Re: [Qemu-devel] a quesion

[Peter Maydell]

On 16 August 2016 at 14:53, Michael Rolnik <address@hidden> wrote:
> 1. How to implement a device that has 4 registers in IO space e.g. AVR
> EEPROM?

Since for your AVR target the IO space is just turned into
accesses to physical memory, ie the inb/outb default case
does something like this:

+            cpu_physical_memory_read(PHYS_BASE_REGS + port
+                                              + AVR_CPU_IO_REGS_BASE,
&data, 1);

you don't need to do anything special for the device being
in IO space. You just need to implement a device which has
a MemoryRegion which handles its 4 registers, and then
have the board or SoC create that device and map it into
the memory space at the right address. hw/misc/zynq_slcr.c
is perhaps one example of a device that's just some simple
registers (though it has a lot more than 4, the principles
are the same).

> 2. what is a SoC container object? How?

An "SoC container" is a device which doesn't have any interesting
functionality itself, but just creates a lot of other devices
and maps them to the right places in the address space. A good
example is hw/arm/fsl-imx6.c.

thanks
-- PMM