u-boot/arch/x86/include/asm/pirq_routing.h
Bin Meng b5b6b01960 x86: Support platform PIRQ routing
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>
2015-04-29 18:51:49 -06:00

139 lines
4.6 KiB
C

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