diff options
Diffstat (limited to 'drivers/nvmem/vf610-ocotp.c')
| -rw-r--r-- | drivers/nvmem/vf610-ocotp.c | 263 |
1 files changed, 263 insertions, 0 deletions
diff --git a/drivers/nvmem/vf610-ocotp.c b/drivers/nvmem/vf610-ocotp.c new file mode 100644 index 000000000..466230948 --- /dev/null +++ b/drivers/nvmem/vf610-ocotp.c @@ -0,0 +1,263 @@ +/* + * Copyright (C) 2015 Toradex AG. + * + * Author: Sanchayan Maity <sanchayan.maity@toradex.com> + * + * Based on the barebox ocotp driver, + * Copyright (c) 2010 Baruch Siach <baruch@tkos.co.il> + * Orex Computed Radiography + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 and + * only version 2 as published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + */ + +#include <linux/clk.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> +#include <linux/slab.h> + +/* OCOTP Register Offsets */ +#define OCOTP_CTRL_REG 0x00 +#define OCOTP_CTRL_SET 0x04 +#define OCOTP_CTRL_CLR 0x08 +#define OCOTP_TIMING 0x10 +#define OCOTP_DATA 0x20 +#define OCOTP_READ_CTRL_REG 0x30 +#define OCOTP_READ_FUSE_DATA 0x40 + +/* OCOTP Register bits and masks */ +#define OCOTP_CTRL_WR_UNLOCK 16 +#define OCOTP_CTRL_WR_UNLOCK_KEY 0x3E77 +#define OCOTP_CTRL_WR_UNLOCK_MASK GENMASK(31, 16) +#define OCOTP_CTRL_ADDR 0 +#define OCOTP_CTRL_ADDR_MASK GENMASK(6, 0) +#define OCOTP_CTRL_RELOAD_SHADOWS BIT(10) +#define OCOTP_CTRL_ERR BIT(9) +#define OCOTP_CTRL_BUSY BIT(8) + +#define OCOTP_TIMING_STROBE_READ 16 +#define OCOTP_TIMING_STROBE_READ_MASK GENMASK(21, 16) +#define OCOTP_TIMING_RELAX 12 +#define OCOTP_TIMING_RELAX_MASK GENMASK(15, 12) +#define OCOTP_TIMING_STROBE_PROG 0 +#define OCOTP_TIMING_STROBE_PROG_MASK GENMASK(11, 0) + +#define OCOTP_READ_CTRL_READ_FUSE 0x1 + +#define VF610_OCOTP_TIMEOUT 100000 + +#define BF(value, field) (((value) << field) & field##_MASK) + +#define DEF_RELAX 20 + +static const int base_to_fuse_addr_mappings[][2] = { + {0x400, 0x00}, + {0x410, 0x01}, + {0x420, 0x02}, + {0x450, 0x05}, + {0x4F0, 0x0F}, + {0x600, 0x20}, + {0x610, 0x21}, + {0x620, 0x22}, + {0x630, 0x23}, + {0x640, 0x24}, + {0x650, 0x25}, + {0x660, 0x26}, + {0x670, 0x27}, + {0x6F0, 0x2F}, + {0x880, 0x38}, + {0x890, 0x39}, + {0x8A0, 0x3A}, + {0x8B0, 0x3B}, + {0x8C0, 0x3C}, + {0x8D0, 0x3D}, + {0x8E0, 0x3E}, + {0x8F0, 0x3F}, + {0xC80, 0x78}, + {0xC90, 0x79}, + {0xCA0, 0x7A}, + {0xCB0, 0x7B}, + {0xCC0, 0x7C}, + {0xCD0, 0x7D}, + {0xCE0, 0x7E}, + {0xCF0, 0x7F}, +}; + +struct vf610_ocotp { + void __iomem *base; + struct clk *clk; + struct device *dev; + struct nvmem_device *nvmem; + int timing; +}; + +static int vf610_ocotp_wait_busy(void __iomem *base) +{ + int timeout = VF610_OCOTP_TIMEOUT; + + while ((readl(base) & OCOTP_CTRL_BUSY) && --timeout) + udelay(10); + + if (!timeout) { + writel(OCOTP_CTRL_ERR, base + OCOTP_CTRL_CLR); + return -ETIMEDOUT; + } + + udelay(10); + + return 0; +} + +static int vf610_ocotp_calculate_timing(struct vf610_ocotp *ocotp_dev) +{ + u32 clk_rate; + u32 relax, strobe_read, strobe_prog; + u32 timing; + + clk_rate = clk_get_rate(ocotp_dev->clk); + + /* Refer section OTP read/write timing parameters in TRM */ + relax = clk_rate / (1000000000 / DEF_RELAX) - 1; + strobe_prog = clk_rate / (1000000000 / 10000) + 2 * (DEF_RELAX + 1) - 1; + strobe_read = clk_rate / (1000000000 / 40) + 2 * (DEF_RELAX + 1) - 1; + + timing = BF(relax, OCOTP_TIMING_RELAX); + timing |= BF(strobe_read, OCOTP_TIMING_STROBE_READ); + timing |= BF(strobe_prog, OCOTP_TIMING_STROBE_PROG); + + return timing; +} + +static int vf610_get_fuse_address(int base_addr_offset) +{ + int i; + + for (i = 0; i < ARRAY_SIZE(base_to_fuse_addr_mappings); i++) { + if (base_to_fuse_addr_mappings[i][0] == base_addr_offset) + return base_to_fuse_addr_mappings[i][1]; + } + + return -EINVAL; +} + +static int vf610_ocotp_read(void *context, unsigned int offset, + void *val, size_t bytes) +{ + struct vf610_ocotp *ocotp = context; + void __iomem *base = ocotp->base; + u32 reg, *buf = val; + int fuse_addr; + int ret; + + while (bytes > 0) { + fuse_addr = vf610_get_fuse_address(offset); + if (fuse_addr > 0) { + writel(ocotp->timing, base + OCOTP_TIMING); + ret = vf610_ocotp_wait_busy(base + OCOTP_CTRL_REG); + if (ret) + return ret; + + reg = readl(base + OCOTP_CTRL_REG); + reg &= ~OCOTP_CTRL_ADDR_MASK; + reg &= ~OCOTP_CTRL_WR_UNLOCK_MASK; + reg |= BF(fuse_addr, OCOTP_CTRL_ADDR); + writel(reg, base + OCOTP_CTRL_REG); + + writel(OCOTP_READ_CTRL_READ_FUSE, + base + OCOTP_READ_CTRL_REG); + ret = vf610_ocotp_wait_busy(base + OCOTP_CTRL_REG); + if (ret) + return ret; + + if (readl(base) & OCOTP_CTRL_ERR) { + dev_dbg(ocotp->dev, "Error reading from fuse address %x\n", + fuse_addr); + writel(OCOTP_CTRL_ERR, base + OCOTP_CTRL_CLR); + } + + /* + * In case of error, we do not abort and expect to read + * 0xBADABADA as mentioned by the TRM. We just read this + * value and return. + */ + *buf = readl(base + OCOTP_READ_FUSE_DATA); + } else { + *buf = 0; + } + + buf++; + bytes -= 4; + offset += 4; + } + + return 0; +} + +static struct nvmem_config ocotp_config = { + .name = "ocotp", + .stride = 4, + .word_size = 4, + .reg_read = vf610_ocotp_read, +}; + +static const struct of_device_id ocotp_of_match[] = { + { .compatible = "fsl,vf610-ocotp", }, + {/* sentinel */}, +}; +MODULE_DEVICE_TABLE(of, ocotp_of_match); + +static int vf610_ocotp_probe(struct platform_device *pdev) +{ + struct device *dev = &pdev->dev; + struct resource *res; + struct vf610_ocotp *ocotp_dev; + + ocotp_dev = devm_kzalloc(dev, sizeof(struct vf610_ocotp), GFP_KERNEL); + if (!ocotp_dev) + return -ENOMEM; + + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); + ocotp_dev->base = devm_ioremap_resource(dev, res); + if (IS_ERR(ocotp_dev->base)) + return PTR_ERR(ocotp_dev->base); + + ocotp_dev->clk = devm_clk_get(dev, NULL); + if (IS_ERR(ocotp_dev->clk)) { + dev_err(dev, "failed getting clock, err = %ld\n", + PTR_ERR(ocotp_dev->clk)); + return PTR_ERR(ocotp_dev->clk); + } + ocotp_dev->dev = dev; + ocotp_dev->timing = vf610_ocotp_calculate_timing(ocotp_dev); + + ocotp_config.size = resource_size(res); + ocotp_config.priv = ocotp_dev; + ocotp_config.dev = dev; + + ocotp_dev->nvmem = devm_nvmem_register(dev, &ocotp_config); + + return PTR_ERR_OR_ZERO(ocotp_dev->nvmem); +} + +static struct platform_driver vf610_ocotp_driver = { + .probe = vf610_ocotp_probe, + .driver = { + .name = "vf610-ocotp", + .of_match_table = ocotp_of_match, + }, +}; +module_platform_driver(vf610_ocotp_driver); +MODULE_AUTHOR("Sanchayan Maity <sanchayan.maity@toradex.com>"); +MODULE_DESCRIPTION("Vybrid OCOTP driver"); +MODULE_LICENSE("GPL v2"); |