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author | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-17 02:20:36 +0400 |
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committer | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-17 02:20:36 +0400 |
commit | 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch) | |
tree | 0bba044c4ce775e45a88a51686b5d9f90697ea9d /include/linux/pg.h | |
download | linux-1da177e4c3f41524e886b7f1b8a0c1fc7321cac2.tar.xz |
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
Diffstat (limited to 'include/linux/pg.h')
-rw-r--r-- | include/linux/pg.h | 63 |
1 files changed, 63 insertions, 0 deletions
diff --git a/include/linux/pg.h b/include/linux/pg.h new file mode 100644 index 000000000000..db994bb0c794 --- /dev/null +++ b/include/linux/pg.h @@ -0,0 +1,63 @@ +/* pg.h (c) 1998 Grant R. Guenther <grant@torque.net> + Under the terms of the GNU General Public License + + + pg.h defines the user interface to the generic ATAPI packet + command driver for parallel port ATAPI devices (pg). The + driver is loosely modelled after the generic SCSI driver, sg, + although the actual interface is different. + + The pg driver provides a simple character device interface for + sending ATAPI commands to a device. With the exception of the + ATAPI reset operation, all operations are performed by a pair + of read and write operations to the appropriate /dev/pgN device. + A write operation delivers a command and any outbound data in + a single buffer. Normally, the write will succeed unless the + device is offline or malfunctioning, or there is already another + command pending. If the write succeeds, it should be followed + immediately by a read operation, to obtain any returned data and + status information. A read will fail if there is no operation + in progress. + + As a special case, the device can be reset with a write operation, + and in this case, no following read is expected, or permitted. + + There are no ioctl() operations. Any single operation + may transfer at most PG_MAX_DATA bytes. Note that the driver must + copy the data through an internal buffer. In keeping with all + current ATAPI devices, command packets are assumed to be exactly + 12 bytes in length. + + To permit future changes to this interface, the headers in the + read and write buffers contain a single character "magic" flag. + Currently this flag must be the character "P". + +*/ + +#define PG_MAGIC 'P' +#define PG_RESET 'Z' +#define PG_COMMAND 'C' + +#define PG_MAX_DATA 32768 + +struct pg_write_hdr { + + char magic; /* == PG_MAGIC */ + char func; /* PG_RESET or PG_COMMAND */ + int dlen; /* number of bytes expected to transfer */ + int timeout; /* number of seconds before timeout */ + char packet[12]; /* packet command */ + +}; + +struct pg_read_hdr { + + char magic; /* == PG_MAGIC */ + char scsi; /* "scsi" status == sense key */ + int dlen; /* size of device transfer request */ + int duration; /* time in seconds command took */ + char pad[12]; /* not used */ + +}; + +/* end of pg.h */ |