static irqreturn_t scsi_falcon_intr (int irq, void *dummy, struct pt_regs *fp)
{
#ifdef REAL_DMA
int dma_stat;
/* Turn off DMA and select sector counter register before
* accessing the status register (Atari recommendation!)
*/
st_dma.dma_mode_status = 0x90;
dma_stat = st_dma.dma_mode_status;
/* Bit 0 indicates some error in the DMA process... don't know
* what happened exactly (no further docu).
*/
if (!(dma_stat & 0x01)) {
/* DMA error */
printk(KERN_CRIT "SCSI DMA error near 0x%08lx!\n", SCSI_DMA_GETADR());
}
/* If the DMA was active, but now bit 1 is not clear, it is some
* other 5380 interrupt that finishes the DMA transfer. We have to
* calculate the number of residual bytes and give a warning if
* bytes are stuck in the ST-DMA fifo (there's no way to reach them!)
*/
if (atari_dma_active && (dma_stat & 0x02)) {
unsigned long transferred;
transferred = SCSI_DMA_GETADR() - atari_dma_startaddr;
/* The ST-DMA address is incremented in 2-byte steps, but the
* data are written only in 16-byte chunks. If the number of
* transferred bytes is not divisible by 16, the remainder is
* lost somewhere in outer space.
*/
if (transferred & 15)
printk(KERN_ERR "SCSI DMA error: %ld bytes lost in "
"ST-DMA fifo\n", transferred & 15);
atari_dma_residual = HOSTDATA_DMALEN - transferred;
DMA_PRINTK("SCSI DMA: There are %ld residual bytes.\n",
atari_dma_residual);
}
else
atari_dma_residual = 0;
atari_dma_active = 0;
if (atari_dma_orig_addr) {
/* If the dribble buffer was used on a read operation, copy the DMA-ed
* data to the original destination address.
*/
memcpy(atari_dma_orig_addr, phys_to_virt(atari_dma_startaddr),
HOSTDATA_DMALEN - atari_dma_residual);
atari_dma_orig_addr = NULL;
}
#endif /* REAL_DMA */
NCR5380_intr (0, 0, 0);
return IRQ_HANDLED;
}
static void atari_scsi_fetch_restbytes( void )
{
int nr;
char *src, *dst;
/* fetch rest bytes in the DMA register */
dst = (char *)SCSI_DMA_READ_P( dma_addr );
if ((nr = ((long)dst & 3))) {
/* there are 'nr' bytes left for the last long address before the
DMA pointer */
dst = (char *)( (unsigned long)dst & ~3 );
DMA_PRINTK("SCSI DMA: there are %d rest bytes for phys addr 0x%08lx",
nr, (long)dst);
dst = (char *)PTOV(dst); /* The content of the DMA pointer
* is a physical address! */
DMA_PRINTK(" = virt addr 0x%08lx\n", (long)dst);
for( src = (char *)&tt_scsi_dma.dma_restdata; nr > 0; --nr )
*dst++ = *src++;
}
}
static void atari_scsi_fetch_restbytes( void )
{
int nr;
char *src, *dst;
unsigned long phys_dst;
/* fetch rest bytes in the DMA register */
phys_dst = SCSI_DMA_READ_P(dma_addr);
nr = phys_dst & 3;
if (nr) {
/* there are 'nr' bytes left for the last long address
before the DMA pointer */
phys_dst ^= nr;
DMA_PRINTK("SCSI DMA: there are %d rest bytes for phys addr 0x%08lx",
nr, phys_dst);
/* The content of the DMA pointer is a physical address! */
dst = phys_to_virt(phys_dst);
DMA_PRINTK(" = virt addr %p\n", dst);
for (src = (char *)&tt_scsi_dma.dma_restdata; nr != 0; --nr)
*dst++ = *src++;
}
}
unsigned long atari_scsi_dma_setup( struct Scsi_Host *instance, void *data,
unsigned long count, int dir )
{
unsigned long addr = virt_to_phys( data );
DMA_PRINTK("scsi%d: setting up dma, data = %p, phys = %lx, count = %ld, "
"dir = %d\n", instance->host_no, data, addr, count, dir);
if (!IS_A_TT() && !STRAM_ADDR(addr)) {
/* If we have a non-DMAable address on a Falcon, use the dribble
* buffer; 'orig_addr' != 0 in the read case tells the interrupt
* handler to copy data from the dribble buffer to the originally
* wanted address.
