path: root/drivers/net/can/softing/softing_main.c

/*
 * Copyright (C) 2008-2010
 *
 * - Kurt Van Dijck, EIA Electronics
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the version 2 of the GNU General Public License
 * as published by the Free Software Foundation
 *
 * 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
 */

#include <linux/module.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <asm/io.h>

#include "softing.h"

#define TX_ECHO_SKB_MAX (((TXMAX+1)/2)-1)

/*
 * test is a specific CAN netdev
 * is online (ie. up 'n running, not sleeping, not busoff
 */
static inline int canif_is_active(struct net_device *netdev)
{
	struct can_priv *can = netdev_priv(netdev);

	if (!netif_running(netdev))
		return 0;
	return (can->state <= CAN_STATE_ERROR_PASSIVE);
}

/* reset DPRAM */
static inline void softing_set_reset_dpram(struct softing *card)
{
	if (card->pdat->generation >= 2) {
		spin_lock_bh(&card->spin);
		iowrite8(ioread8(&card->dpram[DPRAM_V2_RESET]) & ~1,
				&card->dpram[DPRAM_V2_RESET]);
		spin_unlock_bh(&card->spin);
	}
}

static inline void softing_clr_reset_dpram(struct softing *card)
{
	if (card->pdat->generation >= 2) {
		spin_lock_bh(&card->spin);
		iowrite8(ioread8(&card->dpram[DPRAM_V2_RESET]) | 1,
				&card->dpram[DPRAM_V2_RESET]);
		spin_unlock_bh(&card->spin);
	}
}

/* trigger the tx queue-ing */
static netdev_tx_t softing_netdev_start_xmit(struct sk_buff *skb,
		struct net_device *dev)
{
	struct softing_priv *priv = netdev_priv(dev);
	struct softing *card = priv->card;
	int ret;
	uint8_t *ptr;
	uint8_t fifo_wr, fifo_rd;
	struct can_frame *cf = (struct can_frame *)skb->data;
	uint8_t buf[DPRAM_TX_SIZE];

	if (can_dropped_invalid_skb(dev, skb))
		return NETDEV_TX_OK;

	spin_lock(&card->spin);

	ret = NETDEV_TX_BUSY;
	if (!card->fw.up ||
			(card->tx.pending >= TXMAX) ||
			(priv->tx.pending >= TX_ECHO_SKB_MAX))
		goto xmit_done;
	fifo_wr = ioread8(&card->dpram[DPRAM_TX_WR]);
	fifo_rd = ioread8(&card->dpram[DPRAM_TX_RD]);
	if (fifo_wr == fifo_rd)
		/* fifo full */
		goto xmit_done;
	memset(buf, 0, sizeof(buf));
	ptr = buf;
	*ptr = CMD_TX;
	if (cf->can_id & CAN_RTR_FLAG)
		*ptr |= CMD_RTR;
	if (cf->can_id & CAN_EFF_FLAG)
		*ptr |= CMD_XTD;
	if (priv->index)
		*ptr |= CMD_BUS2;
	++ptr;
	*ptr++ = cf->can_dlc;
	*ptr++ = (cf->can_id >> 0);
	*ptr++ = (cf->can_id >> 8);
	if (cf->can_id & CAN_EFF_FLAG) {
		*ptr++ = (cf->can_id >> 16);
		*ptr++ = (cf->can_id >> 24);
	} else {
		/* increment 1, not 2 as you might think */
		ptr += 1;
	}
	if (!(cf->can_id & CAN_RTR_FLAG))
		memcpy(ptr, &cf->data[0], cf->can_dlc);
	memcpy_toio(&card->dpram[DPRAM_TX + DPRAM_TX_SIZE * fifo_wr],
			buf, DPRAM_TX_SIZE);
	if (++fifo_wr >= DPRAM_TX_CNT)
		fifo_wr = 0;
	iowrite8(fifo_wr, &card->dpram[DPRAM_TX_WR]);
	card->tx.last_bus = priv->index;
	++card->tx.pending;
	++priv->tx.pending;
	can_put_echo_skb(skb, dev, priv->tx.echo_put);
	++priv->tx.echo_put;
	if (priv->tx.echo_put >= TX_ECHO_SKB_MAX)
		priv->tx.echo_put = 0;
	/* can_put_echo_skb() saves the skb, safe to return TX_OK */
	ret = NETDEV_TX_OK;
xmit_done:
	spin_unlock(&card->spin);
	if (card->tx.pending >= TXMAX) {
		int j;
		for (j = 0; j < ARRAY_SIZE(card->net); ++j) {
			if (card->net[j])
				netif_stop_queue(card->net[j]);
		}
	}
	if (ret != NETDEV_TX_OK)
		netif_stop_queue(dev);

	return ret;
}

/*
 * shortcut for skb delivery
 */
int softing_netdev_rx(struct net_device *netdev, const struct can_frame *msg,
		ktime_t ktime)
{
	struct sk_buff *skb;
	struct can_frame *cf;

	skb = alloc_can_skb(netdev, &cf);
	if (!skb)
		return -ENOMEM;
	memcpy