caif_hsi.c 30 KB
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/*
 * Copyright (C) ST-Ericsson AB 2010
 * Contact: Sjur Brendeland / sjur.brandeland@stericsson.com
 * Author:  Daniel Martensson / daniel.martensson@stericsson.com
 *	    Dmitry.Tarnyagin  / dmitry.tarnyagin@stericsson.com
 * License terms: GNU General Public License (GPL) version 2.
 */

#include <linux/init.h>
#include <linux/module.h>
#include <linux/device.h>
#include <linux/platform_device.h>
#include <linux/netdevice.h>
#include <linux/string.h>
#include <linux/list.h>
#include <linux/interrupt.h>
#include <linux/delay.h>
#include <linux/sched.h>
#include <linux/if_arp.h>
#include <linux/timer.h>
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#include <linux/rtnetlink.h>
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#include <net/caif/caif_layer.h>
#include <net/caif/caif_hsi.h>

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Daniel Martensson<daniel.martensson@stericsson.com>");
MODULE_DESCRIPTION("CAIF HSI driver");

/* Returns the number of padding bytes for alignment. */
#define PAD_POW2(x, pow) ((((x)&((pow)-1)) == 0) ? 0 :\
				(((pow)-((x)&((pow)-1)))))

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static int inactivity_timeout = 1000;
module_param(inactivity_timeout, int, S_IRUGO | S_IWUSR);
MODULE_PARM_DESC(inactivity_timeout, "Inactivity timeout on HSI, ms.");

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/*
 * HSI padding options.
 * Warning: must be a base of 2 (& operation used) and can not be zero !
 */
static int hsi_head_align = 4;
module_param(hsi_head_align, int, S_IRUGO);
MODULE_PARM_DESC(hsi_head_align, "HSI head alignment.");

static int hsi_tail_align = 4;
module_param(hsi_tail_align, int, S_IRUGO);
MODULE_PARM_DESC(hsi_tail_align, "HSI tail alignment.");

/*
 * HSI link layer flowcontrol thresholds.
 * Warning: A high threshold value migth increase throughput but it will at
 * the same time prevent channel prioritization and increase the risk of
 * flooding the modem. The high threshold should be above the low.
 */
static int hsi_high_threshold = 100;
module_param(hsi_high_threshold, int, S_IRUGO);
MODULE_PARM_DESC(hsi_high_threshold, "HSI high threshold (FLOW OFF).");

static int hsi_low_threshold = 50;
module_param(hsi_low_threshold, int, S_IRUGO);
MODULE_PARM_DESC(hsi_low_threshold, "HSI high threshold (FLOW ON).");

#define ON 1
#define OFF 0

/*
 * Threshold values for the HSI packet queue. Flowcontrol will be asserted
 * when the number of packets exceeds HIGH_WATER_MARK. It will not be
 * de-asserted before the number of packets drops below LOW_WATER_MARK.
 */
#define LOW_WATER_MARK   hsi_low_threshold
#define HIGH_WATER_MARK  hsi_high_threshold

static LIST_HEAD(cfhsi_list);
static spinlock_t cfhsi_list_lock;

static void cfhsi_inactivity_tout(unsigned long arg)
{
	struct cfhsi *cfhsi = (struct cfhsi *)arg;

	dev_dbg(&cfhsi->ndev->dev, "%s.\n",
		__func__);

	/* Schedule power down work queue. */
	if (!test_bit(CFHSI_SHUTDOWN, &cfhsi->bits))
		queue_work(cfhsi->wq, &cfhsi->wake_down_work);
}

static void cfhsi_abort_tx(struct cfhsi *cfhsi)
{
	struct sk_buff *skb;

	for (;;) {
		spin_lock_bh(&cfhsi->lock);
		skb = skb_dequeue(&cfhsi->qhead);
		if (!skb)
			break;

		cfhsi->ndev->stats.tx_errors++;
		cfhsi->ndev->stats.tx_dropped++;
		spin_unlock_bh(&cfhsi->lock);
		kfree_skb(skb);
	}
	cfhsi->tx_state = CFHSI_TX_STATE_IDLE;
	if (!test_bit(CFHSI_SHUTDOWN, &cfhsi->bits))
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		mod_timer(&cfhsi->timer,
			jiffies + cfhsi->inactivity_timeout);
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	spin_unlock_bh(&cfhsi->lock);
}

static int cfhsi_flush_fifo(struct cfhsi *cfhsi)
{
	char buffer[32]; /* Any reasonable value */
	size_t fifo_occupancy;
	int ret;

	dev_dbg(&cfhsi->ndev->dev, "%s.\n",
		__func__);

	do {
		ret = cfhsi->dev->cfhsi_fifo_occupancy(cfhsi->dev,
				&fifo_occupancy);
		if (ret) {
			dev_warn(&cfhsi->ndev->dev,
				"%s: can't get FIFO occupancy: %d.\n",
				__func__, ret);
			break;
		} else if (!fifo_occupancy)
			/* No more data, exitting normally */
			break;

		fifo_occupancy = min(sizeof(buffer), fifo_occupancy);
		set_bit(CFHSI_FLUSH_FIFO, &cfhsi->bits);
		ret = cfhsi->dev->cfhsi_rx(buffer, fifo_occupancy,
				cfhsi->dev);
		if (ret) {
			clear_bit(CFHSI_FLUSH_FIFO, &cfhsi->bits);
			dev_warn(&cfhsi->ndev->dev,
				"%s: can't read data: %d.\n",
				__func__, ret);
			break;
		}

		ret = 5 * HZ;
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		ret = wait_event_interruptible_timeout(cfhsi->flush_fifo_wait,
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			 !test_bit(CFHSI_FLUSH_FIFO, &cfhsi->bits), ret);

		if (ret < 0) {
			dev_warn(&cfhsi->ndev->dev,
				"%s: can't wait for flush complete: %d.\n",
				__func__, ret);
			break;
		} else if (!ret) {
			ret = -ETIMEDOUT;
			dev_warn(&cfhsi->ndev->dev,
				"%s: timeout waiting for flush complete.\n",
				__func__);
			break;
		}
	} while (1);

	return ret;
}

static int cfhsi_tx_frm(struct cfhsi_desc *desc, struct cfhsi *cfhsi)
{
	int nfrms = 0;
	int pld_len = 0;
	struct sk_buff *skb;
	u8 *pfrm = desc->emb_frm + CFHSI_MAX_EMB_FRM_SZ;

	skb = skb_dequeue(&cfhsi->qhead);
	if (!skb)
		return 0;

