static uint8_t ieee_talk_handler (void)
{
buffer_t *buf;
uint8_t finalbyte;
uint8_t c;
uint8_t res;
buf = find_buffer(ieee_data.secondary_address);
if(buf == NULL) return -1;
while (buf->read) {
do {
finalbyte = (buf->position == buf->lastused);
c = buf->data[buf->position];
if (finalbyte && buf->sendeoi) {
/* Send with EOI */
res = ieee_putc(c, 1);
if(!res) uart_puts_p("EOI: ");
} else {
/* Send without EOI */
res = ieee_putc(c, 0);
}
if(res) {
if(res==0xfc) {
uart_puts_P(PSTR("*** TIMEOUT ABORT***")); uart_putcrlf();
}
if(res!=0xfd) {
uart_putc('c'); uart_puthex(res);
}
return 1;
} else {
uart_putc('>');
uart_puthex(c); uart_putc(' ');
if(isprint(c)) uart_putc(c); else uart_putc('?');
uart_putcrlf();
}
} while (buf->position++ < buf->lastused);
if(buf->sendeoi && ieee_data.secondary_address != 0x0f &&
!buf->recordlen && buf->refill != directbuffer_refill) {
buf->read = 0;
break;
}
if (buf->refill(buf)) {
return -1;
}
/* Search the buffer again, it can change when using large buffers */
buf = find_buffer(ieee_data.secondary_address);
}
return 0;
}
Integer buffer_get_length(Buffer buffer, Error *err)
{
buf_T *buf = find_buffer(buffer, err);
if (!buf) {
return 0;
}
return buf->b_ml.ml_line_count;
}
bool defragment(SimpleSignal* sig) {
if (!sig->isFragmented())
return true;
Uint32 fragId = sig->getFragmentId();
NodeId nodeId = refToNode(sig->header.theSendersBlockRef);
DefragBuffer* dbuf;
if(sig->isFirstFragment()){
// Make sure buffer does not exist
if (find_buffer(nodeId, fragId))
abort();
dbuf = new DefragBuffer(nodeId, fragId);
m_buffers.push_back(dbuf);
} else {
dbuf = find_buffer(nodeId, fragId);
if (dbuf == NULL)
abort();
}
if (dbuf->m_buffer.append(sig->ptr[0].p, sig->ptr[0].sz * sizeof(Uint32)))
abort(); // OOM
if (!sig->isLastFragment())
return false;
// Copy defragmented data into signal...
int length = dbuf->m_buffer.length();
delete[] sig->ptr[0].p;
sig->ptr[0].sz = (length+3)/4;
sig->ptr[0].p = new Uint32[sig->ptr[0].sz];
memcpy(sig->ptr[0].p, dbuf->m_buffer.get_data(), length);
// erase the buffer data
erase_buffer(dbuf);
return true;
}
/* DolphinDOS XZ command */
void save_dolphin(void) {
buffer_t *buf;
uint8_t eoi;
/* find the already open file */
buf = find_buffer(1);
if (!buf)
return;
/* reset buffer position */
buf->position = 2;
buf->lastused = 2;
/* experimental delay to avoid hangs */
delay_us(100);
/* handshaking */
parallel_set_dir(PARALLEL_DIR_IN);
set_data(0);
parallel_clear_rxflag();
parallel_send_handshake();
uart_flush();
/* receive data */
do {
/* flush buffer if full */
if (buf->mustflush)
if (buf->refill(buf))
return; // FIXME: check error handling in Dolphin
while (!parallel_rxflag) ;
buf->data[buf->position] = parallel_read();
mark_buffer_dirty(buf);
if (buf->lastused < buf->position)
buf->lastused = buf->position;
buf->position++;
/* mark for flushing on wrap */
if (buf->position == 0)
buf->mustflush = 1;
eoi = !!IEC_CLOCK;
parallel_clear_rxflag();
parallel_send_handshake();
} while (!eoi);
/* the file will be closed with ATN+0xe1 by DolphinDOS */
}
static unsigned long try_to_load_aligned(unsigned long address,
dev_t dev, int b[], int size)
{
struct buffer_head * bh, * tmp, * arr[8];
unsigned long offset;
int * p;
int block;
bh = create_buffers(address, size);
if (!bh)
return 0;
/* do any of the buffers already exist? punt if so.. */
p = b;
for (offset = 0 ; offset < PAGE_SIZE ; offset += size) {
block = *(p++);
if (!block)
goto not_aligned;
if (find_buffer(dev, block, size))
goto not_aligned;
}
tmp = bh;
p = b;
block = 0;
while (1) {
arr[block++] = bh;
bh->b_count = 1;
bh->b_dirt = 0;
bh->b_uptodate = 0;
bh->b_dev = dev;
bh->b_blocknr = *(p++);
nr_buffers++;
insert_into_queues(bh);
if (bh->b_this_page)
bh = bh->b_this_page;
else
break;
}
buffermem += PAGE_SIZE;
bh->b_this_page = tmp;
mem_map[MAP_NR(address)]++;
read_buffers(arr,block);
while (block-- > 0)
brelse(arr[block]);
++current->maj_flt;
return address;
not_aligned:
while ((tmp = bh) != NULL) {
bh = bh->b_this_page;
put_unused_buffer_head(tmp);
}
return 0;
}
struct buffer_head *get_hash_table(kdev_t dev, block_t block)
{
register struct buffer_head *bh;
while((bh = find_buffer(dev, block))) {
bh->b_count++;
wait_on_buffer(bh);
if (bh->b_dev == dev && bh->b_blocknr == block)
break;
bh->b_count--;
}
return bh;
}
struct buffer_head * getblk(int dev,int block)
{
struct buffer_head * bh, * tmp;
int buffers;
repeat:
if (bh = get_hash_table(dev,block))
return bh;
buffers = NR_BUFFERS;
tmp = free_list;
do {
tmp = tmp->b_next_free;
if (tmp->b_count)
continue;
if (!bh || BADNESS(tmp)<BADNESS(bh)) {
bh = tmp;
if (!BADNESS(tmp))
break;
}
if (tmp->b_dirt)
ll_rw_block(WRITEA,tmp);
/* and repeat until we find something good */
} while (buffers--);
if (!bh) {
sleep_on(&buffer_wait);
goto repeat;
}
wait_on_buffer(bh);
if (bh->b_count)
goto repeat;
while (bh->b_dirt) {
sync_dev(bh->b_dev);
wait_on_buffer(bh);
if (bh->b_count)
goto repeat;
}
/* NOTE!! While we slept waiting for this block, somebody else might */
/* already have added "this" block to the cache. check it */
if (find_buffer(dev,block))
goto repeat;
/* OK, FINALLY we know that this buffer is the only one of it's kind, */
/* and that it's unused (b_count=0), unlocked (b_lock=0), and clean */
bh->b_count=1;
bh->b_dirt=0;
bh->b_uptodate=0;
remove_from_queues(bh);
bh->b_dev=dev;
bh->b_blocknr=block;
insert_into_queues(bh);
return bh;
}
/*
* Ok, this is getblk, and it isn't very clear, again to hinder
* race-conditions. Most of the code is seldom used, (ie repeating),
* so it should be much more efficient than it looks.
