perf/x86/amd: Add IOMMU Performance Counter resource management

Add functionality to check the availability of the AMD IOMMU Performance
Counters and export this functionality to other core drivers, such as in this
case, a perf AMD IOMMU PMU. This feature is not bound to any specific AMD
family/model other than the presence of the IOMMU with P-C enabled.

The AMD IOMMU P-C support static counting only at this time.

Signed-off-by: Steven Kinney <[e-mail]>
Signed-off-by: Suravee Suthikulpanit <[e-mail]>
Signed-off-by: Peter Zijlstra <[e-mail]>
Link: http://lkml.kernel.org/r/[e-mail]
Signed-off-by: Ingo Molnar <[e-mail]>

drivers/iommu/amd_iommu_init.c

···
 	u64 mmio_phys;
 	u16 pci_seg;
 	u16 info;
-	u32 reserved;
+	u32 efr;
 } __attribute__((packed));
 
 /*
···
 u32 amd_iommu_max_pasids __read_mostly = ~0;
 
 bool amd_iommu_v2_present __read_mostly;
+bool amd_iommu_pc_present __read_mostly;
 
 bool amd_iommu_force_isolation __read_mostly;
 
···
  * mapping and unmapping functions for the IOMMU MMIO space. Each AMD IOMMU in
  * the system has one.
  */
-static u8 __iomem * __init iommu_map_mmio_space(u64 address)
+static u8 __iomem * __init iommu_map_mmio_space(u64 address, u64 end)
 {
-	if (!request_mem_region(address, MMIO_REGION_LENGTH, "amd_iommu")) {
-		pr_err("AMD-Vi: Can not reserve memory region %llx for mmio\n",
-			address);
+	if (!request_mem_region(address, end, "amd_iommu")) {
+		pr_err("AMD-Vi: Can not reserve memory region %llx-%llx for mmio\n",
+			address, end);
 		pr_err("AMD-Vi: This is a BIOS bug. Please contact your hardware vendor\n");
 		return NULL;
 	}
 
-	return (u8 __iomem *)ioremap_nocache(address, MMIO_REGION_LENGTH);
+	return (u8 __iomem *)ioremap_nocache(address, end);
 }
 
 static void __init iommu_unmap_mmio_space(struct amd_iommu *iommu)
 {
 	if (iommu->mmio_base)
 		iounmap(iommu->mmio_base);
-	release_mem_region(iommu->mmio_phys, MMIO_REGION_LENGTH);
+	release_mem_region(iommu->mmio_phys, iommu->mmio_phys_end);
 }
 
 /****************************************************************************
···
 	iommu->cap_ptr = h->cap_ptr;
 	iommu->pci_seg = h->pci_seg;
 	iommu->mmio_phys = h->mmio_phys;
-	iommu->mmio_base = iommu_map_mmio_space(h->mmio_phys);
+
+	/* Check if IVHD EFR contains proper max banks/counters */
+	if ((h->efr != 0) &&
+	    ((h->efr & (0xF << 13)) != 0) &&
+	    ((h->efr & (0x3F << 17)) != 0)) {
+		iommu->mmio_phys_end = MMIO_REG_END_OFFSET;
+	} else {
+		iommu->mmio_phys_end = MMIO_CNTR_CONF_OFFSET;
+	}
+
+	iommu->mmio_base = iommu_map_mmio_space(iommu->mmio_phys,
+						iommu->mmio_phys_end);
 	if (!iommu->mmio_base)
 		return -ENOMEM;
 
···
 	return 0;
 }
 
+
+static void init_iommu_perf_ctr(struct amd_iommu *iommu)
+{
+	u64 val = 0xabcd, val2 = 0;
+
+	if (!iommu_feature(iommu, FEATURE_PC))
+		return;
+
+	amd_iommu_pc_present = true;
+
+	/* Check if the performance counters can be written to */
+	if ((0 != amd_iommu_pc_get_set_reg_val(0, 0, 0, 0, &val, true)) ||
+	    (0 != amd_iommu_pc_get_set_reg_val(0, 0, 0, 0, &val2, false)) ||
+	    (val != val2)) {
+		pr_err("AMD-Vi: Unable to write to IOMMU perf counter.\n");
+		amd_iommu_pc_present = false;
+		return;
+	}
+
+	pr_info("AMD-Vi: IOMMU performance counters supported\n");
+
+	val = readl(iommu->mmio_base + MMIO_CNTR_CONF_OFFSET);
+	iommu->max_banks = (u8) ((val >> 12) & 0x3f);
+	iommu->max_counters = (u8) ((val >> 7) & 0xf);
+}
+
+
 static int iommu_init_pci(struct amd_iommu *iommu)
 {
 	int cap_ptr = iommu->cap_ptr;
···
 	if (iommu->cap & (1UL << IOMMU_CAP_NPCACHE))
 		amd_iommu_np_cache = true;
 
+	init_iommu_perf_ctr(iommu);
+
 	if (is_rd890_iommu(iommu->dev)) {
 		int i, j;
 