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	/* Clear offset. */
	desc->offset = 0;

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	/* Check if we can embed a CAIF frame. */
	if (skb->len < CFHSI_MAX_EMB_FRM_SZ) {
		struct caif_payload_info *info;
		int hpad = 0;
		int tpad = 0;

		/* Calculate needed head alignment and tail alignment. */
		info = (struct caif_payload_info *)&skb->cb;

		hpad = 1 + PAD_POW2((info->hdr_len + 1), hsi_head_align);
		tpad = PAD_POW2((skb->len + hpad), hsi_tail_align);

		/* Check if frame still fits with added alignment. */
		if ((skb->len + hpad + tpad) <= CFHSI_MAX_EMB_FRM_SZ) {
			u8 *pemb = desc->emb_frm;
			desc->offset = CFHSI_DESC_SHORT_SZ;
			*pemb = (u8)(hpad - 1);
			pemb += hpad;

			/* Update network statistics. */
			cfhsi->ndev->stats.tx_packets++;
			cfhsi->ndev->stats.tx_bytes += skb->len;

			/* Copy in embedded CAIF frame. */
			skb_copy_bits(skb, 0, pemb, skb->len);
			consume_skb(skb);
			skb = NULL;
		}
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	}
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	/* Create payload CAIF frames. */
	pfrm = desc->emb_frm + CFHSI_MAX_EMB_FRM_SZ;
	while (nfrms < CFHSI_MAX_PKTS) {
		struct caif_payload_info *info;
		int hpad = 0;
		int tpad = 0;

		if (!skb)
			skb = skb_dequeue(&cfhsi->qhead);

		if (!skb)
			break;

		/* Calculate needed head alignment and tail alignment. */
		info = (struct caif_payload_info *)&skb->cb;

		hpad = 1 + PAD_POW2((info->hdr_len + 1), hsi_head_align);
		tpad = PAD_POW2((skb->len + hpad), hsi_tail_align);

		/* Fill in CAIF frame length in descriptor. */
		desc->cffrm_len[nfrms] = hpad + skb->len + tpad;

		/* Fill head padding information. */
		*pfrm = (u8)(hpad - 1);
		pfrm += hpad;

		/* Update network statistics. */
		cfhsi->ndev->stats.tx_packets++;
		cfhsi->ndev->stats.tx_bytes += skb->len;

		/* Copy in CAIF frame. */
		skb_copy_bits(skb, 0, pfrm, skb->len);

		/* Update payload length. */
		pld_len += desc->cffrm_len[nfrms];

		/* Update frame pointer. */
		pfrm += skb->len + tpad;
		consume_skb(skb);
		skb = NULL;

		/* Update number of frames. */
		nfrms++;
	}

	/* Unused length fields should be zero-filled (according to SPEC). */
	while (nfrms < CFHSI_MAX_PKTS) {
		desc->cffrm_len[nfrms] = 0x0000;
		nfrms++;
	}

	/* Check if we can piggy-back another descriptor. */
	skb = skb_peek(&cfhsi->qhead);
	if (skb)
		desc->header |= CFHSI_PIGGY_DESC;
	else
		desc->header &= ~CFHSI_PIGGY_DESC;

	return CFHSI_DESC_SZ + pld_len;
}

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static void cfhsi_tx_done(struct cfhsi *cfhsi)
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{
	struct cfhsi_desc *desc = NULL;
	int len = 0;
	int res;

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	dev_dbg(&cfhsi->ndev->dev, "%s.\n", __func__);
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	if (test_bit(CFHSI_SHUTDOWN, &cfhsi->bits))
		return;

	desc = (struct cfhsi_desc *)cfhsi->tx_buf;

	do {
		/*
		 * Send flow on if flow off has been previously signalled
		 * and number of packets is below low water mark.
		 */
		spin_lock_bh(&cfhsi->lock);
		if (cfhsi->flow_off_sent &&
				cfhsi->qhead.qlen <= cfhsi->q_low_mark &&
				cfhsi->cfdev.flowctrl) {

			cfhsi->flow_off_sent = 0;
			cfhsi->cfdev.flowctrl(cfhsi->ndev, ON);
		}
		spin_unlock_bh(&cfhsi->lock);

		/* Create HSI frame. */
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		do {
			len = cfhsi_tx_frm(desc, cfhsi);
			if (!len) {
				spin_lock_bh(&cfhsi->lock);
				if (unlikely(skb_peek(&cfhsi->qhead))) {
					spin_unlock_bh(&cfhsi->lock);
					continue;
				}
				cfhsi->tx_state = CFHSI_TX_STATE_IDLE;
				/* Start inactivity timer. */
				mod_timer(&cfhsi->timer,
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					jiffies + cfhsi->inactivity_timeout);
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				spin_unlock_bh(&cfhsi->lock);
				goto done;
			}
		} while (!len);
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		/* Set up new transfer. */
		res = cfhsi->dev->cfhsi_tx(cfhsi->tx_buf, len, cfhsi->dev);
		if (WARN_ON(res < 0)) {
			dev_err(&cfhsi->ndev->dev, "%s: TX error %d.\n",
				__func__, res);
		}
	} while (res < 0);
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done:
	return;
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}

static void cfhsi_tx_done_cb(struct cfhsi_drv *drv)
{
	struct cfhsi *cfhsi;

	cfhsi = container_of(drv, struct cfhsi, drv);
	dev_dbg(&cfhsi->ndev->dev, "%s.\n",
		__func__);

	if (test_bit(CFHSI_SHUTDOWN, &cfhsi->bits))
		return;
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	cfhsi_tx_done(cfhsi);
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}

