[PATCH] Initial generic hypertransport interrupt support

This patch implements two functions ht_create_irq and ht_destroy_irq for
use by drivers.  Several other functions are implemented as helpers for
arch specific irq_chip handlers.

The driver for the card I tested this on isn't yet ready to be merged.
However this code is and hypertransport irqs are in use in a few other
places in the kernel.  Not that any of this will get merged before 2.6.19

Because the ipath-ht400 is slightly out of spec this code will need to be
generalized to work there.

I think all of the powerpc uses are for a plain interrupt controller in a
chipset so support for native hypertransport devices is a little less
interesting.

However I think this is a half way decent model on how to separate arch
specific and generic helper code, and I think this is a functional model of
how to get the architecture dependencies out of the msi code.

[akpm@osdl.org: Kconfig fix]
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Cc: Greg KH <greg@kroah.com>
Cc: Andi Kleen <ak@muc.de>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

arch/i386/kernel/io_apic.c

@@ -40,6 +40,7 @@
 #include <asm/i8259.h>
 #include <asm/nmi.h>
 #include <asm/msidef.h>
+#include <asm/hypertransport.h>
 
 #include <mach_apic.h>
 #include <mach_apicdef.h>
@@ -2518,6 +2519,95 @@ struct msi_ops arch_msi_ops = {
 
 #endif /* CONFIG_PCI_MSI */
 
+/*
+ * Hypertransport interrupt support
+ */
+#ifdef CONFIG_HT_IRQ
+
+#ifdef CONFIG_SMP
+
+static void target_ht_irq(unsigned int irq, unsigned int dest)
+{
+	u32 low, high;
+	low  = read_ht_irq_low(irq);
+	high = read_ht_irq_high(irq);
+
+	low  &= ~(HT_IRQ_LOW_DEST_ID_MASK);
+	high &= ~(HT_IRQ_HIGH_DEST_ID_MASK);
+
+	low  |= HT_IRQ_LOW_DEST_ID(dest);
+	high |= HT_IRQ_HIGH_DEST_ID(dest);
+
+	write_ht_irq_low(irq, low);
+	write_ht_irq_high(irq, high);
+}
+
+static void set_ht_irq_affinity(unsigned int irq, cpumask_t mask)
+{
+	unsigned int dest;
+	cpumask_t tmp;
+
+	cpus_and(tmp, mask, cpu_online_map);
+	if (cpus_empty(tmp))
+		tmp = TARGET_CPUS;
+
+	cpus_and(mask, tmp, CPU_MASK_ALL);
+
+	dest = cpu_mask_to_apicid(mask);
+
+	target_ht_irq(irq, dest);
+	set_native_irq_info(irq, mask);
+}
+#endif
+
+static struct hw_interrupt_type ht_irq_chip = {
+	.name		= "PCI-HT",
+	.mask		= mask_ht_irq,
+	.unmask		= unmask_ht_irq,
+	.ack		= ack_ioapic_irq,
+#ifdef CONFIG_SMP
+	.set_affinity	= set_ht_irq_affinity,
+#endif
+	.retrigger	= ioapic_retrigger_irq,
+};
+
+int arch_setup_ht_irq(unsigned int irq, struct pci_dev *dev)
+{
+	int vector;
+
+	vector = assign_irq_vector(irq);
+	if (vector >= 0) {
+		u32 low, high;
+		unsigned dest;
+		cpumask_t tmp;
+
+		cpus_clear(tmp);
+		cpu_set(vector >> 8, tmp);
+		dest = cpu_mask_to_apicid(tmp);
+
+		high = 	HT_IRQ_HIGH_DEST_ID(dest);
+
+		low =	HT_IRQ_LOW_BASE |
+			HT_IRQ_LOW_DEST_ID(dest) |
+			HT_IRQ_LOW_VECTOR(vector) |
+			((INT_DEST_MODE == 0) ?
+				HT_IRQ_LOW_DM_PHYSICAL :
+				HT_IRQ_LOW_DM_LOGICAL) |
+			HT_IRQ_LOW_RQEOI_EDGE |
+			((INT_DELIVERY_MODE != dest_LowestPrio) ?
+				HT_IRQ_LOW_MT_FIXED :
+				HT_IRQ_LOW_MT_ARBITRATED) |
+			HT_IRQ_LOW_IRQ_MASKED;
+
+		write_ht_irq_low(irq, low);
+		write_ht_irq_high(irq, high);
+
+		set_irq_chip_and_handler(irq, &ht_irq_chip, handle_edge_irq);
+	}
+	return vector;
+}
+#endif /* CONFIG_HT_IRQ */
+
 /* --------------------------------------------------------------------------
                           ACPI-based IOAPIC Configuration
    -------------------------------------------------------------------------- */

