![Mika Westerberg](/assets/img/avatar_default.png)
A surprise link down may retrain very quickly causing the same slot generate a link up event before handling the link down event completes. Since the link is active, the power off work queued from the first link down will cause a second down event when power is disabled. However, the link up event sets the slot state to POWERON_STATE before the event to handle this is enqueued, making the second down event believe it needs to do something. This creates constant link up and down event cycle. To prevent this it is better to handle each event at the time in order it occurred, so change the driver to use ordered workqueue instead. A normal device hotplug triggers two events (presense detect and link up) that are already handled properly in the driver but we currently log an error if we find an existing device in the slot. Since this is not an error change the log level to be debug instead to avoid scaring users. This is based on the original work by Ashok Raj. Link: https://patchwork.kernel.org/patch/9469023 Suggested-by: Bjorn Helgaas <bhelgaas@google.com> Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
517 lines
13 KiB
C
517 lines
13 KiB
C
/*
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* PCI Express Hot Plug Controller Driver
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*
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* Copyright (C) 1995,2001 Compaq Computer Corporation
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* Copyright (C) 2001 Greg Kroah-Hartman (greg@kroah.com)
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* Copyright (C) 2001 IBM Corp.
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* Copyright (C) 2003-2004 Intel Corporation
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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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* Send feedback to <greg@kroah.com>, <kristen.c.accardi@intel.com>
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*
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*/
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#include <linux/module.h>
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#include <linux/kernel.h>
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#include <linux/types.h>
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#include <linux/slab.h>
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#include <linux/pci.h>
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#include "../pci.h"
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#include "pciehp.h"
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static void interrupt_event_handler(struct work_struct *work);
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void pciehp_queue_interrupt_event(struct slot *p_slot, u32 event_type)
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{
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struct event_info *info;
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info = kmalloc(sizeof(*info), GFP_ATOMIC);
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if (!info) {
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ctrl_err(p_slot->ctrl, "dropped event %d (ENOMEM)\n", event_type);
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return;
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}
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INIT_WORK(&info->work, interrupt_event_handler);
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info->event_type = event_type;
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info->p_slot = p_slot;
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queue_work(p_slot->wq, &info->work);
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}
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/* The following routines constitute the bulk of the
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hotplug controller logic
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*/
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static void set_slot_off(struct controller *ctrl, struct slot *pslot)
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{
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/* turn off slot, turn on Amber LED, turn off Green LED if supported*/
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if (POWER_CTRL(ctrl)) {
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pciehp_power_off_slot(pslot);
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/*
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* After turning power off, we must wait for at least 1 second
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* before taking any action that relies on power having been
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* removed from the slot/adapter.
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*/
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msleep(1000);
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}
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pciehp_green_led_off(pslot);
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pciehp_set_attention_status(pslot, 1);
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}
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/**
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* board_added - Called after a board has been added to the system.
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* @p_slot: &slot where board is added
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*
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* Turns power on for the board.
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* Configures board.
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*/
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static int board_added(struct slot *p_slot)
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{
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int retval = 0;
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struct controller *ctrl = p_slot->ctrl;
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struct pci_bus *parent = ctrl->pcie->port->subordinate;
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if (POWER_CTRL(ctrl)) {
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/* Power on slot */
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retval = pciehp_power_on_slot(p_slot);
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if (retval)
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return retval;
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}
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pciehp_green_led_blink(p_slot);
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/* Check link training status */
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retval = pciehp_check_link_status(ctrl);
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if (retval) {
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ctrl_err(ctrl, "Failed to check link status\n");
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goto err_exit;
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}
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/* Check for a power fault */
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if (ctrl->power_fault_detected || pciehp_query_power_fault(p_slot)) {
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ctrl_err(ctrl, "Slot(%s): Power fault\n", slot_name(p_slot));
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retval = -EIO;
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goto err_exit;
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}
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retval = pciehp_configure_device(p_slot);
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if (retval) {
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if (retval != -EEXIST) {
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ctrl_err(ctrl, "Cannot add device at %04x:%02x:00\n",
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pci_domain_nr(parent), parent->number);
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goto err_exit;
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}
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}
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pciehp_green_led_on(p_slot);
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pciehp_set_attention_status(p_slot, 0);
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return 0;
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err_exit:
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set_slot_off(ctrl, p_slot);
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return retval;
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}
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/**
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* remove_board - Turns off slot and LEDs
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* @p_slot: slot where board is being removed
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*/
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static int remove_board(struct slot *p_slot)
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{
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int retval;
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struct controller *ctrl = p_slot->ctrl;
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retval = pciehp_unconfigure_device(p_slot);
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if (retval)
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return retval;
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if (POWER_CTRL(ctrl)) {
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pciehp_power_off_slot(p_slot);
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/*
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* After turning power off, we must wait for at least 1 second
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* before taking any action that relies on power having been
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* removed from the slot/adapter.