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static int cfhsi_rx_desc(struct cfhsi_desc *desc, struct cfhsi *cfhsi)
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{
	int xfer_sz = 0;
	int nfrms = 0;
	u16 *plen = NULL;
	u8 *pfrm = NULL;

	if ((desc->header & ~CFHSI_PIGGY_DESC) ||
			(desc->offset > CFHSI_MAX_EMB_FRM_SZ)) {
		dev_err(&cfhsi->ndev->dev, "%s: Invalid descriptor.\n",
			__func__);
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		return -EPROTO;
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	}

	/* Check for embedded CAIF frame. */
	if (desc->offset) {
		struct sk_buff *skb;
		u8 *dst = NULL;
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		int len = 0;
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		pfrm = ((u8 *)desc) + desc->offset;

		/* Remove offset padding. */
		pfrm += *pfrm + 1;

		/* Read length of CAIF frame (little endian). */
		len = *pfrm;
		len |= ((*(pfrm+1)) << 8) & 0xFF00;
		len += 2;	/* Add FCS fields. */

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		/* Sanity check length of CAIF frame. */
		if (unlikely(len > CFHSI_MAX_CAIF_FRAME_SZ)) {
			dev_err(&cfhsi->ndev->dev, "%s: Invalid length.\n",
				__func__);
			return -EPROTO;
		}
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		/* Allocate SKB (OK even in IRQ context). */
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		skb = alloc_skb(len + 1, GFP_ATOMIC);
		if (!skb) {
			dev_err(&cfhsi->ndev->dev, "%s: Out of memory !\n",
				__func__);
			return -ENOMEM;
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		}
		caif_assert(skb != NULL);

		dst = skb_put(skb, len);
		memcpy(dst, pfrm, len);

		skb->protocol = htons(ETH_P_CAIF);
		skb_reset_mac_header(skb);
		skb->dev = cfhsi->ndev;

		/*
		 * We are called from a arch specific platform device.
		 * Unfortunately we don't know what context we're
		 * running in.
		 */
		if (in_interrupt())
			netif_rx(skb);
		else
			netif_rx_ni(skb);

		/* Update network statistics. */
		cfhsi->ndev->stats.rx_packets++;
		cfhsi->ndev->stats.rx_bytes += len;
	}

	/* Calculate transfer length. */
	plen = desc->cffrm_len;
	while (nfrms < CFHSI_MAX_PKTS && *plen) {
		xfer_sz += *plen;
		plen++;
		nfrms++;
	}

	/* Check for piggy-backed descriptor. */
	if (desc->header & CFHSI_PIGGY_DESC)
		xfer_sz += CFHSI_DESC_SZ;

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	if ((xfer_sz % 4) || (xfer_sz > (CFHSI_BUF_SZ_RX - CFHSI_DESC_SZ))) {
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		dev_err(&cfhsi->ndev->dev,
				"%s: Invalid payload len: %d, ignored.\n",
			__func__, xfer_sz);
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		return -EPROTO;
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	}
	return xfer_sz;
}

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static int cfhsi_rx_pld(struct cfhsi_desc *desc, struct cfhsi *cfhsi)
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{
	int rx_sz = 0;
	int nfrms = 0;
	u16 *plen = NULL;
	u8 *pfrm = NULL;

	/* Sanity check header and offset. */
	if (WARN_ON((desc->header & ~CFHSI_PIGGY_DESC) ||
			(desc->offset > CFHSI_MAX_EMB_FRM_SZ))) {
		dev_err(&cfhsi->ndev->dev, "%s: Invalid descriptor.\n",
			__func__);
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		return -EPROTO;
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	}

	/* Set frame pointer to start of payload. */
	pfrm = desc->emb_frm + CFHSI_MAX_EMB_FRM_SZ;
	plen = desc->cffrm_len;
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	/* Skip already processed frames. */
	while (nfrms < cfhsi->rx_state.nfrms) {
		pfrm += *plen;
		rx_sz += *plen;
		plen++;
		nfrms++;
	}

	/* Parse payload. */
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	while (nfrms < CFHSI_MAX_PKTS && *plen) {
		struct sk_buff *skb;
		u8 *dst = NULL;
		u8 *pcffrm = NULL;
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		int len = 0;
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		/* CAIF frame starts after head padding. */
		pcffrm = pfrm + *pfrm + 1;

		/* Read length of CAIF frame (little endian). */
		len = *pcffrm;
		len |= ((*(pcffrm + 1)) << 8) & 0xFF00;
		len += 2;	/* Add FCS fields. */

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		/* Sanity check length of CAIF frames. */
		if (unlikely(len > CFHSI_MAX_CAIF_FRAME_SZ)) {
			dev_err(&cfhsi->ndev->dev, "%s: Invalid length.\n",
				__func__);
			return -EPROTO;
		}

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		/* Allocate SKB (OK even in IRQ context). */
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		skb = alloc_skb(len + 1, GFP_ATOMIC);
		if (!skb) {
			dev_err(&cfhsi->ndev->dev, "%s: Out of memory !\n",
				__func__);
			cfhsi->rx_state.nfrms = nfrms;
			return -ENOMEM;
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		}
		caif_assert(skb != NULL);

		dst = skb_put(skb, len);
		memcpy(dst, pcffrm, len);

		skb->protocol = htons(ETH_P_CAIF);
		skb_reset_mac_header(skb);
		skb->dev = cfhsi->ndev;

		/*
		 * We're called from a platform device,
		 * and don't know the context we're running in.
		 */
		if (in_interrupt())
			netif_rx(skb);
		else
			netif_rx_ni(skb);

		/* Update network statistics. */
		cfhsi->ndev->stats.rx_packets++;
		cfhsi->ndev->stats.rx_bytes += len;

		pfrm += *plen;
		rx_sz += *plen;
		plen++;
		nfrms++;
	}

	return rx_sz;
}

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static void cfhsi_rx_done(struct cfhsi *cfhsi)
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{
	int res;
	int desc_pld_len = 0;
	struct cfhsi_desc *desc = NULL;

	desc = (struct cfhsi_desc *)cfhsi->rx_buf;

