[patch 3/3] x86, ioapic: consolidate the explicit EOI code

From: Suresh Siddha
Date: Thu Aug 11 2011 - 17:44:40 EST


Consolidate the io-apic EOI code in clear_IO_APIC_pin() and eoi_ioapic_irq().

Signed-off-by: Suresh Siddha <suresh.b.siddha@xxxxxxxxx>
Cc: Thomas Renninger <trenn@xxxxxxx>
Cc: Rafael Wysocki <rjw@xxxxxxxxxx>
---
arch/x86/kernel/apic/io_apic.c | 137 +++++++++++++++++++----------------------
1 file changed, 64 insertions(+), 73 deletions(-)

Index: linux-2.6-tip/arch/x86/kernel/apic/io_apic.c
===================================================================
--- linux-2.6-tip.orig/arch/x86/kernel/apic/io_apic.c
+++ linux-2.6-tip/arch/x86/kernel/apic/io_apic.c
@@ -581,6 +581,66 @@ static void unmask_ioapic_irq(struct irq
unmask_ioapic(data->chip_data);
}

+/*
+ * IO-APIC versions below 0x20 don't support EOI register.
+ * For the record, here is the information about various versions:
+ * 0Xh 82489DX
+ * 1Xh I/OAPIC or I/O(x)APIC which are not PCI 2.2 Compliant
+ * 2Xh I/O(x)APIC which is PCI 2.2 Compliant
+ * 30h-FFh Reserved
+ *
+ * Some of the Intel ICH Specs (ICH2 to ICH5) documents the io-apic
+ * version as 0x2. This is an error with documentation and these ICH chips
+ * use io-apic's of version 0x20.
+ *
+ * For IO-APIC's with EOI register, we use that to do an explicit EOI.
+ * Otherwise, we simulate the EOI message manually by changing the trigger
+ * mode to edge and then back to level, with RTE being masked during this.
+ */
+static void __eoi_ioapic_pin(int apic, int pin, int vector, struct irq_cfg *cfg)
+{
+ if (mpc_ioapic_ver(apic) >= 0x20) {
+ /*
+ * Intr-remapping uses pin number as the virtual vector
+ * in the RTE. Actual vector is programmed in
+ * intr-remapping table entry. Hence for the io-apic
+ * EOI we use the pin number.
+ */
+ if (cfg && irq_remapped(cfg))
+ io_apic_eoi(apic, pin);
+ else
+ io_apic_eoi(apic, vector);
+ } else {
+ struct IO_APIC_route_entry entry, entry1;
+
+ entry = entry1 = __ioapic_read_entry(apic, pin);
+
+ /*
+ * Mask the entry and change the trigger mode to edge.
+ */
+ entry1.mask = 1;
+ entry1.trigger = IOAPIC_EDGE;
+
+ __ioapic_write_entry(apic, pin, entry1);
+
+ /*
+ * Restore the previous level triggered entry.
+ */
+ __ioapic_write_entry(apic, pin, entry);
+ }
+}
+
+static void eoi_ioapic_irq(unsigned int irq, struct irq_cfg *cfg)
+{
+ struct irq_pin_list *entry;
+ unsigned long flags;
+
+ raw_spin_lock_irqsave(&ioapic_lock, flags);
+ for_each_irq_pin(entry, cfg->irq_2_pin)
+ __eoi_ioapic_pin(entry->apic, entry->pin, cfg->vector, cfg);
+ raw_spin_unlock_irqrestore(&ioapic_lock, flags);
+}
+
static void clear_IO_APIC_pin(unsigned int apic, unsigned int pin)
{
struct IO_APIC_route_entry entry;
@@ -601,23 +661,11 @@ static void clear_IO_APIC_pin(unsigned i
}

if (entry.trigger & entry.irr) {
- if (mpc_ioapic_ver(apic) >= 0x20) {
- unsigned long flags;
+ unsigned long flags;

- raw_spin_lock_irqsave(&ioapic_lock, flags);
- io_apic_eoi(apic, entry.vector);
- raw_spin_unlock_irqrestore(&ioapic_lock, flags);
- } else {
- /*
- * Mechanism by which we clear remoteIRR in this
- * case is by changing the trigger mode to edge and
- * back to level.
- */
- entry.trigger = IOAPIC_EDGE;
- ioapic_write_entry(apic, pin, entry);
- entry.trigger = IOAPIC_LEVEL;
- ioapic_write_entry(apic, pin, entry);
- }
+ raw_spin_lock_irqsave(&ioapic_lock, flags);
+ __eoi_ioapic_pin(apic, pin, entry.vector, NULL);
+ raw_spin_unlock_irqrestore(&ioapic_lock, flags);
}

/*
@@ -2439,63 +2487,6 @@ static void ack_apic_edge(struct irq_dat

atomic_t irq_mis_count;

-/*
- * IO-APIC versions below 0x20 don't support EOI register.
- * For the record, here is the information about various versions:
- * 0Xh 82489DX
- * 1Xh I/OAPIC or I/O(x)APIC which are not PCI 2.2 Compliant
- * 2Xh I/O(x)APIC which is PCI 2.2 Compliant
- * 30h-FFh Reserved
- *
- * Some of the Intel ICH Specs (ICH2 to ICH5) documents the io-apic
- * version as 0x2. This is an error with documentation and these ICH chips
- * use io-apic's of version 0x20.
- *
- * For IO-APIC's with EOI register, we use that to do an explicit EOI.
- * Otherwise, we simulate the EOI message manually by changing the trigger
- * mode to edge and then back to level, with RTE being masked during this.
-*/
-static void eoi_ioapic_irq(unsigned int irq, struct irq_cfg *cfg)
-{
- struct irq_pin_list *entry;
- unsigned long flags;
-
- raw_spin_lock_irqsave(&ioapic_lock, flags);
- for_each_irq_pin(entry, cfg->irq_2_pin) {
- if (mpc_ioapic_ver(entry->apic) >= 0x20) {
- /*
- * Intr-remapping uses pin number as the virtual vector
- * in the RTE. Actual vector is programmed in
- * intr-remapping table entry. Hence for the io-apic
- * EOI we use the pin number.
- */
- if (irq_remapped(cfg))
- io_apic_eoi(entry->apic, entry->pin);
- else
- io_apic_eoi(entry->apic, cfg->vector);
- } else {
- struct IO_APIC_route_entry rte, rte1;
-
- rte = rte1 =
- __ioapic_read_entry(entry->apic, entry->pin);
-
- /*
- * Mask the entry and change the trigger mode to edge.
- */
- rte1.mask = 1;
- rte1.trigger = IOAPIC_EDGE;
-
- __ioapic_write_entry(apic, pin, rte1);
-
- /*
- * Restore the previous level triggered entry.
- */
- __ioapic_write_entry(apic, pin, rte);
- }
- }
- raw_spin_unlock_irqrestore(&ioapic_lock, flags);
-}
-
static void ack_apic_level(struct irq_data *data)
{
struct irq_cfg *cfg = data->chip_data;


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