166 строки
5.1 KiB
C
166 строки
5.1 KiB
C
/*
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* Copyright 2010 2011 Mark Nelson and Tseng-Hui (Frank) Lin, IBM Corporation
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*/
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#include <linux/errno.h>
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#include <linux/slab.h>
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#include <linux/export.h>
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#include <linux/irq.h>
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#include <linux/interrupt.h>
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#include <linux/of.h>
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#include <linux/list.h>
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#include <linux/notifier.h>
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#include <asm/machdep.h>
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#include <asm/rtas.h>
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#include <asm/irq.h>
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#include <asm/io_event_irq.h>
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#include "pseries.h"
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/*
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* IO event interrupt is a mechanism provided by RTAS to return
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* information about hardware error and non-error events. Device
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* drivers can register their event handlers to receive events.
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* Device drivers are expected to use atomic_notifier_chain_register()
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* and atomic_notifier_chain_unregister() to register and unregister
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* their event handlers. Since multiple IO event types and scopes
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* share an IO event interrupt, the event handlers are called one
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* by one until the IO event is claimed by one of the handlers.
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* The event handlers are expected to return NOTIFY_OK if the
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* event is handled by the event handler or NOTIFY_DONE if the
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* event does not belong to the handler.
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*
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* Usage:
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*
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* Notifier function:
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* #include <asm/io_event_irq.h>
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* int event_handler(struct notifier_block *nb, unsigned long val, void *data) {
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* p = (struct pseries_io_event_sect_data *) data;
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* if (! is_my_event(p->scope, p->event_type)) return NOTIFY_DONE;
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* :
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* :
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* return NOTIFY_OK;
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* }
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* struct notifier_block event_nb = {
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* .notifier_call = event_handler,
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* }
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*
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* Registration:
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* atomic_notifier_chain_register(&pseries_ioei_notifier_list, &event_nb);
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*
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* Unregistration:
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* atomic_notifier_chain_unregister(&pseries_ioei_notifier_list, &event_nb);
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*/
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ATOMIC_NOTIFIER_HEAD(pseries_ioei_notifier_list);
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EXPORT_SYMBOL_GPL(pseries_ioei_notifier_list);
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static int ioei_check_exception_token;
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static char ioei_rtas_buf[RTAS_DATA_BUF_SIZE] __cacheline_aligned;
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/**
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* Find the data portion of an IO Event section from event log.
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* @elog: RTAS error/event log.
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*
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* Return:
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* pointer to a valid IO event section data. NULL if not found.
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*/
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static struct pseries_io_event * ioei_find_event(struct rtas_error_log *elog)
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{
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struct pseries_errorlog *sect;
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/* We should only ever get called for io-event interrupts, but if
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* we do get called for another type then something went wrong so
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* make some noise about it.
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* RTAS_TYPE_IO only exists in extended event log version 6 or later.
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* No need to check event log version.
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*/
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if (unlikely(elog->type != RTAS_TYPE_IO)) {
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printk_once(KERN_WARNING "io_event_irq: Unexpected event type %d",
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elog->type);
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return NULL;
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}
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sect = get_pseries_errorlog(elog, PSERIES_ELOG_SECT_ID_IO_EVENT);
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if (unlikely(!sect)) {
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printk_once(KERN_WARNING "io_event_irq: RTAS extended event "
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"log does not contain an IO Event section. "
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"Could be a bug in system firmware!\n");
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return NULL;
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}
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return (struct pseries_io_event *) §->data;
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}
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/*
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* PAPR:
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* - check-exception returns the first found error or event and clear that
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* error or event so it is reported once.
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* - Each interrupt returns one event. If a plateform chooses to report
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* multiple events through a single interrupt, it must ensure that the
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* interrupt remains asserted until check-exception has been used to
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* process all out-standing events for that interrupt.
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*
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* Implementation notes:
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* - Events must be processed in the order they are returned. Hence,
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* sequential in nature.
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* - The owner of an event is determined by combinations of scope,
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* event type, and sub-type. There is no easy way to pre-sort clients
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* by scope or event type alone. For example, Torrent ISR route change
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* event is reported with scope 0x00 (Not Applicatable) rather than
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* 0x3B (Torrent-hub). It is better to let the clients to identify
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* who owns the the event.
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*/
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static irqreturn_t ioei_interrupt(int irq, void *dev_id)
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{
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struct pseries_io_event *event;
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int rtas_rc;
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for (;;) {
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rtas_rc = rtas_call(ioei_check_exception_token, 6, 1, NULL,
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RTAS_VECTOR_EXTERNAL_INTERRUPT,
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virq_to_hw(irq),
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RTAS_IO_EVENTS, 1 /* Time Critical */,
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__pa(ioei_rtas_buf),
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RTAS_DATA_BUF_SIZE);
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if (rtas_rc != 0)
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break;
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event = ioei_find_event((struct rtas_error_log *)ioei_rtas_buf);
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if (!event)
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continue;
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atomic_notifier_call_chain(&pseries_ioei_notifier_list,
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0, event);
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}
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return IRQ_HANDLED;
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}
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static int __init ioei_init(void)
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{
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struct device_node *np;
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ioei_check_exception_token = rtas_token("check-exception");
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if (ioei_check_exception_token == RTAS_UNKNOWN_SERVICE)
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return -ENODEV;
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np = of_find_node_by_path("/event-sources/ibm,io-events");
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if (np) {
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request_event_sources_irqs(np, ioei_interrupt, "IO_EVENT");
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pr_info("IBM I/O event interrupts enabled\n");
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of_node_put(np);
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} else {
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return -ENODEV;
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}
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return 0;
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}
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machine_subsys_initcall(pseries, ioei_init);
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