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	dev_dbg(&cfhsi->ndev->dev, "%s\n", __func__);
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	if (test_bit(CFHSI_SHUTDOWN, &cfhsi->bits))
		return;

	/* Update inactivity timer if pending. */
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	spin_lock_bh(&cfhsi->lock);
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	mod_timer_pending(&cfhsi->timer,
			jiffies + cfhsi->inactivity_timeout);
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	spin_unlock_bh(&cfhsi->lock);
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	if (cfhsi->rx_state.state == CFHSI_RX_STATE_DESC) {
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		desc_pld_len = cfhsi_rx_desc(desc, cfhsi);
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		if (desc_pld_len == -ENOMEM)
			goto restart;
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		if (desc_pld_len == -EPROTO)
			goto out_of_sync;
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	} else {
		int pld_len;

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		if (!cfhsi->rx_state.piggy_desc) {
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			pld_len = cfhsi_rx_pld(desc, cfhsi);
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			if (pld_len == -ENOMEM)
				goto restart;
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			if (pld_len == -EPROTO)
				goto out_of_sync;
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			cfhsi->rx_state.pld_len = pld_len;
		} else {
			pld_len = cfhsi->rx_state.pld_len;
		}
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		if ((pld_len > 0) && (desc->header & CFHSI_PIGGY_DESC)) {
			struct cfhsi_desc *piggy_desc;
			piggy_desc = (struct cfhsi_desc *)
				(desc->emb_frm + CFHSI_MAX_EMB_FRM_SZ +
						pld_len);
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			cfhsi->rx_state.piggy_desc = true;
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			/* Extract piggy-backed descriptor. */
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			desc_pld_len = cfhsi_rx_desc(piggy_desc, cfhsi);
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			if (desc_pld_len == -ENOMEM)
				goto restart;
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			/*
			 * Copy needed information from the piggy-backed
			 * descriptor to the descriptor in the start.
			 */
			memcpy((u8 *)desc, (u8 *)piggy_desc,
					CFHSI_DESC_SHORT_SZ);

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			if (desc_pld_len == -EPROTO)
				goto out_of_sync;
		}
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	}

	memset(&cfhsi->rx_state, 0, sizeof(cfhsi->rx_state));
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	if (desc_pld_len) {
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		cfhsi->rx_state.state = CFHSI_RX_STATE_PAYLOAD;
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		cfhsi->rx_ptr = cfhsi->rx_buf + CFHSI_DESC_SZ;
		cfhsi->rx_len = desc_pld_len;
	} else {
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		cfhsi->rx_state.state = CFHSI_RX_STATE_DESC;
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		cfhsi->rx_ptr = cfhsi->rx_buf;
		cfhsi->rx_len = CFHSI_DESC_SZ;
	}

	if (test_bit(CFHSI_AWAKE, &cfhsi->bits)) {
		/* Set up new transfer. */
		dev_dbg(&cfhsi->ndev->dev, "%s: Start RX.\n",
			__func__);
		res = cfhsi->dev->cfhsi_rx(cfhsi->rx_ptr, cfhsi->rx_len,
				cfhsi->dev);
		if (WARN_ON(res < 0)) {
			dev_err(&cfhsi->ndev->dev, "%s: RX error %d.\n",
				__func__, res);
			cfhsi->ndev->stats.rx_errors++;
			cfhsi->ndev->stats.rx_dropped++;
		}
	}
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	return;

restart:
	if (++cfhsi->rx_state.retries > CFHSI_MAX_RX_RETRIES) {
		dev_err(&cfhsi->ndev->dev, "%s: No memory available "
			"in %d iterations.\n",
			__func__, CFHSI_MAX_RX_RETRIES);
		BUG();
	}
	mod_timer(&cfhsi->rx_slowpath_timer, jiffies + 1);
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	return;

out_of_sync:
	dev_err(&cfhsi->ndev->dev, "%s: Out of sync.\n", __func__);
	print_hex_dump_bytes("--> ", DUMP_PREFIX_NONE,
			cfhsi->rx_buf, CFHSI_DESC_SZ);
	schedule_work(&cfhsi->out_of_sync_work);
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}

static void cfhsi_rx_slowpath(unsigned long arg)
{
	struct cfhsi *cfhsi = (struct cfhsi *)arg;

	dev_dbg(&cfhsi->ndev->dev, "%s.\n",
		__func__);

	cfhsi_rx_done(cfhsi);
631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646
}

static void cfhsi_rx_done_cb(struct cfhsi_drv *drv)
{
	struct cfhsi *cfhsi;

	cfhsi = container_of(drv, struct cfhsi, drv);
	dev_dbg(&cfhsi->ndev->dev, "%s.\n",
		__func__);

	if (test_bit(CFHSI_SHUTDOWN, &cfhsi->bits))
		return;

	if (test_and_clear_bit(CFHSI_FLUSH_FIFO, &cfhsi->bits))
		wake_up_interruptible(&cfhsi->flush_fifo_wait);
	else
647
		cfhsi_rx_done(cfhsi);
648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665
}

static void cfhsi_wake_up(struct work_struct *work)
{
	struct cfhsi *cfhsi = NULL;
	int res;
	int len;
	long ret;

	cfhsi = container_of(work, struct cfhsi, wake_up_work);

	if (test_bit(CFHSI_SHUTDOWN, &cfhsi->bits))
		return;

	if (unlikely(test_bit(CFHSI_AWAKE, &cfhsi->bits))) {
		/* It happenes when wakeup is requested by
		 * both ends at the same time. */
		clear_bit(CFHSI_WAKE_UP, &cfhsi->bits);
666
		clear_bit(CFHSI_WAKE_UP_ACK, &cfhsi->bits);
667 668 669 670 671 672 673 674 675 676
		return;
	}

	/* Activate wake line. */
	cfhsi->dev->cfhsi_wake_up(cfhsi->dev);

	dev_dbg(&cfhsi->ndev->dev, "%s: Start waiting.\n",
		__func__);

