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GSI (Global System Interrupt) is an extension of just a linear array of IRQs. It takes IOAPICs into account for example. Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
85 lines
1.8 KiB
Rust
85 lines
1.8 KiB
Rust
// Copyright © 2019 Intel Corporation
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//
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// SPDX-License-Identifier: Apache-2.0 OR BSD-3-Clause
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use std::collections::btree_map::BTreeMap;
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use std::result;
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#[derive(Debug)]
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pub enum Error {
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Overflow,
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}
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pub type Result<T> = result::Result<T, Error>;
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/// GsiApic
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#[derive(Copy, Clone)]
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pub struct GsiApic {
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base: u32,
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irqs: u32,
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}
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impl GsiApic {
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/// New GSI APIC
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pub fn new(base: u32, irqs: u32) -> Self {
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GsiApic { base, irqs }
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}
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}
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/// GsiAllocator
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pub struct GsiAllocator {
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apics: BTreeMap<u32, u32>,
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next_irq: u32,
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next_gsi: u32,
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}
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impl GsiAllocator {
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/// New GSI allocator
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pub fn new(apics: Vec<GsiApic>) -> Self {
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let mut allocator = GsiAllocator {
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apics: BTreeMap::new(),
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next_irq: 0xffff_ffff,
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next_gsi: 0,
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};
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for apic in &apics {
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if apic.base < allocator.next_irq {
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allocator.next_irq = apic.base;
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}
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if apic.base + apic.irqs > allocator.next_gsi {
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allocator.next_gsi = apic.base + apic.irqs;
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}
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allocator.apics.insert(apic.base, apic.irqs);
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}
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allocator
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}
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/// Allocate a GSI
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pub fn allocate_gsi(&mut self) -> Result<u32> {
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self.next_gsi = self.next_gsi.checked_add(1).ok_or(Error::Overflow)?;
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Ok(self.next_gsi - 1)
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}
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/// Allocate an IRQ
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pub fn allocate_irq(&mut self) -> Result<u32> {
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let mut irq: u32 = 0;
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for (base, irqs) in self.apics.iter() {
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// HACKHACK - This only works with 1 single IOAPIC...
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if self.next_irq >= *base && self.next_irq < *base + *irqs {
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irq = self.next_irq;
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self.next_irq += 1;
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}
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}
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if irq == 0 {
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return Err(Error::Overflow);
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}
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Ok(irq)
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}
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}
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