1 files changed, 712 insertions, 0 deletions

diff --git a/drivers/isdn/pcbit/layer2.c b/drivers/isdn/pcbit/layer2.c
new file mode 100644
index 000000000..46e1240ae
--- /dev/null
+++ b/drivers/isdn/pcbit/layer2.c
@@ -0,0 +1,712 @@
+/*
+ * PCBIT-D low-layer interface
+ *
+ * Copyright (C) 1996 Universidade de Lisboa
+ *
+ * Written by Pedro Roque Marques (roque@di.fc.ul.pt)
+ *
+ * This software may be used and distributed according to the terms of
+ * the GNU General Public License, incorporated herein by reference.
+ */
+
+/*
+ * 19991203 - Fernando Carvalho - takion@superbofh.org
+ * Hacked to compile with egcs and run with current version of isdn modules
+ */
+
+/*
+ *        Based on documentation provided by Inesc:
+ *        - "Interface com bus do PC para o PCBIT e PCBIT-D", Inesc, Jan 93
+ */
+
+/*
+ *        TODO: better handling of errors
+ *              re-write/remove debug printks
+ */
+
+#include <linux/string.h>
+#include <linux/kernel.h>
+#include <linux/types.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+#include <linux/interrupt.h>
+#include <linux/workqueue.h>
+#include <linux/mm.h>
+#include <linux/skbuff.h>
+
+#include <linux/isdnif.h>
+
+#include <asm/io.h>
+
+
+#include "pcbit.h"
+#include "layer2.h"
+#include "edss1.h"
+
+#undef DEBUG_FRAG
+
+
+/*
+ *  Prototypes
+ */
+
+static void pcbit_transmit(struct pcbit_dev *dev);
+
+static void pcbit_recv_ack(struct pcbit_dev *dev, unsigned char ack);
+
+static void pcbit_l2_error(struct pcbit_dev *dev);
+static void pcbit_l2_active_conf(struct pcbit_dev *dev, u_char info);
+static void pcbit_l2_err_recover(unsigned long data);
+
+static void pcbit_firmware_bug(struct pcbit_dev *dev);
+
+static __inline__ void
+pcbit_sched_delivery(struct pcbit_dev *dev)
+{
+	schedule_work(&dev->qdelivery);
+}
+
+
+/*
+ *  Called from layer3
+ */
+
+int
+pcbit_l2_write(struct pcbit_dev *dev, ulong msg, ushort refnum,
+	       struct sk_buff *skb, unsigned short hdr_len)
+{
+	struct frame_buf *frame,
+		*ptr;
+	unsigned long flags;
+
+	if (dev->l2_state != L2_RUNNING && dev->l2_state != L2_LOADING) {
+		dev_kfree_skb(skb);
+		return -1;
+	}
+	if ((frame = kmalloc(sizeof(struct frame_buf),
+			     GFP_ATOMIC)) == NULL) {
+		dev_kfree_skb(skb);
+		return -1;
+	}
+	frame->msg = msg;
+	frame->refnum = refnum;
+	frame->copied = 0;
+	frame->hdr_len = hdr_len;
+
+	if (skb)
+		frame->dt_len = skb->len - hdr_len;
+	else
+		frame->dt_len = 0;
+
+	frame->skb = skb;
+
+	frame->next = NULL;
+
+	spin_lock_irqsave(&dev->lock, flags);
+
+	if (dev->write_queue == NULL) {
+		dev->write_queue = frame;
+		spin_unlock_irqrestore(&dev->lock, flags);
+		pcbit_transmit(dev);
+	} else {
+		for (ptr = dev->write_queue; ptr->next; ptr = ptr->next);
+		ptr->next = frame;
+
+		spin_unlock_irqrestore(&dev->lock, flags);
+	}
+	return 0;
+}
+
+static __inline__ void
+pcbit_tx_update(struct pcbit_dev *dev, ushort len)
+{
+	u_char info;
+
+	dev->send_seq = (dev->send_seq + 1) % 8;
+
+	dev->fsize[dev->send_seq] = len;
+	info = 0;
+	info |= dev->rcv_seq << 3;
+	info |= dev->send_seq;
+
