Fixed MTP to work with TWRP

arch/powerpc/kernel/eeh_event.c

@@ -0,0 +1,196 @@
+/*
+ * 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.  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., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
+ *
+ * Copyright (c) 2005 Linas Vepstas <linas@linas.org>
+ */
+
+#include <linux/delay.h>
+#include <linux/list.h>
+#include <linux/sched.h>
+#include <linux/semaphore.h>
+#include <linux/pci.h>
+#include <linux/slab.h>
+#include <linux/kthread.h>
+#include <asm/eeh_event.h>
+#include <asm/ppc-pci.h>
+
+/** Overview:
+ *  EEH error states may be detected within exception handlers;
+ *  however, the recovery processing needs to occur asynchronously
+ *  in a normal kernel context and not an interrupt context.
+ *  This pair of routines creates an event and queues it onto a
+ *  work-queue, where a worker thread can drive recovery.
+ */
+
+static DEFINE_SPINLOCK(eeh_eventlist_lock);
+static struct semaphore eeh_eventlist_sem;
+LIST_HEAD(eeh_eventlist);
+
+/**
+ * eeh_event_handler - Dispatch EEH events.
+ * @dummy - unused
+ *
+ * The detection of a frozen slot can occur inside an interrupt,
+ * where it can be hard to do anything about it.  The goal of this
+ * routine is to pull these detection events out of the context
+ * of the interrupt handler, and re-dispatch them for processing
+ * at a later time in a normal context.
+ */
+static int eeh_event_handler(void * dummy)
+{
+	unsigned long flags;
+	struct eeh_event *event;
+	struct eeh_pe *pe;
+
+	while (!kthread_should_stop()) {
+		if (down_interruptible(&eeh_eventlist_sem))
+			break;
+
+		/* Fetch EEH event from the queue */
+		spin_lock_irqsave(&eeh_eventlist_lock, flags);
+		event = NULL;
+		if (!list_empty(&eeh_eventlist)) {
+			event = list_entry(eeh_eventlist.next,
+					   struct eeh_event, list);
+			list_del(&event->list);
+		}
+		spin_unlock_irqrestore(&eeh_eventlist_lock, flags);
+		if (!event)
+			continue;
+
+		/* We might have event without binding PE */
+		pe = event->pe;
+		if (pe) {
+			eeh_pe_state_mark(pe, EEH_PE_RECOVERING);
+			if (pe->type & EEH_PE_PHB)
+				pr_info("EEH: Detected error on PHB#%d\n",
+					 pe->phb->global_number);
+			else
+				pr_info("EEH: Detected PCI bus error on "
+					"PHB#%d-PE#%x\n",
+					pe->phb->global_number, pe->addr);
+			eeh_handle_event(pe);
+			eeh_pe_state_clear(pe, EEH_PE_RECOVERING);
+		} else {
+			eeh_handle_event(NULL);
+		}
+
+		kfree(event);
+	}
+
+	return 0;
+}
+
+/**
+ * eeh_event_init - Start kernel thread to handle EEH events
+ *
+ * This routine is called to start the kernel thread for processing
+ * EEH event.
+ */
+int eeh_event_init(void)
+{
+	struct task_struct *t;
+	int ret = 0;
+
+	/* Initialize semaphore */
+	sema_init(&eeh_eventlist_sem, 0);
+
+	t = kthread_run(eeh_event_handler, NULL, "eehd");
+	if (IS_ERR(t)) {
+		ret = PTR_ERR(t);
+		pr_err("%s: Failed to start EEH daemon (%d)\n",
+			__func__, ret);
+		return ret;
+	}
+
+	return 0;
+}
+
+/**
+ * eeh_send_failure_event - Generate a PCI error event
+ * @pe: EEH PE
+ *
+ * This routine can be called within an interrupt context;
+ * the actual event will be delivered in a normal context
+ * (from a workqueue).
+ */
+int eeh_send_failure_event(struct eeh_pe *pe)
+{
+	unsigned long flags;
+	struct eeh_event *event;
+
+	event = kzalloc(sizeof(*event), GFP_ATOMIC);
+	if (!event) {
+		pr_err("EEH: out of memory, event not handled\n");
+		return -ENOMEM;
+	}
+	event->pe = pe;
+
+	/* We may or may not be called in an interrupt context */
+	spin_lock_irqsave(&eeh_eventlist_lock, flags);
+	list_add(&event->list, &eeh_eventlist);
+	spin_unlock_irqrestore(&eeh_eventlist_lock, flags);
+
+	/* For EEH deamon to knick in */
+	up(&eeh_eventlist_sem);
+
+	return 0;
+}
+
+/**
+ * eeh_remove_event - Remove EEH event from the queue
+ * @pe: Event binding to the PE
+ * @force: Event will be removed unconditionally
+ *
+ * On PowerNV platform, we might have subsequent coming events
+ * is part of the former one. For that case, those subsequent
+ * coming events are totally duplicated and unnecessary, thus
+ * they should be removed.
+ */
+void eeh_remove_event(struct eeh_pe *pe, bool force)
+{
+	unsigned long flags;
+	struct eeh_event *event, *tmp;
+
+	/*
+	 * If we have NULL PE passed in, we have dead IOC
+	 * or we're sure we can report all existing errors
+	 * by the caller.
+	 *
+	 * With "force", the event with associated PE that
+	 * have been isolated, the event won't be removed
+	 * to avoid event lost.
+	 */
+	spin_lock_irqsave(&eeh_eventlist_lock, flags);
+	list_for_each_entry_safe(event, tmp, &eeh_eventlist, list) {
+		if (!force && event->pe &&
+		    (event->pe->state & EEH_PE_ISOLATED))
+			continue;
+
+		if (!pe) {
+			list_del(&event->list);
+			kfree(event);
+		} else if (pe->type & EEH_PE_PHB) {
+			if (event->pe && event->pe->phb == pe->phb) {
+				list_del(&event->list);
+				kfree(event);
+			}
+		} else if (event->pe == pe) {
+			list_del(&event->list);
+			kfree(event);
+		}
+	}
+	spin_unlock_irqrestore(&eeh_eventlist_lock, flags);
+}