1 files changed, 65 insertions, 0 deletions
diff --git a/src/soc/intel/broadwell/cpu/bootblock.c b/src/soc/intel/broadwell/cpu/bootblock.c
new file mode 100644
index 0000000000..d6883c6436
--- /dev/null
+++ b/src/soc/intel/broadwell/cpu/bootblock.c
@@ -0,0 +1,65 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+
+#include <stdint.h>
+#include <arch/bootblock.h>
+#include <arch/io.h>
+#include <cpu/x86/msr.h>
+#include <halt.h>
+#include <soc/rcba.h>
+#include <soc/msr.h>
+#include <delay.h>
+
+static void set_flex_ratio_to_tdp_nominal(void)
+{
+	msr_t flex_ratio, msr;
+	u32 soft_reset;
+	u8 nominal_ratio;
+
+	/* Check for Flex Ratio support */
+	flex_ratio = rdmsr(MSR_FLEX_RATIO);
+	if (!(flex_ratio.lo & FLEX_RATIO_EN))
+		return;
+
+	/* Check for >0 configurable TDPs */
+	msr = rdmsr(MSR_PLATFORM_INFO);
+	if (((msr.hi >> 1) & 3) == 0)
+		return;
+
+	/* Use nominal TDP ratio for flex ratio */
+	msr = rdmsr(MSR_CONFIG_TDP_NOMINAL);
+	nominal_ratio = msr.lo & 0xff;
+
+	/* See if flex ratio is already set to nominal TDP ratio */
+	if (((flex_ratio.lo >> 8) & 0xff) == nominal_ratio)
+		return;
+
+	/* Set flex ratio to nominal TDP ratio */
+	flex_ratio.lo &= ~0xff00;
+	flex_ratio.lo |= nominal_ratio << 8;
+	flex_ratio.lo |= FLEX_RATIO_LOCK;
+	wrmsr(MSR_FLEX_RATIO, flex_ratio);
+
+	/* Set flex ratio in soft reset data register bits 11:6.
+	 * RCBA region is enabled in southbridge bootblock */
+	soft_reset = RCBA32(SOFT_RESET_DATA);
+	soft_reset &= ~(0x3f << 6);
+	soft_reset |= (nominal_ratio & 0x3f) << 6;
+	RCBA32(SOFT_RESET_DATA) = soft_reset;
+
+	/* Set soft reset control to use register value */
+	RCBA32_OR(SOFT_RESET_CTRL, 1);
+
+	/* Delay before reset to avoid potential TPM lockout */
+	mdelay(30);
+
+	/* Issue warm reset, will be "CPU only" due to soft reset data */
+	outb(0x0, 0xcf9);
+	outb(0x6, 0xcf9);
+	halt();
+}
+
+void bootblock_early_cpu_init(void)
+{
+	/* Set flex ratio and reset if needed */
+	set_flex_ratio_to_tdp_nominal();
+}