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*/
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msleep(1000);
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}
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/* turn off Green LED */
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pciehp_green_led_off(p_slot);
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return 0;
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}
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struct power_work_info {
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struct slot *p_slot;
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struct work_struct work;
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unsigned int req;
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#define DISABLE_REQ 0
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#define ENABLE_REQ 1
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};
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/**
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* pciehp_power_thread - handle pushbutton events
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* @work: &struct work_struct describing work to be done
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*
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* Scheduled procedure to handle blocking stuff for the pushbuttons.
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* Handles all pending events and exits.
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*/
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static void pciehp_power_thread(struct work_struct *work)
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{
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struct power_work_info *info =
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container_of(work, struct power_work_info, work);
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struct slot *p_slot = info->p_slot;
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int ret;
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switch (info->req) {
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case DISABLE_REQ:
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mutex_lock(&p_slot->hotplug_lock);
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pciehp_disable_slot(p_slot);
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mutex_unlock(&p_slot->hotplug_lock);
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mutex_lock(&p_slot->lock);
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p_slot->state = STATIC_STATE;
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mutex_unlock(&p_slot->lock);
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break;
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case ENABLE_REQ:
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mutex_lock(&p_slot->hotplug_lock);
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ret = pciehp_enable_slot(p_slot);
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mutex_unlock(&p_slot->hotplug_lock);
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if (ret)
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pciehp_green_led_off(p_slot);
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mutex_lock(&p_slot->lock);
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p_slot->state = STATIC_STATE;
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mutex_unlock(&p_slot->lock);
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break;
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default:
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break;
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}
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kfree(info);
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}
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static void pciehp_queue_power_work(struct slot *p_slot, int req)
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{
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struct power_work_info *info;
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p_slot->state = (req == ENABLE_REQ) ? POWERON_STATE : POWEROFF_STATE;
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info = kmalloc(sizeof(*info), GFP_KERNEL);
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if (!info) {
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ctrl_err(p_slot->ctrl, "no memory to queue %s request\n",
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(req == ENABLE_REQ) ? "poweron" : "poweroff");
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return;
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}
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info->p_slot = p_slot;
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INIT_WORK(&info->work, pciehp_power_thread);
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info->req = req;
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queue_work(p_slot->wq, &info->work);
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}
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void pciehp_queue_pushbutton_work(struct work_struct *work)
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{
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struct slot *p_slot = container_of(work, struct slot, work.work);
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mutex_lock(&p_slot->lock);
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switch (p_slot->state) {
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case BLINKINGOFF_STATE:
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pciehp_queue_power_work(p_slot, DISABLE_REQ);
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break;
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case BLINKINGON_STATE:
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pciehp_queue_power_work(p_slot, ENABLE_REQ);
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break;
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default:
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break;
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}
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mutex_unlock(&p_slot->lock);
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}
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/*
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* Note: This function must be called with slot->lock held
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*/
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static void handle_button_press_event(struct slot *p_slot)
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{
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struct controller *ctrl = p_slot->ctrl;
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u8 getstatus;
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switch (p_slot->state) {
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case STATIC_STATE:
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pciehp_get_power_status(p_slot, &getstatus);
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if (getstatus) {
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p_slot->state = BLINKINGOFF_STATE;
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ctrl_info(ctrl, "Slot(%s): Powering off due to button press\n",
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slot_name(p_slot));
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} else {
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p_slot->state = BLINKINGON_STATE;
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ctrl_info(ctrl, "Slot(%s) Powering on due to button press\n",
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slot_name(p_slot));
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}
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/* blink green LED and turn off amber */
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pciehp_green_led_blink(p_slot);
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pciehp_set_attention_status(p_slot, 0);
