Re: [Qemu-devel] [PATCH 1/3] sh: SE7750 board definition

[Nobuhiro Iwamatsu]

Shin-ichiro KAWASAKI wrote:
> Nobuhiro Iwamatsu wrote:
> > Paul Mundt wrote:
> > > On Mon, Jan 12, 2009 at 12:48:02PM +0900, Shin-ichiro KAWASAKI wrote:
> > > > > > +    cpu_physical_memory_write(SH7750_BCR1_A7, (uint8_t *)&bcr1, 4);
> > > > > > +    cpu_physical_memory_write(SH7750_BCR2_A7, (uint8_t *)&bcr2, 2);
> > > > > > +
> > > > > > +    /* Start from P2 area */
> > > > > > +    env->pc = SDRAM_BASE | 0xa0000000;
> > > > > > +
> > > > > > +    /* pass kernel cmdline */
> > > > > > +    if (kernel_cmdline) {
> > > > > > +        pstrcpy((char *)phys_load_addr + ENTRY_OFFSET + 
> > > > > > COMMAND_LINE_OFFSET,
> > > > > > +                strlen(kernel_cmdline) + 1, kernel_cmdline);
> > > > > > +        env->pc += 0x80000;
> > > > > > +        phys_load_addr += 0x80000;
> > > > > > +    }
> > > > > do you known the flash model present on the real board?
> > > > No, I don't.
> > > > The patches for SE7750 are all implemented using informations in 
> > > > linux source code.
> > > > I visited Solution Engine site (in Japanese) but could not find 
> > > > useful specs.
> > > > http://www.hitachi-ul.co.jp/system/SH-SE/shiyou.html
> > > I haven't seen one of these boards in at least 7 years, so I can't help
> > > you with specifications. Yoshii-san or Iwamatsu-san might know, though?
> > > SE7751 should have the same flash model and layout IIRC.
> > This board can not get from Hitachi-ULSI now and this is too old.
> > I can send it later by examining the flash memory of this board.
> > # I do not understand the meaning that supports this board ....

Flash model is 29lv160t.
> I should have explained it.  To avoid messy many board support,
> board should be selected carefully.
>
> I wanted a board which can test SCI (not SCIF) console emulation.
> I'm sure that SE7750 supports both SCI and SCIF, and it is suitable
> to check SCI work.  For this purpose, any other board is OK if it
> uses SCI for console.
>
> # The reason I stick to SCI is r2d+ board's RTC.  The r2d+ board uses
> # SCI not for console but for SPI connection with RTC chip.  Before
> # thinking about RTC emulation, SCI emulation should be done.

OK.

> Another reason for SE7750 is support for TOPPERS. TOPPERS is an open
> source realtime OS. I think QEMU will be a strong tool for TOPPERS
> developers.  They already utilizes SkyEye, the ARM dedicated CPU
> simulator for board-less development. Of course SkyEye cannot be
> used for the work for SuperH.
>
> Here's the list of the CPUs and boards which can run TOPPERS.
>  http://www.toppers.jp/en/jsp-kernel-e.html
> SE7750 is the only one board which has SuperH, can run TOPPERS, and
> has Linux kernel's default config.
>
> We should focus on completing SH-Linux emulation before thinking about
> other OSes.  But if I have to add new board emulation, I think SE7750
> is a good choice.

I understood.
But this board can not get now and CPU is too old.
And you don't have this. How do you develop this board and IP?

# Does the development of SH of Toppers still continue?

> > BTW, I have question about Qemu-sh board support.
> > Does the developer of Qemu-SH try to support all boards?
> > I think that it is good to make it the base of Qemu-SH by
> > thinking about one board as virtual as MIPS.
> >
> > Because first of all, I am not so interested in the support of the board.
> > I am interested in emulation of CPU and the userland.
> > In the current situation, the number of supported real boards increases
> > when the support of CPU increases. The code of the board enters whenever
> > CPU is supported.
> > I think that you should decide a virtual board of SH and switch CPU.
> >
> > How about you?
> Good idea.  I agree that virtual board is useful.
> I wonder how linux kernel config will be.
> Or on what kind of policy, its specs should be decided?
I think that the Qemu-sh developer talk about it.
# Though the talk might be not settled....
Or get from other architectures (ex. MIPS).
Or I thought create of configurable mechanism to be good.

Best regards,
 Nobuhiro