/* * Copyright (C) 2016 Broadcom * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License as * published by the Free Software Foundation version 2. * * This program is distributed "as is" WITHOUT ANY WARRANTY of any * kind, whether express or implied; without even the implied warranty * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. */ #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/of_address.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; 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" }, { .compatible = "brcm,ocotp-v2" }, { }, }; MODULE_DEVICE_TABLE(of, bcm_otpc_dt_ids); static int bcm_otpc_probe(struct platform_device *pdev) { struct device *dev = &pdev->dev; struct device_node *dn = dev->of_node; struct resource *res; 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; if (of_device_is_compatible(dev->of_node, "brcm,ocotp")) priv->map = &otp_map; else if (of_device_is_compatible(dev->of_node, "brcm,ocotp-v2")) priv->map = &otp_map_v2; else { dev_err(dev, "%s otpc config map not defined\n", __func__); return -EINVAL; } /* Get OTP base address register. */ res = platform_get_resource(pdev, IORESOURCE_MEM, 0); priv->base = devm_ioremap_resource(dev, res); 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 = of_property_read_u32(dn, "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 (of_device_is_compatible(dev->of_node, "brcm,ocotp-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, }, }; module_platform_driver(bcm_otpc_driver); MODULE_DESCRIPTION("Broadcom OTPC driver"); MODULE_LICENSE("GPL v2");