4 files changed, 112 insertions, 0 deletions
diff --git a/src/soc/amd/common/block/include/amdblocks/stb.h b/src/soc/amd/common/block/include/amdblocks/stb.h
new file mode 100644
index 0000000000..51b01948f8
--- /dev/null
+++ b/src/soc/amd/common/block/include/amdblocks/stb.h
@@ -0,0 +1,21 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+
+#ifndef AMD_BLOCK_STB_H
+#define AMD_BLOCK_STB_H
+
+#include <types.h>
+
+#define AMD_STB_PMI_0			0x30600
+
+#define AMD_STB_COREBOOT_MARKER		0xBAADF00D
+
+struct stb_entry_struct {
+	uint32_t ts;
+	uint32_t val;
+};
+
+void write_stb_to_console(void);
+void init_spill_buffer(void);
+void add_stb_to_timestamp_buffer(void);
+
+#endif /* AMD_BLOCK_STB_H */
diff --git a/src/soc/amd/common/block/stb/Kconfig b/src/soc/amd/common/block/stb/Kconfig
new file mode 100644
index 0000000000..8935e92556
--- /dev/null
+++ b/src/soc/amd/common/block/stb/Kconfig
@@ -0,0 +1,17 @@
+config SOC_AMD_COMMON_BLOCK_STB
+	bool
+	select SOC_AMD_COMMON_BLOCK_SMN
+	help
+	  Select in the SOC if it supports the Smart Trace Buffer
+
+if SOC_AMD_COMMON_BLOCK_STB
+
+config WRITE_STB_BUFFER_TO_CONSOLE
+	bool "Write STB entries to the console log"
+	default n
+	help
+	  This option will tell coreboot to print the STB buffer at various
+	  points through the boot process. Note that this will prevent the
+	  entries from being stored if the Spill-to-DRAM feature is enabled.
+
+endif
diff --git a/src/soc/amd/common/block/stb/Makefile.inc b/src/soc/amd/common/block/stb/Makefile.inc
new file mode 100644
index 0000000000..5ce9c4b228
--- /dev/null
+++ b/src/soc/amd/common/block/stb/Makefile.inc
@@ -0,0 +1,7 @@
+ifeq ($(CONFIG_SOC_AMD_COMMON_BLOCK_STB),y)
+
+bootblock-y += stb.c
+romstage-y += stb.c
+ramstage-y += stb.c
+
+endif # CONFIG_SOC_AMD_COMMON_BLOCK_STB
diff --git a/src/soc/amd/common/block/stb/stb.c b/src/soc/amd/common/block/stb/stb.c
new file mode 100644
index 0000000000..074a4ed714
--- /dev/null
+++ b/src/soc/amd/common/block/stb/stb.c
@@ -0,0 +1,67 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+
+#include <amdblocks/smn.h>
+#include <amdblocks/stb.h>
+#include <bootstate.h>
+#include <console/console.h>
+#include <soc/stb.h>
+
+#define STB_ENTRIES_PER_ROW 4
+
+static void stb_write32(uint32_t reg, uint32_t val)
+{
+	smn_write32(STB_CFG_SMN_ADDR + reg, val);
+}
+
+static uint32_t stb_read32(uint32_t reg)
+{
+	return smn_read32(STB_CFG_SMN_ADDR + reg);
+}
+
+void write_stb_to_console(void)
+{
+	int i;
+	int printed_data = 0;
+	struct stb_entry_struct stb_val;
+
+	/* Add a marker into the STB so it's easy to see where the end is. */
+	stb_write32(AMD_STB_PMI_0, AMD_STB_COREBOOT_MARKER);
+
+	for (i = 0; i < AMD_STB_SDRAM_FIFO_SIZE; i++) {
+		/*
+		 * It's possible to do a single read and leave the timestamp as the first
+		 * value of a pair, but by default the value will be first and time stamp
+		 * second.  We're just assuming that nothing has messed up the ordering.
+		 */
+		stb_val.val = stb_read32(AMD_STB_PMI_0);
+		stb_val.ts = stb_read32(AMD_STB_PMI_0);
+
+		if (stb_val.val == AMD_STB_COREBOOT_MARKER) {
+			if (!printed_data)
+				printk(BIOS_DEBUG, "No Smart Trace Buffer Data available.\n");
+			else
+				// Don't print the coreboot marker
+				printk(BIOS_DEBUG, "\n");
+			return;
+		}
+
+		if (i == 0)
+			printk(BIOS_DEBUG, "Available Smart Trace Buffer data:\n");
+		if ((i % STB_ENTRIES_PER_ROW) == 0)
+			printk(BIOS_DEBUG, "%04d,", i);
+		printk(BIOS_DEBUG, " 0x%08x,0x%08x, ", stb_val.ts, stb_val.val);
+		if ((i % STB_ENTRIES_PER_ROW) == STB_ENTRIES_PER_ROW - 1)
+			printk(BIOS_DEBUG, "\n");
+		printed_data = 1;
+
+	}
+
+}
+
+static void final_stb_console(void *unused)
+{
+	if (CONFIG(WRITE_STB_BUFFER_TO_CONSOLE))
+		write_stb_to_console();
+}
+
+BOOT_STATE_INIT_ENTRY(BS_PAYLOAD_BOOT, BS_ON_ENTRY, final_stb_console, NULL);