linux_kernel/drivers/pci/hotplug/pciehp_ctrl.c

// SPDX-License-Identifier: GPL-2.0+
/*
 * PCI Express Hot Plug Controller Driver
 *
 * Copyright (C) 1995,2001 Compaq Computer Corporation
 * Copyright (C) 2001 Greg Kroah-Hartman (greg@kroah.com)
 * Copyright (C) 2001 IBM Corp.
 * Copyright (C) 2003-2004 Intel Corporation
 *
 * All rights reserved.
 *
 * Send feedback to <greg@kroah.com>, <kristen.c.accardi@intel.com>
 *
 */

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/types.h>
#include <linux/slab.h>
#include <linux/pci.h>
#include "../pci.h"
#include "pciehp.h"

static void interrupt_event_handler(struct work_struct *work);

void pciehp_queue_interrupt_event(struct slot *p_slot, u32 event_type)
{
	struct event_info *info;

	info = kmalloc(sizeof(*info), GFP_ATOMIC);
	if (!info) {
		ctrl_err(p_slot->ctrl, "dropped event %d (ENOMEM)\n", event_type);
		return;
	}

	INIT_WORK(&info->work, interrupt_event_handler);
	info->event_type = event_type;
	info->p_slot = p_slot;
	queue_work(p_slot->wq, &info->work);
}

/* The following routines constitute the bulk of the
   hotplug controller logic
 */

static void set_slot_off(struct controller *ctrl, struct slot *pslot)
{
	/* turn off slot, turn on Amber LED, turn off Green LED if supported*/
	if (POWER_CTRL(ctrl)) {
		pciehp_power_off_slot(pslot);

		/*
		 * After turning power off, we must wait for at least 1 second
		 * before taking any action that relies on power having been
		 * removed from the slot/adapter.
		 */
		msleep(1000);
	}

	pciehp_green_led_off(pslot);
	pciehp_set_attention_status(pslot, 1);
}

/**
 * board_added - Called after a board has been added to the system.
 * @p_slot: &slot where board is added
 *
 * Turns power on for the board.
 * Configures board.
 */
static int board_added(struct slot *p_slot)
{
	int retval = 0;
	struct controller *ctrl = p_slot->ctrl;
	struct pci_bus *parent = ctrl->pcie->port->subordinate;

	if (POWER_CTRL(ctrl)) {
		/* Power on slot */
		retval = pciehp_power_on_slot(p_slot);
		if (retval)
			return retval;
	}

	pciehp_green_led_blink(p_slot);

	/* Check link training status */
	retval = pciehp_check_link_status(ctrl);
	if (retval) {
		ctrl_err(ctrl, "Failed to check link status\n");
		goto err_exit;
	}

	/* Check for a power fault */
	if (ctrl->power_fault_detected || pciehp_query_power_fault(p_slot)) {
		ctrl_err(ctrl, "Slot(%s): Power fault\n", slot_name(p_slot));
		retval = -EIO;
		goto err_exit;
	}

	retval = pciehp_configure_device(p_slot);
	if (retval) {
		if (retval != -EEXIST) {
			ctrl_err(ctrl, "Cannot add device at %04x:%02x:00\n",
				 pci_domain_nr(parent), parent->number);
			goto err_exit;
		}
	}

	pciehp_green_led_on(p_slot);
	pciehp_set_attention_status(p_slot, 0);
	return 0;

err_exit:
	set_slot_off(ctrl, p_slot);
	return retval;
}

/**
 * remove_board - Turns off slot and LEDs
 * @p_slot: slot where board is being removed
 */
static int remove_board(struct slot *p_slot)
{
	int retval;
	struct controller *ctrl = p_slot->ctrl;

	retval = pciehp_unconfigure_device(p_slot);
	if (retval)
		return retval;

	if (POWER_CTRL(ctrl)) {
		pciehp_power_off_slot(p_slot);