*/
struct buffer_head * getblk(int dev,int block)
{
struct buffer_head * tmp;
repeat:
if ((tmp=get_hash_table(dev,block)))
return tmp;
tmp = free_list;
do {
if (!tmp->b_count) {
wait_on_buffer(tmp); /* we still have to wait */
if (!tmp->b_count) /* on it, it might be dirty */
break;
}
tmp = tmp->b_next_free;
} while (tmp != free_list || (tmp=NULL));
/* Kids, don't try THIS at home ^^^^^. Magic */
if (!tmp) {
printk("Sleeping on free buffer ..");
sleep_on(&buffer_wait);
printk("ok\n");
goto repeat;
}
tmp->b_count++;
remove_from_queues(tmp);
/*
* Now, when we know nobody can get to this node (as it's removed from the
* free list), we write it out. We can sleep here without fear of race-
* conditions.
*/
if (tmp->b_dirt)
sync_dev(tmp->b_dev);
/* update buffer contents */
tmp->b_dev=dev;
tmp->b_blocknr=block;
tmp->b_dirt=0;
tmp->b_uptodate=0;
/* NOTE!! While we possibly slept in sync_dev(), somebody else might have
* added "this" block already, so check for that. Thank God for goto's.
*/
if (find_buffer(dev,block)) {
tmp->b_dev=0; /* ok, someone else has beaten us */
tmp->b_blocknr=0; /* to it - free this block and */
tmp->b_count=0; /* try again */
insert_into_queues(tmp);
goto repeat;
}
/* and then insert into correct position */
insert_into_queues(tmp);
return tmp;
}
/*
* Why like this, I hear you say... The reason is race-conditions.
* As we don't lock buffers (unless we are readint them, that is),
* something might happen to it while we sleep (ie a read-error
* will force it bad). This shouldn't really happen currently, but
* the code is ready.
*/
struct buffer_head * get_hash_table(int dev, int block)
{
struct buffer_head * bh;
for (;;) {
if (!(bh=find_buffer(dev,block)))
return NULL;
bh->b_count++;
wait_on_buffer(bh);
if (bh->b_dev == dev && bh->b_blocknr == block)
return bh;
bh->b_count--;
}
}
void make_buffer_name_uniq(char *bname)
{
int num = 0;
char basen[NBUFN];
char bufn[NBUFN];
if (NULL == find_buffer(bname, FALSE))
return;
strcpy(basen, bname);
basen[14] = '\0';
basen[15] = '\0';
while(TRUE) {
sprintf(bufn, "%s%d", basen, num++);
if (NULL == find_buffer(bufn, FALSE)) {
strcpy(bname, bufn);
return;
}
assert(num < 100); /* fail after 100 */
}
}
/*
* Why like this, I hear you say... The reason is race-conditions.
* As we don't lock buffers (unless we are readint them, that is),
* something might happen to it while we sleep (ie a read-error
* will force it bad). This shouldn't really happen currently, but
* the code is ready.
*/
struct buffer_head * get_hash_table(int dev, int block)
{
struct buffer_head * bh;
repeat:
if (!(bh=find_buffer(dev,block)))
return NULL;
bh->b_count++;
wait_on_buffer(bh);
if (bh->b_dev != dev || bh->b_blocknr != block) {
brelse(bh);
goto repeat;
}
return bh;
}
/*
* Why like this, I hear you say... The reason is race-conditions.
* As we don't lock buffers (unless we are readint them, that is),
* something might happen to it while we sleep (ie a read-error
* will force it bad). This shouldn't really happen currently, but
* the code is ready.
