diff options
Diffstat (limited to 'drivers/nvmem/bcm-ocotp.c')
| -rw-r--r-- | drivers/nvmem/bcm-ocotp.c | 313 |
1 files changed, 313 insertions, 0 deletions
diff --git a/drivers/nvmem/bcm-ocotp.c b/drivers/nvmem/bcm-ocotp.c new file mode 100644 index 0000000000..2490f44caa --- /dev/null +++ b/drivers/nvmem/bcm-ocotp.c @@ -0,0 +1,313 @@ +// SPDX-License-Identifier: GPL-2.0-only +// Copyright (C) 2016 Broadcom + +#include <linux/acpi.h> +#include <linux/delay.h> +#include <linux/device.h> +#include <linux/io.h> +#include <linux/module.h> +#include <linux/nvmem-provider.h> +#include <linux/of.h> +#include <linux/platform_device.h> + +/* + * # of tries for OTP Status. The time to execute a command varies. The slowest + * commands are writes which also vary based on the # of bits turned on. Writing + * 0xffffffff takes ~3800 us. + */ +#define OTPC_RETRIES 5000 + +/* Sequence to enable OTP program */ +#define OTPC_PROG_EN_SEQ { 0xf, 0x4, 0x8, 0xd } + +/* OTPC Commands */ +#define OTPC_CMD_READ 0x0 +#define OTPC_CMD_OTP_PROG_ENABLE 0x2 +#define OTPC_CMD_OTP_PROG_DISABLE 0x3 +#define OTPC_CMD_PROGRAM 0x8 + +/* OTPC Status Bits */ +#define OTPC_STAT_CMD_DONE BIT(1) +#define OTPC_STAT_PROG_OK BIT(2) + +/* OTPC register definition */ +#define OTPC_MODE_REG_OFFSET 0x0 +#define OTPC_MODE_REG_OTPC_MODE 0 +#define OTPC_COMMAND_OFFSET 0x4 +#define OTPC_COMMAND_COMMAND_WIDTH 6 +#define OTPC_CMD_START_OFFSET 0x8 +#define OTPC_CMD_START_START 0 +#define OTPC_CPU_STATUS_OFFSET 0xc +#define OTPC_CPUADDR_REG_OFFSET 0x28 +#define OTPC_CPUADDR_REG_OTPC_CPU_ADDRESS_WIDTH 16 +#define OTPC_CPU_WRITE_REG_OFFSET 0x2c + +#define OTPC_CMD_MASK (BIT(OTPC_COMMAND_COMMAND_WIDTH) - 1) +#define OTPC_ADDR_MASK (BIT(OTPC_CPUADDR_REG_OTPC_CPU_ADDRESS_WIDTH) - 1) + + +struct otpc_map { + /* in words. */ + u32 otpc_row_size; + /* 128 bit row / 4 words support. */ + u16 data_r_offset[4]; + /* 128 bit row / 4 words support. */ + u16 data_w_offset[4]; +}; + +static struct otpc_map otp_map = { + .otpc_row_size = 1, + .data_r_offset = {0x10}, + .data_w_offset = {0x2c}, +}; + +static struct otpc_map otp_map_v2 = { + .otpc_row_size = 2, + .data_r_offset = {0x10, 0x5c}, + .data_w_offset = {0x2c, 0x64}, +}; + +struct otpc_priv { + struct device *dev; + void __iomem *base; + const struct otpc_map *map; + struct nvmem_config *config; +}; + +static inline void set_command(void __iomem *base, u32 command) +{ + writel(command & OTPC_CMD_MASK, base + OTPC_COMMAND_OFFSET); +} + +static inline void set_cpu_address(void __iomem *base, u32 addr) +{ + writel(addr & OTPC_ADDR_MASK, base + OTPC_CPUADDR_REG_OFFSET); +} + +static inline void set_start_bit(void __iomem *base) +{ + writel(1 << OTPC_CMD_START_START, base + OTPC_CMD_START_OFFSET); +} + +static inline void reset_start_bit(void __iomem *base) +{ + writel(0, base + OTPC_CMD_START_OFFSET); +} + +static inline void write_cpu_data(void __iomem *base, u32 value) +{ + writel(value, base + OTPC_CPU_WRITE_REG_OFFSET); +} + +static int poll_cpu_status(void __iomem *base, u32 value) +{ + u32 status; + u32 retries; + + for (retries = 0; retries < OTPC_RETRIES; retries++) { + status = readl(base + OTPC_CPU_STATUS_OFFSET); + if (status & value) + break; + udelay(1); + } + if (retries == OTPC_RETRIES) + return -EAGAIN; + + return 0; +} + +static int enable_ocotp_program(void __iomem *base) +{ + static const u32 vals[] = OTPC_PROG_EN_SEQ; + int i; + int ret; + + /* Write the magic sequence to enable programming */ + set_command(base, OTPC_CMD_OTP_PROG_ENABLE); + for (i = 0; i < ARRAY_SIZE(vals); i++) { + write_cpu_data(base, vals[i]); + set_start_bit(base); + ret = poll_cpu_status(base, OTPC_STAT_CMD_DONE); + reset_start_bit(base); + if (ret) + return ret; + } + + return poll_cpu_status(base, OTPC_STAT_PROG_OK); +} + +static int disable_ocotp_program(void __iomem *base) +{ + int ret; + + set_command(base, OTPC_CMD_OTP_PROG_DISABLE); + set_start_bit(base); + ret = poll_cpu_status(base, OTPC_STAT_PROG_OK); + reset_start_bit(base); + + return ret; +} + +static int bcm_otpc_read(void *context, unsigned int offset, void *val, + size_t