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Re: [Qemu-devel] Re: [RFC][PATCH 4/4] Add support for Marvell 88w8618 /
From: |
Jan Kiszka |
Subject: |
Re: [Qemu-devel] Re: [RFC][PATCH 4/4] Add support for Marvell 88w8618 / MusicPal |
Date: |
Sun, 20 Apr 2008 17:52:20 +0200 |
User-agent: |
Thunderbird 2.0.0.12 (X11/20080226) |
andrzej zaborowski wrote:
> On 19/04/2008, Jan Kiszka <address@hidden> wrote:
>> andrzej zaborowski wrote:
>> > On 18/04/2008, Jan Kiszka <address@hidden> wrote:
>> >> Andrzej, as you have written the wm8750, do you already know where which
>> >> volume level would have to be applied (open-coded or via some
>> >> AUD_set_volume)? I'm currently only using LOUT2VOL, and I'm a bit lazy
>> >> to study the datasheet /wrt all the mixer details.
>> >
>> > My idea was to open
>> > http://www.wolfsonmicro.com/uploads/documents/en/WM8750.pdf and on the
>> > first page every Wolfson datasheet has its diagram of all audio paths
>> > (of which there are always too many) and then trace with my finger the
>> > path between the source (the I2C or I2S interfaces) and the sink (the
>> > analog output), and then multiply all the volume values that are
>> > applied there (both analog and digital) and pass that to host mixer
>> > through some functions in audio/ for the given SWVoice - but we don't
>> > have any such functions and I'm ok with using the host mixer manually.
>> > (VirtualBox has them implemented iirc) So yes, maybe it makes sense
>> > to multiply the samples for the moment and use only LOUTnVOL /
>> > ROUTnVOL values as these are used by the guests we're interested in.
>>
>>
>> Done, and it finally works. One of the two quirks I found in wm8750 made
>> the switch a bit hairy. Patches will follow.
>
> Thanks. I pushed the patch with fixes. Regarding the wm8750_fini
> patch, I'll #if 0 it because it's possible that a board will have this
> chip on something hotpluggable and will need to create and destroy it
> various times and it's easy to miss something in the clean-up.
> Regarding the volume patch, I'll make a look-up table at one point,
Don't understand yet why (are you afraid of pow, libm, or float in
general?), but if it helps to get things merged... ;)
> and then merge. Also, if we have 16-bit data and 7-bit volume scale
> maybe we're fine with scalling only the most-significant-byte and
Hmm, wasn't endianness about finding out which byte is most-significant
and which not? :->
> avoiding endianness headaches (or maybe not). Nevertheless the
> MusicPal emulator should be bootable without that.
>
>>
>> >
>> >>
>> >> >>> - 128×64 display with brightness control
>> >> >>> - all input buttons
>> >> >>>
>> >> >>> Using up to 32 MB flash, I hit a limit /wrt phys_ram_size. I worked
>> >> >>> around this for now by extending MAX_BIOS_SIZE to 32 MB, surely
>> not a
>> >> >>> nice solution.
>> >> >> You can use -m 150 or similar.
>> >> >>
>> >> >> Please also format the code similarly to rest of Qemu.
>> >> >
>> >> > That would just increase ram_size, thus won't help as I need memory
>> >> > beyond it (here for the pflash in R/W mode).
>> >
>> > Yes, I had not looked at how ram_size was used in the musicpal board
>> > initialisation, sorry.
>> >
>> >>
>> >> OK, I see what you mean after looking at your N800 patches: You apply a
>> >> fixed RAM size, leaving the rest of what the user provided via -m to
>> >> SRAM and flash. Not optimal IMHO, you may sometimes also want to play
>> >> with the RAM size even if the real devices has a fixed amount. And it is
>> >> far from being intuitive as well.
>> >
>> > Yes, although you allow the user to set also a smaller RAM than what
>> > the virtual machine expects.
>>
>>
>> That's indeed something the machine should take of (if there are such
>> hard limits).
