Re: [PATCH v3] ppc/amigaone: Allow running AmigaOS without firmware image

[BALATON Zoltan]

On Tue, 28 Nov 2023, Cédric Le Goater wrote:
> On 11/28/23 02:32, BALATON Zoltan wrote:
> > The machine uses a modified U-Boot under GPL license but the sources
> > of it are lost with only a binary available so it cannot be included
> > in QEMU. Allow running without the firmware image which can be used
> > when calling a boot loader directly and thus simplifying booting
> > guests. We need a small routine that AmigaOS calls from ROM which is
> > added in this case to allow booting AmigaOS without external firmware
> > image.
> >
> > Signed-off-by: BALATON Zoltan <balaton@eik.bme.hu>
>
> Since this is 8.2 material :
>
>
> Fixes: d9656f860a38 ("hw/ppc: Add emulation of AmigaOne XE board")

This has missed rc2 but I hope there still will be a pull request before 
rc3 which is the last chance now. I've sent a v4 which simpilifies the 
inserted code as I've found there's no need to do it like in the rom as 
the only place it's called from just cares about the result.

I forgot the Fixes tag again, sorry, but the one above is still the same.

Regards,
BALATON Zoltan

> Thanks,
>
> C.
>
>
>
> > ---
> > v3: Instead of -bios none do this when no -bios option given, use
> > constants for address and rom_add_blob_fixed() to add dummy_fw.
> > This makes both code and usage a bit simpler.
> >
> >   hw/ppc/amigaone.c | 35 +++++++++++++++++++++++------------
> >   1 file changed, 23 insertions(+), 12 deletions(-)
> >
> > diff --git a/hw/ppc/amigaone.c b/hw/ppc/amigaone.c
> > index 992a55e632..ddfa09457a 100644
> > --- a/hw/ppc/amigaone.c
> > +++ b/hw/ppc/amigaone.c
> > @@ -36,10 +36,19 @@
> >    * -device VGA,romfile=VGABIOS-lgpl-latest.bin
> >    * from http://www.nongnu.org/vgabios/ instead.
> >    */
> > -#define PROM_FILENAME "u-boot-amigaone.bin"
> >   #define PROM_ADDR 0xfff00000
> >   #define PROM_SIZE (512 * KiB)
> >   +/* AmigaOS calls this routine from ROM, use this if no firmware loaded 
> > */
> > +static const char dummy_fw[] = {
> > +    0x38, 0x00, 0x00, 0x08, /* li      r0,8 */
> > +    0x7c, 0x09, 0x03, 0xa6, /* mtctr   r0 */
> > +    0x54, 0x63, 0xf8, 0x7e, /* srwi    r3,r3,1 */
> > +    0x42, 0x00, 0xff, 0xfc, /* bdnz    0x8 */
> > +    0x7c, 0x63, 0x18, 0xf8, /* not     r3,r3 */
> > +    0x4e, 0x80, 0x00, 0x20, /* blr */
> > +};
> > +
> >   static void amigaone_cpu_reset(void *opaque)
> >   {
> >       PowerPCCPU *cpu = opaque;
> > @@ -60,8 +69,6 @@ static void amigaone_init(MachineState *machine)
> >       PowerPCCPU *cpu;
> >       CPUPPCState *env;
> >       MemoryRegion *rom, *pci_mem, *mr;
> > -    const char *fwname = machine->firmware ?: PROM_FILENAME;
> > -    char *filename;
> >       ssize_t sz;
> >       PCIBus *pci_bus;
> >       Object *via;
> > @@ -94,20 +101,24 @@ static void amigaone_init(MachineState *machine)
> >       }
> >         /* allocate and load firmware */
> > -    filename = qemu_find_file(QEMU_FILE_TYPE_BIOS, fwname);
> > -    if (filename) {
> > -        rom = g_new(MemoryRegion, 1);
> > -        memory_region_init_rom(rom, NULL, "rom", PROM_SIZE, &error_fatal);
> > -        memory_region_add_subregion(get_system_memory(), PROM_ADDR, rom);
> > +    rom = g_new(MemoryRegion, 1);
> > +    memory_region_init_rom(rom, NULL, "rom", PROM_SIZE, &error_fatal);
> > +    memory_region_add_subregion(get_system_memory(), PROM_ADDR, rom);
> > +    if (!machine->firmware) {
> > +        rom_add_blob_fixed("dummy-fw", dummy_fw, sizeof(dummy_fw),
> > +                           PROM_ADDR + PROM_SIZE - 0x80);
> > +    } else {
> > +        g_autofree char *filename = qemu_find_file(QEMU_FILE_TYPE_BIOS,
> > +                                                   machine->firmware);
> > +        if (!filename) {
> > +            error_report("Could not find firmware '%s'", 
> > machine->firmware);
> > +            exit(1);
> > +        }
> >           sz = load_image_targphys(filename, PROM_ADDR, PROM_SIZE);
> >           if (sz <= 0 || sz > PROM_SIZE) {
> >               error_report("Could not load firmware '%s'", filename);
> >               exit(1);
> >           }
> > -        g_free(filename);
> > -    } else if (!qtest_enabled()) {
> > -        error_report("Could not find firmware '%s'", fwname);
> > -        exit(1);
> >       }
> >         /* Articia S */