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

[BALATON Zoltan <balaton@eik.bme.hu>]

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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 */
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