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// 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) {
if (host->native_shpc_hotplug)
return 0;
return -ENODEV;
}
/*
* In the absence of _OSC, we're always allowed to manage the SHPC.
* However, if an OSHP method is present, we must execute it so the
* firmware can transfer control to the OS, e.g., direct interrupts
* to the OS instead of to the firmware.
*
* N.B. The PCI Firmware Spec (r3.2, sec 4.8) does not endorse
* searching up the ACPI hierarchy, so the loops below are suspect.
*/
handle = ACPI_HANDLE(&pdev->dev);
if (!handle) {
/*
* This hotplug controller was not listed in the ACPI name
* space at all. Try to get ACPI handle of parent PCI bus.
*/
struct pci_bus *pbus;
for (pbus = pdev->bus; pbus; pbus = pbus->parent) {
handle = acpi_pci_get_bridge_handle(pbus);
if (handle)
break;
}
}
while (handle) {
acpi_get_name(handle, ACPI_FULL_PATHNAME, &string);
pci_info(pdev, "Requesting control of SHPC hotplug via OSHP (%s)\n",
(char *)string.pointer);
status = acpi_run_oshp(handle);
if (ACPI_SUCCESS(status))
goto got_one;
if (acpi_is_root_bridge(handle))
break;
chandle = handle;
status = acpi_get_parent(chandle, &handle);
if (ACPI_FAILURE(status))
break;
}
pci_info(pdev, "Cannot get control of SHPC hotplug\n");
kfree(string.pointer);
return -ENODEV;
got_one:
pci_info(pdev, "Gained control of SHPC hotplug (%s)\n",
(char *)string.pointer);
kfree(string.pointer);
return 0;
}
EXPORT_SYMBOL(acpi_get_hp_hw_control_from_firmware);
static int pcihp_is_ejectable(acpi_handle handle)
{
acpi_status status;
unsigned long long removable;
if (!acpi_has_method(handle, "_ADR"))
return 0;
if (acpi_has_method(handle, "_EJ0"))
return 1;
status = acpi_evaluate_integer(handle, "_RMV", NULL, &removable);
if (ACPI_SUCCESS(status) && removable)
return 1;
return 0;
}
/**
* acpi_pci_check_ejectable - check if handle is ejectable ACPI PCI slot
* @pbus: the PCI bus of the PCI slot corresponding to 'handle'
* @handle: ACPI handle to check
*
* Return 1 if handle is ejectable PCI slot, 0 otherwise.
*/
int acpi_pci_check_ejectable(struct pci_bus *pbus, acpi_handle handle)
{
acpi_handle bridge_handle, parent_handle;
bridge_handle = acpi_pci_get_bridge_handle(pbus);
if (!bridge_handle)
return 0;
if ((ACPI_FAILURE(acpi_get_parent(handle, &parent_handle))))
return 0;
if (bridge_handle != parent_handle)
return 0;
return pcihp_is_ejectable(handle);
}
EXPORT_SYMBOL_GPL(acpi_pci_check_ejectable);
static acpi_status
check_hotplug(acpi_handle handle, u32 lvl, void *context, void **rv)
{
int *found = (int *)context;
if (pcihp_is_ejectable(handle)) {
*found = 1;
return AE_CTRL_TERMINATE;
}
return AE_OK;
}
/**
* acpi_pci_detect_ejectable - check if the PCI bus has ejectable slots
* @handle: handle of the PCI bus to scan
*
* Returns 1 if the PCI bus has ACPI based ejectable slots, 0 otherwise.
*/
int acpi_pci_detect_ejectable(acpi_handle handle)
{
int found = 0;
if (!handle)
return found;
acpi_walk_namespace(ACPI_TYPE_DEVICE, handle, 1,
check_hotplug, NULL, (void *)&found, NULL);
return found;
}
EXPORT_SYMBOL_GPL(acpi_pci_detect_ejectable);
module_param(debug_acpi, bool, 0644);
MODULE_PARM_DESC(debug_acpi, "Debugging mode for ACPI enabled or not");
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