*/
struct buffer_head * get_hash_table(int dev, int block, int size)
{
struct buffer_head * bh;
for (;;) {
if (!(bh=find_buffer(dev,block,size)))
return NULL;
bh->b_count++;
wait_on_buffer(bh);
if (bh->b_dev == dev && bh->b_blocknr == block && bh->b_size == size) {
put_last_free(bh);
return bh;
}
bh->b_count--;
}
}
struct buffer_head * getblk(int dev,int block)
{
// printk("getblk -------------------------------- 1\n");
struct buffer_head *tmp,*bh;
repeat:
if((bh = get_hash_buffer(dev,block)))
return bh;
tmp = buffer_free_list;
do{
if(tmp->b_count)
continue;
if(!bh || (BADNESS(bh) > BADNESS(tmp)))
{
bh = tmp;
if(!BADNESS(tmp))
break;
}
}while((tmp = tmp->b_next_free) != buffer_free_list);
if(!bh)
{
sleep_on(&buffer_wait);
goto repeat;
}
wait_on_buffer(bh);
if(bh->b_count)
goto repeat;
/* while(bh->b_dirt)
{
sync_dev(bh->b_dev);
wait_on_buffer(bh);
if(bh_b_count)
goto repeat;
}
*/
///已经被其他的进程取走
if(find_buffer(dev,block))
goto repeat;
bh->b_count = 1;
bh->b_dirt = 0;
bh->b_uptodate = 0;
remove_from_queues(bh);
bh->b_dev = dev;
bh->b_blocknr = block;
insert_into_queues(bh);
return bh;
}
/*
* 代码为什么会是这样子的？我听见你问... 原因是竞争条件。由于我们没有对
* 缓冲区上锁（除非我们正在读取它们中的数据），那么当我们（进程）睡眠时
* 缓冲区可能会发生一些问题（例如一个读错误将导致该缓冲区出错）。目前
* 这种情况实际上是不会发生的，但处理的代码已经准备好了。
*/
struct buffer_head * get_hash_table(int dev, int block)
{
struct buffer_head * bh;
for (;;) {
// 在高速缓冲中寻找给定设备和指定块的缓冲区，如果没有找到则返回NULL，退出。
if (!(bh=find_buffer(dev,block)))
return NULL;
// 对该缓冲区增加引用计数，并等待该缓冲区解锁（如果已被上锁）。
bh->b_count++;
wait_on_buffer(bh);
// 由于经过了睡眠状态，因此有必要再验证该缓冲区块的正确性，并返回缓冲区头指针。
if (bh->b_dev == dev && bh->b_blocknr == block)
return bh;
// 如果该缓冲区所属的设备号或块号在睡眠时发生了改变，则撤消对它的引用计数，重新寻找。
bh->b_count--;
}
}
static ssize_t buffered_pread(couch_file_handle handle, void *buf, size_t nbyte, off_t offset)
{
#if LOG_BUFFER
//fprintf(stderr, "r");
#endif
buffered_file_handle *h = (buffered_file_handle*)handle;
// Flush the write buffer before trying to read anything:
couchstore_error_t err = flush_buffer(h->write_buffer);
if (err < 0) {
return err;
}
ssize_t total_read = 0;
while (nbyte > 0) {
file_buffer* buffer = find_buffer(h, offset);
// Read as much as we can from the current buffer:
ssize_t nbyte_read = read_from_buffer(buffer, buf, nbyte, offset);
if (nbyte_read == 0) {
/*if (nbyte > buffer->capacity) {
// Remainder won't fit in a single buffer, so just read it directly:
nbyte_read = h->raw_ops->pread(h->raw_ops_handle, buf, nbyte, offset);
if (nbyte_read < 0) {
return nbyte_read;
}
} else*/ {
// Move the buffer to cover the remainder of the data to be read.
off_t block_start = offset - (offset % READ_BUFFER_CAPACITY);
err = load_buffer_from(buffer, block_start, (size_t)(offset + nbyte - block_start));
if (err < 0) {
return err;
}
nbyte_read = read_from_buffer(buffer, buf, nbyte, offset);
if (nbyte_read == 0)
break; // must be at EOF
}
}
buf = (char*)buf + nbyte_read;
nbyte -= nbyte_read;
offset += nbyte_read;
total_read += nbyte_read;
}
return total_read;
}
struct buffer_head *getblk(kdev_t dev, block_t block)
{
register struct buffer_head *bh;
/* If there are too many dirty buffers, we wake up the update process
* now so as to ensure that there are still clean buffers available
* for user processes to use (and dirty) */
do {
bh = get_hash_table(dev, block);
if (bh != NULL) {
if (buffer_clean(bh) && buffer_uptodate(bh))
put_last_lru(bh);
return bh;
}
/* I think the following check is redundant
* So I will remove it for now
*/
} while(find_buffer(dev, block));
/*
* Create a buffer for this job.
*/
bh = get_free_buffer();
/* OK, FINALLY we know that this buffer is the only one of its kind,
* and that it's unused (b_count=0), unlocked (buffer_locked=0), and clean
*/
bh->b_count = 1;
bh->b_dirty = 0;
bh->b_lock = 0;
bh->b_uptodate = 0;
bh->b_dev = dev;
bh->b_blocknr = block;
bh->b_seg = kernel_ds;
return bh;
}
static void reiserfsck_check_cached_tree (int dev, int block, int size)
{
struct buffer_head * bh;
int what_node;
bh = find_buffer(dev, block, size);
if (bh == 0)
return;
if (!buffer_uptodate (bh)) {
die ("reiserfsck_check_cached_tree: found notuptodate buffer");
}
bh->b_count ++;
if (!B_IS_IN_TREE (bh)) {
die ("reiserfsck_check_cached_tree: buffer (%b %z) not in tree", bh, bh);
}
what_node = who_is_this (bh->b_data, bh->b_size);
if ((what_node != THE_LEAF && what_node != THE_INTERNAL) ||
!is_block_used (bh->b_blocknr) ||
(is_leaf_node (bh) && is_leaf_bad (bh)) ||
(is_internal_node(bh) && is_internal_bad (bh)))
die ("reiserfsck_check_cached_tree: bad node in the tree");
if (is_internal_node (bh)) {
int i;
struct disk_child * dc;
