From: Tomasz Nowicki <tn@xxxxxxxxxxxx>
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@xxxxxxxxxxxx>
Signed-off-by: Dongdong Liu <liudongdong3@xxxxxxxxxx>
Signed-off-by: Christopher Covington <cov@xxxxxxxxxxxxxx>
Signed-off-by: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
---
drivers/acpi/pci_mcfg.c | 92 ++++++++++++++++++++++++++++++++++++++++++++---
1 file changed, 86 insertions(+), 6 deletions(-)
diff --git a/drivers/acpi/pci_mcfg.c b/drivers/acpi/pci_mcfg.c
index ffcc651..1ef7285 100644
--- a/drivers/acpi/pci_mcfg.c
+++ b/drivers/acpi/pci_mcfg.c
@@ -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));
- res.start = root->mcfg_addr + (bus_res->start << 20);
- res.end = res.start + (resource_size(bus_res) << 20) - 1;
- res.flags = IORESOURCE_MEM;
+ 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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