diff options
Diffstat (limited to 'drivers/nvmem/stm32-romem.c')
| -rw-r--r-- | drivers/nvmem/stm32-romem.c | 202 |
1 files changed, 202 insertions, 0 deletions
diff --git a/drivers/nvmem/stm32-romem.c b/drivers/nvmem/stm32-romem.c new file mode 100644 index 000000000..354be5268 --- /dev/null +++ b/drivers/nvmem/stm32-romem.c @@ -0,0 +1,202 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * STM32 Factory-programmed memory read access driver + * + * Copyright (C) 2017, STMicroelectronics - All Rights Reserved + * Author: Fabrice Gasnier <fabrice.gasnier@st.com> for STMicroelectronics. + */ + +#include <linux/arm-smccc.h> +#include <linux/io.h> +#include <linux/module.h> +#include <linux/nvmem-provider.h> +#include <linux/of_device.h> + +/* BSEC secure service access from non-secure */ +#define STM32_SMC_BSEC 0x82001003 +#define STM32_SMC_READ_SHADOW 0x01 +#define STM32_SMC_PROG_OTP 0x02 +#define STM32_SMC_WRITE_SHADOW 0x03 +#define STM32_SMC_READ_OTP 0x04 + +/* shadow registers offest */ +#define STM32MP15_BSEC_DATA0 0x200 + +/* 32 (x 32-bits) lower shadow registers */ +#define STM32MP15_BSEC_NUM_LOWER 32 + +struct stm32_romem_cfg { + int size; +}; + +struct stm32_romem_priv { + void __iomem *base; + struct nvmem_config cfg; +}; + +static int stm32_romem_read(void *context, unsigned int offset, void *buf, + size_t bytes) +{ + struct stm32_romem_priv *priv = context; + u8 *buf8 = buf; + int i; + + for (i = offset; i < offset + bytes; i++) + *buf8++ = readb_relaxed(priv->base + i); + + return 0; +} + +static int stm32_bsec_smc(u8 op, u32 otp, u32 data, u32 *result) +{ +#if IS_ENABLED(CONFIG_HAVE_ARM_SMCCC) + struct arm_smccc_res res; + + arm_smccc_smc(STM32_SMC_BSEC, op, otp, data, 0, 0, 0, 0, &res); + if (res.a0) + return -EIO; + + if (result) + *result = (u32)res.a1; + + return 0; +#else + return -ENXIO; +#endif +} + +static int stm32_bsec_read(void *context, unsigned int offset, void *buf, + size_t bytes) +{ + struct stm32_romem_priv *priv = context; + struct device *dev = priv->cfg.dev; + u32 roffset, rbytes, val; + u8 *buf8 = buf, *val8 = (u8 *)&val; + int i, j = 0, ret, skip_bytes, size; + + /* Round unaligned access to 32-bits */ + roffset = rounddown(offset, 4); + skip_bytes = offset & 0x3; + rbytes = roundup(bytes + skip_bytes, 4); + + if (roffset + rbytes > priv->cfg.size) + return -EINVAL; + + for (i = roffset; (i < roffset + rbytes); i += 4) { + u32 otp = i >> 2; + + if (otp < STM32MP15_BSEC_NUM_LOWER) { + /* read lower data from shadow registers */ + val = readl_relaxed( + priv->base + STM32MP15_BSEC_DATA0 + i); + } else { + ret = stm32_bsec_smc(STM32_SMC_READ_SHADOW, otp, 0, + &val); + if (ret) { + dev_err(dev, "Can't read data%d (%d)\n", otp, + ret); + return ret; + } + } + /* skip first bytes in case of unaligned read */ + if (skip_bytes) + size = min(bytes, (size_t)(4 - skip_bytes)); + else + size = min(bytes, (size_t)4); + memcpy(&buf8[j], &val8[skip_bytes], size); + bytes -= size; + j += size; + skip_bytes = 0; + } + + return 0; +} + +static int stm32_bsec_write(void *context, unsigned int offset, void *buf, + size_t bytes) +{ + struct stm32_romem_priv *priv = context; + struct device *dev = priv->cfg.dev; + u32 *buf32 = buf; + int ret, i; + + /* Allow only writing complete 32-bits aligned words */ + if ((bytes % 4) || (offset % 4)) + return -EINVAL; + + for (i = offset; i < offset + bytes; i += 4) { + ret = stm32_bsec_smc(STM32_SMC_PROG_OTP, i >> 2, *buf32++, + NULL); + if (ret) { + dev_err(dev, "Can't write data%d (%d)\n", i >> 2, ret); + return ret; + } + } + + return 0; +} + +static int stm32_romem_probe(struct platform_device *pdev) +{ + const struct stm32_romem_cfg *cfg; + struct device *dev = &pdev->dev; + struct stm32_romem_priv *priv; + struct resource *res; + + priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL); + if (!priv) + return -ENOMEM; + + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); + priv->base = devm_ioremap_resource(dev, res); + if (IS_ERR(priv->base)) + return PTR_ERR(priv->base); + + priv->cfg.name = "stm32-romem"; + priv->cfg.word_size = 1; + priv->cfg.stride = 1; + priv->cfg.dev = dev; + priv->cfg.priv = priv; + priv->cfg.owner = THIS_MODULE; + + cfg = (const struct stm32_romem_cfg *) + of_match_device(dev->driver->of_match_table, dev)->data; + if (!cfg) { + priv->cfg.read_only = true; + priv->cfg.size = resource_size(res); + priv->cfg.reg_read = stm32_romem_read; + } else { + priv->cfg.size = cfg->size; + priv->cfg.reg_read = stm32_bsec_read; + priv->cfg.reg_write = stm32_bsec_write; + } + + return PTR_ERR_OR_ZERO(devm_nvmem_register(dev, &priv->cfg)); +} + +static const struct stm32_romem_cfg stm32mp15_bsec_cfg = { + .size = 384, /* 96 x 32-bits data words */ +}; + +static const struct of_device_id stm32_romem_of_match[] = { + { .compatible = "st,stm32f4-otp", }, { + .compatible = "st,stm32mp15-bsec", + .data = (void *)&stm32mp15_bsec_cfg, + }, { + }, +}; +MODULE_DEVICE_TABLE(of, stm32_romem_of_match); + +static struct platform_driver stm32_romem_driver = { + .probe = stm32_romem_probe, + .driver = { + .name = "stm32-romem", + .of_match_table = of_match_ptr(stm32_romem_of_match), + }, +}; +module_platform_driver(stm32_romem_driver); + +MODULE_AUTHOR("Fabrice Gasnier <fabrice.gasnier@st.com>"); +MODULE_DESCRIPTION("STMicroelectronics STM32 RO-MEM"); +MODULE_ALIAS("platform:nvmem-stm32-romem"); +MODULE_LICENSE("GPL v2"); |