dc = B_N_CHILD (bh, 0);
for (i = 0; i <= B_NR_ITEMS (bh); i ++, dc ++) {
reiserfsck_check_cached_tree (dev, dc_block_number(dc), size);
g_dkey = B_N_PDELIM_KEY (bh, i);
}
} else if (is_leaf_node (bh)) {
brelse (bh);
return;
} else {
reiserfs_panic ("reiserfsck_check_cached_tree: block %lu has bad block type (%b)",
bh->b_blocknr, bh);
}
brelse (bh);
}
/// Sets the current buffer
///
/// @param id The buffer handle
/// @param[out] err Details of an error that may have occurred
void vim_set_current_buffer(Buffer buffer, Error *err)
{
buf_T *buf = find_buffer(buffer, err);
if (!buf) {
return;
}
try_start();
if (do_buffer(DOBUF_GOTO, DOBUF_FIRST, FORWARD, buf->b_fnum, 0) == FAIL) {
if (try_end(err)) {
return;
}
char msg[256];
snprintf(msg, sizeof(msg), "failed to switch to buffer %d", (int)buffer);
set_api_error(msg, err);
return;
}
try_end(err);
}
//检查指定（设备号和块号）的缓冲区是否已经在高速缓冲中。如果指定块已经在高速缓冲中，则返回
//对应缓冲区头指针退出；如果不在，就需要在高速缓冲中设置一个对应设备号和块号的新项。返回相应
//缓冲区头指针
struct buffer_head * getblk(int dev,int block)
{
struct buffer_head * tmp, * bh;
repeat:
if ( (bh = get_hash_table(dev,block)) )
return bh;
tmp = free_list;
do {
if (tmp->b_count)
continue;
if (!bh || BADNESS(tmp)<BADNESS(bh)) {
bh = tmp;
if (!BADNESS(tmp))
break;
}
/* and repeat until we find something good */
} while ((tmp = tmp->b_next_free) != free_list);
//如果循环检查所有缓冲块都正在被使用（所有缓冲块的头部引用计数都>0)中，则睡眠等待有空闲
//缓冲块可用。当有空闲块可用时本进程会被明确地唤醒。然后我们就跳转到函数开始处重新查找空闲
//缓冲块
if (!bh) {
sleep_on(&buffer_wait);
goto repeat;
}
//如果跑到这里，说明已经找到一个空闲的缓冲区块。于是先等待该缓冲区解锁（如果已经被上锁的话）。
wait_on_buffer(bh);
if (bh->b_count)
goto repeat;
//如果该缓冲区已被修改，则将数据写盘，并再次等待缓冲区解锁。
while (bh->b_dirt) {
sync_dev(bh->b_dev);
wait_on_buffer(bh);
if (bh->b_count)
goto repeat;
}
/* NOTE!! While we slept waiting for this block, somebody else might */
/* already have added "this" block to the cache. check it */
//当进程为了等待该缓冲块而睡眠时，其他进程可能已经将该缓冲块进入高速缓冲中，因此我们也要对此进行检查
if (find_buffer(dev,block))
goto repeat;
/* OK, FINALLY we know that this buffer is the only one of it's kind, */
/* and that it's unused (b_count=0), unlocked (b_lock=0), and clean */
//到了这里，最终我们知道该缓冲块是指定参数的唯一一块，而且目前还没有被占用（b_count=0)
//也没有被上锁(b_lock=0)，而且是干净的(b_dirt=0)
//于是我们占用此缓冲块。置引用计数为1，复位修改标志和有效标志
bh->b_count=1;
bh->b_dirt=0;
bh->b_uptodate=0;
//从hash队列和空闲块链表中移出该缓冲区头，让该缓冲区用于指定设备和其上的指定块。然后根据
//此新的设备号和块号重新插入空闲链表和hash队列新位置处。并最终返回缓冲头指针。
remove_from_queues(bh);
bh->b_dev=dev;
bh->b_blocknr=block;
insert_into_queues(bh);
return bh;
}
struct buffer_head * getblk(int dev, int block, int size)
{
struct buffer_head * bh, * tmp;
int buffers;
repeat:
if (bh = get_hash_table(dev, block, size))
return bh;
if (nr_free_pages > 30)
grow_buffers(size);
buffers = nr_buffers;
bh = NULL;
for (tmp = free_list; buffers-- > 0 ; tmp = tmp->b_next_free) {
if (tmp->b_count || tmp->b_size != size)
continue;
if (!bh || BADNESS(tmp)<BADNESS(bh)) {
bh = tmp;
if (!BADNESS(tmp))
break;
}
#if 0
if (tmp->b_dirt)
ll_rw_block(WRITEA,tmp);
#endif
}
if (!bh && nr_free_pages > 5) {
grow_buffers(size);
goto repeat;
}
/* and repeat until we find something good */
if (!bh) {
sleep_on(&buffer_wait);
goto repeat;
}
wait_on_buffer(bh);
if (bh->b_count || bh->b_size != size)
goto repeat;
if (bh->b_dirt) {
sync_buffers(bh->b_dev);
goto repeat;
}
/* NOTE!! While we slept waiting for this block, somebody else might */
/* already have added "this" block to the cache. check it */
if (find_buffer(dev,block,size))
goto repeat;
/* OK, FINALLY we know that this buffer is the only one of it's kind, */
/* and that it's unused (b_count=0), unlocked (b_lock=0), and clean */
bh->b_count=1;
bh->b_dirt=0;
bh->b_uptodate=0;
remove_from_queues(bh);
bh->b_dev=dev;
bh->b_blocknr=block;
insert_into_queues(bh);
return bh;
}
void ieee_mainloop(void) {
int16_t cmd = 0;
set_error(ERROR_DOSVERSION);
ieee_data.bus_state = BUS_IDLE;
ieee_data.device_state = DEVICE_IDLE;
for(;;) {
switch(ieee_data.bus_state) {
case BUS_SLEEP: /* BUS_SLEEP */
set_atn_irq(0);
ieee_bus_idle();
set_error(ERROR_OK);
set_busy_led(0);
uart_puts_P(PSTR("ieee.c/sleep ")); set_dirty_led(1);
/* Wait until the sleep key is used again */
while (!key_pressed(KEY_SLEEP))
system_sleep();
reset_key(KEY_SLEEP);
set_atn_irq(1);
update_leds();
ieee_data.bus_state = BUS_IDLE;
break;
case BUS_IDLE: /* BUS_IDLE */
ieee_bus_idle();
while(IEEE_ATN) { ; /* wait for ATN */
if (key_pressed(KEY_NEXT | KEY_PREV | KEY_HOME)) {
change_disk();
} else if (key_pressed(KEY_SLEEP)) {
reset_key(KEY_SLEEP);
ieee_data.bus_state = BUS_SLEEP;
break;
} else if (display_found && key_pressed(KEY_DISPLAY)) {
display_service();
reset_key(KEY_DISPLAY);
}
