diff options
Diffstat (limited to 'drivers/pci/hotplug/acpi_pcihp.c')
| -rw-r--r-- | drivers/pci/hotplug/acpi_pcihp.c | 91 |
1 files changed, 38 insertions, 53 deletions
diff --git a/drivers/pci/hotplug/acpi_pcihp.c b/drivers/pci/hotplug/acpi_pcihp.c index a5e66df4ad14..4fedebf2f8c1 100644 --- a/drivers/pci/hotplug/acpi_pcihp.c +++ b/drivers/pci/hotplug/acpi_pcihp.c @@ -1,3 +1,4 @@ +// SPDX-License-Identifier: GPL-2.0+ /* * Common ACPI functions for hot plug platforms * @@ -5,23 +6,7 @@ * * All rights reserved. * - * This program is free software; you can redistribute it and/or modify - * it under the terms of the GNU General Public License as published by - * the Free Software Foundation; either version 2 of the License, or (at - * your option) any later version. - * - * 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, GOOD TITLE or - * NON INFRINGEMENT. See the GNU General Public License for more - * details. - * - * You should have received a copy of the GNU General Public License - * along with this program; if not, write to the Free Software - * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. - * * Send feedback to <kristen.c.accardi@intel.com> - * */ #include <linux/module.h> @@ -76,51 +61,52 @@ static acpi_status acpi_run_oshp(acpi_handle handle) /** * acpi_get_hp_hw_control_from_firmware - * @dev: the pci_dev of the bridge that has a hotplug controller - * @flags: requested control bits for _OSC + * @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, u32 flags) +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 }; - flags &= OSC_PCI_SHPC_NATIVE_HP_CONTROL; - if (!flags) { - err("Invalid flags %u specified!\n", flags); - return -EINVAL; - } + /* + * 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; /* - * Per PCI firmware specification, we should run the ACPI _OSC - * method to get control of hotplug hardware before using it. If - * an _OSC is missing, we look for an OSHP to do the same thing. - * To handle different BIOS behavior, we look for _OSC on a root - * bridge preferentially (according to PCI fw spec). Later for - * OSHP within the scope of the hotplug controller and its parents, - * up to the host bridge under which this controller exists. + * If _OSC exists, it determines whether we're allowed to manage + * the SHPC. We executed it while enumerating the host bridge. */ - handle = acpi_find_root_bridge_handle(pdev); - if (handle) { - acpi_get_name(handle, ACPI_FULL_PATHNAME, &string); - dbg("Trying to get hotplug control for %s\n", - (char *)string.pointer); - status = acpi_pci_osc_control_set(handle, &flags, flags); - if (ACPI_SUCCESS(status)) - goto got_one; - if (status == AE_SUPPORT) - goto no_control; - kfree(string.pointer); - string = (struct acpi_buffer){ ACPI_ALLOCATE_BUFFER, NULL }; + 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. + * space at all. Try to get ACPI handle of parent PCI bus. */ struct pci_bus *pbus; for (pbus = pdev->bus; pbus; pbus = pbus->parent) { @@ -132,8 +118,8 @@ int acpi_get_hp_hw_control_from_firmware(struct pci_dev *pdev, u32 flags) while (handle) { acpi_get_name(handle, ACPI_FULL_PATHNAME, &string); - dbg("Trying to get hotplug control for %s\n", - (char *)string.pointer); + 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; @@ -144,14 +130,13 @@ int acpi_get_hp_hw_control_from_firmware(struct pci_dev *pdev, u32 flags) if (ACPI_FAILURE(status)) break; } -no_control: - dbg("Cannot get control of hotplug hardware for pci %s\n", - pci_name(pdev)); + + pci_info(pdev, "Cannot get control of SHPC hotplug\n"); kfree(string.pointer); return -ENODEV; got_one: - dbg("Gained control for hotplug HW for pci %s (%s)\n", - pci_name(pdev), (char *)string.pointer); + pci_info(pdev, "Gained control of SHPC hotplug (%s)\n", + (char *)string.pointer); kfree(string.pointer); return 0; } @@ -172,7 +157,7 @@ static int pcihp_is_ejectable(acpi_handle handle) } /** - * acpi_pcihp_check_ejectable - check if handle is ejectable ACPI PCI slot + * 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 * @@ -206,7 +191,7 @@ check_hotplug(acpi_handle handle, u32 lvl, void *context, void **rv) /** * acpi_pci_detect_ejectable - check if the PCI bus has ejectable slots - * @handle - handle of the PCI bus to scan + * @handle: handle of the PCI bus to scan * * Returns 1 if the PCI bus has ACPI based ejectable slots, 0 otherwise. */ |