ACPI: CPPC: Add support for CPPC v4

CPPC v4 (ACPI 6.6, Section 8.4.6) adds two optional entries to the
_CPC package:

1. OSPM Nominal Performance (8.4.6.1.2.6): A write-only register that
   lets OSPM inform the platform what it considers nominal performance.
   The platform classifies performance above this level as boost and
   below as throttle for its power/thermal decisions.

2. Resource Priority (8.4.6.1.2.7): A Package of Resource Priority
   Register Descriptor sub-packages that allow OSPM to set relative
   priority among processors for shared resources (boost, throttle,
   L2/L3 cache, memory bandwidth). Parsing the full structure is not
   yet supported; such entries are marked as unsupported.

Add v4 _CPC table parsing (25 entries) and update REG_OPTIONAL to
mark the two new registers as optional.

Signed-off-by: Sumit Gupta <sumitg@nvidia.com>
Reviewed-by: Mario Limonciello (AMD) <superm1@kernel.org>
Reviewed-by: Pierre Gondois <pierre.gondois@arm.com>
Link: https://patch.msgid.link/20260527194626.185286-2-sumitg@nvidia.com
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

diff --git a/drivers/acpi/cppc_acpi.c b/drivers/acpi/cppc_acpi.c
index f370be8715ae2495fcd408c7c941e171a79fd65c..c76cfafa358972435864de65b1dfd9a18d19857a 100644 (file)
--- a/drivers/acpi/cppc_acpi.c
+++ b/drivers/acpi/cppc_acpi.c
@@ -134,7 +134,7 @@ static DEFINE_PER_CPU(struct cpc_desc *, cpc_desc_ptr);
  * cpc_regs[] with the corresponding index. 0 means mandatory and 1
  * means optional.
  */
-#define REG_OPTIONAL (0x1FC7D0)
+#define REG_OPTIONAL (0x7FC7D0)
 
 /*
  * Use the index of the register in per-cpu cpc_regs[] to check if
@@ -751,18 +751,19 @@ int acpi_cppc_processor_probe(struct acpi_processor *pr)
        /*
         * Disregard _CPC if the number of entries in the return package is not
         * as expected, but support future revisions being proper supersets of
-        * the v3 and only causing more entries to be returned by _CPC.
+        * the v4 and only causing more entries to be returned by _CPC.
         */
        if ((cpc_rev == CPPC_V2_REV && num_ent != CPPC_V2_NUM_ENT) ||
            (cpc_rev == CPPC_V3_REV && num_ent != CPPC_V3_NUM_ENT) ||
-           (cpc_rev > CPPC_V3_REV && num_ent <= CPPC_V3_NUM_ENT)) {
+           (cpc_rev == CPPC_V4_REV && num_ent != CPPC_V4_NUM_ENT) ||
+           (cpc_rev > CPPC_V4_REV && num_ent <= CPPC_V4_NUM_ENT)) {
                pr_debug("Unexpected number of _CPC return package entries (%d) for CPU:%d\n",
                         num_ent, pr->id);
                goto out_free;
        }
-       if (cpc_rev > CPPC_V3_REV) {
-               num_ent = CPPC_V3_NUM_ENT;
-               cpc_rev = CPPC_V3_REV;
+       if (cpc_rev > CPPC_V4_REV) {
+               num_ent = CPPC_V4_NUM_ENT;
+               cpc_rev = CPPC_V4_REV;
        }
 
        cpc_ptr->num_entries = num_ent;
@@ -845,6 +846,16 @@ int acpi_cppc_processor_probe(struct acpi_processor *pr)
 
                        cpc_ptr->cpc_regs[i-2].type = ACPI_TYPE_BUFFER;
                        memcpy(&cpc_ptr->cpc_regs[i-2].cpc_entry.reg, gas_t, sizeof(*gas_t));
+               } else if (cpc_obj->type == ACPI_TYPE_PACKAGE && (i - 2) == RESOURCE_PRIORITY) {
+                       /*
+                        * ACPI 6.6, s8.4.6.1.2.7 defines Resource Priority as a
+                        * Package of Resource Priority Register Descriptor sub-packages.
+                        * Parsing the full structure is not yet supported.
+                        * Mark the register as unsupported for now.
+                        */
+                       pr_debug("CPU:%d Resource Priority not supported\n", pr->id);
+                       cpc_ptr->cpc_regs[i-2].type = ACPI_TYPE_INTEGER;
+                       cpc_ptr->cpc_regs[i-2].cpc_entry.int_value = 0;
                } else {
                        pr_debug("Invalid entry type (%d) in _CPC for CPU:%d\n",
                                 i, pr->id);

diff --git a/include/acpi/cppc_acpi.h b/include/acpi/cppc_acpi.h
index d1f02ceec4f98d7c7bee357b1285a9394bd04be1..8693890a72756471fa6ccea003a0b8c81d0c95ae 100644 (file)
--- a/include/acpi/cppc_acpi.h
+++ b/include/acpi/cppc_acpi.h
@@ -17,16 +17,18 @@
 #include <acpi/pcc.h>
 #include <acpi/processor.h>
 
-/* CPPCv2 and CPPCv3 support */
+/* CPPCv2, CPPCv3 and CPPCv4 support */
 #define CPPC_V2_REV    2
 #define CPPC_V3_REV    3
+#define CPPC_V4_REV    4
 #define CPPC_V2_NUM_ENT        21
 #define CPPC_V3_NUM_ENT        23
+#define CPPC_V4_NUM_ENT        25
 
 #define PCC_CMD_COMPLETE_MASK  (1 << 0)
 #define PCC_ERROR_MASK         (1 << 2)
 
-#define MAX_CPC_REG_ENT 21
+#define MAX_CPC_REG_ENT 23
 
 /* CPPC specific PCC commands. */
 #define        CMD_READ 0
@@ -109,6 +111,8 @@ enum cppc_regs {
        REFERENCE_PERF,
        LOWEST_FREQ,
        NOMINAL_FREQ,
+       OSPM_NOMINAL_PERF,
+       RESOURCE_PRIORITY,
 };
 
 /*