system_sleep();
}
if (ieee_data.bus_state != BUS_SLEEP)
ieee_data.bus_state = BUS_FOUNDATN;
break;
case BUS_FOUNDATN: /* BUS_FOUNDATN */
ieee_data.bus_state = BUS_ATNPROCESS;
cmd = ieee_getc();
break;
case BUS_ATNPROCESS: /* BUS_ATNPROCESS */
if(cmd < 0) {
uart_putc('c');
ieee_data.bus_state = BUS_IDLE;
break;
} else cmd &= 0xFF;
uart_puts_p("ATN "); uart_puthex(cmd);
uart_putcrlf();
if (cmd == 0x3f) { /* UNLISTEN */
if(ieee_data.device_state == DEVICE_LISTEN) {
ieee_data.device_state = DEVICE_IDLE;
uart_puts_p("UNLISTEN\r\n");
}
ieee_data.bus_state = BUS_IDLE;
break;
} else if (cmd == 0x5f) { /* UNTALK */
if(ieee_data.device_state == DEVICE_TALK) {
ieee_data.device_state = DEVICE_IDLE;
uart_puts_p("UNTALK\r\n");
}
ieee_data.bus_state = BUS_IDLE;
break;
} else if (cmd == (0x40 + device_address)) { /* TALK */
uart_puts_p("TALK ");
uart_puthex(device_address); uart_putcrlf();
ieee_data.device_state = DEVICE_TALK;
/* disk drives never talk immediatly after TALK, so stay idle
and wait for a secondary address given by 0x60-0x6f DATA */
ieee_data.bus_state = BUS_IDLE;
break;
} else if (cmd == (0x20 + device_address)) { /* LISTEN */
ieee_data.device_state = DEVICE_LISTEN;
uart_puts_p("LISTEN ");
uart_puthex(device_address); uart_putcrlf();
ieee_data.bus_state = BUS_IDLE;
break;
} else if ((cmd & 0xf0) == 0x60) { /* DATA */
/* 8250LP sends data while ATN is still active, so wait
for bus controller to release ATN or we will misinterpret
data as a command */
while(!IEEE_ATN);
if(ieee_data.device_state == DEVICE_LISTEN) {
cmd = ieee_listen_handler(cmd);
cmd_handler();
break;
} else if (ieee_data.device_state == DEVICE_TALK) {
ieee_data.secondary_address = cmd & 0x0f;
uart_puts_p("DATA T ");
uart_puthex(ieee_data.secondary_address);
uart_putcrlf();
if(ieee_talk_handler() == TIMEOUT_ABORT) {
ieee_data.device_state = DEVICE_IDLE;
}
ieee_data.bus_state = BUS_IDLE;
break;
} else {
ieee_data.bus_state = BUS_IDLE;
break;
}
} else if (ieee_data.device_state == DEVICE_IDLE) {
ieee_data.bus_state = BUS_IDLE;
break;
/* ----- if we reach this, we're LISTENer or TALKer ----- */
} else if ((cmd & 0xf0) == 0xe0) { /* CLOSE */
ieee_data.secondary_address = cmd & 0x0f;
uart_puts_p("CLOSE ");
uart_puthex(ieee_data.secondary_address);
uart_putcrlf();
/* Close all buffers if sec. 15 is closed */
if(ieee_data.secondary_address == 15) {
free_multiple_buffers(FMB_USER_CLEAN);
} else {
/* Close a single buffer */
buffer_t *buf;
buf = find_buffer (ieee_data.secondary_address);
if (buf != NULL) {
buf->cleanup(buf);
free_buffer(buf);
}
}
ieee_data.bus_state = BUS_IDLE;
break;
} else if ((cmd & 0xf0) == 0xf0) { /* OPEN */
cmd = ieee_listen_handler(cmd);
cmd_handler();
break;
} else {
/* Command for other device or unknown command */
ieee_data.bus_state = BUS_IDLE;
}
break;
} /* switch */
} /* for() */
}
//// 取高速缓冲中指定的缓冲区。
// 检查所指定的缓冲区是否已经在高速缓冲中，如果不在，就需要在高速缓冲中建立一个对应的新项。
// 返回相应缓冲区头指针。
struct buffer_head * getblk(int dev,int block)
{
struct buffer_head * tmp, * bh;
repeat:
// 搜索hash 表，如果指定块已经在高速缓冲中，则返回对应缓冲区头指针，退出。
if (bh = get_hash_table(dev,block))
return bh;
// 扫描空闲数据块链表，寻找空闲缓冲区。
// 首先让tmp 指向空闲链表的第一个空闲缓冲区头。
tmp = free_list;
do {
// 如果该缓冲区正被使用（引用计数不等于0），则继续扫描下一项。
if (tmp->b_count)
continue;
// 如果缓冲头指针bh 为空，或者tmp 所指缓冲头的标志(修改、锁定)权重小于bh 头标志的权重，
// 则让bh 指向该tmp 缓冲区头。如果该tmp 缓冲区头表明缓冲区既没有修改也没有锁定标志置位，
// 则说明已为指定设备上的块取得对应的高速缓冲区，则退出循环。
if (!bh || BADNESS(tmp)<BADNESS(bh)) {
bh = tmp;
if (!BADNESS(tmp))
break;
}
/* 重复操作直到找到适合的缓冲区 */
} while ((tmp = tmp->b_next_free) != free_list);
// 如果所有缓冲区都正被使用（所有缓冲区的头部引用计数都>0），
// 则睡眠，等待有空闲的缓冲区可用。
if (!bh) {
sleep_on(&buffer_wait);
goto repeat;
}
// 等待该缓冲区解锁（如果已被上锁的话）。
wait_on_buffer(bh);
// 如果该缓冲区又被其它任务使用的话，只好重复上述过程。
if (bh->b_count)
goto repeat;
// 如果该缓冲区已被修改，则将数据写盘，并再次等待缓冲区解锁。如果该缓冲区又被其它任务使用
// 的话，只好再重复上述过程。
while (bh->b_dirt) {
sync_dev(bh->b_dev);
wait_on_buffer(bh);
if (bh->b_count)
goto repeat;
}
/* 注意！！当进程为了等待该缓冲块而睡眠时，其它进程可能已经将该缓冲块 */
/* 加入进高速缓冲中，所以要对此进行检查。 */
// 在高速缓冲hash 表中检查指定设备和块的缓冲区是否已经被加入进去。如果是的话，就再次重复
// 上述过程。
if (find_buffer(dev,block))
goto repeat;
/* OK，最终我们知道该缓冲区是指定参数的唯一一块， */
/* 而且还没有被使用(b_count=0)，未被上锁(b_lock=0)，并且是干净的（未被修改的） */
// 于是让我们占用此缓冲区。置引用计数为1，复位修改标志和有效(更新)标志。
bh->b_count=1;
bh->b_dirt=0;
bh->b_uptodate=0;
// 从hash 队列和空闲块链表中移出该缓冲区头，让该缓冲区用于指定设备和其上的指定块。
remove_from_queues(bh);
bh->b_dev=dev;
bh->b_blocknr=block;
// 然后根据此新的设备号和块号重新插入空闲链表和hash 队列新位置处。并最终返回缓冲头指针。
insert_into_queues(bh);
return bh;
}
static int16_t ieee_listen_handler (uint8_t cmd)
/* Receive characters from IEEE-bus and write them to the
listen buffer adressed by ieee_data.secondary_address.