bytes) +{ + struct otpc_priv *priv = context; + u32 *buf = val; + u32 bytes_read; + u32 address = offset / priv->config->word_size; + int i, ret; + + for (bytes_read = 0; bytes_read < bytes;) { + set_command(priv->base, OTPC_CMD_READ); + set_cpu_address(priv->base, address++); + set_start_bit(priv->base); + ret = poll_cpu_status(priv->base, OTPC_STAT_CMD_DONE); + if (ret) { + dev_err(priv->dev, "otp read error: 0x%x", ret); + return -EIO; + } + + for (i = 0; i < priv->map->otpc_row_size; i++) { + *buf++ = readl(priv->base + + priv->map->data_r_offset[i]); + bytes_read += sizeof(*buf); + } + + reset_start_bit(priv->base); + } + + return 0; +} + +static int bcm_otpc_write(void *context, unsigned int offset, void *val, + size_t bytes) +{ + struct otpc_priv *priv = context; + u32 *buf = val; + u32 bytes_written; + u32 address = offset / priv->config->word_size; + int i, ret; + + if (offset % priv->config->word_size) + return -EINVAL; + + ret = enable_ocotp_program(priv->base); + if (ret) + return -EIO; + + for (bytes_written = 0; bytes_written < bytes;) { + set_command(priv->base, OTPC_CMD_PROGRAM); + set_cpu_address(priv->base, address++); + for (i = 0; i < priv->map->otpc_row_size; i++) { + writel(*buf, priv->base + priv->map->data_w_offset[i]); + buf++; + bytes_written += sizeof(*buf); + } + set_start_bit(priv->base); + ret = poll_cpu_status(priv->base, OTPC_STAT_CMD_DONE); + reset_start_bit(priv->base); + if (ret) { + dev_err(priv->dev, "otp write error: 0x%x", ret); + return -EIO; + } + } + + disable_ocotp_program(priv->base); + + return 0; +} + +static struct nvmem_config bcm_otpc_nvmem_config = { + .name = "bcm-ocotp", + .read_only = false, + .word_size = 4, + .stride = 4, + .reg_read = bcm_otpc_read, + .reg_write = bcm_otpc_write, +}; + +static const struct of_device_id bcm_otpc_dt_ids[] = { + { .compatible = "brcm,ocotp", .data = &otp_map }, + { .compatible = "brcm,ocotp-v2", .data = &otp_map_v2 }, + { }, +}; +MODULE_DEVICE_TABLE(of, bcm_otpc_dt_ids); + +static const struct acpi_device_id bcm_otpc_acpi_ids[] __maybe_unused = { + { .id = "BRCM0700", .driver_data = (kernel_ulong_t)&otp_map }, + { .id = "BRCM0701", .driver_data = (kernel_ulong_t)&otp_map_v2 }, + { /* sentinel */ } +}; +MODULE_DEVICE_TABLE(acpi, bcm_otpc_acpi_ids); + +static int bcm_otpc_probe(struct platform_device *pdev) +{ + struct device *dev = &pdev->dev; + struct otpc_priv *priv; + struct nvmem_device *nvmem; + int err; + u32 num_words; + + priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL); + if (!priv) + return -ENOMEM; + + priv->map = device_get_match_data(dev); + if (!priv->map) + return -ENODEV; + + /* Get OTP base address register. */ + priv->base = devm_platform_ioremap_resource(pdev, 0); + if (IS_ERR(priv->base)) { + dev_err(dev, "unable to map I/O memory\n"); + return PTR_ERR(priv->base); + } + + /* Enable CPU access to OTPC. */ + writel(readl(priv->base + OTPC_MODE_REG_OFFSET) | + BIT(OTPC_MODE_REG_OTPC_MODE), + priv->base + OTPC_MODE_REG_OFFSET); + reset_start_bit(priv->base); + + /* Read size of memory in words. */ + err = device_property_read_u32(dev, "brcm,ocotp-size", &num_words); + if (err) { + dev_err(dev, "size parameter not specified\n"); + return -EINVAL; + } else if (num_words == 0) { + dev_err(dev, "size must be > 0\n"); + return -EINVAL; + } + + bcm_otpc_nvmem_config.size = 4 * num_words; + bcm_otpc_nvmem_config.dev = dev; + bcm_otpc_nvmem_config.priv = priv; + + if (priv->map == &otp_map_v2) { + bcm_otpc_nvmem_config.word_size = 8; + bcm_otpc_nvmem_config.stride = 8; + } + + priv->config = &bcm_otpc_nvmem_config; + + nvmem = devm_nvmem_register(dev, &bcm_otpc_nvmem_config); + if (IS_ERR(nvmem)) { + dev_err(dev, "error registering nvmem config\n"); + return PTR_ERR(nvmem); + } + + return 0; +} + +static struct platform_driver bcm_otpc_driver = { + .probe = bcm_otpc_probe, + .driver = { + .name = "brcm-otpc", + .of_match_table = bcm_otpc_dt_ids, + .acpi_match_table = ACPI_PTR(bcm_otpc_acpi_ids), + }, +}; +module_platform_driver(bcm_otpc_driver); + +MODULE_DESCRIPTION("Broadcom OTPC driver"); +MODULE_LICENSE("GPL v2"); |