Appended to the end of this mail is a patch containing two floppy
driver bug fixes intended for the 2.0 series. The virtual DMA bug can
lead to loss of data on floppies (if virtual DMA is switched on, and
for certain floppy drive controllers). The second bug prevents the
driver from initialzing with the new Winbond W83977AF chips.
I had already contacted Linus earlyer with a virtual DMA patch
against 2.0.33, but I'm afraid that the patch got lost when merging
with the 2.0.34pre patches. So this time, I submit it to you as well
;-)
To make things easyer, I only made one diff for both fixes.
Thanks in advance,
Alain
diff -ur 2.0.36-19/linux/drivers/block/floppy.c linux/drivers/block/floppy.c
--- 2.0.36-19/linux/drivers/block/floppy.c Tue Nov 10 23:12:34 1998
+++ linux/drivers/block/floppy.c Tue Nov 10 23:14:38 1998
@@ -521,6 +521,8 @@
static unsigned char current_drive = 0;
static long current_count_sectors = 0;
static unsigned char sector_t; /* sector in track */
+static unsigned char in_sector_offset; /* offset within physical sector,
+ * expressed in units of 512 bytes */
#ifndef fd_eject
#define fd_eject(x) -EINVAL
@@ -1682,12 +1684,14 @@
if(do_print)
print_result("unexpected interrupt", inr);
if (inr == 0){
+ int max_sensei = 4;
do {
output_byte(FD_SENSEI);
inr = result();
if(do_print)
print_result("sensei", inr);
- } while ((ST0 & 0x83) != UNIT(current_drive) && inr == 2);
+ max_sensei--;
+ } while ((ST0 & 0x83) != UNIT(current_drive) && inr == 2 && max_sensei);
}
if (handler) {
if(intr_count >= 2) {
@@ -2054,7 +2058,7 @@
#define CODE2SIZE (ssize = ((1 << SIZECODE) + 3) >> 2)
#define FM_MODE(x,y) ((y) & ~(((x)->rate & 0x80) >>1))
-#define CT(x) ((x) | 0x40)
+#define CT(x) ((x) | 0xc0)
static void setup_format_params(int track)
{
struct fparm {
@@ -2222,7 +2226,7 @@
/* Interrupt handler evaluating the result of the r/w operation */
static void rw_interrupt(void)
{
- int nr_sectors, ssize, eoc;
+ int nr_sectors, ssize, eoc, heads;
if (!DRS->first_read_date)
DRS->first_read_date = jiffies;
@@ -2234,23 +2238,32 @@
eoc = 1;
else
eoc = 0;
- nr_sectors = ((R_TRACK-TRACK)*_floppy->head+R_HEAD-HEAD) *
- _floppy->sect + ((R_SECTOR-SECTOR+eoc) << SIZECODE >> 2) -
- (sector_t % _floppy->sect) % ssize;
+
+ if(COMMAND & 0x80)
+ heads = 2;
+ else
+ heads = 1;
+
+ nr_sectors = (((R_TRACK-TRACK) * heads +
+ R_HEAD-HEAD) * SECT_PER_TRACK +
+ R_SECTOR-SECTOR + eoc) << SIZECODE >> 2;
#ifdef FLOPPY_SANITY_CHECK
- if (nr_sectors > current_count_sectors + ssize -
- (current_count_sectors + sector_t) % ssize +
- sector_t % ssize){
+ if (nr_sectors / ssize >
+ (in_sector_offset + current_count_sectors + ssize - 1)/ssize) {
DPRINT("long rw: %x instead of %lx\n",
nr_sectors, current_count_sectors);
printk("rs=%d s=%d\n", R_SECTOR, SECTOR);
printk("rh=%d h=%d\n", R_HEAD, HEAD);
printk("rt=%d t=%d\n", R_TRACK, TRACK);
- printk("spt=%d st=%d ss=%d\n", SECT_PER_TRACK,
- sector_t, ssize);
+ printk("heads=%d eoc=%d\n", heads, eoc);
+ printk("spt=%d st=%d ss=%d\n", SECT_PER_TRACK,
+ sector_t, ssize);
+ printk("in_sector_offset=%d\n", in_sector_offset);
}
#endif
+
+ nr_sectors -= in_sector_offset;
INFBOUND(nr_sectors,0);
SUPBOUND(current_count_sectors, nr_sectors);
@@ -2422,6 +2435,32 @@
#endif
}
+/* work around a bug in pseudo DMA
+ * (on some FDCs) pseudo DMA does not stop when the CPU stops
+ * sending data. Hence we need a different way to signal the
+ * transfer length: We use SECT_PER_TRACK. Unfortunately, this
+ * does not work with MT, hence we can only transfer one head at
+ * a time
+ */
+static void virtualdmabug_workaround(void) {
+ int hard_sectors, end_sector;
+ if(CT(COMMAND) == FD_WRITE) {
+ COMMAND &= ~0x80; /* switch off multiple track mode */
+
+ hard_sectors = raw_cmd->length >> (7 + SIZECODE);
+ end_sector = SECTOR + hard_sectors - 1;
+#ifdef FLOPPY_SANITY_CHECK
+ if(end_sector > SECT_PER_TRACK) {
+ printk("too many sectors %d > %d\n",
+ end_sector, SECT_PER_TRACK);
+ return;
+ }
+#endif
+ SECT_PER_TRACK = end_sector; /* make sure SECT_PER_TRACK points
+ * to end of transfer */
+ }
+}
+
/*
* Formulate a read/write request.