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queue_delayed_work(p_slot->wq, &p_slot->work, 5*HZ);
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break;
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case BLINKINGOFF_STATE:
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case BLINKINGON_STATE:
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/*
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* Cancel if we are still blinking; this means that we
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* press the attention again before the 5 sec. limit
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* expires to cancel hot-add or hot-remove
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*/
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ctrl_info(ctrl, "Slot(%s): Button cancel\n", slot_name(p_slot));
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cancel_delayed_work(&p_slot->work);
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if (p_slot->state == BLINKINGOFF_STATE)
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pciehp_green_led_on(p_slot);
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else
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pciehp_green_led_off(p_slot);
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pciehp_set_attention_status(p_slot, 0);
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ctrl_info(ctrl, "Slot(%s): Action canceled due to button press\n",
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slot_name(p_slot));
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p_slot->state = STATIC_STATE;
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break;
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case POWEROFF_STATE:
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case POWERON_STATE:
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/*
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* Ignore if the slot is on power-on or power-off state;
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* this means that the previous attention button action
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* to hot-add or hot-remove is undergoing
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*/
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ctrl_info(ctrl, "Slot(%s): Button ignored\n",
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slot_name(p_slot));
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break;
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default:
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ctrl_err(ctrl, "Slot(%s): Ignoring invalid state %#x\n",
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slot_name(p_slot), p_slot->state);
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break;
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}
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}
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/*
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* Note: This function must be called with slot->lock held
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*/
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static void handle_link_event(struct slot *p_slot, u32 event)
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{
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struct controller *ctrl = p_slot->ctrl;
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switch (p_slot->state) {
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case BLINKINGON_STATE:
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case BLINKINGOFF_STATE:
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cancel_delayed_work(&p_slot->work);
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/* Fall through */
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case STATIC_STATE:
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pciehp_queue_power_work(p_slot, event == INT_LINK_UP ?
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ENABLE_REQ : DISABLE_REQ);
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break;
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case POWERON_STATE:
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if (event == INT_LINK_UP) {
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ctrl_info(ctrl, "Slot(%s): Link Up event ignored; already powering on\n",
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slot_name(p_slot));
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} else {
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ctrl_info(ctrl, "Slot(%s): Link Down event queued; currently getting powered on\n",
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slot_name(p_slot));
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pciehp_queue_power_work(p_slot, DISABLE_REQ);
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}
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break;
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case POWEROFF_STATE:
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if (event == INT_LINK_UP) {
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ctrl_info(ctrl, "Slot(%s): Link Up event queued; currently getting powered off\n",
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slot_name(p_slot));
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pciehp_queue_power_work(p_slot, ENABLE_REQ);
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} else {
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ctrl_info(ctrl, "Slot(%s): Link Down event ignored; already powering off\n",
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slot_name(p_slot));
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}
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break;
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default:
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ctrl_err(ctrl, "Slot(%s): Ignoring invalid state %#x\n",
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slot_name(p_slot), p_slot->state);
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break;
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}
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}
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static void interrupt_event_handler(struct work_struct *work)
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{
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struct event_info *info = container_of(work, struct event_info, work);
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struct slot *p_slot = info->p_slot;
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struct controller *ctrl = p_slot->ctrl;
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mutex_lock(&p_slot->lock);
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switch (info->event_type) {
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case INT_BUTTON_PRESS:
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handle_button_press_event(p_slot);
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break;
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case INT_POWER_FAULT:
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if (!POWER_CTRL(ctrl))
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break;
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pciehp_set_attention_status(p_slot, 1);
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pciehp_green_led_off(p_slot);
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break;
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case INT_PRESENCE_ON:
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pciehp_queue_power_work(p_slot, ENABLE_REQ);
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break;
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case INT_PRESENCE_OFF:
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/*
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* Regardless of surprise capability, we need to
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* definitely remove a card that has been pulled out!