		/*
		 * After turning power off, we must wait for at least 1 second
		 * before taking any action that relies on power having been
		 * removed from the slot/adapter.
		 */
		msleep(1000);
	}

	/* turn off Green LED */
	pciehp_green_led_off(p_slot);
	return 0;
}

struct power_work_info {
	struct slot *p_slot;
	struct work_struct work;
	unsigned int req;
#define DISABLE_REQ 0
#define ENABLE_REQ  1
};

/**
 * pciehp_power_thread - handle pushbutton events
 * @work: &struct work_struct describing work to be done
 *
 * Scheduled procedure to handle blocking stuff for the pushbuttons.
 * Handles all pending events and exits.
 */
static void pciehp_power_thread(struct work_struct *work)
{
	struct power_work_info *info =
		container_of(work, struct power_work_info, work);
	struct slot *p_slot = info->p_slot;
	int ret;

	switch (info->req) {
	case DISABLE_REQ:
		mutex_lock(&p_slot->hotplug_lock);
		pciehp_disable_slot(p_slot);
		mutex_unlock(&p_slot->hotplug_lock);
		mutex_lock(&p_slot->lock);
		p_slot->state = STATIC_STATE;
		mutex_unlock(&p_slot->lock);
		break;
	case ENABLE_REQ:
		mutex_lock(&p_slot->hotplug_lock);
		ret = pciehp_enable_slot(p_slot);
		mutex_unlock(&p_slot->hotplug_lock);
		if (ret)
			pciehp_green_led_off(p_slot);
		mutex_lock(&p_slot->lock);
		p_slot->state = STATIC_STATE;
		mutex_unlock(&p_slot->lock);
		break;
	default:
		break;
	}

	kfree(info);
}

static void pciehp_queue_power_work(struct slot *p_slot, int req)
{
	struct power_work_info *info;

	p_slot->state = (req == ENABLE_REQ) ? POWERON_STATE : POWEROFF_STATE;

	info = kmalloc(sizeof(*info), GFP_KERNEL);
	if (!info) {
		ctrl_err(p_slot->ctrl, "no memory to queue %s request\n",
			 (req == ENABLE_REQ) ? "poweron" : "poweroff");
		return;
	}
	info->p_slot = p_slot;
	INIT_WORK(&info->work, pciehp_power_thread);
	info->req = req;
	queue_work(p_slot->wq, &info->work);
}

void pciehp_queue_pushbutton_work(struct work_struct *work)
{
	struct slot *p_slot = container_of(work, struct slot, work.work);

	mutex_lock(&p_slot->lock);
	switch (p_slot->state) {
	case BLINKINGOFF_STATE:
		pciehp_queue_power_work(p_slot, DISABLE_REQ);
		break;
	case BLINKINGON_STATE:
		pciehp_queue_power_work(p_slot, ENABLE_REQ);
		break;
	default:
		break;
	}
	mutex_unlock(&p_slot->lock);
}

/*
 * Note: This function must be called with slot->lock held
 */
static void handle_button_press_event(struct slot *p_slot)
{
	struct controller *ctrl = p_slot->ctrl;
	u8 getstatus;