If a new command is received (ATN set), return it
*/
{
buffer_t *buf;
int16_t c;
ieee_data.secondary_address = cmd & 0x0f;
buf = find_buffer(ieee_data.secondary_address);
/* Abort if there is no buffer or it's not open for writing */
/* and it isn't an OPEN command */
if ((buf == NULL || !buf->write) && (cmd & 0xf0) != 0xf0) {
uart_putc('c');
return -1;
}
switch(cmd & 0xf0) {
case 0x60:
uart_puts_p("DATA L ");
break;
case 0xf0:
uart_puts_p("OPEN ");
break;
default:
uart_puts_p("Unknown LH! ");
break;
}
uart_puthex(ieee_data.secondary_address);
uart_putcrlf();
c = -1;
for(;;) {
/* Get a character ignoring timeout but but watching ATN */
while((c = ieee_getc()) < 0);
if (c & FLAG_ATN) return c;
uart_putc('<');
if (c & FLAG_EOI) {
uart_puts_p("EOI ");
ieee_data.ieeeflags |= EOI_RECVD;
} else ieee_data.ieeeflags &= ~EOI_RECVD;
uart_puthex(c); uart_putc(' ');
c &= 0xff; /* needed for isprint */
if(isprint(c)) uart_putc(c); else uart_putc('?');
uart_putcrlf();
if((cmd & 0x0f) == 0x0f || (cmd & 0xf0) == 0xf0) {
if (command_length < CONFIG_COMMAND_BUFFER_SIZE)
command_buffer[command_length++] = c;
if (ieee_data.ieeeflags & EOI_RECVD)
/* Filenames are just a special type of command =) */
ieee_data.ieeeflags |= COMMAND_RECVD;
} else {
/* Flush buffer if full */
if (buf->mustflush) {
if (buf->refill(buf)) return -2;
/* Search the buffer again, */
/* it can change when using large buffers */
buf = find_buffer(ieee_data.secondary_address);
}
buf->data[buf->position] = c;
mark_buffer_dirty(buf);
if (buf->lastused < buf->position) buf->lastused = buf->position;
buf->position++;
/* Mark buffer for flushing if position wrapped */
if (buf->position == 0) buf->mustflush = 1;
/* REL files must be syncronized on EOI */
if(buf->recordlen && (ieee_data.ieeeflags & EOI_RECVD)) {
if (buf->refill(buf)) return -2;
}
} /* else-buffer */
} /* for(;;) */
}
//// 取高速缓冲中指定的缓冲区。
// 检查所指定的缓冲区是否已经在高速缓冲中，如果不在，就需要在高速缓冲中建立一个对应的新项。
// 返回相应缓冲区头指针。
struct buffer_head *
getblk( int dev, int block )
{
struct buffer_head *tmp, *bh;
repeat:
// 搜索hash 表，如果指定块已经在高速缓冲中，则返回对应缓冲区头指针，退出。
if( bh = get_hash_table( dev, block ) )
{
return bh;
}
// 扫描空闲数据块链表，寻找空闲缓冲区。
// 首先让tmp 指向空闲链表的第一个空闲缓冲区头。
tmp = free_list;
do
{
// 如果该缓冲区正被使用（引用计数不等于0），则继续扫描下一项。
if( tmp->b_count )
{
continue;
}
// 如果缓冲头指针bh 为空，或者tmp 所指缓冲头的标志(修改、锁定)权重小于bh 头标志的权重，
// 则让bh 指向该tmp 缓冲区头。如果该tmp 缓冲区头表明缓冲区既没有修改也没有锁定标志置位，
// 则说明已为指定设备上的块取得对应的高速缓冲区，则退出循环。
if( !bh || BADNESS( tmp ) < BADNESS( bh ) )
{
bh = tmp;
if( !BADNESS( tmp ) )
{
break;
}
}
/* and repeat until we find something good *//* 重复操作直到找到适合的缓冲区 */
}
while( ( tmp = tmp->b_next_free ) != free_list );
// 如果所有缓冲区都正被使用（所有缓冲区的头部引用计数都>0），则睡眠，等待有空闲的缓冲区可用。
if( !bh )
{
sleep_on( &buffer_wait );
goto repeat;
}
// 等待该缓冲区解锁（如果已被上锁的话）。
wait_on_buffer( bh );
// 如果该缓冲区又被其它任务使用的话，只好重复上述过程。
if( bh->b_count )
{
goto repeat;
}
// 如果该缓冲区已被修改，则将数据写盘，并再次等待缓冲区解锁。如果该缓冲区又被其它任务使用
// 的话，只好再重复上述过程。
while( bh->b_dirt )
{
sync_dev( bh->b_dev );
wait_on_buffer( bh );
if( bh->b_count )
{
goto repeat;
}
}
/* NOTE!! While we slept waiting for this block, somebody else might */
/* already have added "this" block to the cache. check it */
/* 注意！！当进程为了等待该缓冲块而睡眠时，其它进程可能已经将该缓冲块 */
** /
// 在高速缓冲hash 表中检查指定设备和块的缓冲区是否已经被加入进去。如果是的话，就再次重复
// 上述过程。
if( find_buffer( dev, block ) )
{
goto repeat;
}
/* OK, FINALLY we know that this buffer is the only one of it's kind, */
/* and that it's unused (b_count=0), unlocked (b_lock=0), and clean */
/* OK，最终我们知道该缓冲区是指定参数的唯一一块，*/
/* 而且还没有被使用(b_count=0)，未被上锁(b_lock=0)，并且是干净的（未被修改的）*/
// 于是让我们占用此缓冲区。置引用计数为1，复位修改标志和有效(更新)标志。
bh->b_count = 1;
bh->b_dirt = 0;
bh->b_uptodate = 0;
// 从hash 队列和空闲块链表中移出该缓冲区头，让该缓冲区用于指定设备和其上的指定块。
remove_from_queues( bh );
bh->b_dev = dev;
bh->b_blocknr = block;
// 然后根据此新的设备号和块号重新插入空闲链表和hash 队列新位置处。并最终返回缓冲头指针。
insert_into_queues( bh );
return bh;
}
/**
* file_open - open a file on given secondary
* @secondary: secondary address used in OPEN call
*
* This function opens the file named in command_buffer on the given
* secondary address. All special names and prefixes/suffixed are handled
* here, e.g. $/#/@/,S,W
*/
void file_open(uint8_t secondary) {
buffer_t *buf;
uint8_t i = 0;
uint8_t recordlen = 0;
/* If the secondary is already in use, close the existing buffer */
buf = find_buffer(secondary);
if (buf != NULL) {
/* FIXME: What should we do if an error occurs? */
cleanup_and_free_buffer(buf);
}
/* Assume everything will go well unless proven otherwise */
