[coreboot-gerrit] Change in coreboot[master]: soc/intel/cannonlake: Add kconfig to override CPU flex ratio

[Subrata Banik (Code Review)]

Subrata Banik has uploaded this change for review. ( https://review.coreboot.org/c/coreboot/+/36864 )

Change subject: soc/intel/cannonlake: Add kconfig to override CPU flex ratio
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soc/intel/cannonlake: Add kconfig to override CPU flex ratio

This patch provides options to override FIT default CPU flex
ratio from coreboot code. CONFIG_CPU_FLEX_RATIO to provide the
required CPU ratio and CONFIG_OVERRIDE_CPU_FLEX_RATIO to tell if
override is required.

TEST=Without override flex_ratio is 0 and verified booting to
OS after overriding with flex_ratio value 5.

Change-Id: Ib01650f52f3d402f669e7e7f5b28a648b86f08ec
Signed-off-by: Subrata Banik 
---
M src/soc/intel/cannonlake/Kconfig
M src/soc/intel/cannonlake/romstage/fsp_params.c
2 files changed, 17 insertions(+), 1 deletion(-)

git pull ssh://review.coreboot.org:29418/coreboot refs/changes/64/36864/1

diff --git a/src/soc/intel/cannonlake/Kconfig b/src/soc/intel/cannonlake/Kconfig
index 5731cff..3f7afea 100644
--- a/src/soc/intel/cannonlake/Kconfig
+++ b/src/soc/intel/cannonlake/Kconfig
@@ -332,4 +332,17 @@
    hex
    default 0x40000 # 256KB

+config OVERRIDE_CPU_FLEX_RATIO
+	bool
+	help
+	  Provide an option to override CPU ratio value.
+
+config CPU_FLEX_RATIO
+	hex
+	depends on OVERRIDE_CPU_FLEX_RATIO
+	default 0
+	help
+	  CPU ratio value controls the maximum processor non-turbo ratio.
+	  Valid Range 0 to 63. CPU Ratio is 0 when disabled.
+
 endif
diff --git a/src/soc/intel/cannonlake/romstage/fsp_params.c b/src/soc/intel/cannonlake/romstage/fsp_params.c
index 996c135..5c0328b 100644
--- a/src/soc/intel/cannonlake/romstage/fsp_params.c
+++ b/src/soc/intel/cannonlake/romstage/fsp_params.c
@@ -77,7 +77,10 @@
    /* Set CpuRatio to match existing MSR value */
    msr_t flex_ratio;
    flex_ratio = rdmsr(MSR_FLEX_RATIO);
-	m_cfg->CpuRatio = (flex_ratio.lo >> 8) & 0xff;
+	if (CONFIG(OVERRIDE_CPU_FLEX_RATIO))
+		m_cfg->CpuRatio = CONFIG_CPU_FLEX_RATIO;
+	else
+		m_cfg->CpuRatio = (flex_ratio.lo >> 8) & 0xff;

/* If ISH is enabled, enable ISH elements */
    if (!dev)