+	writeb(info, dev->sh_mem + BANK4);
+
+}
+
+/*
+ * called by interrupt service routine or by write_2
+ */
+
+static void
+pcbit_transmit(struct pcbit_dev *dev)
+{
+	struct frame_buf *frame = NULL;
+	unsigned char unacked;
+	int flen;               /* fragment frame length including all headers */
+	int free;
+	int count,
+		cp_len;
+	unsigned long flags;
+	unsigned short tt;
+
+	if (dev->l2_state != L2_RUNNING && dev->l2_state != L2_LOADING)
+		return;
+
+	unacked = (dev->send_seq + (8 - dev->unack_seq)) & 0x07;
+
+	spin_lock_irqsave(&dev->lock, flags);
+
+	if (dev->free > 16 && dev->write_queue && unacked < 7) {
+
+		if (!dev->w_busy)
+			dev->w_busy = 1;
+		else {
+			spin_unlock_irqrestore(&dev->lock, flags);
+			return;
+		}
+
+
+		frame = dev->write_queue;
+		free = dev->free;
+
+		spin_unlock_irqrestore(&dev->lock, flags);
+
+		if (frame->copied == 0) {
+
+			/* Type 0 frame */
+
+			ulong	msg;
+
+			if (frame->skb)
+				flen = FRAME_HDR_LEN + PREHDR_LEN + frame->skb->len;
+			else
+				flen = FRAME_HDR_LEN + PREHDR_LEN;
+
+			if (flen > free)
+				flen = free;
+
+			msg = frame->msg;
+
+			/*
+			 *  Board level 2 header
+			 */
+
+			pcbit_writew(dev, flen - FRAME_HDR_LEN);
+
+			pcbit_writeb(dev, GET_MSG_CPU(msg));
+
+			pcbit_writeb(dev, GET_MSG_PROC(msg));
+
+			/* TH */
+			pcbit_writew(dev, frame->hdr_len + PREHDR_LEN);
+
+			/* TD */
+			pcbit_writew(dev, frame->dt_len);
+
+
+			/*
+			 *  Board level 3 fixed-header
+			 */
+
+			/* LEN = TH */
+			pcbit_writew(dev, frame->hdr_len + PREHDR_LEN);
+
+			/* XX */
+			pcbit_writew(dev, 0);
+
+			/* C + S */
+			pcbit_writeb(dev, GET_MSG_CMD(msg));
+			pcbit_writeb(dev, GET_MSG_SCMD(msg));
+
+			/* NUM */
+			pcbit_writew(dev, frame->refnum);
+
+			count = FRAME_HDR_LEN + PREHDR_LEN;
+		} else {
+			/* Type 1 frame */
+
+			flen = 2 + (frame->skb->len - frame->copied);
+
+			if (flen > free)
+				flen = free;
+
+			/* TT */
+			tt = ((ushort) (flen - 2)) | 0x8000U;	/* Type 1 */
+			pcbit_writew(dev, tt);
+
+			count = 2;
+		}
+
+		if (frame->skb) {
+			cp_len = frame->skb->len - frame->copied;
+			if (cp_len > flen - count)
+				cp_len = flen - count;
+
+			memcpy_topcbit(dev, frame->skb->data + frame->copied,
+				       cp_len);
+			frame->copied += cp_len;
+		}
+		/* bookkeeping */
+		dev->free -= flen;
+		pcbit_tx_update(dev, flen);
+
+		spin_lock_irqsave(&dev->lock, flags);
+
+		if (frame->skb == NULL || frame->copied == frame->skb->len) {
+
+			dev->write_queue = frame->next;
+
+			if (frame->skb != NULL) {
+				/* free frame */
+				dev_kfree_skb(frame->skb);
+			}
+			kfree(frame);
+		}
+		dev->w_busy = 0;
+		spin_unlock_irqrestore(&dev->lock, flags);
+	} else {
+		spin_unlock_irqrestore(&dev->lock, flags);
+#ifdef DEBUG
+		printk(KERN_DEBUG "unacked %d free %d write_queue %s\n",
+		       unacked, dev->free, dev->write_queue ? "not empty" :
+		       "empty");
+#endif
+	}
+}
+
+
+/*
+ *  deliver a queued frame to the upper layer
+ */
+
+void
+pcbit_deliver(struct work_struct *work)
+{
+	struct frame_buf *frame;
+	unsigned long flags, msg;
