Re: [Qemu-devel] [12 patches] FDC: improve emulation

[Blue Swirl]

On 4/16/08, Hervé Poussineau <address@hidden> wrote:
> Hi,
>
>  I've done big improvements on floppy drive controller.
>  For easier reviewing, I've tried to split them up in differents parts.
> Sorry if some parts are still big.
>  Each patch applies on top of the previous one.
>
>  If only some of them are accepted, I can provide a global patch for only
> these ones. Patches which needs more work will be resubmitted later.
>
>  List of attached patches:
>
>  fdc_01_lookuptable.diff
>  - Adds a command lookup table, as suggested by Fabrice at
> http://lists.gnu.org/archive/html/qemu-devel/2008-04/msg00143.html
>  - This also moves initialization functions at the bottom of the file to
> prevent multiple forward declarations.
>
>  fdc_02_seek_next_sector.diff
>  - Extract seeking to next sector handling in a function. Add a sector seek
> in PIO read and write modes
>
>  fdc_03_status_ab.diff
>  - Fixes status A and status B registers. It removes one Sun4m mutation.
> Also removes the internal FD_CTRL_INTR flag.
>
>  fdc_04_status_012.diff
>  - Fixes status0, status1 and status2 handling, which were broken in
> read/write commands and in some subtle ways. Status are now calculated
> during command execution and not at the very end.
>  - This allows removing of one hack in
> fdctrl_handle_sense_interrupt_status().
>
>  fdc_05_dmaen.diff
>  - Handles correctly FD_MSR_NONDMA/FD_DOR_NONDMA flags, and uses them when
> possible. Fixes a problem with SPECIFY command. This allows removing of last
> Sun4m mutation.
>
>  fdc_06_dor_reg.diff
>  - Better handling of DOR register. DOR register drives external motors, but
> it not limited to existing drives.
>  - Use FD_DOR_nRESET flag instead of internal FD_CTRL_RESET flag.
>  - Support writing to DOR register even in reset mode (as said in
> specification)
>
>  fdc_07_msr_reg.diff
>  - Stores controller state in MSR register instead of internal state field.
> This simplifies the fdctrl_read_main_status() function, which may be called
> in some tight loops.
>
>  fdc_08_cleanup.diff
>  - Removes useless fields in fdrive_t structure.
>  - Adds a message when bdrv_read/bdrv_write calls fail.
>
>  fdc_09_tdr_reg.diff
>  - Replaces bootsel field by the whole tdr register. It may be easier if we
> want to later add support for tapes.
>
>  fdc_10_4_fds.diff
>  - Supports up to 4 floppy drives if MAX_FD is set to 4.
>
>  fdc_11_cur_drv.diff
>  - Replaces access to cur_drv field by macros.
>
>  fdc_12_pio_write.diff
>  - Fixes transfer data length.
>  - Fixes buffer overflow in PIO mode write.
>
>  Floppy controller works better than before in Sun4m. It now gets READ
> commands and correctly detects if floppy is write-protected or not.
> Unfortunately, no valid filesystem seems to be found on the floppy.

Maybe the TC signal should be used (fdctrl_handle_tc)? I didn't know
what to do with it, but Linux uses it when transferring data.