arch/x86_64/kernel/io_apic.c

@@ -43,6 +43,7 @@
 #include <asm/dma.h>
 #include <asm/nmi.h>
 #include <asm/msidef.h>
+#include <asm/hypertransport.h>
 
 static int assign_irq_vector(int irq, cpumask_t mask);
 
@@ -1772,6 +1773,101 @@ struct msi_ops arch_msi_ops = {
 
 #endif
 
+/*
+ * Hypertransport interrupt support
+ */
+#ifdef CONFIG_HT_IRQ
+
+#ifdef CONFIG_SMP
+
+static void target_ht_irq(unsigned int irq, unsigned int dest, u8 vector)
+{
+	u32 low, high;
+	low  = read_ht_irq_low(irq);
+	high = read_ht_irq_high(irq);
+
+	low  &= ~(HT_IRQ_LOW_VECTOR_MASK | HT_IRQ_LOW_DEST_ID_MASK);
+	high &= ~(HT_IRQ_HIGH_DEST_ID_MASK);
+
+	low  |= HT_IRQ_LOW_VECTOR(vector) | HT_IRQ_LOW_DEST_ID(dest);
+	high |= HT_IRQ_HIGH_DEST_ID(dest);
+
+	write_ht_irq_low(irq, low);
+	write_ht_irq_high(irq, high);
+}
+
+static void set_ht_irq_affinity(unsigned int irq, cpumask_t mask)
+{
+	unsigned int dest;
+	cpumask_t tmp;
+	int vector;
+
+	cpus_and(tmp, mask, cpu_online_map);
+	if (cpus_empty(tmp))
+		tmp = TARGET_CPUS;
+
+	cpus_and(mask, tmp, CPU_MASK_ALL);
+
+	vector = assign_irq_vector(irq, mask);
+	if (vector < 0)
+		return;
+
+	cpus_clear(tmp);
+	cpu_set(vector >> 8, tmp);
+	dest = cpu_mask_to_apicid(tmp);
+
+	target_ht_irq(irq, dest, vector & 0xff);
+	set_native_irq_info(irq, mask);
+}
+#endif
+
+static struct hw_interrupt_type ht_irq_chip = {
+	.name		= "PCI-HT",
+	.mask		= mask_ht_irq,
+	.unmask		= unmask_ht_irq,
+	.ack		= ack_apic_edge,
+#ifdef CONFIG_SMP
+	.set_affinity	= set_ht_irq_affinity,
+#endif
+	.retrigger	= ioapic_retrigger_irq,
+};
+
+int arch_setup_ht_irq(unsigned int irq, struct pci_dev *dev)
+{
+	int vector;
+
+	vector = assign_irq_vector(irq, TARGET_CPUS);
+	if (vector >= 0) {
+		u32 low, high;
+		unsigned dest;
+		cpumask_t tmp;
+
+		cpus_clear(tmp);
+		cpu_set(vector >> 8, tmp);
+		dest = cpu_mask_to_apicid(tmp);
+
+		high = 	HT_IRQ_HIGH_DEST_ID(dest);
+
+		low =	HT_IRQ_LOW_BASE |
+			HT_IRQ_LOW_DEST_ID(dest) |
+			HT_IRQ_LOW_VECTOR(vector) |
+			((INT_DEST_MODE == 0) ?
+				HT_IRQ_LOW_DM_PHYSICAL :
+				HT_IRQ_LOW_DM_LOGICAL) |
+			HT_IRQ_LOW_RQEOI_EDGE |
+			((INT_DELIVERY_MODE != dest_LowestPrio) ?
+				HT_IRQ_LOW_MT_FIXED :
+				HT_IRQ_LOW_MT_ARBITRATED);
+
+		write_ht_irq_low(irq, low);
+		write_ht_irq_high(irq, high);
+
+		set_irq_chip_and_handler(irq, &ht_irq_chip, handle_edge_irq);
+	}
+	return vector;
+}
+#endif /* CONFIG_HT_IRQ */
+
 /* --------------------------------------------------------------------------
                           ACPI-based IOAPIC Configuration
    -------------------------------------------------------------------------- */