+	struct pcbit_dev *dev =
+		container_of(work, struct pcbit_dev, qdelivery);
+
+	spin_lock_irqsave(&dev->lock, flags);
+
+	while ((frame = dev->read_queue)) {
+		dev->read_queue = frame->next;
+		spin_unlock_irqrestore(&dev->lock, flags);
+
+		msg = 0;
+		SET_MSG_CPU(msg, 0);
+		SET_MSG_PROC(msg, 0);
+		SET_MSG_CMD(msg, frame->skb->data[2]);
+		SET_MSG_SCMD(msg, frame->skb->data[3]);
+
+		frame->refnum = *((ushort *)frame->skb->data + 4);
+		frame->msg = *((ulong *)&msg);
+
+		skb_pull(frame->skb, 6);
+
+		pcbit_l3_receive(dev, frame->msg, frame->skb, frame->hdr_len,
+				 frame->refnum);
+
+		kfree(frame);
+
+		spin_lock_irqsave(&dev->lock, flags);
+	}
+
+	spin_unlock_irqrestore(&dev->lock, flags);
+}
+
+/*
+ * Reads BANK 2 & Reassembles
+ */
+
+static void
+pcbit_receive(struct pcbit_dev *dev)
+{
+	unsigned short tt;
+	u_char cpu,
+		proc;
+	struct frame_buf *frame = NULL;
+	unsigned long flags;
+	u_char type1;
+
+	if (dev->l2_state != L2_RUNNING && dev->l2_state != L2_LOADING)
+		return;
+
+	tt = pcbit_readw(dev);
+
+	if ((tt & 0x7fffU) > 511) {
+		printk(KERN_INFO "pcbit: invalid frame length -> TT=%04x\n",
+		       tt);
+		pcbit_l2_error(dev);
+		return;
+	}
+	if (!(tt & 0x8000U)) {  /* Type 0 */
+		type1 = 0;
+
+		if (dev->read_frame) {
+			printk(KERN_DEBUG "pcbit_receive: Type 0 frame and read_frame != NULL\n");
+			/* discard previous queued frame */
+			kfree_skb(dev->read_frame->skb);
+			kfree(dev->read_frame);
+			dev->read_frame = NULL;
+		}
+		frame = kzalloc(sizeof(struct frame_buf), GFP_ATOMIC);
+
+		if (frame == NULL) {
+			printk(KERN_WARNING "kmalloc failed\n");
+			return;
+		}
+
+		cpu = pcbit_readb(dev);
+		proc = pcbit_readb(dev);
+
+
+		if (cpu != 0x06 && cpu != 0x02) {
+			printk(KERN_DEBUG "pcbit: invalid cpu value\n");
+			kfree(frame);
+			pcbit_l2_error(dev);
+			return;
+		}
+		/*
+		 * we discard cpu & proc on receiving
+		 * but we read it to update the pointer
+		 */
+
+		frame->hdr_len = pcbit_readw(dev);
+		frame->dt_len = pcbit_readw(dev);
+
+		/*
+		 * 0 sized packet
+		 * I don't know if they are an error or not...
+		 * But they are very frequent
+		 * Not documented
+		 */
+
+		if (frame->hdr_len == 0) {
+			kfree(frame);
+#ifdef DEBUG
+			printk(KERN_DEBUG "0 sized frame\n");
+#endif
+			pcbit_firmware_bug(dev);
+			return;
+		}
+		/* sanity check the length values */
+		if (frame->hdr_len > 1024 || frame->dt_len > 2048) {
+#ifdef DEBUG
+			printk(KERN_DEBUG "length problem: ");
+			printk(KERN_DEBUG "TH=%04x TD=%04x\n",
+			       frame->hdr_len,
+			       frame->dt_len);
+#endif
+			pcbit_l2_error(dev);
+			kfree(frame);
+			return;
+		}
+		/* minimum frame read */
+
+		frame->skb = dev_alloc_skb(frame->hdr_len + frame->dt_len +
+					   ((frame->hdr_len + 15) & ~15));
+
+		if (!frame->skb) {
+			printk(KERN_DEBUG "pcbit_receive: out of memory\n");
+			kfree(frame);
+			return;
+		}
+		/* 16 byte alignment for IP */
+		if (frame->dt_len)
+			skb_reserve(frame->skb, (frame->hdr_len + 15) & ~15);
+
+	} else {
+		/* Type 1 */
+		type1 = 1;
+		tt &= 0x7fffU;
+
+		if (!(frame = dev->read_frame)) {
