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https://github.com/AuxXxilium/linux_dsm_epyc7002.git
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c9ffa5a586
There is a problem that some non hot-pluggable PCIe slots are detected as hot-pluggable by pciehp on some platforms. The immediate cause of this problem is that hot-plug capable bit in the Slot Capabilities register is set even for non hot-pluggable slots on those platforms. It seems a BIOS/hardware problem, but we need workaround about that. Some of those platforms define hot-pluggable PCIe slots on ACPI namespace properly, while hot-plug capable bit in the Slot Capabilities register is set improperly. So using ACPI namespace information in pciehp to detect PCIe hot-pluggable slots would be a workaround. This patch adds 'pciehp_detect_mode' module option. When 'acpi' is specified, pciehp uses ACPI namespace information to detect PCIe hot-pluggable slots. Signed-off-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com> Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
115 lines
3.0 KiB
C
115 lines
3.0 KiB
C
/*
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* ACPI related functions for PCI Express Hot Plug driver.
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*
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* Copyright (C) 2008 Kenji Kaneshige
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* Copyright (C) 2008 Fujitsu Limited.
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*
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* All rights reserved.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or (at
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* your option) any later version.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
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* NON INFRINGEMENT. See the GNU General Public License for more
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* details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*
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*/
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#include <linux/acpi.h>
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#include "pciehp.h"
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#define PCIEHP_DETECT_PCIE (0)
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#define PCIEHP_DETECT_ACPI (1)
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#define PCIEHP_DETECT_DEFAULT PCIEHP_DETECT_PCIE
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static int slot_detection_mode;
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static char *pciehp_detect_mode;
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module_param(pciehp_detect_mode, charp, 0444);
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MODULE_PARM_DESC(pciehp_detect_mode,
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"Slot detection mode: pcie, acpi\n"
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" pcie - Use PCIe based slot detection (default)\n"
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" acpi - Use ACPI for slot detection\n");
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static int is_ejectable(acpi_handle handle)
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{
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acpi_status status;
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acpi_handle tmp;
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unsigned long long removable;
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status = acpi_get_handle(handle, "_ADR", &tmp);
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if (ACPI_FAILURE(status))
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return 0;
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status = acpi_get_handle(handle, "_EJ0", &tmp);
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if (ACPI_SUCCESS(status))
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return 1;
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status = acpi_evaluate_integer(handle, "_RMV", NULL, &removable);
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if (ACPI_SUCCESS(status) && removable)
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return 1;
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return 0;
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}
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static acpi_status
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check_hotplug(acpi_handle handle, u32 lvl, void *context, void **rv)
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{
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int *found = (int *)context;
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if (is_ejectable(handle)) {
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*found = 1;
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return AE_CTRL_TERMINATE;
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}
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return AE_OK;
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}
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static int pciehp_detect_acpi_slot(struct pci_bus *pbus)
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{
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acpi_handle handle;
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struct pci_dev *pdev = pbus->self;
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int found = 0;
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if (!pdev){
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int seg = pci_domain_nr(pbus), busnr = pbus->number;
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handle = acpi_get_pci_rootbridge_handle(seg, busnr);
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} else
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handle = DEVICE_ACPI_HANDLE(&(pdev->dev));
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if (!handle)
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return 0;
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acpi_walk_namespace(ACPI_TYPE_DEVICE, handle, (u32)1,
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check_hotplug, (void *)&found, NULL);
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return found;
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}
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int pciehp_acpi_slot_detection_check(struct pci_dev *dev)
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{
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if (slot_detection_mode != PCIEHP_DETECT_ACPI)
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return 0;
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if (pciehp_detect_acpi_slot(dev->subordinate))
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return 0;
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return -ENODEV;
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}
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static int __init parse_detect_mode(void)
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{
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if (!pciehp_detect_mode)
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return PCIEHP_DETECT_DEFAULT;
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if (!strcmp(pciehp_detect_mode, "pcie"))
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return PCIEHP_DETECT_PCIE;
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if (!strcmp(pciehp_detect_mode, "acpi"))
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return PCIEHP_DETECT_ACPI;
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warn("bad specifier '%s' for pciehp_detect_mode. Use default\n",
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pciehp_detect_mode);
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return PCIEHP_DETECT_DEFAULT;
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}
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void __init pciehp_acpi_slot_detection_init(void)
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{
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slot_detection_mode = parse_detect_mode();
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}
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