Re: [PATCH v2 12/12] hw/isa/vt82c686: Implement relocation and toggling of SuperI/O functions

[Bernhard Beschow]

Am 19. Dezember 2023 00:26:15 UTC schrieb BALATON Zoltan <balaton@eik.bme.hu>:
>On Mon, 18 Dec 2023, Bernhard Beschow wrote:
>> The VIA south bridges are able to relocate and toggle (enable or disable) 
>> their
>> SuperI/O functions. So far this is hardcoded such that all functions are 
>> always
>> enabled and are located at fixed addresses.
>> 
>> Some PC BIOSes seem to probe for I/O occupancy before activating such a 
>> function
>> and issue an error in case of a conflict. Since the functions are enabled on
>> reset, conflicts are always detected. Prevent that by implementing relocation
>> and toggling of the SuperI/O functions.
>> 
>> Note that all SuperI/O functions are now deactivated upon reset (except for
>> VT82C686B's serial ports where Fuloong 2e's rescue-yl seems to expect them 
>> to be
>> enabled by default). Rely on firmware -- or in case of pegasos2 on board 
>> code if
>> no -bios is given -- to configure the functions accordingly.
>
>Pegasos2 emulates firmware when no -bios is given, this was explained in 
>previos commit so maybe not needed to be explained it here again so you could 
>drop the comment between -- -- but I don't mind.
>
>> Signed-off-by: Bernhard Beschow <shentey@gmail.com>
>> ---
>> hw/isa/vt82c686.c | 121 ++++++++++++++++++++++++++++++++++------------
>> 1 file changed, 90 insertions(+), 31 deletions(-)
>> 
>> diff --git a/hw/isa/vt82c686.c b/hw/isa/vt82c686.c
>> index 9c2333a277..be202d23cf 100644
>> --- a/hw/isa/vt82c686.c
>> +++ b/hw/isa/vt82c686.c
>> @@ -15,6 +15,9 @@
>> 
>> #include "qemu/osdep.h"
>> #include "hw/isa/vt82c686.h"
>> +#include "hw/block/fdc.h"
>> +#include "hw/char/parallel-isa.h"
>> +#include "hw/char/serial.h"
>> #include "hw/pci/pci.h"
>> #include "hw/qdev-properties.h"
>> #include "hw/ide/pci.h"
>> @@ -343,6 +346,35 @@ static const TypeInfo via_superio_info = {
>> 
>> #define TYPE_VT82C686B_SUPERIO "vt82c686b-superio"
>> 
>> +static void vt82c686b_superio_update(ViaSuperIOState *s)
>> +{
>> +    isa_parallel_set_enabled(s->superio.parallel[0],
>> +                             (s->regs[0xe2] & 0x3) != 3);
>> +    isa_serial_set_enabled(s->superio.serial[0], s->regs[0xe2] & BIT(2));
>> +    isa_serial_set_enabled(s->superio.serial[1], s->regs[0xe2] & BIT(3));
>> +    isa_fdc_set_enabled(s->superio.floppy, s->regs[0xe2] & BIT(4));
>> +
>> +    isa_fdc_set_iobase(s->superio.floppy, (s->regs[0xe3] & 0xfc) << 2);
>> +    isa_parallel_set_iobase(s->superio.parallel[0], s->regs[0xe6] << 2);
>> +    isa_serial_set_iobase(s->superio.serial[0], (s->regs[0xe7] & 0xfe) << 
>> 2);
>> +    isa_serial_set_iobase(s->superio.serial[1], (s->regs[0xe8] & 0xfe) << 
>> 2);
>> +}
>
>I wonder if some code duplication could be saved by adding a shared 
>via_superio_update() for this further up in the abstract via-superio class 
>instead of this method and vt8231_superio_update() below. This common method 
>in abstract class would need to handle the differences which seem to be reg 
>addresses offset by 0x10 and VT8231 having only 1 serial port. These could 
>either be handled by adding function parameters or fields to ViaSuperIOState 
>for this that the subclasses can set and the method check. (Such as reg 
>base=0xe2 for vt82c686 and 0xf2 for vt8231 and num_serial or similar for how 
>many ports are there then can have a for loop for those that would only run 
>once for vt8231).

Only the enable bits and the parallel port base address line up, the serial 
port(s) and the floppy would need special treatment. Not worth it IMO.

