@@ -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);