	switch (p_slot->state) {
	case STATIC_STATE:
		pciehp_get_power_status(p_slot, &getstatus);
		if (getstatus) {
			p_slot->state = BLINKINGOFF_STATE;
			ctrl_info(ctrl, "Slot(%s): Powering off due to button press\n",
				  slot_name(p_slot));
		} else {
			p_slot->state = BLINKINGON_STATE;
			ctrl_info(ctrl, "Slot(%s) Powering on due to button press\n",
				  slot_name(p_slot));
		}
		/* blink green LED and turn off amber */
		pciehp_green_led_blink(p_slot);
		pciehp_set_attention_status(p_slot, 0);
		queue_delayed_work(p_slot->wq, &p_slot->work, 5*HZ);
		break;
	case BLINKINGOFF_STATE:
	case BLINKINGON_STATE:
		/*
		 * Cancel if we are still blinking; this means that we
		 * press the attention again before the 5 sec. limit
		 * expires to cancel hot-add or hot-remove
		 */
		ctrl_info(ctrl, "Slot(%s): Button cancel\n", slot_name(p_slot));
		cancel_delayed_work(&p_slot->work);
		if (p_slot->state == BLINKINGOFF_STATE)
			pciehp_green_led_on(p_slot);
		else
			pciehp_green_led_off(p_slot);
		pciehp_set_attention_status(p_slot, 0);
		ctrl_info(ctrl, "Slot(%s): Action canceled due to button press\n",
			  slot_name(p_slot));
		p_slot->state = STATIC_STATE;
		break;
	case POWEROFF_STATE:
	case POWERON_STATE:
		/*
		 * Ignore if the slot is on power-on or power-off state;
		 * this means that the previous attention button action
		 * to hot-add or hot-remove is undergoing
		 */
		ctrl_info(ctrl, "Slot(%s): Button ignored\n",
			  slot_name(p_slot));
		break;
	default:
		ctrl_err(ctrl, "Slot(%s): Ignoring invalid state %#x\n",
			 slot_name(p_slot), p_slot->state);
		break;
	}
}

/*
 * Note: This function must be called with slot->lock held
 */
static void handle_link_event(struct slot *p_slot, u32 event)
{
	struct controller *ctrl = p_slot->ctrl;

	switch (p_slot->state) {
	case BLINKINGON_STATE:
	case BLINKINGOFF_STATE:
		cancel_delayed_work(&p_slot->work);
		/* Fall through */
	case STATIC_STATE:
		pciehp_queue_power_work(p_slot, event == INT_LINK_UP ?
					ENABLE_REQ : DISABLE_REQ);
		break;
	case POWERON_STATE:
		if (event == INT_LINK_UP) {
			ctrl_info(ctrl, "Slot(%s): Link Up event ignored; already powering on\n",
				  slot_name(p_slot));
		} else {
			ctrl_info(ctrl, "Slot(%s): Link Down event queued; currently getting powered on\n",
				  slot_name(p_slot));
			pciehp_queue_power_work(p_slot, DISABLE_REQ);
		}
		break;
	case POWEROFF_STATE:
		if (event == INT_LINK_UP) {
			ctrl_info(ctrl, "Slot(%s): Link Up event queued; currently getting powered off\n",
				  slot_name(p_slot));
			pciehp_queue_power_work(p_slot, ENABLE_REQ);
		} else {
			ctrl_info(ctrl, "Slot(%s): Link Down event ignored; already powering off\n",
				  slot_name(p_slot));
		}
		break;
	default:
		ctrl_err(ctrl, "Slot(%s): Ignoring invalid state %#x\n",
			 slot_name(p_slot), p_slot->state);
		break;
	}
}

static void interrupt_event_handler(struct work_struct *work)
{
	struct event_info *info = container_of(work, struct event_info, work);
	struct slot *p_slot = info->p_slot;
	struct controller *ctrl = p_slot->ctrl;

	mutex_lock(&p_slot->lock);
	switch (info->event_type) {
	case INT_BUTTON_PRESS:
		handle_button_press_event(p_slot);
		break;
	case INT_POWER_FAULT:
		if (!POWER_CTRL(ctrl))
			break;
		pciehp_set_attention_status(p_slot, 1);
		pciehp_green_led_off(p_slot);
		break;
	case INT_PRESENCE_ON:
		pciehp_queue_power_work(p_slot, ENABLE_REQ);
		break;
	case INT_PRESENCE_OFF:
		/*
		 * Regardless of surprise capability, we need to
		 * definitely remove a card that has been pulled out!
		 */
		pciehp_queue_power_work(p_slot, DISABLE_REQ);
		break;
	case INT_LINK_UP:
	case INT_LINK_DOWN:
		handle_link_event(p_slot, info->event_type);
		break;
	default:
		break;
	}
	mutex_unlock(&p_slot->lock);

