diff options
Diffstat (limited to 'sys/dev/fdc/fdc.c')
| -rw-r--r-- | sys/dev/fdc/fdc.c | 41 |
1 files changed, 38 insertions, 3 deletions
diff --git a/sys/dev/fdc/fdc.c b/sys/dev/fdc/fdc.c index 70fab4b..7f1cb27 100644 --- a/sys/dev/fdc/fdc.c +++ b/sys/dev/fdc/fdc.c @@ -213,6 +213,17 @@ FDC_ACCESSOR(fdunit, FDUNIT, int) #define FDC_DMAOV_MAX 25 /* + * Timeout value for the PIO loops to wait until the FDC main status + * register matches our expectations (request for master, direction + * bit). This is supposed to be a number of microseconds, although + * timing might actually not be very accurate. + * + * Timeouts of 100 msec are believed to be required for some broken + * (old) hardware. + */ +#define FDSTS_TIMEOUT 100000 + +/* * Number of subdevices that can be used for different density types. * By now, the lower 6 bit of the minor number are reserved for this, * allowing for up to 64 subdevices, but we only use 16 out of this. @@ -1480,7 +1491,15 @@ fd_in(struct fdc_data *fdc, int *ptr) != (NE7_DIO|NE7_RQM) && j-- > 0) { if (i == NE7_RQM) return fdc_err(fdc, "ready for output in input\n"); - DELAY(1); + /* + * After (maybe) 1 msec of waiting, back off to larger + * stepping to get the timing more accurate. + */ + if (FDSTS_TIMEOUT - j > 1000) { + DELAY(1000); + j -= 999; + } else + DELAY(1); } if (j <= 0) return fdc_err(fdc, bootverbose? "input ready timeout\n": 0); @@ -1505,13 +1524,29 @@ out_fdc(struct fdc_data *fdc, int x) /* Check that the direction bit is set */ i = FDSTS_TIMEOUT; while ((fdsts_rd(fdc) & NE7_DIO) && i-- > 0) - DELAY(1); + /* + * After (maybe) 1 msec of waiting, back off to larger + * stepping to get the timing more accurate. + */ + if (FDSTS_TIMEOUT - i > 1000) { + DELAY(1000); + i -= 999; + } else + DELAY(1); if (i <= 0) return fdc_err(fdc, "direction bit not set\n"); /* Check that the floppy controller is ready for a command */ i = FDSTS_TIMEOUT; while ((fdsts_rd(fdc) & NE7_RQM) == 0 && i-- > 0) - DELAY(1); + /* + * After (maybe) 1 msec of waiting, back off to larger + * stepping to get the timing more accurate. + */ + if (FDSTS_TIMEOUT - i > 1000) { + DELAY(1000); + i -= 999; + } else + DELAY(1); if (i <= 0) return fdc_err(fdc, bootverbose? "output ready timeout\n": 0); |
