On Fri, Feb 14, 2025 at 4:27 PM Sebastian Huber
<sebastian.hu...@embedded-brains.de> wrote:
>
> Real-time kernels such as RTEMS or Zephyr may use a static device tree
> built into the kernel image. Do not require to use the -dtb option if
> -kernel is used for the microchip-icicle-kit machine.
That's a fair point, but it might also confuse people who expect QEMU
to generate a DTB if they don't specify one.
This at least needs a documentation update, but a warning log might
also be warranted if no `-dtb` is supplied
Alistair
>
> Signed-off-by: Sebastian Huber <sebastian.hu...@embedded-brains.de>
> ---
> hw/riscv/microchip_pfsoc.c | 53 ++++++++++++++++++--------------------
> 1 file changed, 25 insertions(+), 28 deletions(-)
>
> diff --git a/hw/riscv/microchip_pfsoc.c b/hw/riscv/microchip_pfsoc.c
> index 2ddc3464bb..f9e256df52 100644
> --- a/hw/riscv/microchip_pfsoc.c
> +++ b/hw/riscv/microchip_pfsoc.c
> @@ -516,7 +516,6 @@ static void
> microchip_icicle_kit_machine_init(MachineState *machine)
> uint64_t mem_low_size, mem_high_size;
> hwaddr firmware_load_addr;
> const char *firmware_name;
> - bool kernel_as_payload = false;
> target_ulong firmware_end_addr, kernel_start_addr;
> uint64_t kernel_entry;
> uint64_t fdt_load_addr;
> @@ -589,25 +588,12 @@ static void
> microchip_icicle_kit_machine_init(MachineState *machine)
> *
> * This ensures backwards compatibility with how we used to expose -bios
> * to users but allows them to run through direct kernel booting as well.
> - *
> - * When -kernel is used for direct boot, -dtb must be present to provide
> - * a valid device tree for the board, as we don't generate device tree.
> */
>
> - if (machine->kernel_filename && machine->dtb) {
> - int fdt_size;
> - machine->fdt = load_device_tree(machine->dtb, &fdt_size);
> - if (!machine->fdt) {
> - error_report("load_device_tree() failed");
> - exit(1);
> - }
> -
> + if (machine->kernel_filename) {
> firmware_name = RISCV64_BIOS_BIN;
> firmware_load_addr = memmap[MICROCHIP_PFSOC_DRAM_LO].base;
> - kernel_as_payload = true;
> - }
> -
> - if (!kernel_as_payload) {
> + } else {
> firmware_name = BIOS_FILENAME;
> firmware_load_addr = RESET_VECTOR;
> }
> @@ -617,7 +603,7 @@ static void
> microchip_icicle_kit_machine_init(MachineState *machine)
> &firmware_load_addr,
> NULL);
>
> riscv_boot_info_init(&boot_info, &s->soc.u_cpus);
> - if (kernel_as_payload) {
> + if (machine->kernel_filename) {
> kernel_start_addr = riscv_calc_kernel_start_addr(&boot_info,
> firmware_end_addr);
>
> @@ -625,19 +611,30 @@ static void
> microchip_icicle_kit_machine_init(MachineState *machine)
> true, NULL);
> kernel_entry = boot_info.image_low_addr;
>
> - /* Compute the fdt load address in dram */
> - hwaddr kernel_ram_base = memmap[MICROCHIP_PFSOC_DRAM_LO].base;
> - hwaddr kernel_ram_size = memmap[MICROCHIP_PFSOC_DRAM_LO].size;
> -
> - if (kernel_entry - kernel_ram_base >= kernel_ram_size) {
> - kernel_ram_base = memmap[MICROCHIP_PFSOC_DRAM_HI].base;
> - kernel_ram_size = mem_high_size;
> + if (machine->dtb) {
> + int fdt_size;
> + machine->fdt = load_device_tree(machine->dtb, &fdt_size);
> + if (!machine->fdt) {
> + error_report("load_device_tree() failed");
> + exit(1);
> + }
> +
> + /* Compute the FDT load address in DRAM */
> + hwaddr kernel_ram_base = memmap[MICROCHIP_PFSOC_DRAM_LO].base;
> + hwaddr kernel_ram_size = memmap[MICROCHIP_PFSOC_DRAM_LO].size;
> +
> + if (kernel_entry - kernel_ram_base >= kernel_ram_size) {
> + kernel_ram_base = memmap[MICROCHIP_PFSOC_DRAM_HI].base;
> + kernel_ram_size = mem_high_size;
> + }
> +
> + fdt_load_addr = riscv_compute_fdt_addr(kernel_ram_base,
> kernel_ram_size,
> + machine, &boot_info);
> + riscv_load_fdt(fdt_load_addr, machine->fdt);
> + } else {
> + fdt_load_addr = 0;
> }
>
> - fdt_load_addr = riscv_compute_fdt_addr(kernel_ram_base,
> kernel_ram_size,
> - machine, &boot_info);
> - riscv_load_fdt(fdt_load_addr, machine->fdt);
> -
> /* Load the reset vector */
> riscv_setup_rom_reset_vec(machine, &s->soc.u_cpus,
> firmware_load_addr,
> memmap[MICROCHIP_PFSOC_ENVM_DATA].base,
> --
> 2.43.0
>
>
