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/*
* Copyright (C) 2016 Broadcom
* Author: Jayachandran C <jchandra@broadcom.com>
* Copyright (C) 2016 Semihalf
* Author: Tomasz Nowicki <tn@semihalf.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License, version 2, as
* published by the Free Software Foundation (the "GPL").
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License version 2 (GPLv2) for more details.
*
* You should have received a copy of the GNU General Public License
* version 2 (GPLv2) along with this source code.
*/
#define pr_fmt(fmt) "ACPI: " fmt
#include <linux/kernel.h>
#include <linux/pci.h>
#include <linux/pci-acpi.h>
#include <linux/pci-ecam.h>
/* Structure to hold entries from the MCFG table */
struct mcfg_entry {
struct list_head list;
phys_addr_t addr;
u16 segment;
u8 bus_start;
u8 bus_end;
};
/* List to save MCFG entries */
static LIST_HEAD(pci_mcfg_list);
int pci_mcfg_lookup(struct acpi_pci_root *root, struct resource *cfgres,
struct pci_ecam_ops **ecam_ops)
{
struct pci_ecam_ops *ops = &pci_generic_ecam_ops;
struct resource *bus_res = &root->secondary;
u16 seg = root->segment;
struct mcfg_entry *e;
struct resource res;
/* Use address from _CBA if present, otherwise lookup MCFG */
if (root->mcfg_addr)
goto skip_lookup;
/*
* We expect exact match, unless MCFG entry end bus covers more than
* specified by caller.
*/
list_for_each_entry(e, &pci_mcfg_list, list) {
if (e->segment == seg && e->bus_start == bus_res->start &&
e->bus_end >= bus_res->end) {
root->mcfg_addr = e->addr;
}
}
if (!root->mcfg_addr)
return -ENXIO;
skip_lookup:
memset(&res, 0, sizeof(res));
res.start = root->mcfg_addr + (bus_res->start << 20);
res.end = res.start + (resource_size(bus_res) << 20) - 1;
res.flags = IORESOURCE_MEM;
*cfgres = res;
*ecam_ops = ops;
return 0;
}
static __init int pci_mcfg_parse(struct acpi_table_header *header)
{
struct acpi_table_mcfg *mcfg;
struct acpi_mcfg_allocation *mptr;
struct mcfg_entry *e, *arr;
int i, n;
if (header->length < sizeof(struct acpi_table_mcfg))
return -EINVAL;
n = (header->length - sizeof(struct acpi_table_mcfg)) /
sizeof(struct acpi_mcfg_allocation);
mcfg = (struct acpi_table_mcfg *)header;
mptr = (struct acpi_mcfg_allocation *) &mcfg[1];
arr = kcalloc(n, sizeof(*arr), GFP_KERNEL);
if (!arr)
return -ENOMEM;
for (i = 0, e = arr; i < n; i++, mptr++, e++) {
e->segment = mptr->pci_segment;
e->addr = mptr->address;
e->bus_start = mptr->start_bus_number;
e->bus_end = mptr->end_bus_number;
list_add(&e->list, &pci_mcfg_list);
}
pr_info("MCFG table detected, %d entries\n", n);
return 0;
}
/* Interface called by ACPI - parse and save MCFG table */
void __init pci_mmcfg_late_init(void)
{
int err = acpi_table_parse(ACPI_SIG_MCFG, pci_mcfg_parse);
if (err)
pr_err("Failed to parse MCFG (%d)\n", err);
}
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