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Commit c29d9db3 authored by Suresh Siddha's avatar Suresh Siddha Committed by Ingo Molnar
Browse files

x86, ioapic: Fix the EOI register detection mechanism 



Maciej W. Rozycki reported:

> 82093AA I/O APIC has its version set to 0x11 and it
> does not support the EOI register.  Similarly I/O APICs
> integrated into the 82379AB south bridge and the 82374EB/SB
> EISA component.

IO-APIC versions below 0x20 don't support EOI register.

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 and indeed has a working
EOI register for the io-apic.

Fix the EOI register detection mechanism to check for version
0x20 and beyond.

And also, a platform can potentially  have io-apic's with
different versions. Make the EOI register check per io-apic.

Reported-by: default avatarMaciej W. Rozycki <macro@linux-mips.org>
Signed-off-by: default avatarSuresh Siddha <suresh.b.siddha@intel.com>
Cc: ebiederm@xmission.com
Cc: garyhade@us.ibm.com
LKML-Reference: <20091201233335.065361533@sbs-t61.sc.intel.com>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent ca64c47c

arch/x86/kernel/apic/io_apic.c

+61 −54
Original line number Diff line number Diff line
@@ -539,15 +539,12 @@ static void __init replace_pin_at_irq_node(struct irq_cfg *cfg, int node, 
	add_pin_to_irq_node(cfg, node, newapic, newpin);

}



static void io_apic_modify_irq(struct irq_cfg *cfg,

static void __io_apic_modify_irq(struct irq_pin_list *entry,

				 int mask_and, int mask_or,

				 void (*final)(struct irq_pin_list *entry))

{

	int pin;

	struct irq_pin_list *entry;

	unsigned int reg, pin;



	for_each_irq_pin(entry, cfg->irq_2_pin) {

		unsigned int reg;

	pin = entry->pin;

	reg = io_apic_read(entry->apic, 0x10 + pin * 2);

	reg &= mask_and;
@@ -556,6 +553,27 @@ static void io_apic_modify_irq(struct irq_cfg *cfg, 
	if (final)

		final(entry);

}



static void io_apic_modify_irq(struct irq_cfg *cfg,

			       int mask_and, int mask_or,

			       void (*final)(struct irq_pin_list *entry))

{

	struct irq_pin_list *entry;



	for_each_irq_pin(entry, cfg->irq_2_pin)

		__io_apic_modify_irq(entry, mask_and, mask_or, final);

}



static void __mask_and_edge_IO_APIC_irq(struct irq_pin_list *entry)

{

	__io_apic_modify_irq(entry, ~IO_APIC_REDIR_LEVEL_TRIGGER,

			     IO_APIC_REDIR_MASKED, NULL);

}



static void __unmask_and_level_IO_APIC_irq(struct irq_pin_list *entry)

{

	__io_apic_modify_irq(entry, ~IO_APIC_REDIR_MASKED,

			     IO_APIC_REDIR_LEVEL_TRIGGER, NULL);

}



static void __unmask_IO_APIC_irq(struct irq_cfg *cfg)
@@ -579,18 +597,6 @@ static void __mask_IO_APIC_irq(struct irq_cfg *cfg) 
	io_apic_modify_irq(cfg, ~0, IO_APIC_REDIR_MASKED, &io_apic_sync);

}



static void __mask_and_edge_IO_APIC_irq(struct irq_cfg *cfg)

{

	io_apic_modify_irq(cfg, ~IO_APIC_REDIR_LEVEL_TRIGGER,

			IO_APIC_REDIR_MASKED, NULL);

}



static void __unmask_and_level_IO_APIC_irq(struct irq_cfg *cfg)

{

	io_apic_modify_irq(cfg, ~IO_APIC_REDIR_MASKED,

			IO_APIC_REDIR_LEVEL_TRIGGER, NULL);

}



static void mask_IO_APIC_irq_desc(struct irq_desc *desc)

{

	struct irq_cfg *cfg = desc->chip_data;
@@ -2492,17 +2498,42 @@ static void ack_apic_edge(unsigned int irq) 


atomic_t irq_mis_count;



static int use_eoi_reg __read_mostly;



/*

 * 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;



	for_each_irq_pin(entry, cfg->irq_2_pin) {

		if (mp_ioapics[entry->apic].apicver >= 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(irq))

				io_apic_eoi(entry->apic, entry->pin);

			else

				io_apic_eoi(entry->apic, cfg->vector);

		} else {

			__mask_and_edge_IO_APIC_irq(entry);

			__unmask_and_level_IO_APIC_irq(entry);

		}

	}

}
@@ -2520,23 +2551,6 @@ static void eoi_ioapic_irq(struct irq_desc *desc) 
	spin_unlock_irqrestore(&ioapic_lock, flags);

}



static int ioapic_supports_eoi(void)

{

	struct pci_dev *root;



	root = pci_get_bus_and_slot(0, PCI_DEVFN(0, 0));

	if (root && root->vendor == PCI_VENDOR_ID_INTEL &&

	    mp_ioapics[0].apicver >= 0x2) {

		use_eoi_reg = 1;

		printk(KERN_INFO "IO-APIC supports EOI register\n");

	} else

		printk(KERN_INFO "IO-APIC doesn't support EOI\n");



	return 0;

}



fs_initcall(ioapic_supports_eoi);



static void ack_apic_level(unsigned int irq)

{

	struct irq_desc *desc = irq_to_desc(irq);
@@ -2587,14 +2601,7 @@ static void ack_apic_level(unsigned int irq) 
	if (!(v & (1 << (i & 0x1f)))) {

		atomic_inc(&irq_mis_count);



		if (use_eoi_reg)

		eoi_ioapic_irq(desc);

		else {

			spin_lock(&ioapic_lock);

			__mask_and_edge_IO_APIC_irq(cfg);

			__unmask_and_level_IO_APIC_irq(cfg);

			spin_unlock(&ioapic_lock);

		}

	}



	/* Now we can move and renable the irq */