On 2016-11-30 08:33, Thomas Huth wrote:
> On 30.11.2016 02:01, Tom Rini wrote:
> > Hey all,
> > 
> > I'm trying to make use of the r2d platform for U-Boot testing via QEMU.
> > After applying a series[1] I can use the kernel.org sh4 toolchain to get
> > a u-boot.bin that runs, mostly.  I say mostly as first of all I have to
> > pass "-monitor null -serial null -serial stdio -nographic" to
> > qemu-system-sh4 and in that order for me to get output from U-Boot on
> > the prompt.  On other platforms such as arm and vexpress or i386 and the
> > 'pc' machine I do not need to do this.  Does anyone have any idea why
> > this might be and where to start poking in the code to fix this?

The reason is that u-boot and the linux kernel do not have the same way
to number the serial port than the physical hardware. Therefore u-boot
and the Linux kernel use the second physical serial port .The question is
whether we should number our ports from the software (or part of the
sofrware) or hardware point of view.

> The "-serial" parameter is related to the serial_hds[] array in the
> code, so you could search for that one.
> The following line in hw/sh4/r2d.c looks somewhat suspicious:
>     sm501_init(address_space_mem, 0x10000000, SM501_VRAM_SIZE,
>                irq[SM501], serial_hds[2]);
> Why is this machine always using serial_hds[2] and not a lower index?
> ... Maybe the maintainer of the board (Magnus) knows the answer here...

The third serial port is provided by the graphic chipset. The first two
serial ports are provided by the SH7750 CPU, see in hw/sh4/sh7750.c.


Aurelien Jarno                          GPG: 4096R/1DDD8C9B
aurel...@aurel32.net                 http://www.aurel32.net

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