diff options
| author | Tim Wawrzynczak <twawrzynczak@chromium.org> | 2022-08-16 14:25:56 -0600 |
|---|---|---|
| committer | Felix Held <felix-coreboot@felixheld.de> | 2022-09-01 14:08:46 +0000 |
| commit | 4dfcd7acdc705994cd20c27d5e3edfae31672b64 (patch) | |
| tree | d4675d556ea773af54fcb20eaa2df22bbae3350c /src/mainboard/google/brya/acpi | |
| parent | afa72ee6842b14ebca7b403961784336c0361fe1 (diff) | |
mb/google/brya/acpi: Save/restore/clear some registers over GC6
Nvidia recommends saving and restoring the LTR Enable bit in PCIe config
space for the PCIe root port before/after GC6 entry. Also the detectable
error bit should be cleared, as there may be errors expected during the
GC6 flow.
BUG=b:214581763
TEST=no more correctable errors after GC6 entry/exit
Signed-off-by: Tim Wawrzynczak <twawrzynczak@chromium.org>
Change-Id: I058ce1b3f17fb6cc59785a85efaf9ea0504cf2ee
Reviewed-on: https://review.coreboot.org/c/coreboot/+/66808
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Anil Kumar K <anil.kumar.k@intel.corp-partner.google.com>
Reviewed-by: Ivy Jian <ivy.jian@quanta.corp-partner.google.com>
Diffstat (limited to 'src/mainboard/google/brya/acpi')
| -rw-r--r-- | src/mainboard/google/brya/acpi/peg.asl | 5 | ||||
| -rw-r--r-- | src/mainboard/google/brya/acpi/power.asl | 25 |
2 files changed, 30 insertions, 0 deletions
diff --git a/src/mainboard/google/brya/acpi/peg.asl b/src/mainboard/google/brya/acpi/peg.asl index e804c78e3b..d0c76c8dc8 100644 --- a/src/mainboard/google/brya/acpi/peg.asl +++ b/src/mainboard/google/brya/acpi/peg.asl @@ -6,9 +6,14 @@ External (\_SB.PCI0.PEG0.PEGP.NPOF, MethodObj) OperationRegion (PCIC, PCI_Config, 0x00, 0x100) Field (PCIC, AnyAcc, NoLock, Preserve) { + Offset (0x4a), + CEDR, 1, /* Correctable Error Detected, RW/1C/V */ Offset (0x52), , 13, LASX, 1, /* Link Active Status */ + Offset (0x69), + , 2, + LREN, 1, /* LTR Enabled */ Offset (0xe0), , 7, NCB7, 1, /* Scratch bit to save L2/3 state */ diff --git a/src/mainboard/google/brya/acpi/power.asl b/src/mainboard/google/brya/acpi/power.asl index 67aee5b50e..ecd48e7a76 100644 --- a/src/mainboard/google/brya/acpi/power.asl +++ b/src/mainboard/google/brya/acpi/power.asl @@ -1,5 +1,7 @@ /* SPDX-License-Identifier: GPL-2.0-or-later */ +#include <device/pci_ids.h> + External (\_SB.PCI0.PMC.IPCS, MethodObj) /* Voltage rail control signals */ @@ -70,6 +72,8 @@ Name (GCOT, 0) #define PMC_RP_IDX (1 << 27) #define PMC_RP_ENABLE (1 << 27) #define PMC_RP_DISABLE 0x0 +/* Copy of LTR enable bit from PEG port */ +Name (SLTR, 0) /* Control the PCIe SRCCLK# for dGPU */ Method (SRCC, 1, Serialized) @@ -94,6 +98,9 @@ Method (GC6I, 0, Serialized) { GC6E = GC6_STATE_TRANSITION + /* Save the PEG port's LTR setting */ + SLTR = LREN + /* Put PCIe link into L2/3 */ \_SB.PCI0.PEG0.DL23 () @@ -152,6 +159,24 @@ Method (GC6O, 0, Serialized) \_SB.PCI0.PEG0.LD23 () Printf ("dGPU exited GC6") + /* Wait for dGPU to reappear on the bus */ + Local0 = 50 + While (NVID != PCI_VID_NVIDIA) + { + Stall (100) + Local0-- + If (Local0 == 0) + { + Break + } + } + + /* Restore the PEG LTR enable bit */ + LREN = SLTR + + /* Clear recoverable errors detected bit */ + CEDR = 1 + GC6E = GC6_STATE_EXITED } |