[PATCH] x86, UV: non-sparse irq based uv_setup_irq()/uv_teardown_irq() functions

[Dean Nelson <dcn@sgi.com>]

Provide a means for UV interrupt MMRs to be setup with the message to be sent
when an MSI-like interrupt is raised.

Signed-off-by: Dean Nelson <dcn@sgi.com>

---

Ingo,

A version of this patch, based on the sparse irq code, you applied to
tip/x86/uv. I'm submitting this verision, which is not based on the
sparse irq code, to replace that patch since the sparse irq code has
been pulled from linux-next, and I'd like this functionality to get
into linux 2.6.28.

The differences between the two patches are minimal. The bulk of it
was to move the code that was added to io_apic.c to io_apic_64.c instead.
I also made a small change to some of the comments.

Thanks,
Dean

 arch/x86/kernel/Makefile     |    2 
 arch/x86/kernel/io_apic_64.c |   67 +++++++++++++++++++++++++++++++++
 arch/x86/kernel/uv_irq.c     |   79 +++++++++++++++++++++++++++++++++++++++
 include/asm-x86/uv/uv_irq.h  |   36 +++++++++++++++++
 4 files changed, 183 insertions(+), 1 deletion(-)

Index: linux/arch/x86/kernel/uv_irq.c
===================================================================
--- /dev/null	1970-01-01 00:00:00.000000000 +0000
+++ linux/arch/x86/kernel/uv_irq.c	2008-10-20 13:08:41.000000000 -0500
@@ -0,0 +1,79 @@
+/*
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file "COPYING" in the main directory of this archive
+ * for more details.
+ *
+ * SGI UV IRQ functions
+ *
+ * Copyright (C) 2008 Silicon Graphics, Inc. All rights reserved.
+ */
+
+#include <linux/module.h>
+#include <linux/irq.h>
+
+#include <asm/apic.h>
+#include <asm/uv/uv_irq.h>
+
+static void uv_noop(unsigned int irq)
+{
+}
+
+static unsigned int uv_noop_ret(unsigned int irq)
+{
+	return 0;
+}
+
+static void uv_ack_apic(unsigned int irq)
+{
+	ack_APIC_irq();
+}
+
+struct irq_chip uv_irq_chip = {
+	.name		= "UV-CORE",
+	.startup	= uv_noop_ret,
+	.shutdown	= uv_noop,
+	.enable		= uv_noop,
+	.disable	= uv_noop,
+	.ack		= uv_noop,
+	.mask		= uv_noop,
+	.unmask		= uv_noop,
+	.eoi		= uv_ack_apic,
+	.end		= uv_noop,
+};
+
+/*
+ * Set up a mapping of an available irq and vector, and enable the specified
+ * MMR that defines the MSI-like message that is to be sent to the specified
+ * CPU when an interrupt is raised.
+ */
+int uv_setup_irq(char *irq_name, int cpu, int mmr_blade,
+		 unsigned long mmr_offset)
+{
+	int irq;
+	int ret;
+
+	irq = create_irq();
+	if (irq <= 0)
+		return -EBUSY;
+
+	ret = arch_enable_uv_irq(irq_name, irq, cpu, mmr_blade, mmr_offset);
+	if (ret != irq)
+		destroy_irq(irq);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(uv_setup_irq);
+
+/*
+ * Tear down a mapping of an irq and vector, and disable the specified MMR that
+ * defined the MSI-like message that was to be sent to the specified CPU when
+ * an interrupt was raised.
+ *
+ * Set mmr_blade and mmr_offset to what was passed in on uv_setup_irq().
+ */
+void uv_teardown_irq(unsigned int irq, int mmr_blade, unsigned long mmr_offset)
+{
+	arch_disable_uv_irq(mmr_blade, mmr_offset);
+	destroy_irq(irq);
+}
+EXPORT_SYMBOL_GPL(uv_teardown_irq);
Index: linux/include/asm-x86/uv/uv_irq.h
===================================================================
--- /dev/null	1970-01-01 00:00:00.000000000 +0000
+++ linux/include/asm-x86/uv/uv_irq.h	2008-10-20 12:44:25.000000000 -0500
@@ -0,0 +1,36 @@
+/*
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file "COPYING" in the main directory of this archive
+ * for more details.
+ *
+ * SGI UV IRQ definitions
+ *
+ * Copyright (C) 2008 Silicon Graphics, Inc. All rights reserved.
+ */
+
+#ifndef ASM_X86__UV__UV_IRQ_H
+#define ASM_X86__UV__UV_IRQ_H
+
+/* If a generic version of this structure gets defined, eliminate this one. */
+struct uv_IO_APIC_route_entry {
+	__u64	vector		:  8,
+		delivery_mode	:  3,
+		dest_mode	:  1,
+		delivery_status	:  1,
+		polarity	:  1,
+		__reserved_1	:  1,
+		trigger		:  1,
+		mask		:  1,
+		__reserved_2	: 15,
+		dest		: 32;
+};
+
+extern struct irq_chip uv_irq_chip;
+
+extern int arch_enable_uv_irq(char *, unsigned int, int, int, unsigned long);
+extern void arch_disable_uv_irq(int, unsigned long);
+
+extern int uv_setup_irq(char *, int, int, unsigned long);
+extern void uv_teardown_irq(unsigned int, int, unsigned long);
+
+#endif /* ASM_X86__UV__UV_IRQ_H */
Index: linux/arch/x86/kernel/Makefile
===================================================================
--- linux.orig/arch/x86/kernel/Makefile	2008-10-20 12:44:22.000000000 -0500
+++ linux/arch/x86/kernel/Makefile	2008-10-20 12:44:25.000000000 -0500
@@ -109,7 +109,7 @@ obj-$(CONFIG_MICROCODE)			+= microcode.o
 # 64 bit specific files
 ifeq ($(CONFIG_X86_64),y)
         obj-y				+= genapic_64.o genapic_flat_64.o genx2apic_uv_x.o tlb_uv.o
-	obj-y				+= bios_uv.o uv_sysfs.o
+	obj-y				+= bios_uv.o uv_sysfs.o uv_irq.o
         obj-y				+= genx2apic_cluster.o
         obj-y				+= genx2apic_phys.o
         obj-$(CONFIG_X86_PM_TIMER)	+= pmtimer_64.o
Index: linux/arch/x86/kernel/io_apic_64.c
===================================================================
--- linux.orig/arch/x86/kernel/io_apic_64.c	2008-10-20 12:44:22.000000000 -0500
+++ linux/arch/x86/kernel/io_apic_64.c	2008-10-20 13:05:58.000000000 -0500
@@ -51,6 +51,8 @@
 #include <asm/msidef.h>
 #include <asm/hypertransport.h>
 #include <asm/irq_remapping.h>
+#include <asm/uv/uv_hub.h>
+#include <asm/uv/uv_irq.h>
 
