From: Peter Maydell <peter.maydell@linaro.org>
To: Aurelio Remonda <aurelio.remonda@tallertechnologies.com>
Cc: QEMU Developers <qemu-devel@nongnu.org>
Subject: Re: [Qemu-devel] Memory on stellaris board
Date: Thu, 10 Mar 2016 06:24:50 +0700 [thread overview]
Message-ID: <CAFEAcA_gSo7D27uRyKAU-sj83qXkB63m7Q+VgH2qJkwDJs5PVg@mail.gmail.com> (raw)
In-Reply-To: <CANLsssvBN=C_-_i+9Mh7p_o=L3BZy19UJPB1aGFH2SsVAoFwaw@mail.gmail.com>
On 10 March 2016 at 03:56, Aurelio Remonda
<aurelio.remonda@tallertechnologies.com> wrote:
>
>
> On Mon, Mar 7, 2016 at 8:37 PM, Peter Maydell <peter.maydell@linaro.org>
> wrote:
>>
>> On 8 March 2016 at 02:58, Aurelio Remonda
>> <aurelio.remonda@tallertechnologies.com> wrote:
>> > Hello, sorry for taking so long, I am working on this again.
>> > About your last response, I was looking at the struct
>> > stellaris_board_info
>> > ,which contains
>> > dc0, and this entire struct is const. If we need to calculate dc0 based
>> > on
>> > the provided RAM size
>> > or default value at least the dc0 field should not be const.
>>
>> Yes, certainly.
>>
>> You might also need to look at the magic hex numbers in
>> the stellaris_board[] array -- one is labelled /* dc0 */
>> so might be related.
>
> Thanks Peter!
> I have a question about the set_memory_options function, when the m flag is
> present, this function takes the size value (or the default_ram_size) and
> perform
> an QEMU_ALIGN_UP. Let's say you want the board default ram_size, the default
> dc0 value should be 0xff00 (65280) when the align is made this value becomes
> 0x00ffff (65535). This align will make the dc0 value change, so I have to
> make some
> operations on ram_size so dc0 will be as exact as it should.
>
> Something like this:
> ram_size |= ((ram_size-1)>>8);
> board->dc0 |= (ram_size & 0xffff)<<16;
> On stellaris_init function
>
> Then the sram_size and the flash_size are exposed like always. I change the
> magic hex numbers
> in the stellaris_board[] array from 0x00ff007f to 0x0000007f as the
> flash_size
> will not change even with the flag. The default_ram_size is also changed for
> this board to
> be 64K on lm3s6965evb_class_init func:
> mc->default_ram_size = 0x0000ff00;
>
> What do you think of this approach? Thank you!
You should reject unworkable ram sizes rather than silently
changing what the user asked for; this matches our preferred
approach where the user asks for more RAM than the board
can support.
thanks
-- PMM
next prev parent reply other threads:[~2016-03-09 23:25 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-02-03 13:00 [Qemu-devel] Memory on stellaris board Aurelio Remonda
2016-02-03 13:34 ` Peter Maydell
2016-02-03 13:45 ` Aurelio Remonda
2016-02-05 16:09 ` Aurelio Remonda
2016-02-05 16:23 ` Peter Maydell
2016-02-05 16:55 ` Aurelio Remonda
2016-02-05 17:00 ` Peter Maydell
2016-02-11 12:46 ` Aurelio Remonda
2016-02-11 13:01 ` Peter Maydell
2016-03-07 19:58 ` Aurelio Remonda
2016-03-07 23:37 ` Peter Maydell
2016-03-09 20:56 ` Aurelio Remonda
2016-03-09 23:24 ` Peter Maydell [this message]
2016-03-10 0:23 ` Aurelio Remonda
2016-03-10 1:54 ` Peter Maydell
2016-03-11 14:12 ` Aurelio Remonda
2016-03-11 22:31 ` Peter Maydell
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