*/
if (dir)
memcpy( atari_dma_buffer, data, count );
else
atari_dma_orig_addr = data;
addr = atari_dma_phys_buffer;
}
atari_dma_startaddr = addr; /* Needed for calculating residual later. */
/* Cache cleanup stuff: On writes, push any dirty cache out before sending
* it to the peripheral. (Must be done before DMA setup, since at least
* the ST-DMA begins to fill internal buffers right after setup. For
* reads, invalidate any cache, may be altered after DMA without CPU
* knowledge.
*
* ++roman: For the Medusa, there's no need at all for that cache stuff,
* because the hardware does bus snooping (fine!).
*/
dma_cache_maintenance( addr, count, dir );
if (count == 0)
printk(KERN_NOTICE "SCSI warning: DMA programmed for 0 bytes !\n");
if (IS_A_TT()) {
tt_scsi_dma.dma_ctrl = dir;
SCSI_DMA_WRITE_P( dma_addr, addr );
SCSI_DMA_WRITE_P( dma_cnt, count );
tt_scsi_dma.dma_ctrl = dir | 2;
}
else { /* ! IS_A_TT */
/* set address */
SCSI_DMA_SETADR( addr );
/* toggle direction bit to clear FIFO and set DMA direction */
dir <<= 8;
st_dma.dma_mode_status = 0x90 | dir;
st_dma.dma_mode_status = 0x90 | (dir ^ 0x100);
st_dma.dma_mode_status = 0x90 | dir;
udelay(40);
/* On writes, round up the transfer length to the next multiple of 512
* (see also comment at atari_dma_xfer_len()). */
st_dma.fdc_acces_seccount = (count + (dir ? 511 : 0)) >> 9;
udelay(40);
st_dma.dma_mode_status = 0x10 | dir;
udelay(40);
/* need not restore value of dir, only boolean value is tested */
atari_dma_active = 1;
}
return( count );
}
static irqreturn_t scsi_tt_intr (int irq, void *dummy, struct pt_regs *fp)
{
#ifdef REAL_DMA
int dma_stat;
dma_stat = tt_scsi_dma.dma_ctrl;
INT_PRINTK("scsi%d: NCR5380 interrupt, DMA status = %02x\n",
atari_scsi_host->host_no, dma_stat & 0xff);
/* Look if it was the DMA that has interrupted: First possibility
* is that a bus error occurred...
*/
if (dma_stat & 0x80) {
if (!scsi_dma_is_ignored_buserr( dma_stat )) {
printk(KERN_ERR "SCSI DMA caused bus error near 0x%08lx\n",
SCSI_DMA_READ_P(dma_addr));
printk(KERN_CRIT "SCSI DMA bus error -- bad DMA programming!");
}
}
/* If the DMA is active but not finished, we have the case
* that some other 5380 interrupt occurred within the DMA transfer.
* This means we have residual bytes, if the desired end address
* is not yet reached. Maybe we have to fetch some bytes from the
* rest data register, too. The residual must be calculated from
* the address pointer, not the counter register, because only the
* addr reg counts bytes not yet written and pending in the rest
* data reg!
*/
if ((dma_stat & 0x02) && !(dma_stat & 0x40)) {
atari_dma_residual = HOSTDATA_DMALEN - (SCSI_DMA_READ_P( dma_addr ) -
atari_dma_startaddr);
DMA_PRINTK("SCSI DMA: There are %ld residual bytes.\n",
atari_dma_residual);
if ((signed int)atari_dma_residual < 0)
atari_dma_residual = 0;
if ((dma_stat & 1) == 0) {
/* After read operations, we maybe have to
transport some rest bytes */
atari_scsi_fetch_restbytes();
}
else {
/* There seems to be a nasty bug in some SCSI-DMA/NCR
combinations: If a target disconnects while a write
operation is going on, the address register of the
DMA may be a few bytes farer than it actually read.
This is probably due to DMA prefetching and a delay
between DMA and NCR. Experiments showed that the
dma_addr is 9 bytes to high, but this could vary.
The problem is, that the residual is thus calculated
wrong and the next transfer will start behind where
it should. So we round up the residual to the next
multiple of a sector size, if it isn't already a
multiple and the originally expected transfer size
was. The latter condition is there to ensure that
the correction is taken only for "real" data
transfers and not for, e.g., the parameters of some
other command. These shouldn't disconnect anyway.
