acpi: Convert part of acpi_table to use acpi_ctx

The current code uses an address but a pointer would result in fewer
casts. Also it repeats the alignment code in a lot of places so this would
be better done in a helper function.

Update write_acpi_tables() to make use of the new acpi_ctx structure,
adding a few helpers to clean things up.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Wolfgang Wallner <wolfgang.wallner@br-automation.com>
diff --git a/include/acpi/acpi_table.h b/include/acpi/acpi_table.h
index a2bd929..6fd4c52 100644
--- a/include/acpi/acpi_table.h
+++ b/include/acpi/acpi_table.h
@@ -23,6 +23,8 @@
 
 #if !defined(__ACPI__)
 
+struct acpi_ctx;
+
 /*
  * RSDP (Root System Description Pointer)
  * Note: ACPI 1.0 didn't have length, xsdt_address, and ext_checksum
@@ -515,6 +517,40 @@
  */
 void acpi_fill_header(struct acpi_table_header *header, char *signature);
 
+/**
+ * acpi_align() - Align the ACPI output pointer to a 16-byte boundary
+ *
+ * @ctx: ACPI context
+ */
+void acpi_align(struct acpi_ctx *ctx);
+
+/**
+ * acpi_align64() - Align the ACPI output pointer to a 64-byte boundary
+ *
+ * @ctx: ACPI context
+ */
+void acpi_align64(struct acpi_ctx *ctx);
+
+/**
+ * acpi_inc() - Increment the ACPI output pointer by a bit
+ *
+ * The pointer is NOT aligned afterwards.
+ *
+ * @ctx: ACPI context
+ * @amount: Amount to increment by
+ */
+void acpi_inc(struct acpi_ctx *ctx, uint amount);
+
+/**
+ * acpi_inc_align() - Increment the ACPI output pointer by a bit and align
+ *
+ * The pointer is aligned afterwards to a 16-byte boundary
+ *
+ * @ctx: ACPI context
+ * @amount: Amount to increment by
+ */
+void acpi_inc_align(struct acpi_ctx *ctx, uint amount);
+
 #endif /* !__ACPI__*/
 
 #include <asm/acpi_table.h>