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Subject[PATCH] QIC-02 tape broken buffaddr
I don't have a QIC-02 tape drive to test, but its driver source
looks long broken. Note the comment at line 2836 "TODO:
does _get_dma_pages() really return the physical address?" and
follow uses of buffaddr - sometimes physical, sometimes virtual.

Which worked in 2.2, with ISA DMA ignoring PAGE_OFFSET bits, and
bus_to_virt() or'ing them; but 2.4 bus_to_virt() adds PAGE_OFFSET.
Patch below against 2.4.2-ac9, applies to 2.4.[012] offset -2 lines.

Hugh

--- 2.4.2-ac9/drivers/char/tpqic02.c Fri Mar 2 18:22:36 2001
+++ linux/drivers/char/tpqic02.c Fri Mar 2 18:23:42 2001
@@ -210,7 +210,7 @@
* must ensure that a large enough buffer is passed to the kernel, in order
* to reduce tape repositioning wear and tear.
*/
-static unsigned long buffaddr; /* physical address of buffer */
+static void *buffaddr; /* virtual address of buffer */

/* This translates minor numbers to the corresponding recording format: */
static const char *format_names[] = {
@@ -1378,7 +1378,7 @@
flags=claim_dma_lock();
clear_dma_ff(QIC02_TAPE_DMA);
set_dma_mode(QIC02_TAPE_DMA, dma_mode);
- set_dma_addr(QIC02_TAPE_DMA, buffaddr+dma_bytes_done); /* full address */
+ set_dma_addr(QIC02_TAPE_DMA, virt_to_bus(buffaddr) + dma_bytes_done);
set_dma_count(QIC02_TAPE_DMA, TAPE_BLKSIZE);

/* start tape DMA controller */
@@ -1923,7 +1923,7 @@
/* copy buffer to user-space in one go */
if (bytes_done>0)
{
- err = copy_to_user( (void *) buf, (void *) bus_to_virt(buffaddr), bytes_done);
+ err = copy_to_user(buf, buffaddr, bytes_done);
if (err)
{
return -EFAULT;
@@ -2076,7 +2076,7 @@
/* copy from user to DMA buffer and initiate transfer. */
if (bytes_todo>0)
{
- err = copy_from_user( (void *) bus_to_virt(buffaddr), (const void *) buf, bytes_todo);
+ err = copy_from_user(buffaddr, buf, bytes_todo);
if (err)
{
return -EFAULT;
@@ -2782,7 +2782,7 @@
release_region(QIC02_TAPE_PORT, QIC02_TAPE_PORT_RANGE);
if (buffaddr)
{
- free_pages(buffaddr, get_order(TPQBUF_SIZE));
+ free_pages((unsigned long)buffaddr, get_order(TPQBUF_SIZE));
}
buffaddr = 0; /* Better to cause a panic than overwite someone else */
status_zombie = YES;
@@ -2832,9 +2832,7 @@
request_region(QIC02_TAPE_PORT, QIC02_TAPE_PORT_RANGE, TPQIC02_NAME);

/* Setup the page-address for the dma transfer. */
-
- /*** TODO: does _get_dma_pages() really return the physical address?? ****/
- buffaddr = __get_dma_pages(GFP_KERNEL,get_order(TPQBUF_SIZE));
+ buffaddr = (void *)__get_dma_pages(GFP_KERNEL, get_order(TPQBUF_SIZE));

if (!buffaddr)
{
@@ -2842,7 +2840,7 @@
return -EBUSY; /* Not ideal, EAGAIN perhaps? */
}

- memset( (void*) buffaddr, 0, TPQBUF_SIZE );
+ memset(buffaddr, 0, TPQBUF_SIZE);

printk(TPQIC02_NAME ": Settings: IRQ %d, DMA %d, IO 0x%x, IFC %s\n",
QIC02_TAPE_IRQ, QIC02_TAPE_DMA,
-
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