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Re: [Qemu-devel] [PATCH v8 3/4] fdc: add function to determine drive chs
From: |
Michael S. Tsirkin |
Subject: |
Re: [Qemu-devel] [PATCH v8 3/4] fdc: add function to determine drive chs limits |
Date: |
Wed, 17 Feb 2016 22:15:32 +0200 |
On Wed, Feb 17, 2016 at 09:25:32PM +0300, Roman Kagan wrote:
> When populating ACPI objects for floppy drives one needs to provide the
> maximum values for cylinder, sector, and head number the drive supports.
>
> This patch adds a function that iterates through the array of predefined
> floppy drive formats and returns the maximum values of c, h, s, out of
> those matching the given floppy drive type.
>
> Signed-off-by: Roman Kagan <address@hidden>
> Cc: Igor Mammedov <address@hidden>
> Cc: "Michael S. Tsirkin" <address@hidden>
> Cc: Marcel Apfelbaum <address@hidden>
> Cc: John Snow <address@hidden>
> Cc: Laszlo Ersek <address@hidden>
> Cc: Kevin O'Connor <address@hidden>
> ---
> changes since v7:
> - use drive max c,h,s rather than the current diskette geometry
>
> hw/block/fdc.c | 23 +++++++++++++++++++++++
> include/hw/block/fdc.h | 2 ++
> 2 files changed, 25 insertions(+)
>
> diff --git a/hw/block/fdc.c b/hw/block/fdc.c
> index 9838d21..fc3aef9 100644
> --- a/hw/block/fdc.c
> +++ b/hw/block/fdc.c
> @@ -2557,6 +2557,29 @@ FloppyDriveType isa_fdc_get_drive_type(ISADevice *fdc,
> int i)
> return isa->state.drives[i].drive;
> }
>
> +void isa_fdc_get_drive_max_chs(FloppyDriveType type,
> + uint8_t *maxc, uint8_t *maxh, uint8_t *maxs)
> +{
> + const FDFormat *fdf;
> +
> + *maxc = *maxh = *maxs = 0;
> + for (fdf = fd_formats; fdf->drive != FLOPPY_DRIVE_TYPE_NONE; fdf++) {
> + if (fdf->drive != type) {
> + continue;
> + }
Hmm. How does this interact with the fallback/autodetect thing?
I understand what it does rather vaguely.
I wonder whether we can just ignore the type and take
global maximum in all cases.
> + if (*maxc < fdf->max_track) {
> + *maxc = fdf->max_track;
> + }
> + if (*maxh < fdf->max_head) {
> + *maxh = fdf->max_head;
> + }
> + if (*maxs < fdf->last_sect) {
> + *maxs = fdf->last_sect;
> + }
> + }
> + (*maxc)--;
Why not just *maxc = fdf->max_track - 1 above?
> +}
> +
> static const VMStateDescription vmstate_isa_fdc ={
> .name = "fdc",
> .version_id = 2,
> diff --git a/include/hw/block/fdc.h b/include/hw/block/fdc.h
> index adce14f..1749dab 100644
> --- a/include/hw/block/fdc.h
> +++ b/include/hw/block/fdc.h
> @@ -15,5 +15,7 @@ void sun4m_fdctrl_init(qemu_irq irq, hwaddr io_base,
> DriveInfo **fds, qemu_irq *fdc_tc);
>
> FloppyDriveType isa_fdc_get_drive_type(ISADevice *fdc, int i);
> +void isa_fdc_get_drive_max_chs(FloppyDriveType type,
> + uint8_t *maxc, uint8_t *maxh, uint8_t *maxs);
>
> #endif
> --
> 2.5.0
[Qemu-devel] [PATCH v8 4/4] i386: populate floppy drive information in DSDT, Roman Kagan, 2016/02/17
[Qemu-devel] [PATCH v8 1/4] i386/acpi: make floppy controller object dynamic, Roman Kagan, 2016/02/17