Re: [Qemu-ppc] [PATCH v2 3/6] PPC 85xx: Add qemu-ppce500 machine

[Scott Wood]

On Thu, 2014-02-06 at 13:48 +0100, Alexander Graf wrote:
> On 04.02.2014, at 03:19, Scott Wood <address@hidden> wrote:
> 
> > On Fri, 2014-01-31 at 12:16 +0100, Alexander Graf wrote:
> >> +void pci_init_board(void)
> >> +{
> >> +  struct fsl_pci_info pci_info;
> >> +  const void *fdt = get_fdt();
> >> +  int pci_node;
> >> +
> >> +  puts("\n");
> >> +
> >> +  pci_node = fdt_path_offset(fdt, "/pci");
> >> +  if (pci_node < 0) {
> >> +          printf("PCI: disabled\n\n");
> >> +          return;
> >> +  }
> >> +
> >> +  SET_STD_PCI_INFO(pci_info, 1);
> >> +
> >> +  fsl_setup_hose(&pci1_hose, pci_info.regs);
> >> +  printf("PCI: 32 bit, 66 MHz, async, host, base address %lx\n",
> >> +          pci_info.regs);
> > 
> > Why hardcode these things in a message?  Just don't print anything if
> > you don't have the info.
> 
> To make it look more akin to a real e500 board. But I'll change it.

It's a paravirt target...

> >> +void init_tlbs_dynamic(void)
> >> +{
> >> +  unsigned long fdt_tlb = (unsigned long)get_fdt() & ~0xffffful;
> >> +  u32 mas0, mas1, mas2, mas3, mas7;
> >> +  phys_size_t ram_size;
> >> +
> >> +  /*
> >> +   * Create a temporary AS=1 map for the fdt
> >> +   *
> >> +   * We use ESEL=0 here to overwrite the previous AS=0 map for ourselves
> >> +   * which was only 4k big. This way we don't have to clear any other 
> >> maps.
> >> +   */
> >> +  mas0 = MAS0_TLBSEL(1) | MAS0_ESEL(0);
> >> +  mas1 = MAS1_VALID | MAS1_TID(0) | MAS1_TS | MAS1_TSIZE(BOOKE_PAGESZ_1M);
> >> +  mas2 = FSL_BOOKE_MAS2(fdt_tlb, 0);
> >> +  mas3 = FSL_BOOKE_MAS3(fdt_tlb, 0, MAS3_SW|MAS3_SR|MAS3_SX);
> >> +  mas7 = FSL_BOOKE_MAS7(fdt_tlb);
> >> +
> >> +  write_tlb(mas0, mas1, mas2, mas3, mas7);
> > 
> > How do you know you're not creating an overlapping TLB entry?  You
> > should map this to a fixed virtual address that you know is safe.
> 
> Ok. I'll map it behind CCSRBAR.

I'd give it its own CONFIG symbol to be explicitly located in the header
file.

> >> +  /* Create a dynamic AS=0 CCSRBAR mapping */
> >> +  mas0 = MAS0_TLBSEL(1) | MAS0_ESEL(13);
> >> +  mas1 = MAS1_VALID | MAS1_TID(0) | MAS1_TSIZE(BOOKE_PAGESZ_1M);
> >> +  mas2 = FSL_BOOKE_MAS2(CONFIG_SYS_CCSRBAR, MAS2_I|MAS2_G);
> >> +  mas3 = FSL_BOOKE_MAS3(CONFIG_SYS_CCSRBAR_PHYS, 0, MAS3_SW|MAS3_SR);
> >> +  mas7 = FSL_BOOKE_MAS7(CONFIG_SYS_CCSRBAR_PHYS);
> > 
> > CCSRBAR may be 1M or 16M (assuming qemu-ppce500 sticks with a CCSR-ish
> > layout at all).  Really we should be creating explicit maps for
> > everything we find in the device tree that we care about.
> 
> I don't understand that part. We do create explicit maps for everything we 
> care about, no?

No, you map CCSR as a whole, rather than the UART, PCI controller regs,
etc.  If you want to that, ideally the size of CCSR should come from the
device tree as well as the address.

-Scott