+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;
+}
+