1 files changed, 129 insertions, 5 deletions

diff --git a/drivers/nvmem/stm32-romem.c b/drivers/nvmem/stm32-romem.c
index 07e98b53b391..354be526897f 100644
--- a/drivers/nvmem/stm32-romem.c
+++ b/drivers/nvmem/stm32-romem.c
@@ -6,11 +6,29 @@
  * 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;
@@ -29,8 +47,98 @@ static int stm32_romem_read(void *context, unsigned int offset, void *buf,
 	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;
@@ -45,21 +153,37 @@ static int stm32_romem_probe(struct platform_device *pdev)
 		return PTR_ERR(priv->base);
 
 	priv->cfg.name = "stm32-romem";
-	priv->cfg.read_only = true;
 	priv->cfg.word_size = 1;
 	priv->cfg.stride = 1;
-	priv->cfg.size = resource_size(res);
-	priv->cfg.reg_read = stm32_romem_read;
 	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,stm32f4-otp", }, {
+		.compatible = "st,stm32mp15-bsec",
+		.data = (void *)&stm32mp15_bsec_cfg,
+	}, {
+	},
 };
 MODULE_DEVICE_TABLE(of, stm32_romem_of_match);