The PMIIDR value is composed by the values in PMPIDR registers.
We can use PMPIDR registers as alternative for device
identification for systems that do not implement PMIIDR.

Reviewed-by: Ilkka Koskinen <ilkka@os.amperecomputing.com>
Signed-off-by: Besar Wicaksono <bwicaksono@nvidia.com>
---
 drivers/perf/arm_cspmu/arm_cspmu.c    | 44 +++++++++++++++++++++++++--
 drivers/perf/arm_cspmu/arm_cspmu.h    | 35 +++++++++++++++++++--
 drivers/perf/arm_cspmu/nvidia_cspmu.c |  2 +-
 3 files changed, 75 insertions(+), 6 deletions(-)

diff --git a/drivers/perf/arm_cspmu/arm_cspmu.c b/drivers/perf/arm_cspmu/arm_cspmu.c
index 43770c8ecd14..d0ec1eb8272f 100644
--- a/drivers/perf/arm_cspmu/arm_cspmu.c
+++ b/drivers/perf/arm_cspmu/arm_cspmu.c
@@ -322,14 +322,14 @@ static struct arm_cspmu_impl_match impl_match[] = {
 	{
 		.module_name	= "nvidia_cspmu",
 		.pmiidr_val	= ARM_CSPMU_IMPL_ID_NVIDIA,
-		.pmiidr_mask	= ARM_CSPMU_PMIIDR_IMPLEMENTER,
+		.pmiidr_mask	= PMIIDR_IMPLEMENTER,
 		.module		= NULL,
 		.impl_init_ops	= NULL,
 	},
 	{
 		.module_name	= "ampere_cspmu",
 		.pmiidr_val	= ARM_CSPMU_IMPL_ID_AMPERE,
-		.pmiidr_mask	= ARM_CSPMU_PMIIDR_IMPLEMENTER,
+		.pmiidr_mask	= PMIIDR_IMPLEMENTER,
 		.module		= NULL,
 		.impl_init_ops	= NULL,
 	},
@@ -351,6 +351,44 @@ static struct arm_cspmu_impl_match *arm_cspmu_impl_match_get(u32 pmiidr)
 	return NULL;
 }
 
+static u32 arm_cspmu_get_pmiidr(struct arm_cspmu *cspmu)
+{
+	u32 pmiidr, pmpidr;
+
+	pmiidr = readl(cspmu->base0 + PMIIDR);
+
+	if (pmiidr != 0)
+		return pmiidr;
+
+	/* Construct PMIIDR value from PMPIDRs. */
+
+	pmpidr = readl(cspmu->base0 + PMPIDR0);
+	pmiidr |= FIELD_PREP(PMIIDR_PRODUCTID_PART_0,
+				FIELD_GET(PMPIDR0_PART_0, pmpidr));
+
+	pmpidr = readl(cspmu->base0 + PMPIDR1);
+	pmiidr |= FIELD_PREP(PMIIDR_PRODUCTID_PART_1,
+				FIELD_GET(PMPIDR1_PART_1, pmpidr));
+	pmiidr |= FIELD_PREP(PMIIDR_IMPLEMENTER_DES_0,
+				FIELD_GET(PMPIDR1_DES_0, pmpidr));
+
+	pmpidr = readl(cspmu->base0 + PMPIDR2);
+	pmiidr |= FIELD_PREP(PMIIDR_VARIANT,
+				FIELD_GET(PMPIDR2_REVISION, pmpidr));
+	pmiidr |= FIELD_PREP(PMIIDR_IMPLEMENTER_DES_1,
+				FIELD_GET(PMPIDR2_DES_1, pmpidr));
+
+	pmpidr = readl(cspmu->base0 + PMPIDR3);
+	pmiidr |= FIELD_PREP(PMIIDR_REVISION,
+				FIELD_GET(PMPIDR3_REVAND, pmpidr));
+
+	pmpidr = readl(cspmu->base0 + PMPIDR4);
+	pmiidr |= FIELD_PREP(PMIIDR_IMPLEMENTER_DES_2,
+				FIELD_GET(PMPIDR4_DES_2, pmpidr));
+
+	return pmiidr;
+}
+
 #define DEFAULT_IMPL_OP(name)	.name = arm_cspmu_##name
 
 static int arm_cspmu_init_impl_ops(struct arm_cspmu *cspmu)
@@ -361,7 +399,7 @@ static int arm_cspmu_init_impl_ops(struct arm_cspmu *cspmu)
 
