[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>

1 files changed, 96 insertions, 0 deletions

diff --git a/arch/x86_64/kernel/io_apic.c b/arch/x86_64/kernel/io_apic.c
index 7cc29b50b0c1..31c270fee337 100644
--- a/arch/x86_64/kernel/io_apic.c
+++ b/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
    -------------------------------------------------------------------------- */