drivers/pci/Kconfig

@@ -52,3 +52,12 @@ config PCI_DEBUG
 
 	  When in doubt, say N.
 
+config HT_IRQ
+	bool "Interrupts on hypertransport devices"
+	default y
+	depends on PCI_MSI
+	depends on X86_LOCAL_APIC && X86_IO_APIC
+	help
+	   This allows native hypertransport devices to use interrupts.
+
+	   If unsure say Y.

drivers/pci/Makefile

@@ -26,6 +26,7 @@ obj-$(CONFIG_PPC32) += setup-irq.o
 obj-$(CONFIG_PPC64) += setup-bus.o
 obj-$(CONFIG_MIPS) += setup-bus.o setup-irq.o
 obj-$(CONFIG_X86_VISWS) += setup-irq.o
+obj-$(CONFIG_HT_IRQ) += htirq.o
 
 msiobj-y := msi.o
 msiobj-$(CONFIG_IA64) += msi-apic.o

drivers/pci/htirq.c

@@ -0,0 +1,189 @@
+/*
+ * File:	htirq.c
+ * Purpose:	Hypertransport Interrupt Capability
+ *
+ * Copyright (C) 2006 Linux Networx
+ * Copyright (C) Eric Biederman <ebiederman@lnxi.com>
+ */
+
+#include <linux/irq.h>
+#include <linux/pci.h>
+#include <linux/spinlock.h>
+#include <linux/slab.h>
+#include <linux/gfp.h>
+
+/* Global ht irq lock.
+ *
+ * This is needed to serialize access to the data port in hypertransport
+ * irq capability.
+ *
+ * With multiple simultaneous hypertransport irq devices it might pay
+ * to make this more fine grained.  But start with simple, stupid, and correct.
+ */
+static DEFINE_SPINLOCK(ht_irq_lock);
+
+struct ht_irq_cfg {
+	struct pci_dev *dev;
+	unsigned pos;
+	unsigned idx;
+};
+
+void write_ht_irq_low(unsigned int irq, u32 data)
+{
+	struct ht_irq_cfg *cfg = get_irq_data(irq);
+	unsigned long flags;
+	spin_lock_irqsave(&ht_irq_lock, flags);
+	pci_write_config_byte(cfg->dev, cfg->pos + 2, cfg->idx);
+	pci_write_config_dword(cfg->dev, cfg->pos + 4, data);
+	spin_unlock_irqrestore(&ht_irq_lock, flags);
+}
+
+void write_ht_irq_high(unsigned int irq, u32 data)
+{
+	struct ht_irq_cfg *cfg = get_irq_data(irq);
+	unsigned long flags;
+	spin_lock_irqsave(&ht_irq_lock, flags);
+	pci_write_config_byte(cfg->dev, cfg->pos + 2, cfg->idx + 1);
+	pci_write_config_dword(cfg->dev, cfg->pos + 4, data);
+	spin_unlock_irqrestore(&ht_irq_lock, flags);
+}
+
+u32 read_ht_irq_low(unsigned int irq)
+{
+	struct ht_irq_cfg *cfg = get_irq_data(irq);
+	unsigned long flags;
+	u32 data;
+	spin_lock_irqsave(&ht_irq_lock, flags);
+	pci_write_config_byte(cfg->dev, cfg->pos + 2, cfg->idx);
+	pci_read_config_dword(cfg->dev, cfg->pos + 4, &data);
+	spin_unlock_irqrestore(&ht_irq_lock, flags);
+	return data;
+}
+
+u32 read_ht_irq_high(unsigned int irq)
+{
+	struct ht_irq_cfg *cfg = get_irq_data(irq);
+	unsigned long flags;
+	u32 data;
+	spin_lock_irqsave(&ht_irq_lock, flags);
+	pci_write_config_byte(cfg->dev, cfg->pos + 2, cfg->idx + 1);
+	pci_read_config_dword(cfg->dev, cfg->pos + 4, &data);
+	spin_unlock_irqrestore(&ht_irq_lock, flags);
+	return data;
+}
+
