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On x86 boards, platform chipset receives up to four different interrupt signals from PCI devices (INTA/B/C/D), which in turn will be routed to chipset internal PIRQ lines then routed to 8259 PIC finally if configuring the whole system to work under the so-called PIC mode (in contrast to symmetric IO mode which uses IOAPIC). We add two major APIs to aid this, one for routing PIRQ and the other one for generating a PIRQ routing table. Signed-off-by: Bin Meng <bmeng.cn@gmail.com> Acked-by: Simon Glass <sjg@chromium.org>
139 lines
4.6 KiB
C
139 lines
4.6 KiB
C
/*
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* Copyright (C) 2015, Bin Meng <bmeng.cn@gmail.com>
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*
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* Ported from coreboot src/arch/x86/include/arch/pirq_routing.h
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*
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* SPDX-License-Identifier: GPL-2.0+
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*/
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#ifndef _PIRQ_ROUTING_H_
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#define _PIRQ_ROUTING_H_
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/*
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* This is the maximum number on interrupt entries that a PCI device may have.
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* This is NOT the number of slots or devices in the system
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* This is NOT the number of entries in the PIRQ table
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*
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* This tells us that in the PIRQ table, we are going to have 4 link-bitmap
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* entries per PCI device which is fixed at 4: INTA, INTB, INTC, and INTD.
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*
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* CAUTION: If you change this, PIRQ routing will not work correctly.
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*/
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#define MAX_INTX_ENTRIES 4
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#define PIRQ_SIGNATURE \
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(('$' << 0) + ('P' << 8) + ('I' << 16) + ('R' << 24))
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#define PIRQ_VERSION 0x0100
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struct __packed irq_info {
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u8 bus; /* Bus number */
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u8 devfn; /* Device and function number */
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struct __packed {
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u8 link; /* IRQ line ID, 0=not routed */
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u16 bitmap; /* Available IRQs */
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} irq[MAX_INTX_ENTRIES];
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u8 slot; /* Slot number, 0=onboard */
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u8 rfu;
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};
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struct __packed irq_routing_table {
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u32 signature; /* PIRQ_SIGNATURE */
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u16 version; /* PIRQ_VERSION */
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u16 size; /* Table size in bytes */
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u8 rtr_bus; /* busno of the interrupt router */
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u8 rtr_devfn; /* devfn of the interrupt router */
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u16 exclusive_irqs; /* IRQs devoted exclusively to PCI usage */
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u16 rtr_vendor; /* Vendor ID of the interrupt router */
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u16 rtr_device; /* Device ID of the interrupt router */
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u32 miniport_data;
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u8 rfu[11];
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u8 checksum; /* Modulo 256 checksum must give zero */
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struct irq_info slots[CONFIG_IRQ_SLOT_COUNT];
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};
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/**
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* get_irq_slot_count() - Get the number of entries in the irq_info table
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*
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* This calculates the number of entries for the irq_info table.
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*
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* @rt: pointer to the base address of the struct irq_info
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* @return: number of entries
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*/
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static inline int get_irq_slot_count(struct irq_routing_table *rt)
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{
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return (rt->size - 32) / sizeof(struct irq_info);
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}
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/**
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* pirq_check_irq_routed() - Check whether an IRQ is routed to 8259 PIC
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*
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* This function checks whether an IRQ is routed to 8259 PIC for a given link.
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*
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* Note: this function should be provided by the platform codes, as the
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* implementation of interrupt router may be different.
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*
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* @link: link number which represents a PIRQ
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* @irq: the 8259 IRQ number
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* @return: true if the irq is already routed to 8259 for a given link,
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* false elsewise
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*/
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bool pirq_check_irq_routed(int link, u8 irq);
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/**
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* pirq_translate_link() - Translate a link value
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*
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* This function translates a platform-specific link value to a link number.
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* On Intel platforms, the link value is normally a offset into the PCI
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* configuration space into the legacy bridge.
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*
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* Note: this function should be provided by the platform codes, as the
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* implementation of interrupt router may be different.
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*
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* @link: platform-specific link value
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* @return: link number which represents a PIRQ
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*/
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int pirq_translate_link(int link);
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/**
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* pirq_assign_irq() - Assign an IRQ to a PIRQ link
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*
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* This function assigns the IRQ to a PIRQ link so that the PIRQ is routed to
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* the 8259 PIC.
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*
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* Note: this function should be provided by the platform codes, as the
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* implementation of interrupt router may be different.
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*
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* @link: link number which represents a PIRQ
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* @irq: IRQ to which the PIRQ is routed
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*/
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void pirq_assign_irq(int link, u8 irq);
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/**
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* pirq_route_irqs() - Route PIRQs to 8259 PIC
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*
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* This function configures all PCI devices' interrupt pins and maps them to
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* PIRQs and finally 8259 PIC. The routed irq number is written to interrupt
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* line register in the configuration space of the PCI device for OS to use.
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* The configuration source is taken from a struct irq_info table, the format
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* of which is defined in PIRQ routing table spec and PCI BIOS spec.
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*
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* @irq: pointer to the base address of the struct irq_info
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* @num: number of entries in the struct irq_info
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*/
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void pirq_route_irqs(struct irq_info *irq, int num);
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/**
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* copy_pirq_routing_table() - Copy a PIRQ routing table
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*
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* This helper function copies the given PIRQ routing table to a given address.
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* Before copying, it does several sanity tests against the PIRQ routing table.
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* It also fixes up the table checksum and align the given address to a 16 byte
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* boundary to meet the PIRQ routing table spec requirements.
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*
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* @addr: address to store the copied PIRQ routing table
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* @rt: pointer to the PIRQ routing table to copy from
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* @return: end address of the copied PIRQ routing table
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*/
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u32 copy_pirq_routing_table(u32 addr, struct irq_routing_table *rt);
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#endif /* _PIRQ_ROUTING_H_ */
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