	/* Wait for acknowledge. */
677 678 679
	ret = CFHSI_WAKE_TOUT;
	ret = wait_event_interruptible_timeout(cfhsi->wake_up_wait,
					test_and_clear_bit(CFHSI_WAKE_UP_ACK,
680 681 682
							&cfhsi->bits), ret);
	if (unlikely(ret < 0)) {
		/* Interrupted by signal. */
683
		dev_err(&cfhsi->ndev->dev, "%s: Signalled: %ld.\n",
684
			__func__, ret);
685

686 687 688 689
		clear_bit(CFHSI_WAKE_UP, &cfhsi->bits);
		cfhsi->dev->cfhsi_wake_down(cfhsi->dev);
		return;
	} else if (!ret) {
690 691 692
		bool ca_wake = false;
		size_t fifo_occupancy = 0;

693 694 695
		/* Wakeup timeout */
		dev_err(&cfhsi->ndev->dev, "%s: Timeout.\n",
			__func__);
696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718

		/* Check FIFO to check if modem has sent something. */
		WARN_ON(cfhsi->dev->cfhsi_fifo_occupancy(cfhsi->dev,
					&fifo_occupancy));

		dev_err(&cfhsi->ndev->dev, "%s: Bytes in FIFO: %u.\n",
				__func__, (unsigned) fifo_occupancy);

		/* Check if we misssed the interrupt. */
		WARN_ON(cfhsi->dev->cfhsi_get_peer_wake(cfhsi->dev,
							&ca_wake));

		if (ca_wake) {
			dev_err(&cfhsi->ndev->dev, "%s: CA Wake missed !.\n",
				__func__);

			/* Clear the CFHSI_WAKE_UP_ACK bit to prevent race. */
			clear_bit(CFHSI_WAKE_UP_ACK, &cfhsi->bits);

			/* Continue execution. */
			goto wake_ack;
		}

719 720 721 722
		clear_bit(CFHSI_WAKE_UP, &cfhsi->bits);
		cfhsi->dev->cfhsi_wake_down(cfhsi->dev);
		return;
	}
723
wake_ack:
724 725 726 727 728 729 730 731
	dev_dbg(&cfhsi->ndev->dev, "%s: Woken.\n",
		__func__);

	/* Clear power up bit. */
	set_bit(CFHSI_AWAKE, &cfhsi->bits);
	clear_bit(CFHSI_WAKE_UP, &cfhsi->bits);

	/* Resume read operation. */
732 733 734 735 736
	dev_dbg(&cfhsi->ndev->dev, "%s: Start RX.\n", __func__);
	res = cfhsi->dev->cfhsi_rx(cfhsi->rx_ptr, cfhsi->rx_len, cfhsi->dev);

	if (WARN_ON(res < 0))
		dev_err(&cfhsi->ndev->dev, "%s: RX err %d.\n", __func__, res);
737 738 739 740 741 742 743 744 745 746 747 748

	/* Clear power up acknowledment. */
	clear_bit(CFHSI_WAKE_UP_ACK, &cfhsi->bits);

	spin_lock_bh(&cfhsi->lock);

	/* Resume transmit if queue is not empty. */
	if (!skb_peek(&cfhsi->qhead)) {
		dev_dbg(&cfhsi->ndev->dev, "%s: Peer wake, start timer.\n",
			__func__);
		/* Start inactivity timer. */
		mod_timer(&cfhsi->timer,
749
				jiffies + cfhsi->inactivity_timeout);
750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780
		spin_unlock_bh(&cfhsi->lock);
		return;
	}

	dev_dbg(&cfhsi->ndev->dev, "%s: Host wake.\n",
		__func__);

	spin_unlock_bh(&cfhsi->lock);

	/* Create HSI frame. */
	len = cfhsi_tx_frm((struct cfhsi_desc *)cfhsi->tx_buf, cfhsi);

	if (likely(len > 0)) {
		/* Set up new transfer. */
		res = cfhsi->dev->cfhsi_tx(cfhsi->tx_buf, len, cfhsi->dev);
		if (WARN_ON(res < 0)) {
			dev_err(&cfhsi->ndev->dev, "%s: TX error %d.\n",
				__func__, res);
			cfhsi_abort_tx(cfhsi);
		}
	} else {
		dev_err(&cfhsi->ndev->dev,
				"%s: Failed to create HSI frame: %d.\n",
				__func__, len);
	}
}

static void cfhsi_wake_down(struct work_struct *work)
{
	long ret;
	struct cfhsi *cfhsi = NULL;
781 782
	size_t fifo_occupancy = 0;
	int retry = CFHSI_WAKE_TOUT;
783 784

	cfhsi = container_of(work, struct cfhsi, wake_down_work);
785
	dev_dbg(&cfhsi->ndev->dev, "%s.\n", __func__);
786 787 788 789 790 791 792 793

	if (test_bit(CFHSI_SHUTDOWN, &cfhsi->bits))
		return;

	/* Deactivate wake line. */
	cfhsi->dev->cfhsi_wake_down(cfhsi->dev);

	/* Wait for acknowledge. */
794
	ret = CFHSI_WAKE_TOUT;
795
	ret = wait_event_interruptible_timeout(cfhsi->wake_down_wait,
796 797
					test_and_clear_bit(CFHSI_WAKE_DOWN_ACK,
							&cfhsi->bits), ret);
798 799
	if (ret < 0) {
		/* Interrupted by signal. */
800
		dev_err(&cfhsi->ndev->dev, "%s: Signalled: %ld.\n",
801 802 803
			__func__, ret);
		return;
	} else if (!ret) {
804 805
		bool ca_wake = true;

806
		/* Timeout */
807
		dev_err(&cfhsi->ndev->dev, "%s: Timeout.\n", __func__);
808 809 810 811 812 813 814

		/* Check if we misssed the interrupt. */
		WARN_ON(cfhsi->dev->cfhsi_get_peer_wake(cfhsi->dev,
							&ca_wake));
		if (!ca_wake)
			dev_err(&cfhsi->ndev->dev, "%s: CA Wake missed !.\n",
				__func__);
815 816
	}