+void mask_ht_irq(unsigned int irq)
+{
+	struct ht_irq_cfg *cfg;
+	unsigned long flags;
+	u32 data;
+
+	cfg = get_irq_data(irq);
+
+	spin_lock_irqsave(&ht_irq_lock, flags);
+	pci_write_config_byte(cfg->dev, cfg->pos + 2, cfg->idx);
+	pci_read_config_dword(cfg->dev, cfg->pos + 4, &data);
+	data |= 1;
+	pci_write_config_dword(cfg->dev, cfg->pos + 4, data);
+	spin_unlock_irqrestore(&ht_irq_lock, flags);
+}
+
+void unmask_ht_irq(unsigned int irq)
+{
+	struct ht_irq_cfg *cfg;
+	unsigned long flags;
+	u32 data;
+
+	cfg = get_irq_data(irq);
+
+	spin_lock_irqsave(&ht_irq_lock, flags);
+	pci_write_config_byte(cfg->dev, cfg->pos + 2, cfg->idx);
+	pci_read_config_dword(cfg->dev, cfg->pos + 4, &data);
+	data &= ~1;
+	pci_write_config_dword(cfg->dev, cfg->pos + 4, data);
+	spin_unlock_irqrestore(&ht_irq_lock, flags);
+}
+
+/**
+ * ht_create_irq - create an irq and attach it to a device.
+ * @dev: The hypertransport device to find the irq capability on.
+ * @idx: Which of the possible irqs to attach to.
+ *
+ * ht_create_irq is needs to be called for all hypertransport devices
+ * that generate irqs.
+ *
+ * The irq number of the new irq or a negative error value is returned.
+ */
+int ht_create_irq(struct pci_dev *dev, int idx)
+{
+	struct ht_irq_cfg *cfg;
+	unsigned long flags;
+	u32 data;
+	int max_irq;
+	int pos;
+	int irq;
+
+	pos = pci_find_capability(dev, PCI_CAP_ID_HT);
+	while (pos) {
+		u8 subtype;
+		pci_read_config_byte(dev, pos + 3, &subtype);
+		if (subtype == HT_CAPTYPE_IRQ)
+			break;
+		pos = pci_find_next_capability(dev, pos, PCI_CAP_ID_HT);
+	}
+	if (!pos)
+		return -EINVAL;
+
+	/* Verify the idx I want to use is in range */
+	spin_lock_irqsave(&ht_irq_lock, flags);
+	pci_write_config_byte(dev, pos + 2, 1);
+	pci_read_config_dword(dev, pos + 4, &data);
+	spin_unlock_irqrestore(&ht_irq_lock, flags);
+
+	max_irq = (data >> 16) & 0xff;
+	if ( idx > max_irq)
+		return -EINVAL;
+
+	cfg = kmalloc(sizeof(*cfg), GFP_KERNEL);
+	if (!cfg)
+		return -ENOMEM;
+
+	cfg->dev = dev;
+	cfg->pos = pos;
+	cfg->idx = 0x10 + (idx * 2);
+
+	irq = create_irq();
+	if (irq < 0) {
+		kfree(cfg);
+		return -EBUSY;
+	}
+	set_irq_data(irq, cfg);
+
+	if (arch_setup_ht_irq(irq, dev) < 0) {
+		ht_destroy_irq(irq);
+		return -EBUSY;
+	}
+
+	return irq;
+}
+
+/**
+ * ht_destroy_irq - destroy an irq created with ht_create_irq
+ *
+ * This reverses ht_create_irq removing the specified irq from
+ * existence.  The irq should be free before this happens.
+ */
+void ht_destroy_irq(unsigned int irq)
+{
+	struct ht_irq_cfg *cfg;
+
+	cfg = get_irq_data(irq);
+	set_irq_chip(irq, NULL);
+	set_irq_data(irq, NULL);
+	destroy_irq(irq);
+
+	kfree(cfg);
+}
+
+EXPORT_SYMBOL(ht_create_irq);
+EXPORT_SYMBOL(ht_destroy_irq);

