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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-27 10:05:51 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-27 10:05:51 +0000 |
commit | 5d1646d90e1f2cceb9f0828f4b28318cd0ec7744 (patch) | |
tree | a94efe259b9009378be6d90eb30d2b019d95c194 /drivers/pci/hotplug/acpi_pcihp.c | |
parent | Initial commit. (diff) | |
download | linux-5d1646d90e1f2cceb9f0828f4b28318cd0ec7744.tar.xz linux-5d1646d90e1f2cceb9f0828f4b28318cd0ec7744.zip |
Adding upstream version 5.10.209.upstream/5.10.209upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'drivers/pci/hotplug/acpi_pcihp.c')
-rw-r--r-- | drivers/pci/hotplug/acpi_pcihp.c | 212 |
1 files changed, 212 insertions, 0 deletions
diff --git a/drivers/pci/hotplug/acpi_pcihp.c b/drivers/pci/hotplug/acpi_pcihp.c new file mode 100644 index 000000000..2750a64ce --- /dev/null +++ b/drivers/pci/hotplug/acpi_pcihp.c @@ -0,0 +1,212 @@ +// 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_pcihp_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"); |