>
>> +static int vmstate_vt82c686b_superio_post_load(void *opaque, int version_id)
>> +{
>> +    ViaSuperIOState *s = opaque;
>> +
>> +    vt82c686b_superio_update(s);
>> +
>> +    return 0;
>
>You could lose some blank lines here. You seem to love them, half of your 
>cover letter is just blank lines :-)

Yes, I want people to see the light rather than a wall (of text) ;-)

> but I'm the opposite and like more code to fit in one screen even on todays 
> displays that are wider than tall. So this funciton would take less space 
> without blank lines. (Even the local variable may not be necessary as you 
> don't access any fields within and void * should just cast without a warning 
> but for spelling out the desired type as a reminder I'm ok with leaving that 
> but no excessive blank lines please if you don't mind that much.)

In this case I'll remove the s variable and the blank line above the return if 
that's so important to you.

Best regards,
Bernhard
>
>Regards,
>BALATON Zoltan
>
>> +}
>> +
>> +static const VMStateDescription vmstate_vt82c686b_superio = {
>> +    .name = "vt82c686b_superio",
>> +    .version_id = 1,
>> +    .post_load = vmstate_vt82c686b_superio_post_load,
>> +};
>> +
>> static void vt82c686b_superio_cfg_write(void *opaque, hwaddr addr,
>>                                         uint64_t data, unsigned size)
>> {
>> @@ -368,7 +400,11 @@ static void vt82c686b_superio_cfg_write(void *opaque, 
>> hwaddr addr,
>>     case 0xfd ... 0xff:
>>         /* ignore write to read only registers */
>>         return;
>> -    /* case 0xe6 ... 0xe8: Should set base port of parallel and serial */
>> +    case 0xe2 ... 0xe3:
>> +    case 0xe6 ... 0xe8:
>> +        sc->regs[idx] = data;
>> +        vt82c686b_superio_update(sc);
>> +        return;
>>     default:
>>         qemu_log_mask(LOG_UNIMP,
>>                       "via_superio_cfg: unimplemented register 0x%x\n", idx);
>> @@ -393,25 +429,24 @@ static void vt82c686b_superio_reset(DeviceState *dev)
>> 
>>     memset(s->regs, 0, sizeof(s->regs));
>>     /* Device ID */
>> -    vt82c686b_superio_cfg_write(s, 0, 0xe0, 1);
>> -    vt82c686b_superio_cfg_write(s, 1, 0x3c, 1);
>> -    /* Function select - all disabled */
>> -    vt82c686b_superio_cfg_write(s, 0, 0xe2, 1);
>> -    vt82c686b_superio_cfg_write(s, 1, 0x03, 1);
>> +    s->regs[0xe0] = 0x3c;
>> +    /*
>> +     * Function select - only serial enabled
>> +     * Fuloong 2e's rescue-yl prints to the serial console w/o enabling it. 
>> This
>> +     * suggests that the serial ports are enabled by default, so override 
>> the
>> +     * datasheet.
>> +     */
>> +    s->regs[0xe2] = 0x0f;
>>     /* Floppy ctrl base addr 0x3f0-7 */
>> -    vt82c686b_superio_cfg_write(s, 0, 0xe3, 1);
>> -    vt82c686b_superio_cfg_write(s, 1, 0xfc, 1);
>> +    s->regs[0xe3] = 0xfc;
>>     /* Parallel port base addr 0x378-f */
>> -    vt82c686b_superio_cfg_write(s, 0, 0xe6, 1);
>> -    vt82c686b_superio_cfg_write(s, 1, 0xde, 1);
>> +    s->regs[0xe6] = 0xde;
>>     /* Serial port 1 base addr 0x3f8-f */
>> -    vt82c686b_superio_cfg_write(s, 0, 0xe7, 1);
>> -    vt82c686b_superio_cfg_write(s, 1, 0xfe, 1);
>> +    s->regs[0xe7] = 0xfe;
>>     /* Serial port 2 base addr 0x2f8-f */
>> -    vt82c686b_superio_cfg_write(s, 0, 0xe8, 1);
>> -    vt82c686b_superio_cfg_write(s, 1, 0xbe, 1);
>> +    s->regs[0xe8] = 0xbe;
>> 
>> -    vt82c686b_superio_cfg_write(s, 0, 0, 1);
>> +    vt82c686b_superio_update(s);
>> }
>> 
>> static void vt82c686b_superio_init(Object *obj)
>> @@ -429,6 +464,7 @@ static void vt82c686b_superio_class_init(ObjectClass 
>> *klass, void *data)
>>     sc->parallel.count = 1;
>>     sc->ide.count = 0; /* emulated by via-ide */
>>     sc->floppy.count = 1;
