drivers/spi/spi-amd.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause
 //
 // AMD SPI controller driver
 //
 // Copyright (c) 2020, Advanced Micro Devices, Inc.
 //
 // Author: Sanjay R Mehta <sanju.mehta@amd.com>

 #include <linux/acpi.h>
 #include <linux/init.h>
 #include <linux/module.h>
 #include <linux/platform_device.h>
 #include <linux/delay.h>
 #include <linux/spi/spi.h>

 #define AMD_SPI_CTRL0_REG	0x00
 #define AMD_SPI_EXEC_CMD	BIT(16)
 #define AMD_SPI_FIFO_CLEAR	BIT(20)
 #define AMD_SPI_BUSY		BIT(31)

 #define AMD_SPI_OPCODE_MASK	0xFF

 #define AMD_SPI_ALT_CS_REG	0x1D
 #define AMD_SPI_ALT_CS_MASK	0x3

 #define AMD_SPI_FIFO_BASE	0x80
 #define AMD_SPI_TX_COUNT_REG	0x48
 #define AMD_SPI_RX_COUNT_REG	0x4B
 #define AMD_SPI_STATUS_REG	0x4C

 #define AMD_SPI_MEM_SIZE	200

 /* M_CMD OP codes for SPI */
 #define AMD_SPI_XFER_TX		1
 #define AMD_SPI_XFER_RX		2

 struct amd_spi {
 	void __iomem *io_remap_addr;
 	unsigned long io_base_addr;
 	u32 rom_addr;
 	u8 chip_select;
 };

 static inline u8 amd_spi_readreg8(struct spi_master *master, int idx)
 {
 	struct amd_spi *amd_spi = spi_master_get_devdata(master);

 	return ioread8((u8 __iomem *)amd_spi->io_remap_addr + idx);
 }

 static inline void amd_spi_writereg8(struct spi_master *master, int idx,
 				     u8 val)
 {
 	struct amd_spi *amd_spi = spi_master_get_devdata(master);

 	iowrite8(val, ((u8 __iomem *)amd_spi->io_remap_addr + idx));
 }

 static inline void amd_spi_setclear_reg8(struct spi_master *master, int idx,
 					 u8 set, u8 clear)
 {
 	u8 tmp = amd_spi_readreg8(master, idx);

 	tmp = (tmp & ~clear) | set;
 	amd_spi_writereg8(master, idx, tmp);
 }

 static inline u32 amd_spi_readreg32(struct spi_master *master, int idx)
 {
 	struct amd_spi *amd_spi = spi_master_get_devdata(master);

 	return ioread32((u8 __iomem *)amd_spi->io_remap_addr + idx);
 }

 static inline void amd_spi_writereg32(struct spi_master *master, int idx,
 				      u32 val)
 {
 	struct amd_spi *amd_spi = spi_master_get_devdata(master);

 	iowrite32(val, ((u8 __iomem *)amd_spi->io_remap_addr + idx));
 }

 static inline void amd_spi_setclear_reg32(struct spi_master *master, int idx,
 					  u32 set, u32 clear)
 {
 	u32 tmp = amd_spi_readreg32(master, idx);

 	tmp = (tmp & ~clear) | set;
 	amd_spi_writereg32(master, idx, tmp);
 }

 static void amd_spi_select_chip(struct spi_master *master)
 {
 	struct amd_spi *amd_spi = spi_master_get_devdata(master);
 	u8 chip_select = amd_spi->chip_select;

 	amd_spi_setclear_reg8(master, AMD_SPI_ALT_CS_REG, chip_select,
 			      AMD_SPI_ALT_CS_MASK);
 }

 static void amd_spi_clear_fifo_ptr(struct spi_master *master)
 {
 	amd_spi_setclear_reg32(master, AMD_SPI_CTRL0_REG, AMD_SPI_FIFO_CLEAR,
 			       AMD_SPI_FIFO_CLEAR);
 }

 static void amd_spi_set_opcode(struct spi_master *master, u8 cmd_opcode)
 {
 	amd_spi_setclear_reg32(master, AMD_SPI_CTRL0_REG, cmd_opcode,
 			       AMD_SPI_OPCODE_MASK);
 }

 static inline void amd_spi_set_rx_count(struct spi_master *master,
 					u8 rx_count)
 {
 	amd_spi_setclear_reg8(master, AMD_SPI_RX_COUNT_REG, rx_count, 0xff);
 }

 static inline void amd_spi_set_tx_count(struct spi_master *master,
 					u8 tx_count)
 {
 	amd_spi_setclear_reg8(master, AMD_SPI_TX_COUNT_REG, tx_count, 0xff);
 }

 static inline int amd_spi_busy_wait(struct amd_spi *amd_spi)
 {
 	bool spi_busy;
 	int timeout = 100000;

