Viewing file:  layer2.c (14.25 KB) -rw-r--r--
Select action/file-type:
 (+) |  (+) |  (+) | Code (+) | Session (+) |  (+) | SDB (+) |  (+) |  (+) |  (+) |  (+) |  (+) |
/*
* 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/sched.h>
#include <linux/string.h>
#include <linux/kernel.h>
#include <linux/types.h>
#include <linux/slab.h>
#include <linux/interrupt.h>
#include <linux/tqueue.h>
#include <linux/mm.h>
#include <linux/skbuff.h>
#include <linux/isdnif.h>
#include <asm/system.h>
#include <asm/io.h>
#include "pcbit.h"
#include "layer2.h"
#include "edss1.h"
#undef DEBUG_FRAG
/*
* task queue struct
*/
/*
* Layer 3 packet demultiplexer
* drv.c
*/
extern void pcbit_l3_receive(struct pcbit_dev *dev, ulong msg,
struct sk_buff *skb,
ushort hdr_len, ushort refnum);
/*
* Prototypes
*/
void pcbit_deliver(void *data);
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)
{
queue_task(&dev->qdelivery, &tq_immediate);
mark_bh(IMMEDIATE_BH);
}
/*
* 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 = (struct frame_buf *) kmalloc(sizeof(struct frame_buf),
GFP_ATOMIC)) == NULL) {
printk(KERN_WARNING "pcbit_2_write: kmalloc failed\n");
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;
save_flags(flags);
cli();
if (dev->write_queue == NULL) {
dev->write_queue = frame;
restore_flags(flags);
pcbit_transmit(dev);
} else {
for (ptr = dev->write_queue; ptr->next; ptr = ptr->next);
ptr->next = frame;
restore_flags(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;
save_flags(flags);
cli();
if (dev->free > 16 && dev->write_queue && unacked < 7) {
if (!dev->w_busy)
dev->w_busy = 1;
else {
restore_flags(flags);
return;
}
frame = dev->write_queue;
free = dev->free;
restore_flags(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);
save_flags(flags);
cli();
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;
restore_flags(flags);
} else {
restore_flags(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(void *data)
{
struct frame_buf *frame;
unsigned long flags, msg;
struct pcbit_dev *dev = (struct pcbit_dev *) data;
save_flags(flags);
cli();
while ((frame = dev->read_queue)) {
dev->read_queue = frame->next;
restore_flags(flags);
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);
save_flags(flags);
cli();
}
restore_flags(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 */
if (dev->read_frame->skb)
kfree_skb(dev->read_frame->skb);
kfree(dev->read_frame);
dev->read_frame = NULL;
}
frame = kmalloc(sizeof(struct frame_buf), GFP_ATOMIC);
if (frame == NULL) {
printk(KERN_WARNING "kmalloc failed\n");
return;
}
memset(frame, 0, sizeof(struct frame_buf));
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;
if (frame->copied == frame->hdr_len + frame->dt_len) {
save_flags(flags);
cli();
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;
restore_flags(flags);
} else {
save_flags(flags);
cli();
dev->read_frame = frame;
restore_flags(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);
}
}
void
pcbit_irq_handler(int interrupt, void *devptr, struct pt_regs *regs)
{
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;
}
if (dev->interrupt) {
printk(KERN_DEBUG "pcbit: reentering interrupt hander\n");
return;
}
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;
}
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;
}
if (dev->l2_state != L2_RUNNING && dev->l2_state != L2_LOADING) {
dev->interrupt = 0;
return;
}
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);
}
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) {
if (dev->read_frame->skb)
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");
}
|