 	/* Start with a default PMU implementation */
 	cspmu->impl.module = THIS_MODULE;
-	cspmu->impl.pmiidr = readl(cspmu->base0 + PMIIDR);
+	cspmu->impl.pmiidr = arm_cspmu_get_pmiidr(cspmu);
 	cspmu->impl.ops = (struct arm_cspmu_impl_ops) {
 		DEFAULT_IMPL_OP(get_event_attrs),
 		DEFAULT_IMPL_OP(get_format_attrs),
diff --git a/drivers/perf/arm_cspmu/arm_cspmu.h b/drivers/perf/arm_cspmu/arm_cspmu.h
index 21d7e6e2f2da..16799d596e9a 100644
--- a/drivers/perf/arm_cspmu/arm_cspmu.h
+++ b/drivers/perf/arm_cspmu/arm_cspmu.h
@@ -87,6 +87,11 @@
 #define PMCFGR				0xE00
 #define PMCR				0xE04
 #define PMIIDR				0xE08
+#define PMPIDR0				0xFE0
+#define PMPIDR1				0xFE4
+#define PMPIDR2				0xFE8
+#define PMPIDR3				0xFEC
+#define PMPIDR4				0xFD0
 
 /* PMCFGR register field */
 #define PMCFGR_NCG			GENMASK(31, 28)
@@ -116,8 +121,34 @@
 #define PMCR_E				BIT(0)
 
 /* PMIIDR register field */
-#define ARM_CSPMU_PMIIDR_IMPLEMENTER	GENMASK(11, 0)
-#define ARM_CSPMU_PMIIDR_PRODUCTID	GENMASK(31, 20)
+#define PMIIDR_IMPLEMENTER		GENMASK(11, 0)
+#define PMIIDR_IMPLEMENTER_DES_0	GENMASK(3, 0)
+#define PMIIDR_IMPLEMENTER_DES_1	GENMASK(6, 4)
+#define PMIIDR_IMPLEMENTER_DES_2	GENMASK(11, 8)
+#define PMIIDR_REVISION			GENMASK(15, 12)
+#define PMIIDR_VARIANT			GENMASK(19, 16)
+#define PMIIDR_PRODUCTID		GENMASK(31, 20)
+#define PMIIDR_PRODUCTID_PART_0		GENMASK(27, 20)
+#define PMIIDR_PRODUCTID_PART_1		GENMASK(31, 28)
+
+/* PMPIDR0 register field */
+#define PMPIDR0_PART_0			GENMASK(7, 0)
+
+/* PMPIDR1 register field */
+#define PMPIDR1_DES_0			GENMASK(7, 4)
+#define PMPIDR1_PART_1			GENMASK(3, 0)
+
+/* PMPIDR2 register field */
+#define PMPIDR2_REVISION		GENMASK(7, 4)
+#define PMPIDR2_DES_1			GENMASK(2, 0)
+
+/* PMPIDR3 register field */
+#define PMPIDR3_REVAND			GENMASK(7, 4)
+#define PMPIDR3_CMOD			GENMASK(3, 0)
+
+/* PMPIDR4 register field */
+#define PMPIDR4_SIZE			GENMASK(7, 4)
+#define PMPIDR4_DES_2			GENMASK(3, 0)
 
 /* JEDEC-assigned JEP106 identification code */
 #define ARM_CSPMU_IMPL_ID_NVIDIA	0x36B
diff --git a/drivers/perf/arm_cspmu/nvidia_cspmu.c b/drivers/perf/arm_cspmu/nvidia_cspmu.c
index dc6d4e3e2a1b..b6cec351a142 100644
--- a/drivers/perf/arm_cspmu/nvidia_cspmu.c
+++ b/drivers/perf/arm_cspmu/nvidia_cspmu.c
@@ -322,7 +322,7 @@ static int nv_cspmu_init_ops(struct arm_cspmu *cspmu)
 	if (!ctx)
 		return -ENOMEM;
 
-	prodid = FIELD_GET(ARM_CSPMU_PMIIDR_PRODUCTID, cspmu->impl.pmiidr);
+	prodid = FIELD_GET(PMIIDR_PRODUCTID, cspmu->impl.pmiidr);
 
 	/* Find matching PMU. */
 	for (; match->prodid; match++) {
-- 
2.50.1