include/asm-i386/hypertransport.h

@@ -0,0 +1,42 @@
+#ifndef ASM_HYPERTRANSPORT_H
+#define ASM_HYPERTRANSPORT_H
+
+/*
+ * Constants for x86 Hypertransport Interrupts.
+ */
+
+#define HT_IRQ_LOW_BASE			0xf8000000
+
+#define HT_IRQ_LOW_VECTOR_SHIFT		16
+#define  HT_IRQ_LOW_VECTOR_MASK		0x00ff0000
+#define  HT_IRQ_LOW_VECTOR(v)		(((v) << HT_IRQ_LOW_VECTOR_SHIFT) & HT_IRQ_LOW_VECTOR_MASK)
+
+#define HT_IRQ_LOW_DEST_ID_SHIFT	8
+#define  HT_IRQ_LOW_DEST_ID_MASK	0x0000ff00
+#define  HT_IRQ_LOW_DEST_ID(v)		(((v) << HT_IRQ_LOW_DEST_ID_SHIFT) & HT_IRQ_LOW_DEST_ID_MASK)
+
+#define HT_IRQ_LOW_DM_PHYSICAL		0x0000000
+#define HT_IRQ_LOW_DM_LOGICAL		0x0000040
+
+#define HT_IRQ_LOW_RQEOI_EDGE		0x0000000
+#define HT_IRQ_LOW_RQEOI_LEVEL		0x0000020
+
+
+#define HT_IRQ_LOW_MT_FIXED		0x0000000
+#define HT_IRQ_LOW_MT_ARBITRATED	0x0000004
+#define HT_IRQ_LOW_MT_SMI		0x0000008
+#define HT_IRQ_LOW_MT_NMI		0x000000c
+#define HT_IRQ_LOW_MT_INIT		0x0000010
+#define HT_IRQ_LOW_MT_STARTUP		0x0000014
+#define HT_IRQ_LOW_MT_EXTINT		0x0000018
+#define HT_IRQ_LOW_MT_LINT1		0x000008c
+#define HT_IRQ_LOW_MT_LINT0		0x0000098
+
+#define HT_IRQ_LOW_IRQ_MASKED		0x0000001
+
+
+#define HT_IRQ_HIGH_DEST_ID_SHIFT	0
+#define  HT_IRQ_HIGH_DEST_ID_MASK	0x00ffffff
+#define  HT_IRQ_HIGH_DEST_ID(v)		((((v) >> 8) << HT_IRQ_HIGH_DEST_ID_SHIFT) & HT_IRQ_HIGH_DEST_ID_MASK)
+
+#endif /* ASM_HYPERTRANSPORT_H */

