On Fri, Oct 29, 2021 at 09:40:55AM -0500, Rob Herring wrote:
> Use of the of_scan_flat_dt() function predates libfdt and is discouraged
> as libfdt provides a nicer set of APIs. Rework dt_scan_depth1_nodes to
> use libfdt calls directly, and rename it to dt_is_stub() to reflect
> exactly what it checking.
>
> Cc: Catalin Marinas <catalin.marinas@xxxxxxx>
> Cc: Will Deacon <will@xxxxxxxxxx>
> Signed-off-by: Rob Herring <robh@xxxxxxxxxx>
Thanks for reworking this; it looks good to me:
Reviewed-by: Mark Rutland <mark.rutland@xxxxxxx>
Thanks,
Mark.
> ---
> v2:
> - Keep checking for only stub nodes
>
> arch/arm64/kernel/acpi.c | 35 ++++++++++++++---------------------
> 1 file changed, 14 insertions(+), 21 deletions(-)
>
> diff --git a/arch/arm64/kernel/acpi.c b/arch/arm64/kernel/acpi.c
> index 1c9c2f7a1c04..7df733427e04 100644
> --- a/arch/arm64/kernel/acpi.c
> +++ b/arch/arm64/kernel/acpi.c
> @@ -22,6 +22,7 @@
> #include <linux/irq_work.h>
> #include <linux/memblock.h>
> #include <linux/of_fdt.h>
> +#include <linux/libfdt.h>
> #include <linux/smp.h>
> #include <linux/serial_core.h>
> #include <linux/pgtable.h>
> @@ -62,29 +63,22 @@ static int __init parse_acpi(char *arg)
> }
> early_param("acpi", parse_acpi);
>
> -static int __init dt_scan_depth1_nodes(unsigned long node,
> - const char *uname, int depth,
> - void *data)
> +static bool __init dt_is_stub(void)
> {
> - /*
> - * Ignore anything not directly under the root node; we'll
> - * catch its parent instead.
> - */
> - if (depth != 1)
> - return 0;
> + int node;
>
> - if (strcmp(uname, "chosen") == 0)
> - return 0;
> + fdt_for_each_subnode(node, initial_boot_params, 0) {
> + const char *name = fdt_get_name(initial_boot_params, node, NULL);
> + if (strcmp(name, "chosen") == 0)
> + continue;
> + if (strcmp(name, "hypervisor") == 0 &&
> + of_flat_dt_is_compatible(node, "xen,xen"))
> + continue;
>
> - if (strcmp(uname, "hypervisor") == 0 &&
> - of_flat_dt_is_compatible(node, "xen,xen"))
> - return 0;
> + return false;
> + }
>
> - /*
> - * This node at depth 1 is neither a chosen node nor a xen node,
> - * which we do not expect.
> - */
> - return 1;
> + return true;
> }
>
> /*
> @@ -205,8 +199,7 @@ void __init acpi_boot_table_init(void)
> * and ACPI has not been [force] enabled (acpi=on|force)
> */
> if (param_acpi_off ||
> - (!param_acpi_on && !param_acpi_force &&
> - of_scan_flat_dt(dt_scan_depth1_nodes, NULL)))
> + (!param_acpi_on && !param_acpi_force && !dt_is_stub()))
> goto done;
>
> /*
> --
> 2.32.0
>