>>
>>
>> >
>> >> The only true solution I see right now is moving qemu_vmalloc into the
>> >> machine initialization code. Is there anything between current
>> >> qemu_vmalloc and machine->init that relies on phys_ram_base being valid
>> >> (and which can't be moved after the machine init) and thus prevents
>> this?
>> >
>> > I had a different idea: add a field ram_constraint in struct
>> > QEMUMachine, which would hold the amount of RAM the machine always
>> > needs (e.g. bios and video RAM), and the low bit could hold a flag
>> > RAM_SIZE_FIXED for machines that have only such RAM (basically the
>> > criteria should be whether it's possible for the guest to detect the
>> > memory size there is on board - on machines like Spitz there's no way)
>>
>>
>> IIRC, embedded boards let the boot loader "detect" this. I see valid
>> scenarios where one wants to play with different sizes and may therefore
>> patch U-Boot - or load the kernel directly which should make QEMU set
>> the related ATAG field appropriately, no?
>
> Yes, in case of a standard firmware like Linux or U-boot - but we
> probably don't need to provide options for everything one may want to
> play with unless it's a valid hardware configuration (like in the PC
> case where you can add and take away RAM sticks), at some point the
> user needs to edit the source either way.
>
> Anyway almost half of the boards in qemu ignored ram_size until now
> and risked the provided size being too low and segfaulting, so with
> the patch I sent in another mail at least there's a check, and the
> check is only done once for all boards so it can be removed from the
> few boards that did it.
>
>>
>> > and for such machines the -m parameter would be invalid. I'll try to
>> > come up with a patch.
>>
>>
>> I originally had the same idea but I dropped it because it would still
>> overload -m with semantics that don't belong there. IMHO -m should only
>> describe the main RAM size, not any additionally by QEMU required memory
>> for establishing fixed SRAM or even for backing up flash devices. That's
>> at least what I would expect from this switch and what the documentation
>> suggests as well so far.
>
> This property is not changed by the patch (I hope).
Yes, it restores the original semantic, at least as long as
RAMSIZE_FIXED is not set. That case is still a bit suboptimal as you
have to provide pessimistic values, e.g. the maximum flash size that can
be used. But I can live with it I guess.
Jan
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- [Qemu-devel] Re: [RFC][PATCH 4/4] Add support for Marvell 88w8618 / MusicPal, (continued)
- [Qemu-devel] Re: [RFC][PATCH 4/4] Add support for Marvell 88w8618 / MusicPal, Jan Kiszka, 2008/04/14
- Re: [Qemu-devel] [RFC][PATCH 4/4] Add support for Marvell 88w8618 / MusicPal, andrzej zaborowski, 2008/04/16
- Re: [Qemu-devel] [RFC][PATCH 4/4] Add support for Marvell 88w8618 / MusicPal, andrzej zaborowski, 2008/04/16
- [Qemu-devel] Re: [RFC][PATCH 4/4] Add support for Marvell 88w8618 / MusicPal, Jan Kiszka, 2008/04/17
- [Qemu-devel] Re: [RFC][PATCH 4/4] Add support for Marvell 88w8618 / MusicPal, Jan Kiszka, 2008/04/18
- Re: [Qemu-devel] Re: [RFC][PATCH 4/4] Add support for Marvell 88w8618 / MusicPal, andrzej zaborowski, 2008/04/18
- [Qemu-devel] Re: [RFC][PATCH 4/4] Add support for Marvell 88w8618 / MusicPal, Jan Kiszka, 2008/04/19
- Re: [Qemu-devel] Re: [RFC][PATCH 4/4] Add support for Marvell 88w8618 / MusicPal, andrzej zaborowski, 2008/04/20
- Re: [Qemu-devel] Re: [RFC][PATCH 4/4] Add support for Marvell 88w8618 / MusicPal,
Jan Kiszka <=
- Re: [Qemu-devel] Re: [RFC][PATCH 4/4] Add support for Marvell 88w8618 / MusicPal, andrzej zaborowski, 2008/04/20
[Qemu-devel] [PATCH] Add support for Marvell 88w8618 / MusicPal, Jan Kiszka, 2008/04/20