platform: xuantie: Harden xuantie link pmu init

Several robustness fixes in xuantie_link_pmu_device_init():

- Use `>= 0` to validate fdt_node_offset_by_compatible() result; the
  previous `> 0` check would miss a node at offset 0.
- Iterate all instances of each PMU compatible instead of only the
  first one, so multi-cluster SoCs initialise every L3 PMU.
- Skip nodes with status = "disabled" via fdt_node_is_enabled().
- Default-inhibit all counters (matches the kernel driver probe
  behaviour) so counters do not free-run between OpenSBI and kernel
  handoff.
- Replace magic numbers with named macros (CNT_BITMAP, AUTHCR_AUTH,
  AUTHCR_INTPEND).
- Bail out early if fdt_get_address_rw() returns NULL.

Signed-off-by: Chen Pei <cp0613@linux.alibaba.com>

Author: cp0613

platform/generic/include/xuantie/xuantie_link.h

@@ -28,6 +28,11 @@
 #define XUANTIE_LINK_PMU_HPCPINTPEND		0x5e8
 #define XUANTIE_LINK_PMU_VENDOR_N_IMP_ID	0x600 // XL300
 
+#define XUANTIE_LINK_PMU_NUM_COUNTERS		6
+#define XUANTIE_LINK_PMU_CNT_BITMAP			GENMASK_ULL(XUANTIE_LINK_PMU_NUM_COUNTERS - 1, 0)
+#define XUANTIE_LINK_PMU_AUTHCR_AUTH		BIT_ULL(40)
+#define XUANTIE_LINK_PMU_AUTHCR_INTPEND		BIT_ULL(32)
+
 /* HPCP dev type */
 #define XUANTIE_LINK_DEV_TYPE_XL100 100
 #define XUANTIE_LINK_DEV_TYPE_XL200 200

platform/generic/xuantie/xuantie_link.c

@@ -12,29 +12,48 @@
 int xuantie_link_pmu_device_init(void)
 {
 #if __riscv_xlen == 64
-	int nodeoffset, rc, dev_type;
-	uint64_t addr;
+	static const struct {
+		const char *compat;
+		int dev_type;
+	} pmu_match[] = {
+		{ "xuantie,xl100-pmu", XUANTIE_LINK_DEV_TYPE_XL100 },
+		{ "xuantie,xl200-pmu", XUANTIE_LINK_DEV_TYPE_XL200 },
+		{ "xuantie,xl300-pmu", XUANTIE_LINK_DEV_TYPE_XL300 },
+	};
 	void *fdt = fdt_get_address_rw();
+	bool found = false;
+	unsigned int i;
 
-	if ((nodeoffset = fdt_node_offset_by_compatible(fdt, -1, "xuantie,xl100-pmu")) > 0)
-		dev_type = XUANTIE_LINK_DEV_TYPE_XL100;
-	else if ((nodeoffset = fdt_node_offset_by_compatible(fdt, -1, "xuantie,xl200-pmu")) > 0)
-		dev_type = XUANTIE_LINK_DEV_TYPE_XL200;
-	else if ((nodeoffset = fdt_node_offset_by_compatible(fdt, -1, "xuantie,xl300-pmu")) > 0)
-		dev_type = XUANTIE_LINK_DEV_TYPE_XL300;
-	else
+	if (!fdt)
 		return SBI_ENODEV;
 
-	rc = fdt_get_node_addr_size(fdt, nodeoffset, 0, &addr, NULL);
-	if (rc)
-		return SBI_ENODEV;
+	for (i = 0; i < array_size(pmu_match); i++) {
+		int nodeoffset = -1;
+
+		while ((nodeoffset = fdt_node_offset_by_compatible(
+				fdt, nodeoffset, pmu_match[i].compat)) >= 0) {
+			uint64_t addr;
+
+			if (!fdt_node_is_enabled(fdt, nodeoffset))
+				continue;
+			if (fdt_get_node_addr_size(fdt, nodeoffset, 0, &addr, NULL))
+				continue;
 
-	if (dev_type == XUANTIE_LINK_DEV_TYPE_XL300)
-		writeq(BIT_ULL(40) | BIT_ULL(32) | 0x3f, (void *)addr + XUANTIE_LINK_PMU_HPCPHAUTHCR);
-	writeq(0x3f, (void *)addr + XUANTIE_LINK_PMU_HPCPMAUTHCR);
-	writeq(0x3f, (void *)addr + XUANTIE_LINK_PMU_HPCPSAUTHCR);
-	writeq(0x1, (void *)addr + XUANTIE_LINK_PMU_L3MAUTHCR);
-	writeq(0x0, (void *)addr + XUANTIE_LINK_PMU_HPCPINHIBIT);
+			if (pmu_match[i].dev_type == XUANTIE_LINK_DEV_TYPE_XL300)
+				writeq(XUANTIE_LINK_PMU_AUTHCR_AUTH |
+				       XUANTIE_LINK_PMU_AUTHCR_INTPEND |
+				       XUANTIE_LINK_PMU_CNT_BITMAP,
+				       (void *)addr + XUANTIE_LINK_PMU_HPCPHAUTHCR);
+			writeq(XUANTIE_LINK_PMU_CNT_BITMAP, (void *)addr + XUANTIE_LINK_PMU_HPCPMAUTHCR);
+			writeq(XUANTIE_LINK_PMU_CNT_BITMAP, (void *)addr + XUANTIE_LINK_PMU_HPCPSAUTHCR);
+			writeq(0x1, (void *)addr + XUANTIE_LINK_PMU_L3MAUTHCR);
+			writeq(XUANTIE_LINK_PMU_CNT_BITMAP, (void *)addr + XUANTIE_LINK_PMU_HPCPINHIBIT);
+			found = true;
+		}
+	}
+
+	if (!found)
+		return SBI_ENODEV;
 #endif
 	return SBI_OK;
 }