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*/
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pciehp_queue_power_work(p_slot, DISABLE_REQ);
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break;
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case INT_LINK_UP:
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case INT_LINK_DOWN:
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handle_link_event(p_slot, info->event_type);
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break;
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default:
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break;
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}
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mutex_unlock(&p_slot->lock);
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kfree(info);
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}
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/*
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* Note: This function must be called with slot->hotplug_lock held
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*/
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int pciehp_enable_slot(struct slot *p_slot)
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{
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u8 getstatus = 0;
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struct controller *ctrl = p_slot->ctrl;
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pciehp_get_adapter_status(p_slot, &getstatus);
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if (!getstatus) {
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ctrl_info(ctrl, "Slot(%s): No adapter\n", slot_name(p_slot));
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return -ENODEV;
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}
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if (MRL_SENS(p_slot->ctrl)) {
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pciehp_get_latch_status(p_slot, &getstatus);
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if (getstatus) {
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ctrl_info(ctrl, "Slot(%s): Latch open\n",
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slot_name(p_slot));
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return -ENODEV;
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}
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}
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if (POWER_CTRL(p_slot->ctrl)) {
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pciehp_get_power_status(p_slot, &getstatus);
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if (getstatus) {
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ctrl_info(ctrl, "Slot(%s): Already enabled\n",
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slot_name(p_slot));
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return 0;
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}
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}
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return board_added(p_slot);
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}
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/*
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* Note: This function must be called with slot->hotplug_lock held
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*/
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int pciehp_disable_slot(struct slot *p_slot)
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{
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u8 getstatus = 0;
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struct controller *ctrl = p_slot->ctrl;
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if (!p_slot->ctrl)
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return 1;
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if (POWER_CTRL(p_slot->ctrl)) {
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pciehp_get_power_status(p_slot, &getstatus);
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if (!getstatus) {
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ctrl_info(ctrl, "Slot(%s): Already disabled\n",
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slot_name(p_slot));
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return -EINVAL;
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}
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}
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return remove_board(p_slot);
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}
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int pciehp_sysfs_enable_slot(struct slot *p_slot)
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{
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int retval = -ENODEV;
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struct controller *ctrl = p_slot->ctrl;
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mutex_lock(&p_slot->lock);
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switch (p_slot->state) {
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case BLINKINGON_STATE:
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cancel_delayed_work(&p_slot->work);
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case STATIC_STATE:
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p_slot->state = POWERON_STATE;
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mutex_unlock(&p_slot->lock);
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mutex_lock(&p_slot->hotplug_lock);
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retval = pciehp_enable_slot(p_slot);
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mutex_unlock(&p_slot->hotplug_lock);
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mutex_lock(&p_slot->lock);
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p_slot->state = STATIC_STATE;
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break;
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case POWERON_STATE:
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ctrl_info(ctrl, "Slot(%s): Already in powering on state\n",
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slot_name(p_slot));
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break;
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case BLINKINGOFF_STATE:
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case POWEROFF_STATE:
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ctrl_info(ctrl, "Slot(%s): Already enabled\n",
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slot_name(p_slot));
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break;
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default:
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ctrl_err(ctrl, "Slot(%s): Invalid state %#x\n",
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slot_name(p_slot), p_slot->state);
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break;
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}
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mutex_unlock(&p_slot->lock);
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return retval;
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}
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int pciehp_sysfs_disable_slot(struct slot *p_slot)
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{
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int retval = -ENODEV;
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struct controller *ctrl = p_slot->ctrl;
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mutex_lock(&p_slot->lock);
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switch (p_slot->state) {
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case BLINKINGOFF_STATE:
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cancel_delayed_work(&p_slot->work);
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case STATIC_STATE:
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p_slot->state = POWEROFF_STATE;
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mutex_unlock(&p_slot->lock);
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mutex_lock(&p_slot->hotplug_lock);
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retval = pciehp_disable_slot(p_slot);
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mutex_unlock(&p_slot->hotplug_lock);
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mutex_lock(&p_slot->lock);
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p_slot->state = STATIC_STATE;
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break;
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case POWEROFF_STATE:
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ctrl_info(ctrl, "Slot(%s): Already in powering off state\n",
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slot_name(p_slot));
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break;
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case BLINKINGON_STATE:
|
|
case POWERON_STATE:
|
|
ctrl_info(ctrl, "Slot(%s): Already disabled\n",
|
|
slot_name(p_slot));
|
|
break;
|
|
default:
|
|
ctrl_err(ctrl, "Slot(%s): Invalid state %#x\n",
|
|
slot_name(p_slot), p_slot->state);
|
|
break;
|
|
}
|
|
mutex_unlock(&p_slot->lock);
|
|
|
|
return retval;
|
|
}
|