>> +    dc->vmsd = &vmstate_vt82c686b_superio;
>> }
>> 
>> static const TypeInfo vt82c686b_superio_info = {
>> @@ -443,6 +479,33 @@ static const TypeInfo vt82c686b_superio_info = {
>> 
>> #define TYPE_VT8231_SUPERIO "vt8231-superio"
>> 
>> +static void vt8231_superio_update(ViaSuperIOState *s)
>> +{
>> +    isa_parallel_set_enabled(s->superio.parallel[0],
>> +                             (s->regs[0xf2] & 0x3) != 3);
>> +    isa_serial_set_enabled(s->superio.serial[0], s->regs[0xf2] & BIT(2));
>> +    isa_fdc_set_enabled(s->superio.floppy, s->regs[0xf2] & BIT(4));
>> +
>> +    isa_serial_set_iobase(s->superio.serial[0], (s->regs[0xf4] & 0xfe) << 
>> 2);
>> +    isa_parallel_set_iobase(s->superio.parallel[0], s->regs[0xf6] << 2);
>> +    isa_fdc_set_iobase(s->superio.floppy, (s->regs[0xf7] & 0xfc) << 2);
>> +}
>> +
>> +static int vmstate_vt8231_superio_post_load(void *opaque, int version_id)
>> +{
>> +    ViaSuperIOState *s = opaque;
>> +
>> +    vt8231_superio_update(s);
>> +
>> +    return 0;
>> +}
>> +
>> +static const VMStateDescription vmstate_vt8231_superio = {
>> +    .name = "vt8231_superio",
>> +    .version_id = 1,
>> +    .post_load = vmstate_vt8231_superio_post_load,
>> +};
>> +
>> static void vt8231_superio_cfg_write(void *opaque, hwaddr addr,
>>                                      uint64_t data, unsigned size)
>> {
>> @@ -465,6 +528,12 @@ static void vt8231_superio_cfg_write(void *opaque, 
>> hwaddr addr,
>>     case 0xfd:
>>         /* ignore write to read only registers */
>>         return;
>> +    case 0xf2:
>> +    case 0xf4:
>> +    case 0xf6 ... 0xf7:
>> +        sc->regs[idx] = data;
>> +        vt8231_superio_update(sc);
>> +        return;
>>     default:
>>         qemu_log_mask(LOG_UNIMP,
>>                       "via_superio_cfg: unimplemented register 0x%x\n", idx);
>> @@ -493,19 +562,15 @@ static void vt8231_superio_reset(DeviceState *dev)
>>     /* Device revision */
>>     s->regs[0xf1] = 0x01;
>>     /* Function select - all disabled */
>> -    vt8231_superio_cfg_write(s, 0, 0xf2, 1);
>> -    vt8231_superio_cfg_write(s, 1, 0x03, 1);
>> +    s->regs[0xf2] = 0x03;
>>     /* Serial port base addr */
>> -    vt8231_superio_cfg_write(s, 0, 0xf4, 1);
>> -    vt8231_superio_cfg_write(s, 1, 0xfe, 1);
>> +    s->regs[0xf4] = 0xfe;
>>     /* Parallel port base addr */
>> -    vt8231_superio_cfg_write(s, 0, 0xf6, 1);
>> -    vt8231_superio_cfg_write(s, 1, 0xde, 1);
>> +    s->regs[0xf6] = 0xde;
>>     /* Floppy ctrl base addr */
>> -    vt8231_superio_cfg_write(s, 0, 0xf7, 1);
>> -    vt8231_superio_cfg_write(s, 1, 0xfc, 1);
>> +    s->regs[0xf7] = 0xfc;
>> 
>> -    vt8231_superio_cfg_write(s, 0, 0, 1);
>> +    vt8231_superio_update(s);
>> }
>> 
>> static void vt8231_superio_init(Object *obj)
>> @@ -513,12 +578,6 @@ static void vt8231_superio_init(Object *obj)
>>     VIA_SUPERIO(obj)->io_ops = &vt8231_superio_cfg_ops;
>> }
>> 
>> -static uint16_t vt8231_superio_serial_iobase(ISASuperIODevice *sio,
>> -                                             uint8_t index)
>> -{
>> -        return 0x2f8; /* FIXME: This should be settable via registers f2-f4 
>> */
>> -}
>> -
>> static void vt8231_superio_class_init(ObjectClass *klass, void *data)
>> {
>>     DeviceClass *dc = DEVICE_CLASS(klass);
>> @@ -526,10 +585,10 @@ static void vt8231_superio_class_init(ObjectClass 
>> *klass, void *data)
>> 
>>     dc->reset = vt8231_superio_reset;
>>     sc->serial.count = 1;
>> -    sc->serial.get_iobase = vt8231_superio_serial_iobase;
>>     sc->parallel.count = 1;
>>     sc->ide.count = 0; /* emulated by via-ide */
>>     sc->floppy.count = 1;
>> +    dc->vmsd = &vmstate_vt8231_superio;
>> }
>> 
>> static const TypeInfo vt8231_superio_info = {
>>