[patch 1/2] intr-remap: generic support for remapping HPET MSIs

[Suresh Siddha]

Generic support for remapping HPET MSI's by parsing the HPET timer block
device scope in the ACPI DRHD tables. This is needed for platforms
supporting interrupt-remapping and MSI capable HPET timer block.

Signed-off-by: Suresh Siddha <suresh.b.siddha@xxxxxxxxx>
Cc: David Woodhouse <dwmw2@xxxxxxxxxxxxx>
Cc: Jesse Barnes <jbarnes@xxxxxxxxxxxxxxxx>
Cc: Venkatesh Pallipadi <venkatesh.pallipadi@xxxxxxxxx>
Cc: Jay Fenlason <fenlason@xxxxxxxxxx>
---

Index: tip/drivers/pci/intr_remapping.c
===================================================================
--- tip.orig/drivers/pci/intr_remapping.c
+++ tip/drivers/pci/intr_remapping.c
@@ -2,6 +2,7 @@
 #include <linux/dmar.h>
 #include <linux/spinlock.h>
 #include <linux/jiffies.h>
+#include <linux/hpet.h>
 #include <linux/pci.h>
 #include <linux/irq.h>
 #include <asm/io_apic.h>
@@ -14,7 +15,8 @@
 #include "pci.h"
 
 static struct ioapic_scope ir_ioapic[MAX_IO_APICS];
-static int ir_ioapic_num;
+static struct hpet_scope ir_hpet[MAX_HPET_TBS];
+static int ir_ioapic_num, ir_hpet_num;
 int intr_remapping_enabled;
 
 static int disable_intremap;
@@ -351,6 +353,16 @@ int flush_irte(int irq)
 	return rc;
 }
 
+struct intel_iommu *map_hpet_to_ir(u8 hpet_id)
+{
+	int i;
+
+	for (i = 0; i < MAX_HPET_TBS; i++)
+		if (ir_hpet[i].id == hpet_id)
+			return ir_hpet[i].iommu;
+	return NULL;
+}
+
 struct intel_iommu *map_ioapic_to_ir(int apic)
 {
 	int i;
@@ -478,6 +490,36 @@ int set_ioapic_sid(struct irte *irte, in
 	return 0;
 }
 
+int set_hpet_sid(struct irte *irte, u8 id)
+{
+	int i;
+	u16 sid = 0;
+
+	if (!irte)
+		return -1;
+
+	for (i = 0; i < MAX_HPET_TBS; i++) {
+		if (ir_hpet[i].id == id) {
+			sid = (ir_hpet[i].bus << 8) | ir_hpet[i].devfn;
+			break;
+		}
+	}
+
+	if (sid == 0) {
+		pr_warning("Failed to set source-id of HPET block (%d)\n", id);
+		return -1;
+	}
+
+	/*
+	 * Should really use SQ_ALL_16. Some platforms are broken.
+	 * While we figure out the right quirks for these broken platforms, use
+	 * SQ_13_IGNORE_3 for now.
+	 */
+	set_irte_sid(irte, SVT_VERIFY_SID_SQ, SQ_13_IGNORE_3, sid);
+
+	return 0;
+}
+
 int set_msi_sid(struct irte *irte, struct pci_dev *dev)
 {
 	struct pci_dev *bridge;
@@ -711,6 +753,34 @@ error:
 	return -1;
 }
 
+static void ir_parse_one_hpet_scope(struct acpi_dmar_device_scope *scope,
+				      struct intel_iommu *iommu)
+{
+	struct acpi_dmar_pci_path *path;
+	u8 bus;
+	int count;
+
+	bus = scope->bus;
+	path = (struct acpi_dmar_pci_path *)(scope + 1);
+	count = (scope->length - sizeof(struct acpi_dmar_device_scope))
+		/ sizeof(struct acpi_dmar_pci_path);
+
+	while (--count > 0) {
+		/*
+		 * Access PCI directly due to the PCI
+		 * subsystem isn't initialized yet.
+		 */
+		bus = read_pci_config_byte(bus, path->dev, path->fn,
+					   PCI_SECONDARY_BUS);
+		path++;
+	}
+	ir_hpet[ir_hpet_num].bus   = bus;
+	ir_hpet[ir_hpet_num].devfn = PCI_DEVFN(path->dev, path->fn);
+	ir_hpet[ir_hpet_num].iommu = iommu;
+	ir_hpet[ir_hpet_num].id    = scope->enumeration_id;
+	ir_hpet_num++;
+}
+
 static void ir_parse_one_ioapic_scope(struct acpi_dmar_device_scope *scope,
 				      struct intel_iommu *iommu)
 {
@@ -740,8 +810,8 @@ static void ir_parse_one_ioapic_scope(st
 	ir_ioapic_num++;
 }
 
