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authorDuncan Laurie <dlaurie@chromium.org>2015-01-20 07:53:27 -0800
committerStefan Reinauer <stefan.reinauer@coreboot.org>2015-04-10 20:17:53 +0200
commitff0f460e764e24d4f7bae7e9dce8967f9cd3e36c (patch)
treeb46032b2780d0b1e7588e7bdba031ad58f55e82d
parentba081ef50dd6cd62de1165e8315aca9b3a40c337 (diff)
downloadcoreboot-ff0f460e764e24d4f7bae7e9dce8967f9cd3e36c.tar.xz
broadwell: Add configuration for tuning VR for C-state operations
Add some configuration options that allow tuning the VR for C-state settings that may be able to reduce noise. - Add option to enable slow VR ramp rate for C-state exit - Add variable to configure the minimum C6/C7 voltage BUG=chrome-os-partner:34771 BRANCH=broadwell TEST=build and boot on samus Change-Id: I01445d62fbfcf200b787b924d8d72685819a4715 Signed-off-by: Stefan Reinauer <reinauer@chromium.org> Original-Commit-Id: ed8f355e60292c82791817ae31bff58ac2390a72 Original-Change-Id: I8af75b69c8b55d3e210170ee96f8e22c2fd76374 Original-Signed-off-by: Duncan Laurie <dlaurie@chromium.org> Original-Reviewed-on: https://chromium-review.googlesource.com/241950 Original-Reviewed-by: Aaron Durbin <adurbin@chromium.org> Reviewed-on: http://review.coreboot.org/9497 Tested-by: build bot (Jenkins) Reviewed-by: Patrick Georgi <pgeorgi@google.com>
-rw-r--r--src/soc/intel/broadwell/chip.h22
-rw-r--r--src/soc/intel/broadwell/cpu.c20
2 files changed, 38 insertions, 4 deletions
diff --git a/src/soc/intel/broadwell/chip.h b/src/soc/intel/broadwell/chip.h
index 703c865a8f..77c517d5ec 100644
--- a/src/soc/intel/broadwell/chip.h
+++ b/src/soc/intel/broadwell/chip.h
@@ -130,6 +130,28 @@ struct soc_intel_broadwell_config {
/* Enable S0iX support */
int s0ix_enable;
+ /*
+ * Minimum voltage for C6/C7 state:
+ * 0x67 = 1.6V (full swing)
+ * ...
+ * 0x79 = 1.7V
+ * ...
+ * 0x83 = 1.8V (no swing)
+ */
+ int vr_cpu_min_vid;
+
+ /*
+ * Set slow VR ramp rate on C-state exit:
+ * 0 = Fast VR ramp rate / 2
+ * 1 = Fast VR ramp rate / 4
+ * 2 = Fast VR ramp rate / 8
+ * 3 = Fast VR ramp rate / 16
+ */
+ int vr_slow_ramp_rate_set;
+
+ /* Enable slow VR ramp rate */
+ int vr_slow_ramp_rate_enable;
+
/* Deep SX enable */
int deep_sx_enable_ac;
int deep_sx_enable_dc;
diff --git a/src/soc/intel/broadwell/cpu.c b/src/soc/intel/broadwell/cpu.c
index b227e0df97..9073241e30 100644
--- a/src/soc/intel/broadwell/cpu.c
+++ b/src/soc/intel/broadwell/cpu.c
@@ -180,6 +180,8 @@ static u32 pcode_mailbox_read(u32 command)
static void initialize_vr_config(void)
{
+ device_t dev = SA_DEV_ROOT;
+ config_t *conf = dev->chip_info;
msr_t msr;
printk(BIOS_DEBUG, "Initializing VR config.\n");
@@ -203,17 +205,27 @@ static void initialize_vr_config(void)
msr.hi |= (0x200 << (40 - 32)); /* 1.0 */
/* Set IOUT_OFFSET to 0. */
msr.hi &= ~0xff;
- /* Set exit ramp rate to fast. */
- msr.hi |= (1 << (50 - 32));
/* Set entry ramp rate to slow. */
msr.hi &= ~(1 << (51 - 32));
/* Enable decay mode on C-state entry. */
msr.hi |= (1 << (52 - 32));
- /* Set the slow ramp rate to be fast ramp rate / 4 */
+ /* Set the slow ramp rate */
msr.hi &= ~(0x3 << (53 - 32));
- msr.hi |= (0x01 << (53 - 32));
+ /* Configure the C-state exit ramp rate. */
+ if (conf->vr_slow_ramp_rate_enable) {
+ /* Configured slow ramp rate. */
+ msr.hi |= ((conf->vr_slow_ramp_rate_set & 0x3) << (53 - 32));
+ /* Set exit ramp rate to slow. */
+ msr.hi &= ~(1 << (50 - 32));
+ } else {
+ /* Fast ramp rate / 4. */
+ msr.hi |= (0x01 << (53 - 32));
+ /* Set exit ramp rate to fast. */
+ msr.hi |= (1 << (50 - 32));
+ }
/* Set MIN_VID (31:24) to allow CPU to have full control. */
msr.lo &= ~0xff000000;
+ msr.lo |= (conf->vr_cpu_min_vid & 0xff) << 24;
wrmsr(MSR_VR_MISC_CONFIG, msr);
/* Configure VR_MISC_CONFIG2 MSR. */