Laszlo Ersek <ler...@redhat.com> writes:
> With the pc-q35-2.4 machine type, if the user creates an ISA FDC manually:
>
> -device isa-fdc,driveA=drive-fdc0-0-0 \
> -drive file=...,if=none,id=drive-fdc0-0-0,format=raw
>
> then the board-default FDC will be skipped, and only the explicitly
> requested FDC will exist. qtree-wise, this is correct; however such an FDC
> is currently not registered in the CMOS, because that code is only reached
> for the board-default FDC.
>
> The pc_cmos_init_late() one-shot reset handler -- one-shot because the
> CMOS is not reprogrammed during warm reset -- should search for any ISA
> FDC devices, created implicitly (by board code) or explicitly, and set the
> CMOS accordingly to the ISA FDC(s) with iobase=0x3f0:
>
> - if there is no such FDC, report both drives absent,
> - if there is exactly one such FDC, report its drives in the CMOS,
> - if there are more than one such FDCs, then pick one (it is not specified
> which one), and print a warning about the ambiguity.
>
> Cc: Jan Tomko <jto...@redhat.com>
> Cc: John Snow <js...@redhat.com>
> Cc: Markus Armbruster <arm...@redhat.com>
> Cc: Paolo Bonzini <pbonz...@redhat.com>
> Cc: Blue Swirl <blauwir...@gmail.com>
> Reported-by: Jan Tomko <jto...@redhat.com>
> Suggested-by: Markus Armbruster <arm...@redhat.com>
> Signed-off-by: Laszlo Ersek <ler...@redhat.com>
> ---
>
> Notes:
> v1:
>
> - Look for ISA FDC with iobase=0x3f0, not distinguishing the board
> default ISA FDC at all [Markus]. Handling the board-default ISA FDC
> uniformly requires scanning the "/unattached" container.
>
> - Checkpatch barfs at this patch (it doesn't recognize the compound
> literal (const char *[]) { ... }). I didn't care; this pattern is
> widely used in the tree. Just run
>
> git grep -F '*[])'
>
> CC'd Blue Swirl for this reason.
>
> hw/i386/pc.c | 57 +++++++++++++++++++++++++++++++++++++++++++++++++++++++--
> 1 file changed, 55 insertions(+), 2 deletions(-)
>
> diff --git a/hw/i386/pc.c b/hw/i386/pc.c
> index 4a835be..bdb2d2d 100644
> --- a/hw/i386/pc.c
> +++ b/hw/i386/pc.c
> @@ -335,6 +335,37 @@ typedef struct pc_cmos_init_late_arg {
> BusState *idebus[2];
> } pc_cmos_init_late_arg;
>
> +typedef struct check_fdc_state {
> + ISADevice *floppy;
> + bool multiple;
> +} CheckFdcState;
> +
> +static int check_fdc(Object *obj, void *opaque)
> +{
> + CheckFdcState *state = opaque;
> + Object *fdc;
> + uint32_t iobase;
> + Error *local_err = NULL;
> +
> + fdc = object_dynamic_cast(obj, TYPE_ISA_FDC);
> + if (!fdc) {
> + return 0;
> + }
> +
> + iobase = object_property_get_int(obj, "iobase", &local_err);
> + if (iobase != 0x3f0) {
> + error_free(local_err);
> + return 0;
> + }
Works, because object_property_get_int() returns -1 on error, and
(uint32_t)-1 != 0x3f0.
Perhaps (local_err || iobase != 0x3f0) would be more obvious.
> +
> + if (state->floppy) {
> + state->multiple = true;
> + } else {
> + state->floppy = ISA_DEVICE(obj);
> + }
> + return 0;
> +}
> +
> static void pc_cmos_init_late(void *opaque)
> {
> pc_cmos_init_late_arg *arg = opaque;
> @@ -343,6 +374,9 @@ static void pc_cmos_init_late(void *opaque)
> int8_t heads, sectors;
> int val;
> int i, trans;
> + const char **container_path;
> + Object *container;
> + CheckFdcState state = { 0 };
>
> val = 0;
> if (ide_get_geometry(arg->idebus[0], 0,
> @@ -372,6 +406,26 @@ static void pc_cmos_init_late(void *opaque)
> }
> rtc_set_memory(s, 0x39, val);
>
> + /*
> + * Locate the FDC at IO address 0x3f0, and configure the CMOS registers
> + * accordingly.
> + */
> + container_path = (const char *[]) { "/unattached", "/peripheral",
> + "/peripheral-anon", NULL };
> + do {
> + container = container_get(qdev_get_machine(), *container_path);
> + object_child_foreach(container, check_fdc, &state);
> + ++container_path;
> + } while (*container_path);
I'd prefer a for loop, because it keeps the loop control in one place.
Stepping an index instead of the only pointer lets us use an
old-fashioned array initializer instead of a fancy compound literal.
static const char *container_path[] = {
"/unattached", "/peripheral", "/peripheral-anon"
};
for (i = 0; i < ARRAY_SIZE(container_path); i++) {
container = container_get(qdev_get_machine(), container_path[i]);
object_child_foreach(container, check_fdc, &state);
}
Matter of taste. I like old-fashioned and non-fancy :)
> +
> + if (state.multiple) {
> + error_report("warning: multiple floppy disk controllers with "
> + "iobase=0x3f0 have been found;\n"
> + "the one being picked for CMOS setup might not reflect "
> + "your intent");
> + }
> + pc_cmos_init_floppy(s, state.floppy);
> +
> qemu_unregister_reset(pc_cmos_init_late, opaque);
> }
>
> @@ -441,9 +495,8 @@ void pc_cmos_init(ram_addr_t ram_size, ram_addr_t
> above_4g_mem_size,
> val |= 0x02; /* FPU is there */
> val |= 0x04; /* PS/2 mouse installed */
> rtc_set_memory(s, REG_EQUIPMENT_BYTE, val);
> - pc_cmos_init_floppy(s, floppy);
>
> - /* hard drives */
> + /* hard drives and FDC */
> arg.rtc_state = s;
> arg.idebus[0] = idebus0;
> arg.idebus[1] = idebus1;
