Fix reading of number of interrupts for IO-APICs
The number read from the io-apic register represents the index of the highest interrupt redirection entry, i.e. the number of interrupts minus one. Change-Id: I54c992e4ff400de24bb9fef5d82251078f92c588 Signed-off-by: Nico Huber <nico.huber@secunet.com> Reviewed-on: http://review.coreboot.org/1624 Tested-by: build bot (Jenkins) Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>
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@ -85,8 +85,11 @@ void setup_ioapic(u32 ioapic_base, u8 ioapic_id)
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/* Read the available number of interrupts. */
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/* Read the available number of interrupts. */
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ioapic_interrupts = (io_apic_read(ioapic_base, 0x01) >> 16) & 0xff;
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ioapic_interrupts = (io_apic_read(ioapic_base, 0x01) >> 16) & 0xff;
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if (!ioapic_interrupts || ioapic_interrupts == 0xff)
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if (ioapic_interrupts == 0xff)
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ioapic_interrupts = 24;
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ioapic_interrupts = 23;
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ioapic_interrupts += 1; /* Bits 23-16 specify the maximum redirection
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entry, which is the number of interrupts
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minus 1. */
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printk(BIOS_DEBUG, "IOAPIC: %d interrupts\n", ioapic_interrupts);
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printk(BIOS_DEBUG, "IOAPIC: %d interrupts\n", ioapic_interrupts);
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#if CONFIG_IOAPIC_INTERRUPTS_ON_FSB
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#if CONFIG_IOAPIC_INTERRUPTS_ON_FSB
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