path: root/drivers/firewire/core-transaction.c

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Core IEEE1394 transaction logic
 *
 * Copyright (C) 2004-2006 Kristian Hoegsberg <krh@bitplanet.net>
 */

#include <linux/bug.h>
#include <linux/completion.h>
#include <linux/device.h>
#include <linux/errno.h>
#include <linux/firewire.h>
#include <linux/firewire-constants.h>
#include <linux/fs.h>
#include <linux/init.h>
#include <linux/jiffies.h>
#include <linux/kernel.h>
#include <linux/list.h>
#include <linux/module.h>
#include <linux/rculist.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/string.h>
#include <linux/timer.h>
#include <linux/types.h>
#include <linux/workqueue.h>

#include <asm/byteorder.h>

#include "core.h"
#include "packet-header-definitions.h"
#include "phy-packet-definitions.h"
#include <trace/events/firewire.h>

#define HEADER_DESTINATION_IS_BROADCAST(header) \
	((async_header_get_destination(header) & 0x3f) == 0x3f)

/* returns 0 if the split timeout handler is already running */
static int try_cancel_split_timeout(struct fw_transaction *t)
{
	if (t->is_split_transaction)
		return timer_delete(&t->split_timeout_timer);
	else
		return 1;
}

// card->transactions.lock must be acquired in advance.
static void remove_transaction_entry(struct fw_card *card, struct fw_transaction *entry)
{
	list_del_init(&entry->link);
	card->transactions.tlabel_mask &= ~(1ULL << entry->tlabel);
}

// Must be called without holding card->transactions.lock.
void fw_cancel_pending_transactions(struct fw_card *card)
{
	struct fw_transaction *t, *tmp;
	LIST_HEAD(pending_list);

	// NOTE: This can be without irqsave when we can guarantee that __fw_send_request() for
	// local destination never runs in any type of IRQ context.
	scoped_guard(spinlock_irqsave, &card->transactions.lock) {
		list_for_each_entry_safe(t, tmp, &card->transactions.list, link) {
			if (try_cancel_split_timeout(t))
				list_move(&t->link, &pending_list);
		}
	}

	list_for_each_entry_safe(t, tmp, &pending_list, link) {
		list_del(&t->link);

		if (!t->with_tstamp) {
			t->callback.without_tstamp(card, RCODE_CANCELLED, NULL, 0,
						   t->callback_data);
		} else {
			t->callback.with_tstamp(card, RCODE_CANCELLED, t->packet.timestamp, 0,
						NULL, 0, t->callback_data);
		}
	}
}

// card->transactions.lock must be acquired in advance.
#define find_and_pop_transaction_entry(card, condition)			\
({									\
	struct fw_transaction *iter, *t = NULL;				\
	list_for_each_entry(iter, &card->transactions.list, link) {	\
		if (condition) {					\
			t = iter;					\
			break;						\
		}							\
	}								\
	if (t && try_cancel_split_timeout(t))				\
		remove_transaction_entry(card, t);			\
	t;								\
})

static int close_transaction(struct fw_transaction *transaction, struct fw_card *card, int rcode,
			     u32 response_tstamp)
{
	struct fw_transaction *t;

	// NOTE: This can be without irqsave when we can guarantee that __fw_send_request() for
	// local destination never runs in any type of IRQ context.
	scoped_guard(spinlock_irqsave, &card->transactions.lock) {
		t = find_and_pop_transaction_entry(card, iter == transaction);
		if (!t)
			return -ENOENT;
	}

	if (!t->with_tstamp) {
		t->callback.without_tstamp(card, rcode, NULL, 0, t->callback_data);
	} else {
		t->callback.with_tstamp(card, rcode, t->packet.timestamp, response_tstamp, NULL, 0,
					t->callback_data);
	}

	return 0;
}

/*
 * Only valid for transactions that are potentially pending (ie have
 * been sent).
 */
int fw_cancel_transaction(struct fw_card *card,
			  struct fw_transaction *transaction)
{
	u32 tstamp;

	/*
	 * Cancel the packet transmission if it's still queued.  That
	 * will call the packet transmission callback which cancels
	 * the transaction.
	 */

	if (card->driver->cancel_packet(card, &transaction->packet) == 0)
		return 0;

	/*
	 * If the request packet has already been sent, we need to see
	 * if the transaction is still pending and remove it in that case.
	 */

	if (transaction->packet.ack == 0) {
		// The timestamp is reused since it was just read now.
		tstamp = transaction->packet.timestamp;
	} else {
		u32 curr_cycle_time = 0;

