[PATCH v5 1/8] ACPI: CPPC: Add IS_OPTIONAL_CPC_REG macro to judge if a cpc_reg is optional

[Lifeng Zheng]

In ACPI 6.5, s8.4.6.1 _CPC (Continuous Performance Control), whether each
of the per-cpu cpc_regs[] is mendatory or optional is defined. Since the
CPC_SUPPORTED() check is only for optional cpc field, another macro to
check if the field is optional is needed.

Signed-off-by: Lifeng Zheng <zhenglifeng1@xxxxxxxxxx>
---
 drivers/acpi/cppc_acpi.c | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/drivers/acpi/cppc_acpi.c b/drivers/acpi/cppc_acpi.c
index f193e713825a..39f019e265da 100644
--- a/drivers/acpi/cppc_acpi.c
+++ b/drivers/acpi/cppc_acpi.c
@@ -129,6 +129,20 @@ static DEFINE_PER_CPU(struct cpc_desc *, cpc_desc_ptr);
 #define CPC_SUPPORTED(cpc) ((cpc)->type == ACPI_TYPE_INTEGER ?		\
 				!!(cpc)->cpc_entry.int_value :		\
 				!IS_NULL_REG(&(cpc)->cpc_entry.reg))
+
+/*
+ * Each bit indicates the optionality of the register in per-cpu
+ * cpc_regs[] with the corresponding index. 0 means mandatory and 1
+ * means optional.
+ */
+#define REG_OPTIONAL (0x1FC7D0)
+
+/*
+ * Use the index of the register in per-cpu cpc_regs[] to check if
+ * it's an optional one.
+ */
+#define IS_OPTIONAL_CPC_REG(reg_idx) (REG_OPTIONAL & (1U << (reg_idx)))
+
 /*
  * Arbitrary Retries in case the remote processor is slow to respond
  * to PCC commands. Keeping it high enough to cover emulators where
-- 
2.33.0