[OpenBIOS] Re: Openbios code for IRQ or interrupt handling?

[Mark Cave-Ayland]

On 18/02/2025 21:34, Jd Lyons via OpenBIOS wrote:
> I don’t know why, I can’t seem to get Openbios to set and interrupt-parent in the init.c for any /cpus, this code should work, no?
>
> void add_cpu_nodes(void) {
>      int num_cpus = fw_cfg_read_i32(FW_CFG_NB_CPUS);
>      printk("Detected %d CPUs\n", num_cpus);
>  /* Ensure /cpus node exists */
>  phandle cpus_node = dt_find_by_path("/cpus");
>  if (!cpus_node) {
>      printk("ERROR: /cpus node not found! Delaying CPU setup.\\n");
>      return;
>  }
>
>  /* Wait until the interrupt controller exists */
>  phandle intc_node = NULL;
>  int retries = 5;
>  while (retries-- > 0) {
>      intc_node = dt_find_by_path("/pci/mac-io/@40000");

Is this for the mac99 machine? If so you probably want 
/pci@f2000000/mac-io@c/interrupt-controller@40000 (see the output of show-devs for 
the full device paths).
>      if (intc_node) {
>          break;
>      }
>      printk("Waiting for /pci/mac-io/@40000...\\n");
>      msleep(100);  // Wait 100ms before retrying
>  }
>
>  if (!intc_node) {
>      printk("ERROR: Interrupt controller (/pci/mac-io/@40000) not found! SMP will not work.\\n");
>      return;
>  }
>
>  for (int i = 0; i < num_cpus; i++) {
>      phandle cpu_node = dt_new_node(cpus_node);
>      if (!cpu_node) {
>          printk("ERROR: Failed to create CPU node for CPU %d!\\n", i);
>          continue;
>      }
>
>      dt_set_property_string(cpu_node, "device_type", "cpu");
>      dt_set_property_string(cpu_node, "compatible", "PowerPC,G4");
>
>      /* Assign a unique CPU interrupt */
>      int cpu_irq[2] = { 16 + i, 0 };
>      dt_set_property_cells(cpu_node, "interrupts", cpu_irq, 2);
>      printk("CPU %d assigned IRQ %d\\n", i, cpu_irq[0]);
>
>      /* Ensure interrupt-parent is set */
>      dt_set_property_phandle(cpu_node, "interrupt-parent", intc_node);
>      printk("CPU %d linked to interrupt-parent /pci/mac-io/@40000\\n", i);
>
>      /* Register CPU ID */
>      PUSH(i);
>      fword("encode-int");
>      push_str("reg");
>      fword("property");
>
>      fword("finish-device");
>      printk("Initialized CPU %d\\n", i);
>  }
>
> }

ATB,

Mark.