+			printk("Type 1 frame and no frame queued\n");
+			/* usually after an error: toss frame */
+			dev->readptr += tt;
+			if (dev->readptr > dev->sh_mem + BANK2 + BANKLEN)
+				dev->readptr -= BANKLEN;
+			return;
+
+		}
+	}
+
+	memcpy_frompcbit(dev, skb_put(frame->skb, tt), tt);
+
+	frame->copied += tt;
+	spin_lock_irqsave(&dev->lock, flags);
+	if (frame->copied == frame->hdr_len + frame->dt_len) {
+
+		if (type1) {
+			dev->read_frame = NULL;
+		}
+		if (dev->read_queue) {
+			struct frame_buf *ptr;
+			for (ptr = dev->read_queue; ptr->next; ptr = ptr->next);
+			ptr->next = frame;
+		} else
+			dev->read_queue = frame;
+
+	} else {
+		dev->read_frame = frame;
+	}
+	spin_unlock_irqrestore(&dev->lock, flags);
+}
+
+/*
+ *  The board sends 0 sized frames
+ *  They are TDATA_CONFs that get messed up somehow
+ *  gotta send a fake acknowledgment to the upper layer somehow
+ */
+
+static __inline__ void
+pcbit_fake_conf(struct pcbit_dev *dev, struct pcbit_chan *chan)
+{
+	isdn_ctrl ictl;
+
+	if (chan->queued) {
+		chan->queued--;
+
+		ictl.driver = dev->id;
+		ictl.command = ISDN_STAT_BSENT;
+		ictl.arg = chan->id;
+		dev->dev_if->statcallb(&ictl);
+	}
+}
+
+static void
+pcbit_firmware_bug(struct pcbit_dev *dev)
+{
+	struct pcbit_chan *chan;
+
+	chan = dev->b1;
+
+	if (chan->fsm_state == ST_ACTIVE) {
+		pcbit_fake_conf(dev, chan);
+	}
+	chan = dev->b2;
+
+	if (chan->fsm_state == ST_ACTIVE) {
+		pcbit_fake_conf(dev, chan);
+	}
+}
+
+irqreturn_t
+pcbit_irq_handler(int interrupt, void *devptr)
+{
+	struct pcbit_dev *dev;
+	u_char info,
+		ack_seq,
+		read_seq;
+
+	dev = (struct pcbit_dev *) devptr;
+
+	if (!dev) {
+		printk(KERN_WARNING "pcbit_irq_handler: wrong device\n");
+		return IRQ_NONE;
+	}
+	if (dev->interrupt) {
+		printk(KERN_DEBUG "pcbit: reentering interrupt handler\n");
+		return IRQ_HANDLED;
+	}
+	dev->interrupt = 1;
+
+	info = readb(dev->sh_mem + BANK3);
+
+	if (dev->l2_state == L2_STARTING || dev->l2_state == L2_ERROR) {
+		pcbit_l2_active_conf(dev, info);
+		dev->interrupt = 0;
+		return IRQ_HANDLED;
+	}
+	if (info & 0x40U) {     /* E bit set */
+#ifdef DEBUG
+		printk(KERN_DEBUG "pcbit_irq_handler: E bit on\n");
+#endif
+		pcbit_l2_error(dev);
+		dev->interrupt = 0;
+		return IRQ_HANDLED;
+	}
+	if (dev->l2_state != L2_RUNNING && dev->l2_state != L2_LOADING) {
+		dev->interrupt = 0;
+		return IRQ_HANDLED;
+	}
+	ack_seq = (info >> 3) & 0x07U;
+	read_seq = (info & 0x07U);
+
+	dev->interrupt = 0;
+
+	if (read_seq != dev->rcv_seq) {
+		while (read_seq != dev->rcv_seq) {
+			pcbit_receive(dev);
+			dev->rcv_seq = (dev->rcv_seq + 1) % 8;
+		}
+		pcbit_sched_delivery(dev);
+	}
+	if (ack_seq != dev->unack_seq) {
+		pcbit_recv_ack(dev, ack_seq);
+	}
+	info = dev->rcv_seq << 3;
+	info |= dev->send_seq;
+
+	writeb(info, dev->sh_mem + BANK4);
+	return IRQ_HANDLED;
+}
+
+
+static void
+pcbit_l2_active_conf(struct pcbit_dev *dev, u_char info)
+{
+	u_char state;
+
+	state = dev->l2_state;
+
+#ifdef DEBUG
+	printk(KERN_DEBUG "layer2_active_confirm\n");
+#endif
+
+
+	if (info & 0x80U) {
+		dev->rcv_seq = info & 0x07U;