*/
if (atari_dma_residual & 0x1ff) {
DMA_PRINTK("SCSI DMA: DMA bug corrected, "
"difference %ld bytes\n",
512 - (atari_dma_residual & 0x1ff));
atari_dma_residual = (atari_dma_residual + 511) & ~0x1ff;
}
}
tt_scsi_dma.dma_ctrl = 0;
}
/* If the DMA is finished, fetch the rest bytes and turn it off */
if (dma_stat & 0x40) {
atari_dma_residual = 0;
if ((dma_stat & 1) == 0)
atari_scsi_fetch_restbytes();
tt_scsi_dma.dma_ctrl = 0;
}
#endif /* REAL_DMA */
NCR5380_intr (0, 0, 0);
#if 0
/* To be sure the int is not masked */
atari_enable_irq( IRQ_TT_MFP_SCSI );
#endif
return IRQ_HANDLED;
}
static unsigned long atari_dma_xfer_len( unsigned long wanted_len,
Scsi_Cmnd *cmd,
int write_flag )
{
unsigned long possible_len, limit;
#ifndef CONFIG_TT_DMA_EMUL
if (MACH_IS_HADES)
/* Hades has no SCSI DMA at all :-( Always force use of PIO */
return( 0 );
#endif
if (IS_A_TT())
/* TT SCSI DMA can transfer arbitrary #bytes */
return( wanted_len );
/* ST DMA chip is stupid -- only multiples of 512 bytes! (and max.
* 255*512 bytes, but this should be enough)
*
* ++roman: Aaargl! Another Falcon-SCSI problem... There are some commands
* that return a number of bytes which cannot be known beforehand. In this
* case, the given transfer length is an "allocation length". Now it
* can happen that this allocation length is a multiple of 512 bytes and
* the DMA is used. But if not n*512 bytes really arrive, some input data
* will be lost in the ST-DMA's FIFO :-( Thus, we have to distinguish
* between commands that do block transfers and those that do byte
* transfers. But this isn't easy... there are lots of vendor specific
* commands, and the user can issue any command via the
* SCSI_IOCTL_SEND_COMMAND.
*
* The solution: We classify SCSI commands in 1) surely block-mode cmd.s,
* 2) surely byte-mode cmd.s and 3) cmd.s with unknown mode. In case 1)
* and 3), the thing to do is obvious: allow any number of blocks via DMA
* or none. In case 2), we apply some heuristic: Byte mode is assumed if
* the transfer (allocation) length is < 1024, hoping that no cmd. not
* explicitly known as byte mode have such big allocation lengths...
* BTW, all the discussion above applies only to reads. DMA writes are
* unproblematic anyways, since the targets aborts the transfer after
* receiving a sufficient number of bytes.
*
* Another point: If the transfer is from/to an non-ST-RAM address, we
* use the dribble buffer and thus can do only STRAM_BUFFER_SIZE bytes.
*/
if (write_flag) {
/* Write operation can always use the DMA, but the transfer size must
* be rounded up to the next multiple of 512 (atari_dma_setup() does
* this).
*/
possible_len = wanted_len;
}
else {
/* Read operations: if the wanted transfer length is not a multiple of
* 512, we cannot use DMA, since the ST-DMA cannot split transfers
* (no interrupt on DMA finished!)
*/
if (wanted_len & 0x1ff)
possible_len = 0;
else {
/* Now classify the command (see above) and decide whether it is
* allowed to do DMA at all */
switch( falcon_classify_cmd( cmd )) {
case CMD_SURELY_BLOCK_MODE:
possible_len = wanted_len;
break;
case CMD_SURELY_BYTE_MODE:
possible_len = 0; /* DMA prohibited */
break;
case CMD_MODE_UNKNOWN:
default:
/* For unknown commands assume block transfers if the transfer
* size/allocation length is >= 1024 */
possible_len = (wanted_len < 1024) ? 0 : wanted_len;
break;
}
}
}
/* Last step: apply the hard limit on DMA transfers */
limit = (atari_dma_buffer && !STRAM_ADDR( virt_to_phys(cmd->SCp.ptr) )) ?
STRAM_BUFFER_SIZE : 255*512;
if (possible_len > limit)
possible_len = limit;
if (possible_len != wanted_len)
DMA_PRINTK("Sorry, must cut DMA transfer size to %ld bytes "
"instead of %ld\n", possible_len, wanted_len);
return( possible_len );
}