817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833
	/* Check FIFO occupancy. */
	while (retry) {
		WARN_ON(cfhsi->dev->cfhsi_fifo_occupancy(cfhsi->dev,
							&fifo_occupancy));

		if (!fifo_occupancy)
			break;

		set_current_state(TASK_INTERRUPTIBLE);
		schedule_timeout(1);
		retry--;
	}

	if (!retry)
		dev_err(&cfhsi->ndev->dev, "%s: FIFO Timeout.\n", __func__);

	/* Clear AWAKE condition. */
834 835
	clear_bit(CFHSI_AWAKE, &cfhsi->bits);

836 837
	/* Cancel pending RX requests. */
	cfhsi->dev->cfhsi_rx_cancel(cfhsi->dev);
838 839 840

}

841 842 843 844 845 846 847 848 849 850 851
static void cfhsi_out_of_sync(struct work_struct *work)
{
	struct cfhsi *cfhsi = NULL;

	cfhsi = container_of(work, struct cfhsi, out_of_sync_work);

	rtnl_lock();
	dev_close(cfhsi->ndev);
	rtnl_unlock();
}

852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 903 904 905 906 907 908 909 910 911 912 913 914 915 916 917 918
static void cfhsi_wake_up_cb(struct cfhsi_drv *drv)
{
	struct cfhsi *cfhsi = NULL;

	cfhsi = container_of(drv, struct cfhsi, drv);
	dev_dbg(&cfhsi->ndev->dev, "%s.\n",
		__func__);

	set_bit(CFHSI_WAKE_UP_ACK, &cfhsi->bits);
	wake_up_interruptible(&cfhsi->wake_up_wait);

	if (test_bit(CFHSI_SHUTDOWN, &cfhsi->bits))
		return;

	/* Schedule wake up work queue if the peer initiates. */
	if (!test_and_set_bit(CFHSI_WAKE_UP, &cfhsi->bits))
		queue_work(cfhsi->wq, &cfhsi->wake_up_work);
}

static void cfhsi_wake_down_cb(struct cfhsi_drv *drv)
{
	struct cfhsi *cfhsi = NULL;

	cfhsi = container_of(drv, struct cfhsi, drv);
	dev_dbg(&cfhsi->ndev->dev, "%s.\n",
		__func__);

	/* Initiating low power is only permitted by the host (us). */
	set_bit(CFHSI_WAKE_DOWN_ACK, &cfhsi->bits);
	wake_up_interruptible(&cfhsi->wake_down_wait);
}

static int cfhsi_xmit(struct sk_buff *skb, struct net_device *dev)
{
	struct cfhsi *cfhsi = NULL;
	int start_xfer = 0;
	int timer_active;

	if (!dev)
		return -EINVAL;

	cfhsi = netdev_priv(dev);

	spin_lock_bh(&cfhsi->lock);

	skb_queue_tail(&cfhsi->qhead, skb);

	/* Sanity check; xmit should not be called after unregister_netdev */
	if (WARN_ON(test_bit(CFHSI_SHUTDOWN, &cfhsi->bits))) {
		spin_unlock_bh(&cfhsi->lock);
		cfhsi_abort_tx(cfhsi);
		return -EINVAL;
	}

	/* Send flow off if number of packets is above high water mark. */
	if (!cfhsi->flow_off_sent &&
		cfhsi->qhead.qlen > cfhsi->q_high_mark &&
		cfhsi->cfdev.flowctrl) {
		cfhsi->flow_off_sent = 1;
		cfhsi->cfdev.flowctrl(cfhsi->ndev, OFF);
	}

	if (cfhsi->tx_state == CFHSI_TX_STATE_IDLE) {
		cfhsi->tx_state = CFHSI_TX_STATE_XFER;
		start_xfer = 1;
	}

919 920
	if (!start_xfer) {
		spin_unlock_bh(&cfhsi->lock);
921
		return 0;
922
	}
923 924 925 926

	/* Delete inactivity timer if started. */
	timer_active = del_timer_sync(&cfhsi->timer);

927 928
	spin_unlock_bh(&cfhsi->lock);

929 930 931 932 933 934 935
	if (timer_active) {
		struct cfhsi_desc *desc = (struct cfhsi_desc *)cfhsi->tx_buf;
		int len;
		int res;

		/* Create HSI frame. */
		len = cfhsi_tx_frm(desc, cfhsi);
936
		WARN_ON(!len);
937 938 939 940 941 942 943 944 945 946 947 948 949 950 951 952 953 954 955 956 957 958 959 960 961 962 963 964 965 966 967 968 969 970 971 972 973 974 975 976 977 978 979 980 981 982 983 984 985 986 987 988 989 990 991 992 993 994 995 996 997 998 999

		/* Set up new transfer. */
		res = cfhsi->dev->cfhsi_tx(cfhsi->tx_buf, len, cfhsi->dev);
		if (WARN_ON(res < 0)) {
			dev_err(&cfhsi->ndev->dev, "%s: TX error %d.\n",
				__func__, res);
			cfhsi_abort_tx(cfhsi);
		}
	} else {
		/* Schedule wake up work queue if the we initiate. */
		if (!test_and_set_bit(CFHSI_WAKE_UP, &cfhsi->bits))
			queue_work(cfhsi->wq, &cfhsi->wake_up_work);
	}

	return 0;
}

static int cfhsi_open(struct net_device *dev)
{
	netif_wake_queue(dev);

	return 0;
}

static int cfhsi_close(struct net_device *dev)
{
	netif_stop_queue(dev);

	return 0;
}

static const struct net_device_ops cfhsi_ops = {
	.ndo_open = cfhsi_open,
	.ndo_stop = cfhsi_close,
	.ndo_start_xmit = cfhsi_xmit
};

