floppy: support arbitrary first-sector numbers
The current floppy_struct allows floppies to number sectors starting from 0 or 1. This patch allows arbitrary first-sector numbers - for example, 0xC1 for Amstrad CPC disks. This extends the existing 1-bit field (FD_ZEROBASED, bit 2 of stretch) to 8 bits (FD_SECTMASK, bits 2 to 9). Currently 0x00 denotes a first sector number of 1, and 0x01 denotes a first sector number of 0. We extend this by interpreting FD_SECTMASK as the first sector number with the LSB flipped. Signed-off-by: Keith Wansbrough <keith@lochan.org> Cc: Alain Knaff <alain@linux.lu> Cc: Michael Kerrisk <mtk.manpages@googlemail.com> Cc: Karel Zak <kzak@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
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@ -423,8 +423,15 @@ static struct floppy_raw_cmd *raw_cmd, default_raw_cmd;
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* 1581's logical side 0 is on physical side 1, whereas the Sharp's logical
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* 1581's logical side 0 is on physical side 1, whereas the Sharp's logical
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* side 0 is on physical side 0 (but with the misnamed sector IDs).
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* side 0 is on physical side 0 (but with the misnamed sector IDs).
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* 'stretch' should probably be renamed to something more general, like
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* 'stretch' should probably be renamed to something more general, like
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* 'options'. Other parameters should be self-explanatory (see also
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* 'options'.
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* setfdprm(8)).
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*
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* Bits 2 through 9 of 'stretch' tell the number of the first sector.
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* The LSB (bit 2) is flipped. For most disks, the first sector
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* is 1 (represented by 0x00<<2). For some CP/M and music sampler
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* disks (such as Ensoniq EPS 16plus) it is 0 (represented as 0x01<<2).
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* For Amstrad CPC disks it is 0xC1 (represented as 0xC0<<2).
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*
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* Other parameters should be self-explanatory (see also setfdprm(8)).
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*/
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*/
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/*
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/*
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Size
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Size
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@ -2236,9 +2243,9 @@ static void setup_format_params(int track)
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}
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}
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}
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}
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}
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}
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if (_floppy->stretch & FD_ZEROBASED) {
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if (_floppy->stretch & FD_SECTBASEMASK) {
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for (count = 0; count < F_SECT_PER_TRACK; count++)
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for (count = 0; count < F_SECT_PER_TRACK; count++)
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here[count].sect--;
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here[count].sect += FD_SECTBASE(_floppy) - 1;
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}
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}
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}
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}
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@ -2649,7 +2656,7 @@ static int make_raw_rw_request(void)
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}
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}
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HEAD = fsector_t / _floppy->sect;
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HEAD = fsector_t / _floppy->sect;
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if (((_floppy->stretch & (FD_SWAPSIDES | FD_ZEROBASED)) ||
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if (((_floppy->stretch & (FD_SWAPSIDES | FD_SECTBASEMASK)) ||
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TESTF(FD_NEED_TWADDLE)) && fsector_t < _floppy->sect)
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TESTF(FD_NEED_TWADDLE)) && fsector_t < _floppy->sect)
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max_sector = _floppy->sect;
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max_sector = _floppy->sect;
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@ -2679,7 +2686,7 @@ static int make_raw_rw_request(void)
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CODE2SIZE;
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CODE2SIZE;
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SECT_PER_TRACK = _floppy->sect << 2 >> SIZECODE;
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SECT_PER_TRACK = _floppy->sect << 2 >> SIZECODE;
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SECTOR = ((fsector_t % _floppy->sect) << 2 >> SIZECODE) +
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SECTOR = ((fsector_t % _floppy->sect) << 2 >> SIZECODE) +
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((_floppy->stretch & FD_ZEROBASED) ? 0 : 1);
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FD_SECTBASE(_floppy);
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/* tracksize describes the size which can be filled up with sectors
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/* tracksize describes the size which can be filled up with sectors
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* of size ssize.
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* of size ssize.
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@ -3311,7 +3318,7 @@ static inline int set_geometry(unsigned int cmd, struct floppy_struct *g,
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g->head <= 0 ||
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g->head <= 0 ||
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g->track <= 0 || g->track > UDP->tracks >> STRETCH(g) ||
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g->track <= 0 || g->track > UDP->tracks >> STRETCH(g) ||
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/* check if reserved bits are set */
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/* check if reserved bits are set */
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(g->stretch & ~(FD_STRETCH | FD_SWAPSIDES | FD_ZEROBASED)) != 0)
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(g->stretch & ~(FD_STRETCH | FD_SWAPSIDES | FD_SECTBASEMASK)) != 0)
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return -EINVAL;
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return -EINVAL;
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if (type) {
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if (type) {
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if (!capable(CAP_SYS_ADMIN))
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if (!capable(CAP_SYS_ADMIN))
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@ -3356,7 +3363,7 @@ static inline int set_geometry(unsigned int cmd, struct floppy_struct *g,
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if (DRS->maxblock > user_params[drive].sect ||
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if (DRS->maxblock > user_params[drive].sect ||
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DRS->maxtrack ||
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DRS->maxtrack ||
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((user_params[drive].sect ^ oldStretch) &
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((user_params[drive].sect ^ oldStretch) &
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(FD_SWAPSIDES | FD_ZEROBASED)))
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(FD_SWAPSIDES | FD_SECTBASEMASK)))
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invalidate_drive(bdev);
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invalidate_drive(bdev);
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else
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else
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process_fd_request();
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process_fd_request();
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@ -15,10 +15,16 @@ struct floppy_struct {
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sect, /* sectors per track */
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sect, /* sectors per track */
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head, /* nr of heads */
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head, /* nr of heads */
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track, /* nr of tracks */
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track, /* nr of tracks */
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stretch; /* !=0 means double track steps */
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stretch; /* bit 0 !=0 means double track steps */
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/* bit 1 != 0 means swap sides */
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/* bits 2..9 give the first sector */
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/* number (the LSB is flipped) */
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#define FD_STRETCH 1
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#define FD_STRETCH 1
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#define FD_SWAPSIDES 2
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#define FD_SWAPSIDES 2
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#define FD_ZEROBASED 4
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#define FD_ZEROBASED 4
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#define FD_SECTBASEMASK 0x3FC
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#define FD_MKSECTBASE(s) (((s) ^ 1) << 2)
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#define FD_SECTBASE(floppy) ((((floppy)->stretch & FD_SECTBASEMASK) >> 2) ^ 1)
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unsigned char gap, /* gap1 size */
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unsigned char gap, /* gap1 size */
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