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path: root/drivers/nvmem/stm32-romem.c
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Diffstat (limited to 'drivers/nvmem/stm32-romem.c')
-rw-r--r--drivers/nvmem/stm32-romem.c294
1 files changed, 294 insertions, 0 deletions
diff --git a/drivers/nvmem/stm32-romem.c b/drivers/nvmem/stm32-romem.c
new file mode 100644
index 0000000000..0f84044bd1
--- /dev/null
+++ b/drivers/nvmem/stm32-romem.c
@@ -0,0 +1,294 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * STM32 Factory-programmed memory read access driver
+ *
+ * Copyright (C) 2017, STMicroelectronics - All Rights Reserved
+ * 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>
+#include <linux/tee_drv.h>
+
+#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->lower = 0;
+
+ 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->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 <fabrice.gasnier@st.com>");
+MODULE_DESCRIPTION("STMicroelectronics STM32 RO-MEM");
+MODULE_ALIAS("platform:nvmem-stm32-romem");
+MODULE_LICENSE("GPL v2");