static void cfhsi_setup(struct net_device *dev)
{
	struct cfhsi *cfhsi = netdev_priv(dev);
	dev->features = 0;
	dev->netdev_ops = &cfhsi_ops;
	dev->type = ARPHRD_CAIF;
	dev->flags = IFF_POINTOPOINT | IFF_NOARP;
	dev->mtu = CFHSI_MAX_PAYLOAD_SZ;
	dev->tx_queue_len = 0;
	dev->destructor = free_netdev;
	skb_queue_head_init(&cfhsi->qhead);
	cfhsi->cfdev.link_select = CAIF_LINK_HIGH_BANDW;
	cfhsi->cfdev.use_frag = false;
	cfhsi->cfdev.use_stx = false;
	cfhsi->cfdev.use_fcs = false;
	cfhsi->ndev = dev;
}

int cfhsi_probe(struct platform_device *pdev)
{
	struct cfhsi *cfhsi = NULL;
	struct net_device *ndev;
	struct cfhsi_dev *dev;
	int res;

	ndev = alloc_netdev(sizeof(struct cfhsi), "cfhsi%d", cfhsi_setup);
1000
	if (!ndev)
1001 1002 1003 1004 1005 1006 1007 1008
		return -ENODEV;

	cfhsi = netdev_priv(ndev);
	cfhsi->ndev = ndev;
	cfhsi->pdev = pdev;

	/* Initialize state vaiables. */
	cfhsi->tx_state = CFHSI_TX_STATE_IDLE;
1009
	cfhsi->rx_state.state = CFHSI_RX_STATE_DESC;
1010 1011 1012 1013 1014 1015 1016 1017 1018 1019 1020 1021 1022 1023 1024 1025 1026 1027 1028 1029 1030 1031 1032 1033 1034 1035 1036 1037 1038 1039 1040 1041 1042

	/* Set flow info */
	cfhsi->flow_off_sent = 0;
	cfhsi->q_low_mark = LOW_WATER_MARK;
	cfhsi->q_high_mark = HIGH_WATER_MARK;

	/* Assign the HSI device. */
	dev = (struct cfhsi_dev *)pdev->dev.platform_data;
	cfhsi->dev = dev;

	/* Assign the driver to this HSI device. */
	dev->drv = &cfhsi->drv;

	/*
	 * Allocate a TX buffer with the size of a HSI packet descriptors
	 * and the necessary room for CAIF payload frames.
	 */
	cfhsi->tx_buf = kzalloc(CFHSI_BUF_SZ_TX, GFP_KERNEL);
	if (!cfhsi->tx_buf) {
		res = -ENODEV;
		goto err_alloc_tx;
	}

	/*
	 * Allocate a RX buffer with the size of two HSI packet descriptors and
	 * the necessary room for CAIF payload frames.
	 */
	cfhsi->rx_buf = kzalloc(CFHSI_BUF_SZ_RX, GFP_KERNEL);
	if (!cfhsi->rx_buf) {
		res = -ENODEV;
		goto err_alloc_rx;
	}

1043 1044 1045 1046 1047 1048 1049 1050 1051 1052 1053 1054 1055
	/* Pre-calculate inactivity timeout. */
	if (inactivity_timeout != -1) {
		cfhsi->inactivity_timeout =
				inactivity_timeout * HZ / 1000;
		if (!cfhsi->inactivity_timeout)
			cfhsi->inactivity_timeout = 1;
		else if (cfhsi->inactivity_timeout > NEXT_TIMER_MAX_DELTA)
			cfhsi->inactivity_timeout = NEXT_TIMER_MAX_DELTA;
	} else {
		cfhsi->inactivity_timeout = NEXT_TIMER_MAX_DELTA;
	}

	/* Initialize recieve vaiables. */
1056 1057 1058 1059 1060 1061 1062 1063 1064
	cfhsi->rx_ptr = cfhsi->rx_buf;
	cfhsi->rx_len = CFHSI_DESC_SZ;

	/* Initialize spin locks. */
	spin_lock_init(&cfhsi->lock);

	/* Set up the driver. */
	cfhsi->drv.tx_done_cb = cfhsi_tx_done_cb;
	cfhsi->drv.rx_done_cb = cfhsi_rx_done_cb;
1065 1066
	cfhsi->drv.wake_up_cb = cfhsi_wake_up_cb;
	cfhsi->drv.wake_down_cb = cfhsi_wake_down_cb;
1067 1068 1069 1070

	/* Initialize the work queues. */
	INIT_WORK(&cfhsi->wake_up_work, cfhsi_wake_up);
	INIT_WORK(&cfhsi->wake_down_work, cfhsi_wake_down);
1071
	INIT_WORK(&cfhsi->out_of_sync_work, cfhsi_out_of_sync);
1072 1073 1074 1075 1076 1077 1078 1079 1080 1081 1082 1083 1084 1085 1086 1087 1088 1089 1090 1091 1092 1093 1094 1095 1096

	/* Clear all bit fields. */
	clear_bit(CFHSI_WAKE_UP_ACK, &cfhsi->bits);
	clear_bit(CFHSI_WAKE_DOWN_ACK, &cfhsi->bits);
	clear_bit(CFHSI_WAKE_UP, &cfhsi->bits);
	clear_bit(CFHSI_AWAKE, &cfhsi->bits);

	/* Create work thread. */
	cfhsi->wq = create_singlethread_workqueue(pdev->name);
	if (!cfhsi->wq) {
		dev_err(&ndev->dev, "%s: Failed to create work queue.\n",
			__func__);
		res = -ENODEV;
		goto err_create_wq;
	}

	/* Initialize wait queues. */
	init_waitqueue_head(&cfhsi->wake_up_wait);
	init_waitqueue_head(&cfhsi->wake_down_wait);
	init_waitqueue_head(&cfhsi->flush_fifo_wait);

	/* Setup the inactivity timer. */
	init_timer(&cfhsi->timer);
	cfhsi->timer.data = (unsigned long)cfhsi;
	cfhsi->timer.function = cfhsi_inactivity_tout;
1097 1098 1099 1100
	/* Setup the slowpath RX timer. */
	init_timer(&cfhsi->rx_slowpath_timer);
	cfhsi->rx_slowpath_timer.data = (unsigned long)cfhsi;
	cfhsi->rx_slowpath_timer.function = cfhsi_rx_slowpath;
1101 1102 1103 1104 1105 1106 1107 1108 1109 1110 1111 1112 1113 1114 1115 1116 1117 1118 1119 1120 1121 1122 1123 1124 1125 1126 1127 1128 1129 1130 1131 1132 1133 1134 1135 1136 1137 1138 1139 1140 1141 1142 1143 1144 1145 1146 1147 1148 1149

