Thiemo Seufer wrote:
Vlad Lungu wrote:
[snip]
+long int initdram(int board_type)
+{
+ /* Sdram is setup by assembler code */
+ /* If memory could be changed, we should return the true value
here */
+ return MEM_SIZE*1024*1024;
Qemu gets the amount of RAM passed via a command line switch, the
qemu-mips emulation sets up a Linux kernel like "command line" in
memory where u-boot could parse it from.
Does it, or just when you pass -kernel to it? I'll check.
Hm, you are right, it does that only for -kernel. Would it make sense
to change that in Qemu?
IDK. Maybe I can probe the RAM size in U-Boot , or if this does not
work, put some info somewhere (RAM, register,
emulated DIP-dwitch), like RAM size, endianness of the CPU.
Since the mips_r4k machine doesn't correspond to any real hardware we
have a bit of leeway with the "hardware" design.
+}
+
+
+int checkboard (void)
+{
+ u32 proc_id;
+
+ proc_id = read_32bit_cp0_register(CP0_PRID);
+
+ switch (proc_id >> 24) {
+ default:
+ printf ("Unsupported cpu %d, proc_id=0x%x\n", proc_id >>
24, proc_id);
+ }
+
+ return 0;
+}
Huh? What is this code good for?
Checking for the type of board, I suppose :-) I think all BSPs have it and
it's called early in the boot process. I could either do only a return 0 or
actually decode CP0_PRID and print something meaningful, if Qemu sets it to
something sensible. Or just print a nice banner.
As it is, this code prints a nice "Unsupported CPU" banner no matter what
(and proceeds anyway instead of bailing out).
True, because it does not care much about this at the moment. Nor do I.
But that can change.
Latest CVS Qemu supports a number of different CPUs (see the -cpu switch),
the default for 32 bit is a 24Kf, and for 64 bit a R4000.
I'll look into this and see what use can we make of CP0_PRID.
Vlad
