diff options
Diffstat (limited to 'src/soc/intel/xeon_sp/cpx/cpu.c')
| -rw-r--r-- | src/soc/intel/xeon_sp/cpx/cpu.c | 31 |
1 files changed, 31 insertions, 0 deletions
diff --git a/src/soc/intel/xeon_sp/cpx/cpu.c b/src/soc/intel/xeon_sp/cpx/cpu.c index 386401f7e3..1df5c1350c 100644 --- a/src/soc/intel/xeon_sp/cpx/cpu.c +++ b/src/soc/intel/xeon_sp/cpx/cpu.c @@ -188,3 +188,34 @@ void cpx_init_cpus(struct device *dev) /* update numa domain for all cpu devices */ xeonsp_init_cpu_config(); } + +msr_t read_msr_ppin(void) +{ + msr_t ppin = {0}; + msr_t msr; + + /* If MSR_PLATFORM_INFO PPIN_CAP is 0, PPIN capability is not supported */ + msr = rdmsr(MSR_PLATFORM_INFO); + if ((msr.lo & MSR_PPIN_CAP) == 0) { + printk(BIOS_ERR, "MSR_PPIN_CAP is 0, PPIN is not supported\n"); + return ppin; + } + + /* Access to MSR_PPIN is permitted only if MSR_PPIN_CTL LOCK is 0 and ENABLE is 1 */ + msr = rdmsr(MSR_PPIN_CTL); + if (msr.lo & MSR_PPIN_CTL_LOCK) { + printk(BIOS_ERR, "MSR_PPIN_CTL_LOCK is 1, PPIN access is not allowed\n"); + return ppin; + } + + if ((msr.lo & MSR_PPIN_CTL_ENABLE) == 0) { + /* Set MSR_PPIN_CTL ENABLE to 1 */ + msr.lo |= MSR_PPIN_CTL_ENABLE; + wrmsr(MSR_PPIN_CTL, msr); + } + ppin = rdmsr(MSR_PPIN); + /* Set enable to 0 after reading MSR_PPIN */ + msr.lo &= ~MSR_PPIN_CTL_ENABLE; + wrmsr(MSR_PPIN_CTL, msr); + return ppin; +} |