set_error(ERROR_OK);
/* Strip 0x0d characters from end of name (C2BD-C2CA) */
if (command_length > 1) {
if (command_buffer[command_length-1] == 0x0d)
command_length -= 1;
else if (command_buffer[command_length-2] == 0x0d)
command_length -= 2;
}
/* Clear the remainder of the command buffer, simplifies parsing */
memset(command_buffer+command_length, 0, sizeof(command_buffer)-command_length);
uart_trace(command_buffer,0,command_length);
/* Direct access? */
if (command_buffer[0] == '#') {
open_buffer(secondary);
return;
}
/* Parse type+mode suffixes */
uint8_t *ptr = command_buffer;
enum open_modes mode = OPEN_READ;
uint8_t filetype = TYPE_DEL;
while(i++ < 2 && *ptr && (ptr = ustrchr(ptr, ','))) {
*ptr = 0;
ptr++;
switch (*ptr) {
case 0:
break;
case 'R': /* Read */
mode = OPEN_READ;
break;
case 'W': /* Write */
mode = OPEN_WRITE;
break;
case 'A': /* Append */
mode = OPEN_APPEND;
break;
case 'M': /* Modify */
mode = OPEN_MODIFY;
break;
case 'D': /* DEL */
filetype = TYPE_DEL;
break;
case 'S': /* SEQ */
filetype = TYPE_SEQ;
break;
case 'P': /* PRG */
filetype = TYPE_PRG;
break;
case 'U': /* USR */
filetype = TYPE_USR;
break;
case 'L': /* REL */
filetype = TYPE_REL;
mode = OPEN_WRITE;
if((ptr = ustrchr(ptr, ',')))
recordlen = *(++ptr);
i = 2; // stop the scan
break;
}
}
/* Load directory? */
if (command_buffer[0] == '$') {
load_directory(secondary);
return;
}
/* Parse path+partition numbers */
uint8_t *fname;
int8_t res;
cbmdirent_t dent;
path_t path;
/* Parse path and file name */
if (parse_path(command_buffer, &path, &fname, 0))
return;
#ifdef CONFIG_M2I
/* For M2I only: Remove trailing spaces from name */
if (partition[path.part].fop == &m2iops) {
res = ustrlen(fname);
while (--res && fname[res] == ' ')
fname[res] = 0;
}
#endif
/* Filename matching */
if (opendir(&matchdh, &path))
return;
do {
res = next_match(&matchdh, fname, NULL, NULL, FLAG_HIDDEN, &dent);
if (res > 0)
/* Error, abort */
return;
/* Don't match on DEL or DIR */
if ((dent.typeflags & TYPE_MASK) != TYPE_DEL &&
(dent.typeflags & TYPE_MASK) != TYPE_DIR)
break;
/* But do match if it's for writing */
if (mode == OPEN_WRITE || secondary == 1)
break;
} while (res == 0);
if(res && filetype == TYPE_REL && !recordlen) {
set_error(ERROR_SYNTAX_UNABLE);
return;
}
/* If match found is a REL... */
if(!res && (dent.typeflags & TYPE_MASK) == TYPE_REL) {
/* requested type must be REL or DEL */
if(filetype != TYPE_REL && filetype != TYPE_DEL) {
set_error(ERROR_FILE_TYPE_MISMATCH);
return;
}
filetype = TYPE_REL;
mode = OPEN_MODIFY;
}
/* Force mode+type for secondaries 0/1 */
switch (secondary) {
case 0:
mode = OPEN_READ;
if (filetype == TYPE_DEL)
filetype = TYPE_PRG;
break;
case 1:
mode = OPEN_WRITE;
if (filetype == TYPE_DEL)
filetype = TYPE_PRG;
break;
default:
if (filetype == TYPE_DEL)
filetype = TYPE_SEQ;
}
if (mode == OPEN_WRITE) {
if (res == 0) {
/* Match found */
if (command_buffer[0] == '@') {
/* Make sure there is a free buffer to open the new file later */
if (!check_free_buffers()) {
set_error(ERROR_NO_CHANNEL);
return;
}
/* Copy dent because file_delete may change it */
cbmdirent_t dentcopy = dent;
/* Rewrite existing file: Delete the old one */
if (file_delete(&path, &dentcopy) == 255)
return;
/* Force fatops to create a new name based on the (long) CBM- */
/* name instead of creating one with the old SFN and no LFN. */
if (dent.opstype == OPSTYPE_FAT || dent.opstype == OPSTYPE_FAT_X00)
dent.pvt.fat.realname[0] = 0;
} else {
/* Write existing file without replacement: Raise error */
set_error(ERROR_FILE_EXISTS);
return;
}
} else {
/* Normal write or non-existing rewrite */
/* Doesn't exist: Copy name to dent */
memset(&dent, 0, sizeof(dent));
ustrncpy(dent.name, fname, CBM_NAME_LENGTH);
set_error(ERROR_OK); // because first_match has set FNF
}
} else if (res != 0) {
/* File not found */
set_error(ERROR_FILE_NOT_FOUND);
return;
}
/* Grab a buffer */
buf = alloc_buffer();
if (!buf)
return;
buf->secondary = secondary;
if(filetype == TYPE_REL) {
display_filename_write(path.part,CBM_NAME_LENGTH,dent.name);
open_rel(&path, &dent, buf, recordlen, (mode == OPEN_MODIFY));
return;
}
switch (mode) {
case OPEN_MODIFY:
case OPEN_READ:
/* Modify is the same as read, but allows reading *ed files. */
/* FAT doesn't have anything equivalent, so both are mapped to READ */
display_filename_read(path.part,CBM_NAME_LENGTH,dent.name);
open_read(&path, &dent, buf);
break;
case OPEN_WRITE:
case OPEN_APPEND:
display_filename_write(path.part,CBM_NAME_LENGTH,dent.name);
open_write(&path, &dent, filetype, buf, (mode == OPEN_APPEND));
break;
}
}
void load_gijoe(UNUSED_PARAMETER) {
buffer_t *buf;
set_data(1);
set_clock(1);
set_atn_irq(0);
/* Wait until the bus has settled */
delay_ms(10);
while (!IEC_DATA || !IEC_CLOCK) ;
while (1) {
/* Handshake */
set_clock(0);
while (IEC_DATA)
if (check_keys())
return;
set_clock(1);
uart_flush();
/* First byte is ignored */
if (gijoe_read_byte() < 0)
return;
/* Read two file name characters */
command_buffer[0] = gijoe_read_byte();
command_buffer[1] = gijoe_read_byte();
set_clock(0);
command_buffer[2] = '*';
command_buffer[3] = 0;
command_length = 3;
/* Open the file */
file_open(0);
uart_flush();
buf = find_buffer(0);
if (!buf) {
set_clock(1);
gijoe_send_byte(0xfe);
gijoe_send_byte(0xfe);
gijoe_send_byte(0xac);
gijoe_send_byte(0xf7);
continue;
}
/* file is open, transfer */
while (1) {
uint8_t i = buf->position;
set_clock(1);
delay_us(2);
do {
if (buf->data[i] == 0xac)
gijoe_send_byte(0xac);
gijoe_send_byte(buf->data[i]);
} while (i++ < buf->lastused);
/* Send end marker and wait for the next name */
if (buf->sendeoi) {
gijoe_send_byte(0xac);
gijoe_send_byte(0xff);
cleanup_and_free_buffer(buf);
break;
}
/* Send "another sector following" marker */
gijoe_send_byte(0xac);
gijoe_send_byte(0xc3);
delay_us(50);
set_clock(0);
/* Read next block */
if (buf->refill(buf)) {
/* Send error marker */
gijoe_send_byte(0xfe);
gijoe_send_byte(0xfe);
gijoe_send_byte(0xac);
gijoe_send_byte(0xf7);
cleanup_and_free_buffer(buf);
break;
}
}
}
}
int jed_buffer_visible (char *b)
{
return buffer_visible (find_buffer(b));
}
/* DolphinDOS XQ command */
void load_dolphin(void) {
/* find the already open buffer */
buffer_t *buf = find_buffer(0);
if (!buf)
return;
buf->position = 2;
/* initial handshaking */
// note about the delays: 100us work, not optimized
// (doesn't matter much outside the loop)
delay_us(100); // experimental delay
parallel_set_dir(PARALLEL_DIR_OUT);
set_clock(0);
parallel_clear_rxflag();
delay_us(100); // experimental delay
parallel_send_handshake();
uart_flush();
delay_us(100); // experimental delay
/* every sector except the last */
uint8_t i;
while (!buf->sendeoi) {
iec_bus_t bus_state = iec_bus_read();
/* transmit first byte */
dolphin_write_hs(buf->data[2]);
/* check DATA state before transmission */
if (bus_state & IEC_BIT_DATA) {
cleanup_and_free_buffer(buf);
return;
}
/* transmit the rest of the sector */
for (i = 3; i != 0; i++)
dolphin_write_hs(buf->data[i]);
/* read next sector */
if (buf->refill(buf)) {
cleanup_and_free_buffer(buf);
return;
}
}
/* last sector */
i = 2;
do {
dolphin_write_hs(buf->data[i]);
} while (i++ < buf->lastused);
/* final handshake */
set_clock(1);
while (!IEC_DATA) ;
parallel_send_handshake();
parallel_set_dir(PARALLEL_DIR_IN);
cleanup_and_free_buffer(buf);
}
struct buffer_head * getblk(dev_t dev, int block, int size)
{
struct buffer_head * bh, * tmp;
int buffers;
static int grow_size = 0;
repeat:
bh = get_hash_table(dev, block, size);
if (bh) {
if (bh->b_uptodate && !bh->b_dirt)
put_last_free(bh);
return bh;
}
grow_size -= size;
if (nr_free_pages > min_free_pages && grow_size <= 0) {
if (grow_buffers(GFP_BUFFER, size))
grow_size = PAGE_SIZE;
}
buffers = nr_buffers;
bh = NULL;
for (tmp = free_list; buffers-- > 0 ; tmp = tmp->b_next_free) {
if (tmp->b_count || tmp->b_size != size)
continue;
if (mem_map[MAP_NR((unsigned long) tmp->b_data)] != 1)
continue;
if (!bh || BADNESS(tmp)<BADNESS(bh)) {
bh = tmp;
if (!BADNESS(tmp))
break;
}
#if 0
if (tmp->b_dirt) {
tmp->b_count++;
ll_rw_block(WRITEA, 1, &tmp);
tmp->b_count--;
}
#endif
}
if (!bh) {
if (nr_free_pages > 5)
if (grow_buffers(GFP_BUFFER, size))
goto repeat;
if (!grow_buffers(GFP_ATOMIC, size))
sleep_on(&buffer_wait);
goto repeat;
}
wait_on_buffer(bh);
if (bh->b_count || bh->b_size != size)
goto repeat;
if (bh->b_dirt) {
sync_buffers(0,0);
goto repeat;
}
/* NOTE!! While we slept waiting for this block, somebody else might */
/* already have added "this" block to the cache. check it */
if (find_buffer(dev,block,size))
goto repeat;
/* OK, FINALLY we know that this buffer is the only one of its kind, */
/* and that it's unused (b_count=0), unlocked (b_lock=0), and clean */
bh->b_count=1;
bh->b_dirt=0;
bh->b_uptodate=0;
bh->b_req=0;
remove_from_queues(bh);
bh->b_dev=dev;
bh->b_blocknr=block;
insert_into_queues(bh);
return bh;
}