 	/* poll for SPI bus to become idle */
 	spi_busy = (ioread32((u8 __iomem *)amd_spi->io_remap_addr +
 		    AMD_SPI_CTRL0_REG) & AMD_SPI_BUSY) == AMD_SPI_BUSY;
 	while (spi_busy) {
 		usleep_range(10, 20);
 		if (timeout-- < 0)
 			return -ETIMEDOUT;

 		spi_busy = (ioread32((u8 __iomem *)amd_spi->io_remap_addr +
 			    AMD_SPI_CTRL0_REG) & AMD_SPI_BUSY) == AMD_SPI_BUSY;
 	}

 	return 0;
 }

 static void amd_spi_execute_opcode(struct spi_master *master)
 {
 	struct amd_spi *amd_spi = spi_master_get_devdata(master);

 	/* Set ExecuteOpCode bit in the CTRL0 register */
 	amd_spi_setclear_reg32(master, AMD_SPI_CTRL0_REG, AMD_SPI_EXEC_CMD,
 			       AMD_SPI_EXEC_CMD);

 	amd_spi_busy_wait(amd_spi);
 }

 static int amd_spi_master_setup(struct spi_device *spi)
 {
 	struct spi_master *master = spi->master;

 	amd_spi_clear_fifo_ptr(master);

 	return 0;
 }

 static inline int amd_spi_fifo_xfer(struct amd_spi *amd_spi,
 				    struct spi_master *master,
 				    struct spi_message *message)
 {
 	struct spi_transfer *xfer = NULL;
 	u8 cmd_opcode;
 	u8 *buf = NULL;
 	u32 m_cmd = 0;
 	u32 i = 0;
 	u32 tx_len = 0, rx_len = 0;

 	list_for_each_entry(xfer, &message->transfers,
 			    transfer_list) {
 		if (xfer->rx_buf)
 			m_cmd = AMD_SPI_XFER_RX;
 		if (xfer->tx_buf)
 			m_cmd = AMD_SPI_XFER_TX;

 		if (m_cmd & AMD_SPI_XFER_TX) {
 			buf = (u8 *)xfer->tx_buf;
 			tx_len = xfer->len - 1;
 			cmd_opcode = *(u8 *)xfer->tx_buf;
 			buf++;
 			amd_spi_set_opcode(master, cmd_opcode);

 			/* Write data into the FIFO. */
 			for (i = 0; i < tx_len; i++) {
 				iowrite8(buf[i],
 					 ((u8 __iomem *)amd_spi->io_remap_addr +
 					 AMD_SPI_FIFO_BASE + i));
 			}

 			amd_spi_set_tx_count(master, tx_len);
 			amd_spi_clear_fifo_ptr(master);
 			/* Execute command */
 			amd_spi_execute_opcode(master);
 		}
 		if (m_cmd & AMD_SPI_XFER_RX) {
 			/*
 			 * Store no. of bytes to be received from
 			 * FIFO
 			 */
 			rx_len = xfer->len;
 			buf = (u8 *)xfer->rx_buf;
 			amd_spi_set_rx_count(master, rx_len);
 			amd_spi_clear_fifo_ptr(master);
 			/* Execute command */
 			amd_spi_execute_opcode(master);
 			/* Read data from FIFO to receive buffer  */
 			for (i = 0; i < rx_len; i++)
 				buf[i] = amd_spi_readreg8(master,
 							  AMD_SPI_FIFO_BASE +
 							  tx_len + i);
 		}
 	}

 	/* Update statistics */
 	message->actual_length = tx_len + rx_len + 1;
 	/* complete the transaction */
 	message->status = 0;
 	spi_finalize_current_message(master);

 	return 0;
 }

 static int amd_spi_master_transfer(struct spi_master *master,
 				   struct spi_message *msg)
 {
 	struct amd_spi *amd_spi = spi_master_get_devdata(master);
 	struct spi_device *spi = msg->spi;

 	amd_spi->chip_select = spi->chip_select;
 	amd_spi_select_chip(master);