+		dev->l2_state = L2_RUNNING;
+	} else
+		dev->l2_state = L2_DOWN;
+
+	if (state == L2_STARTING)
+		wake_up_interruptible(&dev->set_running_wq);
+
+	if (state == L2_ERROR && dev->l2_state == L2_RUNNING) {
+		pcbit_transmit(dev);
+	}
+}
+
+static void
+pcbit_l2_err_recover(unsigned long data)
+{
+
+	struct pcbit_dev *dev;
+	struct frame_buf *frame;
+
+	dev = (struct pcbit_dev *) data;
+
+	del_timer(&dev->error_recover_timer);
+	if (dev->w_busy || dev->r_busy) {
+		init_timer(&dev->error_recover_timer);
+		dev->error_recover_timer.expires = jiffies + ERRTIME;
+		add_timer(&dev->error_recover_timer);
+		return;
+	}
+	dev->w_busy = dev->r_busy = 1;
+
+	if (dev->read_frame) {
+		kfree_skb(dev->read_frame->skb);
+		kfree(dev->read_frame);
+		dev->read_frame = NULL;
+	}
+	if (dev->write_queue) {
+		frame = dev->write_queue;
+#ifdef FREE_ON_ERROR
+		dev->write_queue = dev->write_queue->next;
+
+		if (frame->skb) {
+			dev_kfree_skb(frame->skb);
+		}
+		kfree(frame);
+#else
+		frame->copied = 0;
+#endif
+	}
+	dev->rcv_seq = dev->send_seq = dev->unack_seq = 0;
+	dev->free = 511;
+	dev->l2_state = L2_ERROR;
+
+	/* this is an hack... */
+	pcbit_firmware_bug(dev);
+
+	dev->writeptr = dev->sh_mem;
+	dev->readptr = dev->sh_mem + BANK2;
+
+	writeb((0x80U | ((dev->rcv_seq & 0x07) << 3) | (dev->send_seq & 0x07)),
+	       dev->sh_mem + BANK4);
+	dev->w_busy = dev->r_busy = 0;
+
+}
+
+static void
+pcbit_l2_error(struct pcbit_dev *dev)
+{
+	if (dev->l2_state == L2_RUNNING) {
+
+		printk(KERN_INFO "pcbit: layer 2 error\n");
+
+#ifdef DEBUG
+		log_state(dev);
+#endif
+
+		dev->l2_state = L2_DOWN;
+
+		init_timer(&dev->error_recover_timer);
+		dev->error_recover_timer.function = &pcbit_l2_err_recover;
+		dev->error_recover_timer.data = (ulong) dev;
+		dev->error_recover_timer.expires = jiffies + ERRTIME;
+		add_timer(&dev->error_recover_timer);
+	}
+}
+
+/*
+ * Description:
+ * if board acks frames
+ *   update dev->free
+ *   call pcbit_transmit to write possible queued frames
+ */
+
+static void
+pcbit_recv_ack(struct pcbit_dev *dev, unsigned char ack)
+{
+	int i,
+		count;
+	int unacked;
+
+	unacked = (dev->send_seq + (8 - dev->unack_seq)) & 0x07;
+
+	/* dev->unack_seq < ack <= dev->send_seq; */
+
+	if (unacked) {
+
+		if (dev->send_seq > dev->unack_seq) {
+			if (ack <= dev->unack_seq || ack > dev->send_seq) {
+				printk(KERN_DEBUG
+				       "layer 2 ack unacceptable - dev %d",
+				       dev->id);
+
+				pcbit_l2_error(dev);
+			} else if (ack > dev->send_seq && ack <= dev->unack_seq) {
+				printk(KERN_DEBUG
+				       "layer 2 ack unacceptable - dev %d",
+				       dev->id);
+				pcbit_l2_error(dev);
+			}
+		}
+		/* ack is acceptable */
+
+
+		i = dev->unack_seq;
+
+		do {
+			dev->unack_seq = i = (i + 1) % 8;
+			dev->free += dev->fsize[i];
+		} while (i != ack);
+
+		count = 0;
+		while (count < 7 && dev->write_queue) {
+			u8 lsend_seq = dev->send_seq;
+
+			pcbit_transmit(dev);
+
+			if (dev->send_seq == lsend_seq)
+				break;
+			count++;
+		}
+	} else
+		printk(KERN_DEBUG "recv_ack: unacked = 0\n");
+}