···
 				if (iommu_feature(iommu, (1ULL << i)))
 					pr_cont(" %s", feat_str[i]);
 			}
-		pr_cont("\n");
+			pr_cont("\n");
 		}
 	}
 	if (irq_remapping_enabled)
···
 	return amd_iommu_v2_present;
 }
 EXPORT_SYMBOL(amd_iommu_v2_supported);
+
+/****************************************************************************
+ *
+ * IOMMU EFR Performance Counter support functionality. This code allows
+ * access to the IOMMU PC functionality.
+ *
+ ****************************************************************************/
+
+u8 amd_iommu_pc_get_max_banks(u16 devid)
+{
+	struct amd_iommu *iommu;
+	u8 ret = 0;
+
+	/* locate the iommu governing the devid */
+	iommu = amd_iommu_rlookup_table[devid];
+	if (iommu)
+		ret = iommu->max_banks;
+
+	return ret;
+}
+EXPORT_SYMBOL(amd_iommu_pc_get_max_banks);
+
+bool amd_iommu_pc_supported(void)
+{
+	return amd_iommu_pc_present;
+}
+EXPORT_SYMBOL(amd_iommu_pc_supported);
+
+u8 amd_iommu_pc_get_max_counters(u16 devid)
+{
+	struct amd_iommu *iommu;
+	u8 ret = 0;
+
+	/* locate the iommu governing the devid */
+	iommu = amd_iommu_rlookup_table[devid];
+	if (iommu)
+		ret = iommu->max_counters;
+
+	return ret;
+}
+EXPORT_SYMBOL(amd_iommu_pc_get_max_counters);
+
+int amd_iommu_pc_get_set_reg_val(u16 devid, u8 bank, u8 cntr, u8 fxn,
+				    u64 *value, bool is_write)
+{
+	struct amd_iommu *iommu;
+	u32 offset;
+	u32 max_offset_lim;
+
+	/* Make sure the IOMMU PC resource is available */
+	if (!amd_iommu_pc_present)
+		return -ENODEV;
+
+	/* Locate the iommu associated with the device ID */
+	iommu = amd_iommu_rlookup_table[devid];
+
+	/* Check for valid iommu and pc register indexing */
+	if (WARN_ON((iommu == NULL) || (fxn > 0x28) || (fxn & 7)))
+		return -ENODEV;
+
+	offset = (u32)(((0x40|bank) << 12) | (cntr << 8) | fxn);
+
+	/* Limit the offset to the hw defined mmio region aperture */
+	max_offset_lim = (u32)(((0x40|iommu->max_banks) << 12) |
+				(iommu->max_counters << 8) | 0x28);
+	if ((offset < MMIO_CNTR_REG_OFFSET) ||
+	    (offset > max_offset_lim))
+		return -EINVAL;
+
+	if (is_write) {
+		writel((u32)*value, iommu->mmio_base + offset);
+		writel((*value >> 32), iommu->mmio_base + offset + 4);
+	} else {
+		*value = readl(iommu->mmio_base + offset + 4);
+		*value <<= 32;
+		*value = readl(iommu->mmio_base + offset);
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL(amd_iommu_pc_get_set_reg_val);

drivers/iommu/amd_iommu_proto.h

···
 extern int amd_iommu_domain_clear_gcr3(struct iommu_domain *dom, int pasid);
 extern struct iommu_domain *amd_iommu_get_v2_domain(struct pci_dev *pdev);
 
+/* IOMMU Performance Counter functions */
+extern bool amd_iommu_pc_supported(void);
+extern u8 amd_iommu_pc_get_max_banks(u16 devid);
+extern u8 amd_iommu_pc_get_max_counters(u16 devid);
+extern int amd_iommu_pc_get_set_reg_val(u16 devid, u8 bank, u8 cntr, u8 fxn,
+				    u64 *value, bool is_write);
+
 #define PPR_SUCCESS			0x0
 #define PPR_INVALID			0x1
 #define PPR_FAILURE			0xf

drivers/iommu/amd_iommu_types.h

···
 #define ALIAS_TABLE_ENTRY_SIZE		2
 #define RLOOKUP_TABLE_ENTRY_SIZE	(sizeof(void *))
 
-/* Length of the MMIO region for the AMD IOMMU */
-#define MMIO_REGION_LENGTH       0x4000
-
 /* Capability offsets used by the driver */
 #define MMIO_CAP_HDR_OFFSET	0x00
 #define MMIO_RANGE_OFFSET	0x0c
···
 #define MMIO_STATUS_OFFSET	0x2020
 #define MMIO_PPR_HEAD_OFFSET	0x2030
 #define MMIO_PPR_TAIL_OFFSET	0x2038
+#define MMIO_CNTR_CONF_OFFSET	0x4000
+#define MMIO_CNTR_REG_OFFSET	0x40000
+#define MMIO_REG_END_OFFSET	0x80000
+
 
 
 /* Extended Feature Bits */
···
 
 	/* physical address of MMIO space */
 	u64 mmio_phys;
+
+	/* physical end address of MMIO space */
+	u64 mmio_phys_end;
+
 	/* virtual address of MMIO space */
 	u8 __iomem *mmio_base;
 
···
 
 	/* The l2 indirect registers */
 	u32 stored_l2[0x83];
+
+	/* The maximum PC banks and counters/bank (PCSup=1) */
+	u8 max_banks;
+	u8 max_counters;
 };
 
 struct devid_map {