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path: root/drivers/acpi/pci_mcfg.c
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Diffstat (limited to 'drivers/acpi/pci_mcfg.c')
-rw-r--r--drivers/acpi/pci_mcfg.c126
1 files changed, 126 insertions, 0 deletions
diff --git a/drivers/acpi/pci_mcfg.c b/drivers/acpi/pci_mcfg.c
new file mode 100644
index 000000000000..f3d4570a4f9c
--- /dev/null
+++ b/drivers/acpi/pci_mcfg.c
@@ -0,0 +1,126 @@
+/*
+ * 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>
+
+/* Root pointer to the mapped MCFG table */
+static struct acpi_table_mcfg *mcfg_table;
+static int mcfg_entries;
+
+extern struct pci_cfg_fixup __start_acpi_mcfg_fixups[];
+extern struct pci_cfg_fixup __end_acpi_mcfg_fixups[];
+
+struct pci_ecam_ops *pci_mcfg_get_ops(struct acpi_pci_root *root)
+{
+ int bus_num = root->secondary.start;
+ int domain = root->segment;
+ struct pci_cfg_fixup *f;
+
+ if (!mcfg_table)
+ return &pci_generic_ecam_ops;
+
+ /*
+ * Match against platform specific quirks and return corresponding
+ * CAM ops.
+ *
+ * First match against PCI topology <domain:bus> then use OEM ID and
+ * OEM revision from MCFG table standard header.
+ */
+ for (f = __start_acpi_mcfg_fixups; f < __end_acpi_mcfg_fixups; f++) {
+ if ((f->domain == domain || f->domain == PCI_MCFG_DOMAIN_ANY) &&
+ (f->bus_num == bus_num || f->bus_num == PCI_MCFG_BUS_ANY) &&
+ (!strncmp(f->oem_id, mcfg_table->header.oem_id,
+ ACPI_OEM_ID_SIZE)) &&
+ (f->oem_revision == mcfg_table->header.oem_revision))
+ return f->ops;
+ }
+ /* No quirks, use ECAM */
+ return &pci_generic_ecam_ops;
+}
+
+int pci_mcfg_lookup(struct acpi_pci_root *root)
+{
+ struct acpi_mcfg_allocation *mptr, *entry = NULL;
+ struct resource *bus_res = &root->secondary;
+ int i;
+
+ if (mcfg_table) {
+ mptr = (struct acpi_mcfg_allocation *) &mcfg_table[1];
+ for (i = 0; i < mcfg_entries && !entry; i++, mptr++)
+ if (mptr->pci_segment == root->segment &&
+ mptr->start_bus_number == bus_res->start)
+ entry = mptr;
+ }
+
+ /* not found, use _CBA if available, else error */
+ if (!entry) {
+ if (root->mcfg_addr)
+ return root->mcfg_addr;
+ pr_err("%04x:%pR MCFG lookup failed\n", root->segment, bus_res);
+ return -ENOENT;
+ } else if (root->mcfg_addr && entry->address != root->mcfg_addr) {
+ pr_warn("%04x:%pR CBA %pa != MCFG %lx, using CBA\n",
+ root->segment, bus_res, &root->mcfg_addr,
+ (unsigned long)entry->address);
+ return 0;
+ }
+
+ /* found matching entry, bus range check */
+ if (entry->end_bus_number != bus_res->end) {
+ resource_size_t bus_end = min_t(resource_size_t,
+ entry->end_bus_number, bus_res->end);
+ pr_warn("%04x:%pR bus end mismatch, using %02lx\n",
+ root->segment, bus_res, (unsigned long)bus_end);
+ bus_res->end = bus_end;
+ }
+
+ if (!root->mcfg_addr)
+ root->mcfg_addr = entry->address;
+ return 0;
+}
+
+static __init int pci_mcfg_parse(struct acpi_table_header *header)
+{
+ if (header->length < sizeof(struct acpi_table_mcfg))
+ return -EINVAL;
+
+ mcfg_entries = (header->length - sizeof(struct acpi_table_mcfg)) /
+ sizeof(struct acpi_mcfg_allocation);
+ if (mcfg_entries == 0) {
+ pr_err("MCFG has no entries\n");
+ return -EINVAL;
+ }
+
+ mcfg_table = (struct acpi_table_mcfg *)header;
+ pr_info("MCFG table detected, %d entries\n", mcfg_entries);
+ 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);
+}