[PATCH] htirq: refactor so we only have one function that writes to the chip

This refactoring actually optimizes the code a little by caching the value
that we think the device is programmed with instead of reading it back from
the hardware.  Which simplifies the code a little and should speed things up a
bit.

This patch introduces the concept of a ht_irq_msg and modifies the
architecture read/write routines to update this code.

There is a minor consistency fix here as well as x86_64 forgot to initialize
the htirq as masked.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Cc: Andi Kleen <ak@suse.de>
Acked-by: Bryan O'Sullivan <bos@pathscale.com>
Cc: <olson@pathscale.com>
Cc: Roland Dreier <rolandd@cisco.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 12 insertions, 14 deletions

diff --git a/arch/i386/kernel/io_apic.c b/arch/i386/kernel/io_apic.c
index 507983c513c3..ad84bc2802a6 100644
--- a/arch/i386/kernel/io_apic.c
+++ b/arch/i386/kernel/io_apic.c
@@ -2624,18 +2624,16 @@ void arch_teardown_msi_irq(unsigned int irq)
 
 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);
+        struct ht_irq_msg msg;
+        fetch_ht_irq_msg(irq, &msg);
 
-        low  &= ~(HT_IRQ_LOW_DEST_ID_MASK);
-        high &= ~(HT_IRQ_HIGH_DEST_ID_MASK);
+        msg.address_lo &= ~(HT_IRQ_LOW_DEST_ID_MASK);
+        msg.address_hi &= ~(HT_IRQ_HIGH_DEST_ID_MASK);
 
-        low  |= HT_IRQ_LOW_DEST_ID(dest);
-        high |= HT_IRQ_HIGH_DEST_ID(dest);
+        msg.address_lo |= HT_IRQ_LOW_DEST_ID(dest);
+        msg.address_hi |= HT_IRQ_HIGH_DEST_ID(dest);
 
-        write_ht_irq_low(irq, low);
-        write_ht_irq_high(irq, high);
+        write_ht_irq_msg(irq, &msg);
 }
 
 static void set_ht_irq_affinity(unsigned int irq, cpumask_t mask)
@@ -2673,7 +2671,7 @@ int arch_setup_ht_irq(unsigned int irq, struct pci_dev *dev)
 
         vector = assign_irq_vector(irq);
         if (vector >= 0) {
-                u32 low, high;
+                struct ht_irq_msg msg;
                 unsigned dest;
                 cpumask_t tmp;
 
@@ -2681,9 +2679,10 @@ int arch_setup_ht_irq(unsigned int irq, struct pci_dev *dev)
                 cpu_set(vector >> 8, tmp);
                 dest = cpu_mask_to_apicid(tmp);
 
-                high =  HT_IRQ_HIGH_DEST_ID(dest);
+                msg.address_hi = HT_IRQ_HIGH_DEST_ID(dest);
 
-                low =   HT_IRQ_LOW_BASE |
+                msg.address_lo =
+                        HT_IRQ_LOW_BASE |
                         HT_IRQ_LOW_DEST_ID(dest) |
                         HT_IRQ_LOW_VECTOR(vector) |
                         ((INT_DEST_MODE == 0) ?
@@ -2695,8 +2694,7 @@ int arch_setup_ht_irq(unsigned int irq, struct pci_dev *dev)
                                 HT_IRQ_LOW_MT_ARBITRATED) |
                         HT_IRQ_LOW_IRQ_MASKED;
 
-                write_ht_irq_low(irq, low);
-                write_ht_irq_high(irq, high);
+                write_ht_irq_msg(irq, &msg);
 
                 set_irq_chip_and_handler_name(irq, &ht_irq_chip,
                                               handle_edge_irq, "edge");