[PATCH v4 15/35] acpi: Add processor device

[Patrick Rudolph <patrick.rudolph@9elements.com>]

Add a new method to write the processor device identified by _HID
ACPI0007, that is preferred over the Processor OpCode since ACPI 6.0.

Fixes booting arm using ACPI only since the Processor OpCode isn't
found valid by the Linux kernel.

Signed-off-by: Patrick Rudolph <patrick.rudolph@9elements.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Cc: Simon Glass <sjg@chromium.org>
---
 include/acpi/acpigen.h | 12 ++++++++++++
 lib/acpi/acpigen.c     | 11 +++++++++++
 2 files changed, 23 insertions(+)

diff --git a/include/acpi/acpigen.h b/include/acpi/acpigen.h
index 3aa94d70b9..16df85b9c1 100644
--- a/include/acpi/acpigen.h
+++ b/include/acpi/acpigen.h
@@ -833,6 +833,7 @@ void acpigen_write_dsm_end(struct acpi_ctx *ctx);
  *
  * This emits a Processor package header with the required information. The
  * caller must complete the information and call acpigen_pop_len() at the end
+ * Deprecated since ACPI 6.0.
  *
  * @ctx: ACPI context pointer
  * @cpuindex: CPU number
@@ -842,6 +843,17 @@ void acpigen_write_dsm_end(struct acpi_ctx *ctx);
 void acpigen_write_processor(struct acpi_ctx *ctx, uint cpuindex,
 			     u32 pblock_addr, uint pblock_len);
 
+/**
+ * acpigen_write_processor_device() - Write a Processor device
+ *
+ * Write a device with _HID ACPI0007 identifying a processor.
+ * Replacement for the Processor OpCode.
+ *
+ * @ctx: ACPI context pointer
+ * @cpuindex: CPU number
+ */
+void acpigen_write_processor_device(struct acpi_ctx *ctx, uint cpuindex);
+
 /**
  * acpigen_write_processor_package() - Write a package containing the processors
  *
diff --git a/lib/acpi/acpigen.c b/lib/acpi/acpigen.c
index b95cabb914..427ebc2104 100644
--- a/lib/acpi/acpigen.c
+++ b/lib/acpi/acpigen.c
@@ -361,6 +361,17 @@ void acpigen_write_processor(struct acpi_ctx *ctx, uint cpuindex,
 	acpigen_emit_byte(ctx, pblock_len);
 }
 
+void acpigen_write_processor_device(struct acpi_ctx *ctx, uint cpuindex)
+{
+	char pscope[16];
+
+	snprintf(pscope, sizeof(pscope), ACPI_CPU_STRING, cpuindex);
+	acpigen_write_device(ctx, pscope);
+	acpigen_write_name_string(ctx, "_HID", "ACPI0007");
+	acpigen_write_name_integer(ctx, "_UID", cpuindex);
+	acpigen_pop_len(ctx); /* Device */
+}
+
 void acpigen_write_processor_package(struct acpi_ctx *ctx,
 				     const char *const name,
 				     const uint first_core,
-- 
2.46.0