// 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; 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); amd_spi->io_remap_addr = devm_platform_ioremap_resource(pdev, 0); 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");