[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, 24 insertions, 48 deletions

diff --git a/drivers/pci/htirq.c b/drivers/pci/htirq.c
index 0e27f2404a83..e346fe31f97a 100644
--- a/drivers/pci/htirq.c
+++ b/drivers/pci/htirq.c
@@ -27,82 +27,55 @@ struct ht_irq_cfg {
         struct pci_dev *dev;
         unsigned pos;
         unsigned idx;
+        struct ht_irq_msg msg;
 };
 
-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)
+void write_ht_irq_msg(unsigned int irq, struct ht_irq_msg *msg)
 {
         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);
+        if (cfg->msg.address_lo != msg->address_lo) {
+                pci_write_config_byte(cfg->dev, cfg->pos + 2, cfg->idx);
+                pci_write_config_dword(cfg->dev, cfg->pos + 4, msg->address_lo);
+        }
+        if (cfg->msg.address_hi != msg->address_hi) {
+                pci_write_config_byte(cfg->dev, cfg->pos + 2, cfg->idx + 1);
+                pci_write_config_dword(cfg->dev, cfg->pos + 4, msg->address_hi);
+        }
         spin_unlock_irqrestore(&ht_irq_lock, flags);
-        return data;
+        cfg->msg = *msg;
 }
 
-u32 read_ht_irq_high(unsigned int irq)
+void fetch_ht_irq_msg(unsigned int irq, struct ht_irq_msg *msg)
 {
         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;
+        *msg = cfg->msg;
 }
 
 void mask_ht_irq(unsigned int irq)
 {
         struct ht_irq_cfg *cfg;
-        unsigned long flags;
-        u32 data;
+        struct ht_irq_msg msg;
 
         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);
+        msg = cfg->msg;
+        msg.address_lo |= 1;
+        write_ht_irq_msg(irq, &msg);
 }
 
 void unmask_ht_irq(unsigned int irq)
 {
         struct ht_irq_cfg *cfg;
-        unsigned long flags;
-        u32 data;
+        struct ht_irq_msg msg;
 
         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);
+        msg = cfg->msg;
+        msg.address_lo &= ~1;
+        write_ht_irq_msg(irq, &msg);
 }
 
 /**
@@ -152,6 +125,9 @@ int ht_create_irq(struct pci_dev *dev, int idx)
         cfg->dev = dev;
         cfg->pos = pos;
         cfg->idx = 0x10 + (idx * 2);
+        /* Initialize msg to a value that will never match the first write. */
+        cfg->msg.address_lo = 0xffffffff;
+        cfg->msg.address_hi = 0xffffffff;
 
         irq = create_irq();
         if (irq < 0) {