feat(plat/imx/imx8m/imx8mm): add support for measured boot

Add helper functions to generate event log for imx8mm
when MEASURED_BOOT=1.

Signed-off-by: Ying-Chun Liu (PaulLiu) <paulliu@debian.org>
Change-Id: Ifc947d749055787fbda0b39170aa2eb8865b7802

1 files changed, 200 insertions, 0 deletions

diff --git a/plat/imx/imx8m/imx8m_dyn_cfg_helpers.c b/plat/imx/imx8m/imx8m_dyn_cfg_helpers.c
new file mode 100644
index 000000000..8b2fdd626
--- /dev/null
+++ b/plat/imx/imx8m/imx8m_dyn_cfg_helpers.c
@@ -0,0 +1,200 @@
+/*
+ * Copyright (c) 2022, ARM Limited and Contributors. All rights reserved.
+ * Copyright (c) 2022, Linaro.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include <assert.h>
+
+#include <arch_helpers.h>
+#if MEASURED_BOOT
+#include <common/desc_image_load.h>
+#endif
+#include <common/fdt_wrappers.h>
+#include <libfdt.h>
+
+#define DTB_PROP_HW_LOG_ADDR	"tpm_event_log_addr"
+#define DTB_PROP_HW_LOG_SIZE	"tpm_event_log_size"
+
+#if MEASURED_BOOT
+
+static int imx8m_event_log_fdt_init_overlay(uintptr_t dt_base, int dt_size)
+{
+	int ret;
+	int offset;
+	void *dtb = (void *)dt_base;
+
+	ret = fdt_create_empty_tree(dtb, dt_size);
+	if (ret < 0) {
+		ERROR("cannot create empty dtb tree: %s\n",
+		       fdt_strerror(ret));
+		return ret;
+	}
+
+	offset = fdt_path_offset(dtb, "/");
+	if (offset < 0) {
+		ERROR("cannot find root of the tree: %s\n",
+		       fdt_strerror(offset));
+		return offset;
+	}
+
+	offset = fdt_add_subnode(dtb, offset, "fragment@0");
+	if (offset < 0) {
+		ERROR("cannot add fragment node: %s\n",
+		       fdt_strerror(offset));
+		return offset;
+	}
+
+	ret = fdt_setprop_string(dtb, offset, "target-path", "/");
+	if (ret < 0) {
+		ERROR("cannot set target-path property: %s\n",
+		       fdt_strerror(ret));
+		return ret;
+	}
+
+	offset = fdt_add_subnode(dtb, offset, "__overlay__");
+	if (offset < 0) {
+		ERROR("cannot add __overlay__ node: %s\n",
+		       fdt_strerror(offset));
+		return ret;
+	}
+
+	offset = fdt_add_subnode(dtb, offset, "tpm_event_log");
+	if (offset < 0) {
+		ERROR("cannot add tpm_event_log node: %s\n",
+		       fdt_strerror(offset));
+		return offset;
+	}
+
+	ret = fdt_setprop_string(dtb, offset, "compatible",
+				 "arm,tpm_event_log");
+	if (ret < 0) {
+		ERROR("cannot set compatible property: %s\n",
+		       fdt_strerror(ret));
+		return ret;
+	}
+
+	ret = fdt_setprop_u64(dtb, offset, "tpm_event_log_addr", 0);
+	if (ret < 0) {
+		ERROR("cannot set tpm_event_log_addr property: %s\n",
+		       fdt_strerror(ret));
+		return ret;
+	}
+
+	ret = fdt_setprop_u32(dtb, offset, "tpm_event_log_size", 0);
+	if (ret < 0) {
+		ERROR("cannot set tpm_event_log_size property: %s\n",
+		       fdt_strerror(ret));
+		return ret;
+	}
+
+	return ret;
+}
+
+/*
+ * Write the Event Log address and its size in the DTB.
+ *
+ * This function is supposed to be called only by BL2.
+ *
+ * Returns:
+ *	0 = success
+ *    < 0 = error
+ */
+static int imx8m_set_event_log_info(uintptr_t config_base,
+				  uintptr_t log_addr, size_t log_size)
+{
+	/* As libfdt uses void *, we can't avoid this cast */
+	void *dtb = (void *)config_base;
+	const char *compatible_tpm = "arm,tpm_event_log";
+	uint64_t base = cpu_to_fdt64(log_addr);
+	uint32_t sz = cpu_to_fdt32(log_size);
+	int err, node;
+
+	err = fdt_open_into(dtb, dtb, PLAT_IMX8M_DTO_MAX_SIZE);
+	if (err < 0) {
+		ERROR("Invalid Device Tree at %p: error %d\n", dtb, err);
+		return err;
+	}
+
+	/*
+	 * Verify that the DTB is valid, before attempting to write to it,
+	 * and get the DTB root node.
+	 */
+
+	/* Check if the pointer to DT is correct */
+	err = fdt_check_header(dtb);
+	if (err < 0) {
+		WARN("Invalid DTB file passed\n");
+		return err;
+	}
+
+	/*
+	 * Find the TPM node in device tree.
+	 */
+	node = fdt_node_offset_by_compatible(dtb, -1, compatible_tpm);
+	if (node < 0) {
+		ERROR("The compatible property '%s' not%s", compatible_tpm,
+			" found in the config\n");
+		return node;
+	}
+
+	err = fdt_setprop(dtb, node, DTB_PROP_HW_LOG_ADDR, &base, 8);
+	if (err < 0) {
+		ERROR("Failed to add log addr err %d\n", err);
+		return err;
+	}
+
+	err = fdt_setprop(dtb, node, DTB_PROP_HW_LOG_SIZE, &sz, 4);
+	if (err < 0) {
+		ERROR("Failed to add log addr err %d\n", err);
+		return err;
+	}
+
+	err = fdt_pack(dtb);
+	if (err < 0) {
+		ERROR("Failed to pack Device Tree at %p: error %d\n", dtb, err);
+		return err;
+	}
+
+	/*
+	 * Ensure that the info written to the DTB is visible
+	 * to other images.
+	 */
+	flush_dcache_range(config_base, fdt_totalsize(dtb));
+
+	return err;
+}
+
+/*
+ * This function writes the Event Log address and its size
+ * in the QEMU DTB.
+ *
+ * This function is supposed to be called only by BL2.
+ *
+ * Returns:
+ *	0 = success
+ *    < 0 = error
+ */
+int imx8m_set_nt_fw_info(size_t log_size, uintptr_t *ns_log_addr)
+{
+	uintptr_t ns_addr;
+	int err;
+
+	assert(ns_log_addr != NULL);
+
+	ns_addr = PLAT_IMX8M_DTO_BASE + PLAT_IMX8M_DTO_MAX_SIZE;
+
+	imx8m_event_log_fdt_init_overlay(PLAT_IMX8M_DTO_BASE,
+					  PLAT_IMX8M_DTO_MAX_SIZE);
+
+	/* Write the Event Log address and its size in the DTB */
+	err = imx8m_set_event_log_info(PLAT_IMX8M_DTO_BASE,
+					ns_addr, log_size);
+
+	/* Return Event Log address in Non-secure memory */
+	*ns_log_addr = (err < 0) ? 0UL : ns_addr;
+	return err;
+}
+
+#endif /* MEASURED_BOOT */