	kfree(info);
}

/*
 * Note: This function must be called with slot->hotplug_lock held
 */
int pciehp_enable_slot(struct slot *p_slot)
{
	u8 getstatus = 0;
	struct controller *ctrl = p_slot->ctrl;

	pciehp_get_adapter_status(p_slot, &getstatus);
	if (!getstatus) {
		ctrl_info(ctrl, "Slot(%s): No adapter\n", slot_name(p_slot));
		return -ENODEV;
	}
	if (MRL_SENS(p_slot->ctrl)) {
		pciehp_get_latch_status(p_slot, &getstatus);
		if (getstatus) {
			ctrl_info(ctrl, "Slot(%s): Latch open\n",
				  slot_name(p_slot));
			return -ENODEV;
		}
	}

	if (POWER_CTRL(p_slot->ctrl)) {
		pciehp_get_power_status(p_slot, &getstatus);
		if (getstatus) {
			ctrl_info(ctrl, "Slot(%s): Already enabled\n",
				  slot_name(p_slot));
			return 0;
		}
	}

	return board_added(p_slot);
}

/*
 * Note: This function must be called with slot->hotplug_lock held
 */
int pciehp_disable_slot(struct slot *p_slot)
{
	u8 getstatus = 0;
	struct controller *ctrl = p_slot->ctrl;

	if (!p_slot->ctrl)
		return 1;

	if (POWER_CTRL(p_slot->ctrl)) {
		pciehp_get_power_status(p_slot, &getstatus);
		if (!getstatus) {
			ctrl_info(ctrl, "Slot(%s): Already disabled\n",
				  slot_name(p_slot));
			return -EINVAL;
		}
	}

	return remove_board(p_slot);
}

int pciehp_sysfs_enable_slot(struct slot *p_slot)
{
	int retval = -ENODEV;
	struct controller *ctrl = p_slot->ctrl;

	mutex_lock(&p_slot->lock);
	switch (p_slot->state) {
	case BLINKINGON_STATE:
		cancel_delayed_work(&p_slot->work);
	case STATIC_STATE:
		p_slot->state = POWERON_STATE;
		mutex_unlock(&p_slot->lock);
		mutex_lock(&p_slot->hotplug_lock);
		retval = pciehp_enable_slot(p_slot);
		mutex_unlock(&p_slot->hotplug_lock);
		mutex_lock(&p_slot->lock);
		p_slot->state = STATIC_STATE;
		break;
	case POWERON_STATE:
		ctrl_info(ctrl, "Slot(%s): Already in powering on state\n",
			  slot_name(p_slot));
		break;
	case BLINKINGOFF_STATE:
	case POWEROFF_STATE:
		ctrl_info(ctrl, "Slot(%s): Already enabled\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;
}

int pciehp_sysfs_disable_slot(struct slot *p_slot)
{
	int retval = -ENODEV;
	struct controller *ctrl = p_slot->ctrl;

	mutex_lock(&p_slot->lock);
	switch (p_slot->state) {
	case BLINKINGOFF_STATE:
		cancel_delayed_work(&p_slot->work);
	case STATIC_STATE:
		p_slot->state = POWEROFF_STATE;
		mutex_unlock(&p_slot->lock);
		mutex_lock(&p_slot->hotplug_lock);
		retval = pciehp_disable_slot(p_slot);
		mutex_unlock(&p_slot->hotplug_lock);
		mutex_lock(&p_slot->lock);
		p_slot->state = STATIC_STATE;
		break;
	case POWEROFF_STATE:
		ctrl_info(ctrl, "Slot(%s): Already in powering off state\n",
			  slot_name(p_slot));
		break;
	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;
}