From 935c760ec8101413248da23b6df45f0a7a643c62 Mon Sep 17 00:00:00 2001 From: Tomasz Nowicki Date: Fri, 10 Jun 2016 21:55:13 +0200 Subject: PCI/ACPI: Add generic MCFG table handling On ACPI systems that support memory-mapped config space access, i.e., ECAM, the PCI Firmware Specification says the OS can learn where the ECAM space is from either: - the static MCFG table (for non-hotpluggable bridges), or - the _CBA method (for hotpluggable bridges) The current MCFG table handling code cannot be easily generalized owing to x86-specific quirks, which makes it hard to reuse on other architectures. Implement generic MCFG handling from scratch, including: - Simple MCFG table parsing (via pci_mmcfg_late_init() as in current x86) - MCFG region lookup for a (domain, bus_start, bus_end) tuple [bhelgaas: changelog] Signed-off-by: Tomasz Nowicki Signed-off-by: Jayachandran C Signed-off-by: Bjorn Helgaas Reviewed-by: Lorenzo Pieralisi --- drivers/acpi/pci_mcfg.c | 92 +++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 92 insertions(+) create mode 100644 drivers/acpi/pci_mcfg.c (limited to 'drivers/acpi/pci_mcfg.c') diff --git a/drivers/acpi/pci_mcfg.c b/drivers/acpi/pci_mcfg.c new file mode 100644 index 000000000000..b5b376e081f5 --- /dev/null +++ b/drivers/acpi/pci_mcfg.c @@ -0,0 +1,92 @@ +/* + * Copyright (C) 2016 Broadcom + * Author: Jayachandran C + * Copyright (C) 2016 Semihalf + * Author: Tomasz Nowicki + * + * 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 +#include +#include + +/* 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); + +phys_addr_t pci_mcfg_lookup(u16 seg, struct resource *bus_res) +{ + struct mcfg_entry *e; + + /* + * 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) + return e->addr; + } + + 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); +} -- cgit v1.2.3