include/asm-x86_64/hypertransport.h

@@ -0,0 +1,42 @@
+#ifndef ASM_HYPERTRANSPORT_H
+#define ASM_HYPERTRANSPORT_H
+
+/*
+ * Constants for x86 Hypertransport Interrupts.
+ */
+
+#define HT_IRQ_LOW_BASE			0xf8000000
+
+#define HT_IRQ_LOW_VECTOR_SHIFT		16
+#define  HT_IRQ_LOW_VECTOR_MASK		0x00ff0000
+#define  HT_IRQ_LOW_VECTOR(v)		(((v) << HT_IRQ_LOW_VECTOR_SHIFT) & HT_IRQ_LOW_VECTOR_MASK)
+
+#define HT_IRQ_LOW_DEST_ID_SHIFT	8
+#define  HT_IRQ_LOW_DEST_ID_MASK	0x0000ff00
+#define  HT_IRQ_LOW_DEST_ID(v)		(((v) << HT_IRQ_LOW_DEST_ID_SHIFT) & HT_IRQ_LOW_DEST_ID_MASK)
+
+#define HT_IRQ_LOW_DM_PHYSICAL		0x0000000
+#define HT_IRQ_LOW_DM_LOGICAL		0x0000040
+
+#define HT_IRQ_LOW_RQEOI_EDGE		0x0000000
+#define HT_IRQ_LOW_RQEOI_LEVEL		0x0000020
+
+
+#define HT_IRQ_LOW_MT_FIXED		0x0000000
+#define HT_IRQ_LOW_MT_ARBITRATED	0x0000004
+#define HT_IRQ_LOW_MT_SMI		0x0000008
+#define HT_IRQ_LOW_MT_NMI		0x000000c
+#define HT_IRQ_LOW_MT_INIT		0x0000010
+#define HT_IRQ_LOW_MT_STARTUP		0x0000014
+#define HT_IRQ_LOW_MT_EXTINT		0x0000018
+#define HT_IRQ_LOW_MT_LINT1		0x000008c
+#define HT_IRQ_LOW_MT_LINT0		0x0000098
+
+#define HT_IRQ_LOW_IRQ_MASKED		0x0000001
+
+
+#define HT_IRQ_HIGH_DEST_ID_SHIFT	0
+#define  HT_IRQ_HIGH_DEST_ID_MASK	0x00ffffff
+#define  HT_IRQ_HIGH_DEST_ID(v)		((((v) >> 8) << HT_IRQ_HIGH_DEST_ID_SHIFT) & HT_IRQ_HIGH_DEST_ID_MASK)
+
+#endif /* ASM_HYPERTRANSPORT_H */

include/linux/pci.h

@@ -681,6 +681,23 @@ extern int msi_register(struct msi_ops *ops);
 
 #endif
 
+#ifdef CONFIG_HT_IRQ
+/* Helper functions.. */
+void write_ht_irq_low(unsigned int irq, u32 data);
+void write_ht_irq_high(unsigned int irq, u32 data);
+u32  read_ht_irq_low(unsigned int irq);
+u32  read_ht_irq_high(unsigned int irq);
+void mask_ht_irq(unsigned int irq);
+void unmask_ht_irq(unsigned int irq);
+
+/* The functions a driver should call */
+int  ht_create_irq(struct pci_dev *dev, int idx);
+void ht_destroy_irq(unsigned int irq);
+
+/* The arch hook for getting things started */
+int arch_setup_ht_irq(unsigned int irq, struct pci_dev *dev);
+#endif /* CONFIG_HT_IRQ */
+
 extern void pci_block_user_cfg_access(struct pci_dev *dev);
 extern void pci_unblock_user_cfg_access(struct pci_dev *dev);