		(void)fw_card_read_cycle_time(card, &curr_cycle_time);
		tstamp = cycle_time_to_ohci_tstamp(curr_cycle_time);
	}

	return close_transaction(transaction, card, RCODE_CANCELLED, tstamp);
}
EXPORT_SYMBOL(fw_cancel_transaction);

static void split_transaction_timeout_callback(struct timer_list *timer)
{
	struct fw_transaction *t = timer_container_of(t, timer, split_timeout_timer);
	struct fw_card *card = t->card;

	scoped_guard(spinlock_irqsave, &card->transactions.lock) {
		if (list_empty(&t->link))
			return;
		remove_transaction_entry(card, t);
	}

	if (!t->with_tstamp) {
		t->callback.without_tstamp(card, RCODE_CANCELLED, NULL, 0, t->callback_data);
	} else {
		t->callback.with_tstamp(card, RCODE_CANCELLED, t->packet.timestamp,
					t->split_timeout_cycle, NULL, 0, t->callback_data);
	}
}

// card->transactions.lock should be acquired in advance for the linked list.
static void start_split_transaction_timeout(struct fw_transaction *t, unsigned int delta)
{
	if (list_empty(&t->link) || WARN_ON(t->is_split_transaction))
		return;

	t->is_split_transaction = true;

	mod_timer(&t->split_timeout_timer, jiffies + delta);
}

static u32 compute_split_timeout_timestamp(struct fw_card *card, u32 request_timestamp);

static void transmit_complete_callback(struct fw_packet *packet,
				       struct fw_card *card, int status)
{
	struct fw_transaction *t =
	    container_of(packet, struct fw_transaction, packet);

	trace_async_request_outbound_complete((uintptr_t)t, card->index, packet->generation,
					      packet->speed, status, packet->timestamp);

	switch (status) {
	case ACK_COMPLETE:
		close_transaction(t, card, RCODE_COMPLETE, packet->timestamp);
		break;
	case ACK_PENDING:
	{
		unsigned int delta;

		// NOTE: This can be without irqsave when we can guarantee that __fw_send_request() for
		// local destination never runs in any type of IRQ context.
		scoped_guard(spinlock_irqsave, &card->split_timeout.lock) {
			t->split_timeout_cycle =
				compute_split_timeout_timestamp(card, packet->timestamp) & 0xffff;
			delta = card->split_timeout.jiffies;
		}

		// NOTE: This can be without irqsave when we can guarantee that __fw_send_request() for
		// local destination never runs in any type of IRQ context.
		scoped_guard(spinlock_irqsave, &card->transactions.lock)
			start_split_transaction_timeout(t, delta);
		break;
	}
	case ACK_BUSY_X:
	case ACK_BUSY_A:
	case ACK_BUSY_B:
		close_transaction(t, card, RCODE_BUSY, packet->timestamp);
		break;
	case ACK_DATA_ERROR:
		close_transaction(t, card, RCODE_DATA_ERROR, packet->timestamp);
		break;
	case ACK_TYPE_ERROR:
		close_transaction(t, card, RCODE_TYPE_ERROR, packet->timestamp);
		break;
	default:
		/*
		 * In this case the ack is really a juju specific
		 * rcode, so just forward that to the callback.
		 */
		close_transaction(t, card, status, packet->timestamp);
		break;
	}
}

static void fw_fill_request(struct fw_packet *packet, int tcode, int tlabel,
		int destination_id, int source_id, int generation, int speed,
		unsigned long long offset, void *payload, size_t length)
{
	int ext_tcode;

	if (tcode == TCODE_STREAM_DATA) {
		// The value of destination_id argument should include tag, channel, and sy fields
		// as isochronous packet header has.
		packet->header[0] = destination_id;
		isoc_header_set_data_length(packet->header, length);
		isoc_header_set_tcode(packet->header, TCODE_STREAM_DATA);
		packet->header_length = 4;
		packet->payload = payload;
		packet->payload_length = length;

		goto common;
	}

	if (tcode > 0x10) {
		ext_tcode = tcode & ~0x10;
		tcode = TCODE_LOCK_REQUEST;
	} else
		ext_tcode = 0;

	async_header_set_retry(packet->header, RETRY_X);
	async_header_set_tlabel(packet->header, tlabel);
	async_header_set_tcod