diff options
| -rw-r--r-- | src/northbridge/intel/sandybridge/early_init.c | 44 |
1 files changed, 44 insertions, 0 deletions
diff --git a/src/northbridge/intel/sandybridge/early_init.c b/src/northbridge/intel/sandybridge/early_init.c index 81bf9d5854..b8daedc133 100644 --- a/src/northbridge/intel/sandybridge/early_init.c +++ b/src/northbridge/intel/sandybridge/early_init.c @@ -148,6 +148,41 @@ static void sandybridge_setup_graphics(void) MCHBAR32(0x5418) = reg32; } +static void start_peg_link_training(void) +{ + u32 tmp; + u32 deven; + + /* PEG on IvyBridge+ needs a special startup sequence. + * As the MRC has its own initialization code skip it. */ + if (((pci_read_config16(PCI_DEV(0, 0, 0), PCI_DEVICE_ID) & + BASE_REV_MASK) != BASE_REV_IVB) || + IS_ENABLED(CONFIG_HAVE_MRC)) + return; + + deven = pci_read_config32(PCI_DEV(0, 0, 0), DEVEN); + + if (deven & DEVEN_PEG10) { + tmp = pci_read_config32(PCI_DEV(0, 1, 0), 0xC24) & ~(1 << 16); + pci_write_config32(PCI_DEV(0, 1, 0), 0xC24, tmp | (1 << 5)); + } + + if (deven & DEVEN_PEG11) { + tmp = pci_read_config32(PCI_DEV(0, 1, 1), 0xC24) & ~(1 << 16); + pci_write_config32(PCI_DEV(0, 1, 1), 0xC24, tmp | (1 << 5)); + } + + if (deven & DEVEN_PEG12) { + tmp = pci_read_config32(PCI_DEV(0, 1, 2), 0xC24) & ~(1 << 16); + pci_write_config32(PCI_DEV(0, 1, 2), 0xC24, tmp | (1 << 5)); + } + + if (deven & DEVEN_PEG60) { + tmp = pci_read_config32(PCI_DEV(0, 6, 0), 0xC24) & ~(1 << 16); + pci_write_config32(PCI_DEV(0, 6, 0), 0xC24, tmp | (1 << 5)); + } +} + void sandybridge_early_initialization(int chipset_type) { u32 capid0_a; @@ -177,6 +212,15 @@ void sandybridge_early_initialization(int chipset_type) pci_write_config32(PCI_DEV(0, 0, 0), DEVEN, deven); sandybridge_setup_graphics(); + + /* Write magic value to start PEG link training. + * This should be done in PCI device enumeration, but + * the PCIe specification requires to wait at least 100msec + * after reset for devices to come up. + * As we don't want to increase boot time, enable it early and + * assume the PEG is up as soon as PCI enumeration starts. + * TODO: use time stamps to ensure the timings are met */ + start_peg_link_training(); } void northbridge_romstage_finalize(int s3resume) |