From ff0f460e764e24d4f7bae7e9dce8967f9cd3e36c Mon Sep 17 00:00:00 2001 From: Duncan Laurie Date: Tue, 20 Jan 2015 07:53:27 -0800 Subject: 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 Original-Commit-Id: ed8f355e60292c82791817ae31bff58ac2390a72 Original-Change-Id: I8af75b69c8b55d3e210170ee96f8e22c2fd76374 Original-Signed-off-by: Duncan Laurie Original-Reviewed-on: https://chromium-review.googlesource.com/241950 Original-Reviewed-by: Aaron Durbin Reviewed-on: http://review.coreboot.org/9497 Tested-by: build bot (Jenkins) Reviewed-by: Patrick Georgi --- src/soc/intel/broadwell/cpu.c | 20 ++++++++++++++++---- 1 file changed, 16 insertions(+), 4 deletions(-) (limited to 'src/soc/intel/broadwell/cpu.c') 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. */ -- cgit v1.2.3