diff options
Diffstat (limited to 'drivers/spi/spi-amd.c')
| -rw-r--r-- | drivers/spi/spi-amd.c | 325 |
1 files changed, 325 insertions, 0 deletions
diff --git a/drivers/spi/spi-amd.c b/drivers/spi/spi-amd.c new file mode 100644 index 000000000..a027cfd49 --- /dev/null +++ b/drivers/spi/spi-amd.c @@ -0,0 +1,325 @@ +// 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_FIFO_SIZE 70 +#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 size_t amd_spi_max_transfer_size(struct spi_device *spi) +{ + return AMD_SPI_FIFO_SIZE; +} + +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; + master->max_transfer_size = amd_spi_max_transfer_size; + master->max_message_size = amd_spi_max_transfer_size; + + /* 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"); |