// SPDX-License-Identifier: GPL-2.0 /* * STM32 Factory-programmed memory read access driver * * Copyright (C) 2017, STMicroelectronics - All Rights Reserved * Author: Fabrice Gasnier for STMicroelectronics. */ #include #include #include #include #include #include #include #include #include "stm32-bsec-optee-ta.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 offset */ #define STM32MP15_BSEC_DATA0 0x200 struct stm32_romem_cfg { int size; u8 lower; bool ta; }; struct stm32_romem_priv { void __iomem *base; struct nvmem_config cfg; u8 lower; struct tee_context *ctx; }; 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 < priv->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; } } if (offset + bytes >= priv->lower * 4) dev_warn(dev, "Update of upper OTPs with ECC protection (word programming, only once)\n"); return 0; } static int stm32_bsec_pta_read(void *context, unsigned int offset, void *buf, size_t bytes) { struct stm32_romem_priv *priv = context; return stm32_bsec_optee_ta_read(priv->ctx, offset, buf, bytes); } static int stm32_bsec_pta_write(void *context, unsigned int offset, void *buf, size_t bytes) { struct stm32_romem_priv *priv = context; return stm32_bsec_optee_ta_write(priv->ctx, priv->lower, offset, buf, bytes); } static bool stm32_bsec_smc_check(void) { u32 val; int ret; /* check that the OP-TEE support the BSEC SMC (legacy mode) */ ret = stm32_bsec_smc(STM32_SMC_READ_SHADOW, 0, 0, &val); return !ret; } static bool optee_presence_check(void) { struct device_node *np; bool tee_detected = false; /* check that the OP-TEE node is present and available. */ np = of_find_compatible_node(NULL, NULL, "linaro,optee-tz"); if (np && of_device_is_available(np)) tee_detected = true; of_node_put(np); return tee_detected; } 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; int rc; priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL); if (!priv) return -ENOMEM; priv->base = devm_platform_get_and_ioremap_resource(pdev, 0, &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; priv->cfg.type = NVMEM_TYPE_OTP; priv->cfg.add_legacy_fixed_of_cells = true; priv->lower = 0; cfg = device_get_match_data(dev); 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->lower = cfg->lower; if (cfg->ta || optee_presence_check()) { rc = stm32_bsec_optee_ta_open(&priv->ctx); if (rc) { /* wait for OP-TEE client driver to be up and ready */ if (rc == -EPROBE_DEFER) return -EPROBE_DEFER; /* BSEC PTA is required or SMC not supported */ if (cfg->ta || !stm32_bsec_smc_check()) return rc; } } if (priv->ctx) { rc = devm_add_action_or_reset(dev, stm32_bsec_optee_ta_close, priv->ctx); if (rc) { dev_err(dev, "devm_add_action_or_reset() failed (%d)\n", rc); return rc; } priv->cfg.reg_read = stm32_bsec_pta_read; priv->cfg.reg_write = stm32_bsec_pta_write; } else { 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)); } /* * STM32MP15/13 BSEC OTP regions: 4096 OTP bits (with 3072 effective bits) * => 96 x 32-bits data words * - Lower: 1K bits, 2:1 redundancy, incremental bit programming * => 32 (x 32-bits) lower shadow registers = words 0 to 31 * - Upper: 2K bits, ECC protection, word programming only * => 64 (x 32-bits) = words 32 to 95 */ static const struct stm32_romem_cfg stm32mp15_bsec_cfg = { .size = 384, .lower = 32, .ta = false, }; static const struct stm32_romem_cfg stm32mp13_bsec_cfg = { .size = 384, .lower = 32, .ta = true, }; static const struct of_device_id stm32_romem_of_match[] __maybe_unused = { { .compatible = "st,stm32f4-otp", }, { .compatible = "st,stm32mp15-bsec", .data = (void *)&stm32mp15_bsec_cfg, }, { .compatible = "st,stm32mp13-bsec", .data = (void *)&stm32mp13_bsec_cfg, }, { /* sentinel */ }, }; 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 "); MODULE_DESCRIPTION("STMicroelectronics STM32 RO-MEM"); MODULE_ALIAS("platform:nvmem-stm32-romem"); MODULE_LICENSE("GPL v2");