-static int ir_parse_ioapic_scope(struct acpi_dmar_header *header,
-				 struct intel_iommu *iommu)
+static int ir_parse_ioapic_hpet_scope(struct acpi_dmar_header *header,
+				      struct intel_iommu *iommu)
 {
 	struct acpi_dmar_hardware_unit *drhd;
 	struct acpi_dmar_device_scope *scope;
@@ -765,6 +835,17 @@ static int ir_parse_ioapic_scope(struct 
 			       drhd->address);
 
 			ir_parse_one_ioapic_scope(scope, iommu);
+		} else if (scope->entry_type == ACPI_DMAR_SCOPE_TYPE_HPET) {
+			if (ir_hpet_num == MAX_HPET_TBS) {
+				printk(KERN_WARNING "Exceeded Max HPET blocks\n");
+				return -1;
+			}
+
+			printk(KERN_INFO "HPET id %d under DRHD base"
+			       " 0x%Lx\n", scope->enumeration_id,
+			       drhd->address);
+
+			ir_parse_one_hpet_scope(scope, iommu);
 		}
 		start += scope->length;
 	}
@@ -785,7 +866,7 @@ int __init parse_ioapics_under_ir(void)
 		struct intel_iommu *iommu = drhd->iommu;
 
 		if (ecap_ir_support(iommu->ecap)) {
-			if (ir_parse_ioapic_scope(drhd->hdr, iommu))
+			if (ir_parse_ioapic_hpet_scope(drhd->hdr, iommu))
 				return -1;
 
 			ir_supported = 1;
Index: tip/drivers/pci/intr_remapping.h
===================================================================
--- tip.orig/drivers/pci/intr_remapping.h
+++ tip/drivers/pci/intr_remapping.h
@@ -7,4 +7,11 @@ struct ioapic_scope {
 	unsigned int devfn;	/* PCI devfn number */
 };
 
+struct hpet_scope {
+	struct intel_iommu *iommu;
+	u8 id;
+	unsigned int bus;
+	unsigned int devfn;
+};
+
 #define IR_X2APIC_MODE(mode) (mode ? (1 << 11) : 0)
Index: tip/include/linux/dmar.h
===================================================================
--- tip.orig/include/linux/dmar.h
+++ tip/include/linux/dmar.h
@@ -126,7 +126,9 @@ extern int free_irte(int irq);
 extern int irq_remapped(int irq);
 extern struct intel_iommu *map_dev_to_ir(struct pci_dev *dev);
 extern struct intel_iommu *map_ioapic_to_ir(int apic);
+extern struct intel_iommu *map_hpet_to_ir(u8 id);
 extern int set_ioapic_sid(struct irte *irte, int apic);
+extern int set_hpet_sid(struct irte *irte, u8 id);
 extern int set_msi_sid(struct irte *irte, struct pci_dev *dev);
 #else
 static inline int alloc_irte(struct intel_iommu *iommu, int irq, u16 count)
@@ -158,10 +160,18 @@ static inline struct intel_iommu *map_io
 {
 	return NULL;
 }
+static inline struct intel_iommu *map_hpet_to_ir(unsigned int hpet_id)
+{
+	return NULL;
+}
 static inline int set_ioapic_sid(struct irte *irte, int apic)
 {
 	return 0;
 }
+static inline int set_hpet_sid(struct irte *irte, u8 id)
+{
+	return -1;
+}
 static inline int set_msi_sid(struct irte *irte, struct pci_dev *dev)
 {
 	return 0;
Index: tip/include/linux/hpet.h
===================================================================
--- tip.orig/include/linux/hpet.h
+++ tip/include/linux/hpet.h
@@ -126,4 +126,6 @@ struct hpet_info {
 #define	HPET_DPI	_IO('h', 0x05)	/* disable periodic */
 #define	HPET_IRQFREQ	_IOW('h', 0x6, unsigned long)	/* IRQFREQ usec */
 
+#define MAX_HPET_TBS	8		/* maximum hpet timer blocks */
+
 #endif				/* !__HPET__ */

-- 

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