++	if (ret < 0) {
++		kfree(ctlr);
++		return ret;
++	}
++
++	dev_info(&pdev->dev, "spi frequency: %d Hz\n", sp->spi_freq);
++
++	return devm_spi_register_controller(&pdev->dev, ctlr);
++}
++
++static int mtk_nor_remove(struct platform_device *pdev)
++{
++	struct spi_controller *ctlr;
++	struct mtk_nor *sp;
++
++	ctlr = dev_get_drvdata(&pdev->dev);
++	sp = spi_controller_get_devdata(ctlr);
++
++	mtk_nor_disable_clk(sp);
++
++	return 0;
++}
++
++static struct platform_driver mtk_nor_driver = {
++	.driver = {
++		.name = DRIVER_NAME,
++		.of_match_table = mtk_nor_match,
++	},
++	.probe = mtk_nor_probe,
++	.remove = mtk_nor_remove,
++};
++
++module_platform_driver(mtk_nor_driver);
++
++MODULE_DESCRIPTION("Mediatek SPI NOR controller driver");
++MODULE_AUTHOR("Chuanhong Guo <[email protected]>");
++MODULE_LICENSE("GPL v2");
++MODULE_ALIAS("platform:" DRIVER_NAME);