1 // SPDX-License-Identifier: GPL-2.0
3  * STM32 Factory-programmed memory read access driver
5  * Copyright (C) 2017, STMicroelectronics - All Rights Reserved
9 #include <linux/arm-smccc.h>
12 #include <linux/nvmem-provider.h>
15 /* BSEC secure service access from non-secure */
25 /* 32 (x 32-bits) lower shadow registers */
45 		*buf8++ = readb_relaxed(priv->base + i);  in stm32_romem_read()
50 static int stm32_bsec_smc(u8 op, u32 otp, u32 data, u32 *result)  in stm32_bsec_smc()  argument
55 	arm_smccc_smc(STM32_SMC_BSEC, op, otp, data, 0, 0, 0, 0, &res);  in stm32_bsec_smc()
57 		return -EIO;  in stm32_bsec_smc()
64 	return -ENXIO;  in stm32_bsec_smc()
72 	struct device *dev = priv->cfg.dev;  in stm32_bsec_read()
77 	/* Round unaligned access to 32-bits */  in stm32_bsec_read()
82 	if (roffset + rbytes > priv->cfg.size)  in stm32_bsec_read()
83 		return -EINVAL;  in stm32_bsec_read()
86 		u32 otp = i >> 2;  in stm32_bsec_read()  local
88 		if (otp < STM32MP15_BSEC_NUM_LOWER) {  in stm32_bsec_read()
91 				priv->base + STM32MP15_BSEC_DATA0 + i);  in stm32_bsec_read()
93 			ret = stm32_bsec_smc(STM32_SMC_READ_SHADOW, otp, 0,  in stm32_bsec_read()
96 				dev_err(dev, "Can't read data%d (%d)\n", otp,  in stm32_bsec_read()
103 			size = min(bytes, (size_t)(4 - skip_bytes));  in stm32_bsec_read()
107 		bytes -= size;  in stm32_bsec_read()
119 	struct device *dev = priv->cfg.dev;  in stm32_bsec_write()
123 	/* Allow only writing complete 32-bits aligned words */  in stm32_bsec_write()
125 		return -EINVAL;  in stm32_bsec_write()
142 	struct device *dev = &pdev->dev;  in stm32_romem_probe()
148 		return -ENOMEM;  in stm32_romem_probe()
151 	priv->base = devm_ioremap_resource(dev, res);  in stm32_romem_probe()
152 	if (IS_ERR(priv->base))  in stm32_romem_probe()
153 		return PTR_ERR(priv->base);  in stm32_romem_probe()
155 	priv->cfg.name = "stm32-romem";  in stm32_romem_probe()
156 	priv->cfg.word_size = 1;  in stm32_romem_probe()
157 	priv->cfg.stride = 1;  in stm32_romem_probe()
158 	priv->cfg.dev = dev;  in stm32_romem_probe()
159 	priv->cfg.priv = priv;  in stm32_romem_probe()
160 	priv->cfg.owner = THIS_MODULE;  in stm32_romem_probe()
163 		of_match_device(dev->driver->of_match_table, dev)->data;  in stm32_romem_probe()
165 		priv->cfg.read_only = true;  in stm32_romem_probe()
166 		priv->cfg.size = resource_size(res);  in stm32_romem_probe()
167 		priv->cfg.reg_read = stm32_romem_read;  in stm32_romem_probe()
169 		priv->cfg.size = cfg->size;  in stm32_romem_probe()
170 		priv->cfg.reg_read = stm32_bsec_read;  in stm32_romem_probe()
171 		priv->cfg.reg_write = stm32_bsec_write;  in stm32_romem_probe()
174 	return PTR_ERR_OR_ZERO(devm_nvmem_register(dev, &priv->cfg));  in stm32_romem_probe()
178 	.size = 384, /* 96 x 32-bits data words */
182 	{ .compatible = "st,stm32f4-otp", }, {
183 		.compatible = "st,stm32mp15-bsec",
193 		.name = "stm32-romem",
200 MODULE_DESCRIPTION("STMicroelectronics STM32 RO-MEM");
201 MODULE_ALIAS("platform:nvmem-stm32-romem");