Commit 5b69b85b authored by Tomasz Nowicki's avatar Tomasz Nowicki Committed by Bjorn Helgaas
Browse files

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: default avatarTomasz Nowicki <tn@semihalf.com>
Signed-off-by: default avatarDongdong Liu <liudongdong3@huawei.com>
Signed-off-by: default avatarChristopher Covington <cov@codeaurora.org>
Signed-off-by: default avatarBjorn Helgaas <bhelgaas@google.com>
parent 13983eb8

drivers/acpi/pci_mcfg.c

+86 −6
Original line number Diff line number Diff line
@@ -33,6 +33,69 @@ struct mcfg_entry { 
	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);
@@ -61,14 +124,24 @@ int pci_mcfg_lookup(struct acpi_pci_root *root, struct resource *cfgres, 


	}



	if (!root->mcfg_addr)

		return -ENXIO;



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;
@@ -101,6 +174,13 @@ static __init int pci_mcfg_parse(struct acpi_table_header *header) 
		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;

}

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