kernel_optimize_test/drivers/acpi/pci_mcfg.c
Tomasz Nowicki 5b69b85ba1 PCI/ACPI: Check for platform-specific MCFG quirks
The PCIe spec (r3.0, sec 7.2.2) specifies an "Enhanced Configuration Access
Mechanism" (ECAM) for memory-mapped access to configuration space.  ECAM is
required for PCIe systems unless there's a standard firmware interface for
config access.

In the absence of a firmware interface, we use pci_generic_ecam_ops, and on
ACPI systems, we discover the ECAM space via the MCFG table and/or the _CBA
method.

Unfortunately some systems provide MCFG but don't implement ECAM according
to spec, so we need a mechanism for quirks to make those systems work.

Add an MCFG quirk mechanism to override the config accessor functions
and/or the memory-mapped address space.

A quirk is selected if it matches all of the following:

  - OEM ID
  - OEM Table ID
  - OEM Revision
  - PCI segment (from _SEG)
  - PCI bus number range (from _CRS, wildcard allowed)

If the quirk specifies config accessor functions or a memory-mapped address
range, these override the defaults.

[bhelgaas: changelog, reorder quirk matching, fix oem_revision typo per
Duc, add under #ifdef CONFIG_PCI_QUIRKS]
Signed-off-by: Tomasz Nowicki <tn@semihalf.com>
Signed-off-by: Dongdong Liu <liudongdong3@huawei.com>
Signed-off-by: Christopher Covington <cov@codeaurora.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
2016-12-06 13:45:48 -06:00

195 lines
5.3 KiB
C

/*
* 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;
};
#ifdef CONFIG_PCI_QUIRKS
struct mcfg_fixup {
char oem_id[ACPI_OEM_ID_SIZE + 1];
char oem_table_id[ACPI_OEM_TABLE_ID_SIZE + 1];
u32 oem_revision;
u16 segment;
struct resource bus_range;
struct pci_ecam_ops *ops;
struct resource cfgres;
};
#define MCFG_BUS_RANGE(start, end) DEFINE_RES_NAMED((start), \
((end) - (start) + 1), \
NULL, IORESOURCE_BUS)
#define MCFG_BUS_ANY MCFG_BUS_RANGE(0x0, 0xff)
static struct mcfg_fixup mcfg_quirks[] = {
/* { OEM_ID, OEM_TABLE_ID, REV, SEGMENT, BUS_RANGE, ops, cfgres }, */
};
static char mcfg_oem_id[ACPI_OEM_ID_SIZE];
static char mcfg_oem_table_id[ACPI_OEM_TABLE_ID_SIZE];
static u32 mcfg_oem_revision;
static int pci_mcfg_quirk_matches(struct mcfg_fixup *f, u16 segment,
struct resource *bus_range)
{
if (!memcmp(f->oem_id, mcfg_oem_id, ACPI_OEM_ID_SIZE) &&
!memcmp(f->oem_table_id, mcfg_oem_table_id,
ACPI_OEM_TABLE_ID_SIZE) &&
f->oem_revision == mcfg_oem_revision &&
f->segment == segment &&
resource_contains(&f->bus_range, bus_range))
return 1;
return 0;
}
#endif
static void pci_mcfg_apply_quirks(struct acpi_pci_root *root,
struct resource *cfgres,
struct pci_ecam_ops **ecam_ops)
{
#ifdef CONFIG_PCI_QUIRKS
u16 segment = root->segment;
struct resource *bus_range = &root->secondary;
struct mcfg_fixup *f;
int i;
for (i = 0, f = mcfg_quirks; i < ARRAY_SIZE(mcfg_quirks); i++, f++) {
if (pci_mcfg_quirk_matches(f, segment, bus_range)) {
if (f->cfgres.start)
*cfgres = f->cfgres;
if (f->ops)
*ecam_ops = f->ops;
dev_info(&root->device->dev, "MCFG quirk: ECAM at %pR for %pR with %ps\n",
cfgres, bus_range, *ecam_ops);
return;
}
}
#endif
}
/* 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;
}
}
skip_lookup:
memset(&res, 0, sizeof(res));
if (root->mcfg_addr) {
res.start = root->mcfg_addr + (bus_res->start << 20);
res.end = res.start + (resource_size(bus_res) << 20) - 1;
res.flags = IORESOURCE_MEM;
}
/*
* Allow quirks to override default ECAM ops and CFG resource
* range. This may even fabricate a CFG resource range in case
* MCFG does not have it. Invalid CFG start address means MCFG
* firmware bug or we need another quirk in array.
*/
pci_mcfg_apply_quirks(root, &res, &ops);
if (!res.start)
return -ENXIO;
*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);
}
#ifdef CONFIG_PCI_QUIRKS
/* Save MCFG IDs and revision for quirks matching */
memcpy(mcfg_oem_id, header->oem_id, ACPI_OEM_ID_SIZE);
memcpy(mcfg_oem_table_id, header->oem_table_id, ACPI_OEM_TABLE_ID_SIZE);
mcfg_oem_revision = header->oem_revision;
#endif
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);
}