[acpi] Allow for platforms that provide ACPI tables individually

The ACPI API currently expects platforms to provide access to a single
contiguous ACPI table.  Some platforms (e.g. Linux userspace) do not
provide a convenient way to obtain the entire ACPI table, but do
provide access to individual tables.

All iPXE consumers of the ACPI API require access only to individual
tables.

Redefine the internal API to make acpi_find() an API method, with all
existing implementations delegating to the current RSDT-based
implementation.

Signed-off-by: Michael Brown <mcb30@ipxe.org>

src/arch/x86/include/ipxe/rsdp.h

@@ -15,4 +15,17 @@ FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
 #define ACPI_PREFIX_rsdp __rsdp_
 #endif
 
+/**
+ * Locate ACPI table
+ *
+ * @v signature		Requested table signature
+ * @v index		Requested index of table with this signature
+ * @ret table		Table, or UNULL if not found
+ */
+static inline __attribute__ (( always_inline )) userptr_t
+ACPI_INLINE ( rsdp, acpi_find ) ( uint32_t signature, unsigned int index ) {
+
+	return acpi_find_via_rsdt ( signature, index );
+}
+
 #endif /* _IPXE_RSDP_H */

src/arch/x86/interface/pcbios/rsdp.c

@@ -123,3 +123,4 @@ static userptr_t rsdp_find_rsdt ( void ) {
 }
 
 PROVIDE_ACPI ( rsdp, acpi_find_rsdt, rsdp_find_rsdt );
+PROVIDE_ACPI_INLINE ( rsdp, acpi_find );

src/core/acpi.c

@@ -83,13 +83,13 @@ void acpi_fix_checksum ( struct acpi_header *acpi ) {
 }
 
 /**
- * Locate ACPI table
+ * Locate ACPI table via RSDT
  *
  * @v signature		Requested table signature
  * @v index		Requested index of table with this signature
  * @ret table		Table, or UNULL if not found
  */
-userptr_t acpi_find ( uint32_t signature, unsigned int index ) {
+userptr_t acpi_find_via_rsdt ( uint32_t signature, unsigned int index ) {
 	struct acpi_header acpi;
 	struct acpi_rsdt *rsdtab;
 	typeof ( rsdtab->entry[0] ) entry;

src/core/null_acpi.c

@@ -1,3 +1,3 @@
 #include <ipxe/acpi.h>
 
-PROVIDE_ACPI_INLINE ( null, acpi_find_rsdt );
+PROVIDE_ACPI_INLINE ( null, acpi_find );

src/include/ipxe/acpi.h

@@ -355,6 +355,8 @@ struct acpi_model {
 #define PROVIDE_ACPI_INLINE( _subsys, _api_func ) \
 	PROVIDE_SINGLE_API_INLINE ( ACPI_PREFIX_ ## _subsys, _api_func )
 
+extern userptr_t acpi_find_via_rsdt ( uint32_t signature, unsigned int index );
+
 /* Include all architecture-independent ACPI API headers */
 #include <ipxe/null_acpi.h>
 #include <ipxe/efi/efi_acpi.h>
@@ -369,13 +371,21 @@ struct acpi_model {
  */
 userptr_t acpi_find_rsdt ( void );
 
+/**
+ * Locate ACPI table
+ *
+ * @v signature		Requested table signature
+ * @v index		Requested index of table with this signature
+ * @ret table		Table, or UNULL if not found
+ */
+userptr_t acpi_find ( uint32_t signature, unsigned int index );
+
 extern struct acpi_descriptor *
 acpi_describe ( struct interface *interface );
 #define acpi_describe_TYPE( object_type )				\
 	typeof ( struct acpi_descriptor * ( object_type ) )
 
 extern void acpi_fix_checksum ( struct acpi_header *acpi );
-extern userptr_t acpi_find ( uint32_t signature, unsigned int index );
 extern int acpi_sx ( uint32_t signature );
 extern void acpi_add ( struct acpi_descriptor *desc );
 extern void acpi_del ( struct acpi_descriptor *desc );

src/include/ipxe/efi/efi_acpi.h

@@ -15,4 +15,17 @@ FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
 #define ACPI_PREFIX_efi __efi_
 #endif
 
+/**
+ * Locate ACPI table
+ *
+ * @v signature		Requested table signature
+ * @v index		Requested index of table with this signature
+ * @ret table		Table, or UNULL if not found
+ */
+static inline __attribute__ (( always_inline )) userptr_t
+ACPI_INLINE ( efi, acpi_find ) ( uint32_t signature, unsigned int index ) {
+
+	return acpi_find_via_rsdt ( signature, index );
+}
+
 #endif /* _IPXE_EFI_ACPI_H */

src/include/ipxe/null_acpi.h

@@ -15,8 +15,10 @@ FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
 #define ACPI_PREFIX_null __null_
 #endif
 
-static inline __always_inline userptr_t
+static inline __attribute__ (( always_inline )) userptr_t
-ACPI_INLINE ( null, acpi_find_rsdt ) ( void ) {
+ACPI_INLINE ( null, acpi_find ) ( uint32_t signature __unused,
+				  unsigned int index __unused ) {
+
 	return UNULL;
 }
 

src/interface/efi/efi_acpi.c

@@ -54,3 +54,4 @@ static userptr_t efi_find_rsdt ( void ) {
 }
 
 PROVIDE_ACPI ( efi, acpi_find_rsdt, efi_find_rsdt );
+PROVIDE_ACPI_INLINE ( efi, acpi_find );