 	/*
 	 * Extract spi_transfers from the spi message and
 	 * program the controller.
 	 */
 	amd_spi_fifo_xfer(amd_spi, master, msg);

 	return 0;
 }

 static int amd_spi_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
 	struct spi_master *master;
 	struct amd_spi *amd_spi;
 	struct resource *res;
 	int err = 0;

 	/* Allocate storage for spi_master and driver private data */
 	master = spi_alloc_master(dev, sizeof(struct amd_spi));
 	if (!master) {
 		dev_err(dev, "Error allocating SPI master\n");
 		return -ENOMEM;
 	}

 	amd_spi = spi_master_get_devdata(master);

 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	amd_spi->io_remap_addr = devm_ioremap_resource(&pdev->dev, res);
 	if (IS_ERR(amd_spi->io_remap_addr)) {
 		err = PTR_ERR(amd_spi->io_remap_addr);
 		dev_err(dev, "error %d ioremap of SPI registers failed\n", err);
 		goto err_free_master;
 	}
 	dev_dbg(dev, "io_remap_address: %p\n", amd_spi->io_remap_addr);

 	/* Initialize the spi_master fields */
 	master->bus_num = 0;
 	master->num_chipselect = 4;
 	master->mode_bits = 0;
 	master->flags = SPI_MASTER_HALF_DUPLEX;
 	master->setup = amd_spi_master_setup;
 	master->transfer_one_message = amd_spi_master_transfer;

 	/* Register the controller with SPI framework */
 	err = devm_spi_register_master(dev, master);
 	if (err) {
 		dev_err(dev, "error %d registering SPI controller\n", err);
 		goto err_free_master;
 	}

 	return 0;

 err_free_master:
 	spi_master_put(master);

 	return err;
 }

 #ifdef CONFIG_ACPI
 static const struct acpi_device_id spi_acpi_match[] = {
 	{ "AMDI0061", 0 },
 	{},
 };
 MODULE_DEVICE_TABLE(acpi, spi_acpi_match);
 #endif

 static struct platform_driver amd_spi_driver = {
 	.driver = {
 		.name = "amd_spi",
 		.acpi_match_table = ACPI_PTR(spi_acpi_match),
 	},
 	.probe = amd_spi_probe,
 };

 module_platform_driver(amd_spi_driver);

 MODULE_LICENSE("Dual BSD/GPL");
 MODULE_AUTHOR("Sanjay Mehta <sanju.mehta@amd.com>");
 MODULE_DESCRIPTION("AMD SPI Master Controller Driver");
	// SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause
	//
	// AMD SPI controller driver
	//
	// Copyright (c) 2020, Advanced Micro Devices, Inc.
	//
	// Author: Sanjay R Mehta <sanju.mehta@amd.com>

	#include <linux/acpi.h>
	#include <linux/init.h>
	#include <linux/module.h>
	#include <linux/platform_device.h>
	#include <linux/delay.h>
	#include <linux/spi/spi.h>

	#define AMD_SPI_CTRL0_REG 0x00
	#define AMD_SPI_EXEC_CMD BIT(16)
	#define AMD_SPI_FIFO_CLEAR BIT(20)
	#define AMD_SPI_BUSY BIT(31)

	#define AMD_SPI_OPCODE_MASK 0xFF

	#define AMD_SPI_ALT_CS_REG 0x1D
	#define AMD_SPI_ALT_CS_MASK 0x3

	#define AMD_SPI_FIFO_BASE 0x80
	#define AMD_SPI_TX_COUNT_REG 0x48
	#define AMD_SPI_RX_COUNT_REG 0x4B
	#define AMD_SPI_STATUS_REG 0x4C

	#define AMD_SPI_MEM_SIZE 200

	/* M_CMD OP codes for SPI */
	#define AMD_SPI_XFER_TX 1
	#define AMD_SPI_XFER_RX 2

	struct amd_spi {
	void __iomem *io_remap_addr;
	unsigned long io_base_addr;
	u32 rom_addr;
	u8 chip_select;
	};

	static inline u8 amd_spi_readreg8(struct spi_master *master, int idx)
	{
	struct amd_spi *amd_spi = spi_master_get_devdata(master);

	return ioread8((u8 __iomem *)amd_spi->io_remap_addr + idx);
	}

	static inline void amd_spi_writereg8(struct spi_master *master, int idx,
	u8 val)
	{
	struct amd_spi *amd_spi = spi_master_get_devdata(master);

