From 1909c3ba9f5cf1508202399d7b5c56c5f9533456 Mon Sep 17 00:00:00 2001 From: Patrick Rudolph Date: Sat, 30 Sep 2023 11:18:07 +0200 Subject: [PATCH] cpu/intel/model_206ax: Only use supported C-states MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit When advertising C-state using the ACPI _CST object, make sure to only advertise those that are supported by the CPU. Downgrade if it's not and make sure to not advertise duplicate states. Add debug prints for the finally selected mapping of ACPI C-state vs Intel CPU C-state. Test: Tested on Lenovo X220. All C-states are still advertised as all are supported. Change-Id: Iaaee050e0ce3c29c12e97f5819a29f485a7946c2 Signed-off-by: Patrick Rudolph Reviewed-on: https://review.coreboot.org/c/coreboot/+/78194 Tested-by: build bot (Jenkins) Reviewed-by: Kyösti Mälkki --- src/cpu/intel/model_206ax/acpi.c | 64 +++++++++++++++++++++++++++++--- 1 file changed, 59 insertions(+), 5 deletions(-) diff --git a/src/cpu/intel/model_206ax/acpi.c b/src/cpu/intel/model_206ax/acpi.c index c4f58397e8..f3bd67be4b 100644 --- a/src/cpu/intel/model_206ax/acpi.c +++ b/src/cpu/intel/model_206ax/acpi.c @@ -87,23 +87,77 @@ static void print_supported_cstates(void) printk(BIOS_DEBUG, "\n"); } +/* + * Returns the supported C-state or the next lower one that + * is supported. + */ +static int get_supported_cstate(int cstate) +{ + uint8_t state, substate; + size_t i; + + assert(cstate < NUM_C_STATES); + + for (i = cstate; i > 0; i--) { + state = (cstate_map[i].resource.addrl >> 4) + 1; + substate = cstate_map[i].resource.addrl & 0xf; + if (cpu_get_c_substate_support(state) > substate) + break; + } + + if (cstate != i) + printk(BIOS_INFO, "Requested C-state %s not supported, using %s instead\n", + c_state_names[cstate], c_state_names[i]); + + return i; +} + static void generate_C_state_entries(const struct device *dev) { struct cpu_intel_model_206ax_config *conf = dev->chip_info; - const int acpi_cstates[3] = { conf->acpi_c1, conf->acpi_c2, conf->acpi_c3 }; + int acpi_cstates[3] = { conf->acpi_c1, conf->acpi_c2, conf->acpi_c3 }; acpi_cstate_t acpi_cstate_map[ARRAY_SIZE(acpi_cstates)] = { 0 }; /* Count number of active C-states */ int count = 0; for (int i = 0; i < ARRAY_SIZE(acpi_cstates); i++) { - if (acpi_cstates[i] > 0 && acpi_cstates[i] < ARRAY_SIZE(cstate_map)) { - acpi_cstate_map[count] = cstate_map[acpi_cstates[i]]; - acpi_cstate_map[count].ctype = i + 1; - count++; + /* Remove invalid states */ + if (acpi_cstates[i] >= ARRAY_SIZE(cstate_map)) { + printk(BIOS_ERR, "Invalid C-state in devicetree: %d\n", + acpi_cstates[i]); + acpi_cstates[i] = 0; + continue; + } + /* Skip C0, it's always supported */ + if (acpi_cstates[i] == 0) + continue; + + /* Find supported state. Might downgrade a state. */ + acpi_cstates[i] = get_supported_cstate(acpi_cstates[i]); + + /* Remove duplicate states */ + for (int j = i - 1; j >= 0; j--) { + if (acpi_cstates[i] == acpi_cstates[j]) { + acpi_cstates[i] = 0; + break; + } } } + + /* Convert C-state to ACPI C-states */ + for (int i = 0; i < ARRAY_SIZE(acpi_cstates); i++) { + if (acpi_cstates[i] == 0) + continue; + acpi_cstate_map[count] = cstate_map[acpi_cstates[i]]; + acpi_cstate_map[count].ctype = i + 1; + + count++; + printk(BIOS_DEBUG, "Advertising ACPI C State type C%d as CPU %s\n", + i + 1, c_state_names[acpi_cstates[i]]); + } + acpigen_write_CST_package(acpi_cstate_map, count); }