x86: Move DSDT table to a writer function

Move this table over to use a writer function, moving the code from the
x86 implementation.

Add a pointer to the DSDT in struct acpi_ctx so we can reference it later.

Disable this table for sandbox since we don't actually compile real ASL
code.

Signed-off-by: Simon Glass <sjg@chromium.org>

lib/acpi/Makefile

@@ -10,5 +10,11 @@ obj-y += acpi_writer.o
 # With QEMU the ACPI tables come from there, not from U-Boot
 ifndef CONFIG_QEMU
 obj-y += base.o
+
+# Sandbox does not build a .asl file
+ifndef CONFIG_SANDBOX
+obj-y += dsdt.o
+endif
+
 obj-y += facs.o
 endif

lib/acpi/base.c

@@ -5,6 +5,8 @@
  * Copyright 2021 Google LLC
  */
 
+#define LOG_CATEGORY LOGC_ACPI
+
 #include <common.h>
 #include <acpi/acpi_table.h>
 #include <dm/acpi.h>

lib/acpi/dsdt.c

@@ -0,0 +1,55 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Write the ACPI Differentiated System Description Table (DSDT)
+ *
+ * Copyright 2021 Google LLC
+ */
+
+#define LOG_CATEGORY LOGC_ACPI
+
+#include <common.h>
+#include <acpi/acpi_table.h>
+#include <dm/acpi.h>
+#include <tables_csum.h>
+
+/*
+ * IASL compiles the dsdt entries and writes the hex values
+ * to a C array AmlCode[] (see dsdt.c).
+ */
+extern const unsigned char AmlCode[];
+
+int acpi_write_dsdt(struct acpi_ctx *ctx, const struct acpi_writer *entry)
+{
+	const int thl = sizeof(struct acpi_table_header);
+	struct acpi_table_header *dsdt = ctx->current;
+	int aml_len;
+
+	/* Put the table header first */
+	memcpy(dsdt, &AmlCode, thl);
+	acpi_inc(ctx, thl);
+	log_debug("DSDT starts at %p, hdr ends at %p\n", dsdt, ctx->current);
+
+	/* If the table is not empty, allow devices to inject things */
+	aml_len = dsdt->length - thl;
+	if (aml_len) {
+		void *base = ctx->current;
+		int ret;
+
+		ret = acpi_inject_dsdt(ctx);
+		if (ret)
+			return log_msg_ret("inject", ret);
+		log_debug("Added %lx bytes from inject_dsdt, now at %p\n",
+			  (ulong)(ctx->current - base), ctx->current);
+		log_debug("Copy AML code size %x to %p\n", aml_len,
+			  ctx->current);
+		memcpy(ctx->current, AmlCode + thl, aml_len);
+		acpi_inc(ctx, aml_len);
+	}
+
+	ctx->dsdt = dsdt;
+	dsdt->length = ctx->current - (void *)dsdt;
+	log_debug("Updated DSDT length to %x\n", dsdt->length);
+
+	return 0;
+}
+ACPI_WRITER(3dsdt, "DSDT", acpi_write_dsdt, 0);

lib/acpi/facs.c

@@ -5,6 +5,8 @@
  * Copyright 2021 Google LLC
  */
 
+#define LOG_CATEGORY LOGC_ACPI
+
 #include <common.h>
 #include <acpi/acpi_table.h>
 #include <dm/acpi.h>