	iowrite8(val, ((u8 __iomem *)amd_spi->io_remap_addr + idx));
	}

	static inline void amd_spi_setclear_reg8(struct spi_master *master, int idx,
	u8 set, u8 clear)
	{
	u8 tmp = amd_spi_readreg8(master, idx);

	tmp = (tmp & ~clear) \| set;
	amd_spi_writereg8(master, idx, tmp);
	}

	static inline u32 amd_spi_readreg32(struct spi_master *master, int idx)
	{
	struct amd_spi *amd_spi = spi_master_get_devdata(master);

	return ioread32((u8 __iomem *)amd_spi->io_remap_addr + idx);
	}

	static inline void amd_spi_writereg32(struct spi_master *master, int idx,
	u32 val)
	{
	struct amd_spi *amd_spi = spi_master_get_devdata(master);

	iowrite32(val, ((u8 __iomem *)amd_spi->io_remap_addr + idx));
	}

	static inline void amd_spi_setclear_reg32(struct spi_master *master, int idx,
	u32 set, u32 clear)
	{
	u32 tmp = amd_spi_readreg32(master, idx);

	tmp = (tmp & ~clear) \| set;
	amd_spi_writereg32(master, idx, tmp);
	}

	static void amd_spi_select_chip(struct spi_master *master)
	{
	struct amd_spi *amd_spi = spi_master_get_devdata(master);
	u8 chip_select = amd_spi->chip_select;

	amd_spi_setclear_reg8(master, AMD_SPI_ALT_CS_REG, chip_select,
	AMD_SPI_ALT_CS_MASK);
	}

	static void amd_spi_clear_fifo_ptr(struct spi_master *master)
	{
	amd_spi_setclear_reg32(master, AMD_SPI_CTRL0_REG, AMD_SPI_FIFO_CLEAR,
	AMD_SPI_FIFO_CLEAR);
	}

	static void amd_spi_set_opcode(struct spi_master *master, u8 cmd_opcode)
	{
	amd_spi_setclear_reg32(master, AMD_SPI_CTRL0_REG, cmd_opcode,
	AMD_SPI_OPCODE_MASK);
	}

	static inline void amd_spi_set_rx_count(struct spi_master *master,
	u8 rx_count)
	{
	amd_spi_setclear_reg8(master, AMD_SPI_RX_COUNT_REG, rx_count, 0xff);
	}

	static inline void amd_spi_set_tx_count(struct spi_master *master,
	u8 tx_count)
	{
	amd_spi_setclear_reg8(master, AMD_SPI_TX_COUNT_REG, tx_count, 0xff);
	}

	static inline int amd_spi_busy_wait(struct amd_spi *amd_spi)
	{
	bool spi_busy;
	int timeout = 100000;

	/* poll for SPI bus to become idle */
	spi_busy = (ioread32((u8 __iomem *)amd_spi->io_remap_addr +
	AMD_SPI_CTRL0_REG) & AMD_SPI_BUSY) == AMD_SPI_BUSY;
	while (spi_busy) {
	usleep_range(10, 20);
	if (timeout-- < 0)
	return -ETIMEDOUT;

	spi_busy = (ioread32((u8 __iomem *)amd_spi->io_remap_addr +
	AMD_SPI_CTRL0_REG) & AMD_SPI_BUSY) == AMD_SPI_BUSY;
	}

	return 0;
	}

	static void amd_spi_execute_opcode(struct spi_master *master)
	{
	struct amd_spi *amd_spi = spi_master_get_devdata(master);

	/* Set ExecuteOpCode bit in the CTRL0 register */
	amd_spi_setclear_reg32(master, AMD_SPI_CTRL0_REG, AMD_SPI_EXEC_CMD,
	AMD_SPI_EXEC_CMD);

	amd_spi_busy_wait(amd_spi);
	}

	static int amd_spi_master_setup(struct spi_device *spi)
	{
	struct spi_master *master = spi->master;

	amd_spi_clear_fifo_ptr(master);

	return 0;
	}

	static inline int amd_spi_fifo_xfer(struct amd_spi *amd_spi,
	struct spi_master *master,
	struct spi_message *message)
	{
	struct spi_transfer *xfer = NULL;
	u8 cmd_opcode;
	u8 *buf = NULL;
	u32 m_cmd = 0;
	u32 i = 0;
	u32 tx_len = 0, rx_len = 0;

	list_for_each_entry(xfer, &message->transfers,
	transfer_list) {
	if (xfer->rx_buf)
	m_cmd = AMD_SPI_XFER_RX;
	if (xfer->tx_buf)
	m_cmd = AMD_SPI_XFER_TX;

	if (m_cmd & AMD_SPI_XFER_TX) {
	buf = (u8 *)xfer->tx_buf;
	tx_len = xfer->len - 1;
	cmd_opcode = (u8 )xfer->tx_buf;
	buf++;
	amd_spi_set_opcode(master, cmd_opcode);

