Commit 935c760e authored by Tomasz Nowicki's avatar Tomasz Nowicki Committed by Bjorn Helgaas
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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: default avatarTomasz Nowicki <tn@semihalf.com>
Signed-off-by: default avatarJayachandran C <jchandra@broadcom.com>
Signed-off-by: default avatarBjorn Helgaas <bhelgaas@google.com>
Reviewed-by: default avatarLorenzo Pieralisi <lorenzo.pieralisi@arm.com>
parent 0a70abb3

drivers/acpi/Kconfig

+3 −0
Original line number Diff line number Diff line
@@ -217,6 +217,9 @@ config ACPI_PROCESSOR_IDLE 
	bool

	select CPU_IDLE



config ACPI_MCFG

	bool



config ACPI_CPPC_LIB

	bool

	depends on ACPI_PROCESSOR

drivers/acpi/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -40,6 +40,7 @@ acpi-$(CONFIG_ARCH_MIGHT_HAVE_ACPI_PDC) += processor_pdc.o 
acpi-y				+= ec.o

acpi-$(CONFIG_ACPI_DOCK)	+= dock.o

acpi-y				+= pci_root.o pci_link.o pci_irq.o

obj-$(CONFIG_ACPI_MCFG)		+= pci_mcfg.o

acpi-y				+= acpi_lpss.o acpi_apd.o

acpi-y				+= acpi_platform.o

acpi-y				+= acpi_pnp.o

drivers/acpi/pci_mcfg.c

0 → 100644
+92 −0
Original line number Diff line number Diff line 
/*

 * 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>



/* 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);

}

include/linux/pci-acpi.h

+2 −0
Original line number Diff line number Diff line
@@ -24,6 +24,8 @@ static inline acpi_status pci_acpi_remove_pm_notifier(struct acpi_device *dev) 
}

extern phys_addr_t acpi_pci_root_get_mcfg_addr(acpi_handle handle);



extern phys_addr_t pci_mcfg_lookup(u16 domain, struct resource *bus_res);



static inline acpi_handle acpi_find_root_bridge_handle(struct pci_dev *pdev)

{

	struct pci_bus *pbus = pdev->bus;

include/linux/pci.h

+1 −1
Original line number Diff line number Diff line
@@ -1723,7 +1723,7 @@ void pcibios_free_irq(struct pci_dev *dev); 
extern struct dev_pm_ops pcibios_pm_ops;

#endif



#ifdef CONFIG_PCI_MMCONFIG

#if defined(CONFIG_PCI_MMCONFIG) || defined(CONFIG_ACPI_MCFG)

void __init pci_mmcfg_early_init(void);

void __init pci_mmcfg_late_init(void);

#else

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