	/* Add CAIF HSI device to list. */
	spin_lock(&cfhsi_list_lock);
	list_add_tail(&cfhsi->list, &cfhsi_list);
	spin_unlock(&cfhsi_list_lock);

	/* Activate HSI interface. */
	res = cfhsi->dev->cfhsi_up(cfhsi->dev);
	if (res) {
		dev_err(&cfhsi->ndev->dev,
			"%s: can't activate HSI interface: %d.\n",
			__func__, res);
		goto err_activate;
	}

	/* Flush FIFO */
	res = cfhsi_flush_fifo(cfhsi);
	if (res) {
		dev_err(&ndev->dev, "%s: Can't flush FIFO: %d.\n",
			__func__, res);
		goto err_net_reg;
	}

	/* Register network device. */
	res = register_netdev(ndev);
	if (res) {
		dev_err(&ndev->dev, "%s: Registration error: %d.\n",
			__func__, res);
		goto err_net_reg;
	}

	netif_stop_queue(ndev);

	return res;

 err_net_reg:
	cfhsi->dev->cfhsi_down(cfhsi->dev);
 err_activate:
	destroy_workqueue(cfhsi->wq);
 err_create_wq:
	kfree(cfhsi->rx_buf);
 err_alloc_rx:
	kfree(cfhsi->tx_buf);
 err_alloc_tx:
	free_netdev(ndev);

	return res;
}

1150
static void cfhsi_shutdown(struct cfhsi *cfhsi)
1151 1152 1153 1154 1155 1156 1157 1158 1159 1160 1161 1162
{
	u8 *tx_buf, *rx_buf;

	/* Stop TXing */
	netif_tx_stop_all_queues(cfhsi->ndev);

	/* going to shutdown driver */
	set_bit(CFHSI_SHUTDOWN, &cfhsi->bits);

	/* Flush workqueue */
	flush_workqueue(cfhsi->wq);

1163
	/* Delete timers if pending */
1164
	del_timer_sync(&cfhsi->timer);
1165
	del_timer_sync(&cfhsi->rx_slowpath_timer);
1166 1167 1168 1169

	/* Cancel pending RX request (if any) */
	cfhsi->dev->cfhsi_rx_cancel(cfhsi->dev);

1170
	/* Destroy workqueue */
1171 1172 1173 1174 1175 1176 1177 1178 1179 1180 1181 1182 1183 1184 1185 1186 1187 1188 1189 1190 1191 1192 1193 1194 1195 1196 1197 1198 1199 1200 1201 1202 1203 1204 1205 1206 1207 1208
	destroy_workqueue(cfhsi->wq);

	/* Store bufferes: will be freed later. */
	tx_buf = cfhsi->tx_buf;
	rx_buf = cfhsi->rx_buf;

	/* Flush transmit queues. */
	cfhsi_abort_tx(cfhsi);

	/* Deactivate interface */
	cfhsi->dev->cfhsi_down(cfhsi->dev);

	/* Finally unregister the network device. */
	unregister_netdev(cfhsi->ndev);

	/* Free buffers. */
	kfree(tx_buf);
	kfree(rx_buf);
}

int cfhsi_remove(struct platform_device *pdev)
{
	struct list_head *list_node;
	struct list_head *n;
	struct cfhsi *cfhsi = NULL;
	struct cfhsi_dev *dev;

	dev = (struct cfhsi_dev *)pdev->dev.platform_data;
	spin_lock(&cfhsi_list_lock);
	list_for_each_safe(list_node, n, &cfhsi_list) {
		cfhsi = list_entry(list_node, struct cfhsi, list);
		/* Find the corresponding device. */
		if (cfhsi->dev == dev) {
			/* Remove from list. */
			list_del(list_node);
			spin_unlock(&cfhsi_list_lock);

			/* Shutdown driver. */
1209
			cfhsi_shutdown(cfhsi);
1210 1211 1212 1213 1214 1215 1216 1217 1218 1219 1220 1221 1222 1223 1224 1225 1226 1227 1228 1229 1230 1231 1232 1233 1234 1235 1236 1237 1238 1239 1240 1241

			return 0;
		}
	}
	spin_unlock(&cfhsi_list_lock);
	return -ENODEV;
}

struct platform_driver cfhsi_plat_drv = {
	.probe = cfhsi_probe,
	.remove = cfhsi_remove,
	.driver = {
		   .name = "cfhsi",
		   .owner = THIS_MODULE,
		   },
};

static void __exit cfhsi_exit_module(void)
{
	struct list_head *list_node;
	struct list_head *n;
	struct cfhsi *cfhsi = NULL;

	spin_lock(&cfhsi_list_lock);
	list_for_each_safe(list_node, n, &cfhsi_list) {
		cfhsi = list_entry(list_node, struct cfhsi, list);

		/* Remove from list. */
		list_del(list_node);
		spin_unlock(&cfhsi_list_lock);

		/* Shutdown driver. */
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		cfhsi_shutdown(cfhsi);
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		spin_lock(&cfhsi_list_lock);
	}
	spin_unlock(&cfhsi_list_lock);

	/* Unregister platform driver. */
	platform_driver_unregister(&cfhsi_plat_drv);
}

static int __init cfhsi_init_module(void)
{
	int result;

	/* Initialize spin lock. */
	spin_lock_init(&cfhsi_list_lock);

	/* Register platform driver. */
	result = platform_driver_register(&cfhsi_plat_drv);
	if (result) {
		printk(KERN_ERR "Could not register platform HSI driver: %d.\n",
			result);
		goto err_dev_register;
	}

	return result;

 err_dev_register:
	return result;
}

module_init(cfhsi_init_module);
module_exit(cfhsi_exit_module);