* this routine decides where to load the data (directly to buffer, or to
@@ -2493,11 +2532,17 @@
CODE2SIZE;
SECT_PER_TRACK = _floppy->sect << 2 >> SIZECODE;
SECTOR = ((sector_t % _floppy->sect) << 2 >> SIZECODE) + 1;
+
+ /* tracksize describes the size which can be filled up with sectors
+ * of size ssize.
+ */
tracksize = _floppy->sect - _floppy->sect % ssize;
if (tracksize < _floppy->sect){
SECT_PER_TRACK ++;
if (tracksize <= sector_t % _floppy->sect)
SECTOR--;
+
+ /* if we are beyond tracksize, fill up using smaller sectors */
while (tracksize <= sector_t % _floppy->sect){
while(tracksize + ssize > _floppy->sect){
SIZECODE--;
@@ -2507,10 +2552,15 @@
tracksize += ssize;
}
max_sector = HEAD * _floppy->sect + tracksize;
- } else if (!TRACK && !HEAD && !(_floppy->rate & FD_2M) && probing)
+ } else if (!TRACK && !HEAD && !(_floppy->rate & FD_2M) && probing) {
+ max_sector = _floppy->sect;
+ } else if (!HEAD && CT(COMMAND) == FD_WRITE) {
+ /* for virtual DMA bug workaround */
max_sector = _floppy->sect;
+ }
- aligned_sector_t = sector_t - (sector_t % _floppy->sect) % ssize;
+ in_sector_offset = (sector_t % _floppy->sect) % ssize;
+ aligned_sector_t = sector_t - in_sector_offset;
max_size = CURRENT->nr_sectors;
if ((raw_cmd->track == buffer_track) &&
(current_drive == buffer_drive) &&
@@ -2520,7 +2570,7 @@
copy_buffer(1, max_sector, buffer_max);
return 1;
}
- } else if (aligned_sector_t != sector_t || CURRENT->nr_sectors < ssize){
+ } else if (in_sector_offset || CURRENT->nr_sectors < ssize){
if (CT(COMMAND) == FD_WRITE){
if (sector_t + CURRENT->nr_sectors > ssize &&
sector_t + CURRENT->nr_sectors < ssize + ssize)
@@ -2573,6 +2623,7 @@
indirect, direct, sector_t);
return 0;
}
+ virtualdmabug_workaround();
return 2;
}
}
@@ -2586,7 +2637,7 @@
sector_t > buffer_max ||
sector_t < buffer_min ||
((CT(COMMAND) == FD_READ ||
- (aligned_sector_t == sector_t && CURRENT->nr_sectors >= ssize))&&
+ (!in_sector_offset && CURRENT->nr_sectors >= ssize))&&
max_sector > 2 * max_buffer_sectors + buffer_min &&
max_size + sector_t > 2 * max_buffer_sectors + buffer_min)
/* not enough space */){
@@ -2603,7 +2654,7 @@
* is either aligned or the data already in the buffer
* (buffer will be overwritten) */
#ifdef FLOPPY_SANITY_CHECK
- if (sector_t != aligned_sector_t && buffer_track == -1)
+ if (in_sector_offset && buffer_track == -1)
DPRINT("internal error offset !=0 on write\n");
#endif
buffer_track = raw_cmd->track;
@@ -2614,7 +2665,7 @@
2*max_buffer_sectors+buffer_min-aligned_sector_t);
/* round up current_count_sectors to get dma xfer size */
- raw_cmd->length = sector_t+current_count_sectors-aligned_sector_t;
+ raw_cmd->length = in_sector_offset+current_count_sectors;
raw_cmd->length = ((raw_cmd->length -1)|(ssize-1))+1;
raw_cmd->length <<= 9;
#ifdef FLOPPY_SANITY_CHECK
@@ -2676,6 +2727,8 @@
return 0;
}
#endif
+
+ virtualdmabug_workaround();
return 2;
}
-----------------------------------------------------------------------.
Email: alain@linux.lu Alain Lucien Knaff .
Tel(home): (352) 22 35 41 19, rue Jean l'Aveugle .
Tel(work): (352) 42 42 33 32 L-1148 Luxembourg-City .
Luxembourg .
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