	/* Write data into the FIFO. */
	for (i = 0; i < tx_len; i++) {
	iowrite8(buf[i],
	((u8 __iomem *)amd_spi->io_remap_addr +
	AMD_SPI_FIFO_BASE + i));
	}

	amd_spi_set_tx_count(master, tx_len);
	amd_spi_clear_fifo_ptr(master);
	/* Execute command */
	amd_spi_execute_opcode(master);
	}
	if (m_cmd & AMD_SPI_XFER_RX) {
	/*
	* Store no. of bytes to be received from
	* FIFO
	*/
	rx_len = xfer->len;
	buf = (u8 *)xfer->rx_buf;
	amd_spi_set_rx_count(master, rx_len);
	amd_spi_clear_fifo_ptr(master);
	/* Execute command */
	amd_spi_execute_opcode(master);
	/* Read data from FIFO to receive buffer */
	for (i = 0; i < rx_len; i++)
	buf[i] = amd_spi_readreg8(master,
	AMD_SPI_FIFO_BASE +
	tx_len + i);
	}
	}

	/* Update statistics */
	message->actual_length = tx_len + rx_len + 1;
	/* complete the transaction */
	message->status = 0;
	spi_finalize_current_message(master);

	return 0;
	}

	static int amd_spi_master_transfer(struct spi_master *master,
	struct spi_message *msg)
	{
	struct amd_spi *amd_spi = spi_master_get_devdata(master);
	struct spi_device *spi = msg->spi;

	amd_spi->chip_select = spi->chip_select;
	amd_spi_select_chip(master);

	/*
	* Extract spi_transfers from the spi message and
	* program the controller.
	*/
	amd_spi_fifo_xfer(amd_spi, master, msg);

	return 0;
	}

	static int amd_spi_probe(struct platform_device *pdev)
	{
	struct device *dev = &pdev->dev;
	struct spi_master *master;
	struct amd_spi *amd_spi;
	struct resource *res;
	int err = 0;

	/* Allocate storage for spi_master and driver private data */
	master = spi_alloc_master(dev, sizeof(struct amd_spi));
	if (!master) {
	dev_err(dev, "Error allocating SPI master\n");
	return -ENOMEM;
	}

	amd_spi = spi_master_get_devdata(master);

	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	amd_spi->io_remap_addr = devm_ioremap_resource(&pdev->dev, res);
	if (IS_ERR(amd_spi->io_remap_addr)) {
	err = PTR_ERR(amd_spi->io_remap_addr);
	dev_err(dev, "error %d ioremap of SPI registers failed\n", err);
	goto err_free_master;
	}
	dev_dbg(dev, "io_remap_address: %p\n", amd_spi->io_remap_addr);

	/* Initialize the spi_master fields */
	master->bus_num = 0;
	master->num_chipselect = 4;
	master->mode_bits = 0;
	master->flags = SPI_MASTER_HALF_DUPLEX;
	master->setup = amd_spi_master_setup;
	master->transfer_one_message = amd_spi_master_transfer;

	/* Register the controller with SPI framework */
	err = devm_spi_register_master(dev, master);
	if (err) {
	dev_err(dev, "error %d registering SPI controller\n", err);
	goto err_free_master;
	}

	return 0;

	err_free_master:
	spi_master_put(master);

	return err;
	}

	#ifdef CONFIG_ACPI
	static const struct acpi_device_id spi_acpi_match[] = {
	{ "AMDI0061", 0 },
	{},
	};
	MODULE_DEVICE_TABLE(acpi, spi_acpi_match);
	#endif

	static struct platform_driver amd_spi_driver = {
	.driver = {
	.name = "amd_spi",
	.acpi_match_table = ACPI_PTR(spi_acpi_match),
	},
	.probe = amd_spi_probe,
	};

	module_platform_driver(amd_spi_driver);

	MODULE_LICENSE("Dual BSD/GPL");
	MODULE_AUTHOR("Sanjay Mehta <sanju.mehta@amd.com>");
	MODULE_DESCRIPTION("AMD SPI Master Controller Driver");