From c9ffa5a586a97da4d552f89b8f39eea79a63a612 Mon Sep 17 00:00:00 2001 From: Kenji Kaneshige Date: Wed, 17 Dec 2008 12:07:38 +0900 Subject: PCI: pciehp: add ACPI based slot detection 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 Signed-off-by: Jesse Barnes --- drivers/pci/hotplug/pciehp_acpi.c | 114 ++++++++++++++++++++++++++++++++++++++ 1 file changed, 114 insertions(+) create mode 100644 drivers/pci/hotplug/pciehp_acpi.c (limited to 'drivers/pci/hotplug/pciehp_acpi.c') diff --git a/drivers/pci/hotplug/pciehp_acpi.c b/drivers/pci/hotplug/pciehp_acpi.c new file mode 100644 index 000000000000..0cd49b728045 --- /dev/null +++ b/drivers/pci/hotplug/pciehp_acpi.c @@ -0,0 +1,114 @@ +/* + * ACPI related functions for PCI Express Hot Plug driver. + * + * Copyright (C) 2008 Kenji Kaneshige + * Copyright (C) 2008 Fujitsu Limited. + * + * 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. + * + */ + +#include +#include "pciehp.h" + +#define PCIEHP_DETECT_PCIE (0) +#define PCIEHP_DETECT_ACPI (1) +#define PCIEHP_DETECT_DEFAULT PCIEHP_DETECT_PCIE + +static int slot_detection_mode; +static char *pciehp_detect_mode; +module_param(pciehp_detect_mode, charp, 0444); +MODULE_PARM_DESC(pciehp_detect_mode, + "Slot detection mode: pcie, acpi\n" + " pcie - Use PCIe based slot detection (default)\n" + " acpi - Use ACPI for slot detection\n"); + +static int is_ejectable(acpi_handle handle) +{ + acpi_status status; + acpi_handle tmp; + unsigned long long removable; + status = acpi_get_handle(handle, "_ADR", &tmp); + if (ACPI_FAILURE(status)) + return 0; + status = acpi_get_handle(handle, "_EJ0", &tmp); + if (ACPI_SUCCESS(status)) + return 1; + status = acpi_evaluate_integer(handle, "_RMV", NULL, &removable); + if (ACPI_SUCCESS(status) && removable) + return 1; + return 0; +} + +static acpi_status +check_hotplug(acpi_handle handle, u32 lvl, void *context, void **rv) +{ + int *found = (int *)context; + if (is_ejectable(handle)) { + *found = 1; + return AE_CTRL_TERMINATE; + } + return AE_OK; +} + +static int pciehp_detect_acpi_slot(struct pci_bus *pbus) +{ + acpi_handle handle; + struct pci_dev *pdev = pbus->self; + int found = 0; + + if (!pdev){ + int seg = pci_domain_nr(pbus), busnr = pbus->number; + handle = acpi_get_pci_rootbridge_handle(seg, busnr); + } else + handle = DEVICE_ACPI_HANDLE(&(pdev->dev)); + + if (!handle) + return 0; + + acpi_walk_namespace(ACPI_TYPE_DEVICE, handle, (u32)1, + check_hotplug, (void *)&found, NULL); + return found; +} + +int pciehp_acpi_slot_detection_check(struct pci_dev *dev) +{ + if (slot_detection_mode != PCIEHP_DETECT_ACPI) + return 0; + if (pciehp_detect_acpi_slot(dev->subordinate)) + return 0; + return -ENODEV; +} + +static int __init parse_detect_mode(void) +{ + if (!pciehp_detect_mode) + return PCIEHP_DETECT_DEFAULT; + if (!strcmp(pciehp_detect_mode, "pcie")) + return PCIEHP_DETECT_PCIE; + if (!strcmp(pciehp_detect_mode, "acpi")) + return PCIEHP_DETECT_ACPI; + warn("bad specifier '%s' for pciehp_detect_mode. Use default\n", + pciehp_detect_mode); + return PCIEHP_DETECT_DEFAULT; +} + +void __init pciehp_acpi_slot_detection_init(void) +{ + slot_detection_mode = parse_detect_mode(); +} -- cgit v1.2.3