drivers/pci/hotplug/acpi_pcihp.c

Source file repositories/reference/linux-study-clean/drivers/pci/hotplug/acpi_pcihp.c

File Facts

System
Linux kernel
Corpus path
drivers/pci/hotplug/acpi_pcihp.c
Extension
.c
Size
5839 bytes
Lines
213
Domain
Representative Device Path
Bucket
PCIe NVMe Storage Path
Inferred role
Representative Device Path: exported/initcall integration point
Status
integration implementation candidate

Why This File Exists

Part of the selected hardware vertical slice: PCI discovery, driver binding, NVMe queues, block requests, DMA, interrupts, and completion.

Dependency Surface

Detected Declarations

Annotated Snippet

// SPDX-License-Identifier: GPL-2.0+
/*
 * Common ACPI functions for hot plug platforms
 *
 * Copyright (C) 2006 Intel Corporation
 *
 * All rights reserved.
 *
 * Send feedback to <kristen.c.accardi@intel.com>
 */

#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/kernel.h>
#include <linux/types.h>
#include <linux/pci.h>
#include <linux/pci_hotplug.h>
#include <linux/acpi.h>
#include <linux/pci-acpi.h>
#include <linux/slab.h>

#define MY_NAME	"acpi_pcihp"

#define dbg(fmt, arg...) do { if (debug_acpi) printk(KERN_DEBUG "%s: %s: " fmt, MY_NAME, __func__, ## arg); } while (0)
#define err(format, arg...) printk(KERN_ERR "%s: " format, MY_NAME, ## arg)
#define info(format, arg...) printk(KERN_INFO "%s: " format, MY_NAME, ## arg)
#define warn(format, arg...) printk(KERN_WARNING "%s: " format, MY_NAME, ## arg)

#define	METHOD_NAME__SUN	"_SUN"
#define	METHOD_NAME_OSHP	"OSHP"

static bool debug_acpi;

/* acpi_run_oshp - get control of hotplug from the firmware
 *
 * @handle - the handle of the hotplug controller.
 */
static acpi_status acpi_run_oshp(acpi_handle handle)
{
	acpi_status		status;
	struct acpi_buffer	string = { ACPI_ALLOCATE_BUFFER, NULL };

	acpi_get_name(handle, ACPI_FULL_PATHNAME, &string);

	/* run OSHP */
	status = acpi_evaluate_object(handle, METHOD_NAME_OSHP, NULL, NULL);
	if (ACPI_FAILURE(status))
		if (status != AE_NOT_FOUND)
			printk(KERN_ERR "%s:%s OSHP fails=0x%x\n",
			       __func__, (char *)string.pointer, status);
		else
			dbg("%s:%s OSHP not found\n",
			    __func__, (char *)string.pointer);
	else
		pr_debug("%s:%s OSHP passes\n", __func__,
			(char *)string.pointer);

	kfree(string.pointer);
	return status;
}

/**
 * acpi_get_hp_hw_control_from_firmware
 * @pdev: the pci_dev of the bridge that has a hotplug controller
 *
 * Attempt to take hotplug control from firmware.
 */
int acpi_get_hp_hw_control_from_firmware(struct pci_dev *pdev)
{
	const struct pci_host_bridge *host;
	const struct acpi_pci_root *root;
	acpi_status status;
	acpi_handle chandle, handle;
	struct acpi_buffer string = { ACPI_ALLOCATE_BUFFER, NULL };

	/*
	 * If there's no ACPI host bridge (i.e., ACPI support is compiled
	 * into the kernel but the hardware platform doesn't support ACPI),
	 * there's nothing to do here.
	 */
	host = pci_find_host_bridge(pdev->bus);
	root = acpi_pci_find_root(ACPI_HANDLE(&host->dev));
	if (!root)
		return 0;

	/*
	 * If _OSC exists, it determines whether we're allowed to manage
	 * the SHPC.  We executed it while enumerating the host bridge.
	 */
	if (root->osc_support_set) {

Annotation

Implementation Notes