 #include <mach_ipi.h>
 #include <mach_apic.h>
@@ -2787,6 +2789,71 @@ int arch_setup_ht_irq(unsigned int irq, 
 }
 #endif /* CONFIG_HT_IRQ */
 
+/*
+ * Re-target the irq to the specified CPU and enable the specified MMR located
+ * on the specified blade to allow the sending of MSI-like interrupts to the
+ * specified CPU.
+ */
+int arch_enable_uv_irq(char *irq_name, unsigned int irq, int cpu, int mmr_blade,
+		       unsigned long mmr_offset)
+{
+	const cpumask_t *eligible_cpu = get_cpu_mask(cpu);
+	struct irq_cfg *cfg;
+	int mmr_pnode;
+	unsigned long mmr_value;
+	struct uv_IO_APIC_route_entry *entry;
+	unsigned long flags;
+	int err;
+
+	err = assign_irq_vector(irq, *eligible_cpu);
+	if (err != 0)
+		return err;
+
+	spin_lock_irqsave(&vector_lock, flags);
+	set_irq_chip_and_handler_name(irq, &uv_irq_chip, handle_percpu_irq,
+				      irq_name);
+	spin_unlock_irqrestore(&vector_lock, flags);
+
+	cfg = &irq_cfg[irq];
+
+	mmr_value = 0;
+	entry = (struct uv_IO_APIC_route_entry *)&mmr_value;
+	BUG_ON(sizeof(struct uv_IO_APIC_route_entry) != sizeof(unsigned long));
+
+	entry->vector = cfg->vector;
+	entry->delivery_mode = INT_DELIVERY_MODE;
+	entry->dest_mode = INT_DEST_MODE;
+	entry->polarity = 0;
+	entry->trigger = 0;
+	entry->mask = 0;
+	entry->dest = cpu_mask_to_apicid(*eligible_cpu);
+
+	mmr_pnode = uv_blade_to_pnode(mmr_blade);
+	uv_write_global_mmr64(mmr_pnode, mmr_offset, mmr_value);
+
+	return irq;
+}
+
+/*
+ * Disable the specified MMR located on the specified blade so that MSI-like
+ * interrupts are no longer allowed to be sent.
+ */
+void arch_disable_uv_irq(int mmr_blade, unsigned long mmr_offset)
+{
+	unsigned long mmr_value;
+	struct uv_IO_APIC_route_entry *entry;
+	int mmr_pnode;
+
+	mmr_value = 0;
+	entry = (struct uv_IO_APIC_route_entry *)&mmr_value;
+	BUG_ON(sizeof(struct uv_IO_APIC_route_entry) != sizeof(unsigned long));
+
+	entry->mask = 1;
+
+	mmr_pnode = uv_blade_to_pnode(mmr_blade);
+	uv_write_global_mmr64(mmr_pnode, mmr_offset, mmr_value);
+}
+
 /* --------------------------------------------------------------------------
                           ACPI-based IOAPIC Configuration
    -------------------------------------------------------------------------- */