[loong64] Add I/O API for LoongArch64

Signed-off-by: Xiaotian Wu <wuxiaotian@loongson.cn>
Modified-by: Michael Brown <mcb30@ipxe.org>
Signed-off-by: Michael Brown <mcb30@ipxe.org>

src/arch/loong64/core/loong64_io.c

@@ -0,0 +1,46 @@
+/*
+ * Copyright (c) 2023, Xiaotian Wu <wuxiaotian@loongson.cn>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of the
+ * License, or any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301, USA.
+ *
+ * You can also choose to distribute this program under the terms of
+ * the Unmodified Binary Distribution Licence (as given in the file
+ * COPYING.UBDL), provided that you have satisfied its requirements.
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
+
+#include <ipxe/io.h>
+#include <ipxe/loong64_io.h>
+
+/** @file
+ *
+ * iPXE I/O API for LoongArch64
+ *
+ */
+
+PROVIDE_IOAPI_INLINE ( loong64, phys_to_bus );
+PROVIDE_IOAPI_INLINE ( loong64, bus_to_phys );
+PROVIDE_IOAPI_INLINE ( loong64, readb );
+PROVIDE_IOAPI_INLINE ( loong64, readw );
+PROVIDE_IOAPI_INLINE ( loong64, readl );
+PROVIDE_IOAPI_INLINE ( loong64, readq );
+PROVIDE_IOAPI_INLINE ( loong64, writeb );
+PROVIDE_IOAPI_INLINE ( loong64, writew );
+PROVIDE_IOAPI_INLINE ( loong64, writel );
+PROVIDE_IOAPI_INLINE ( loong64, writeq );
+PROVIDE_IOAPI_INLINE ( loong64, mb );
+PROVIDE_DUMMY_PIO ( loong64 );

src/arch/loong64/include/bits/io.h

@@ -12,4 +12,6 @@ FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
 /** Page shift */
 #define PAGE_SHIFT 12
 
+#include <ipxe/loong64_io.h>
+
 #endif /* _BITS_IO_H */

src/arch/loong64/include/ipxe/loong64_io.h

@@ -0,0 +1,82 @@
+#ifndef _IPXE_LOONG64_IO_H
+#define _IPXE_LOONG64_IO_H
+
+/** @file
+ *
+ * iPXE I/O API for LoongArch64
+ *
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
+
+#ifdef IOAPI_LOONG64
+#define IOAPI_PREFIX_loong64
+#else
+#define IOAPI_PREFIX_loong64 __loong64_
+#endif
+
+#include <ipxe/dummy_pio.h>
+
+/*
+ * Memory space mappings
+ *
+ */
+
+/*
+ * Physical<->Bus address mappings
+ *
+ */
+
+static inline __always_inline unsigned long
+IOAPI_INLINE ( loong64, phys_to_bus ) ( unsigned long phys_addr ) {
+	return phys_addr;
+}
+
+static inline __always_inline unsigned long
+IOAPI_INLINE ( loong64, bus_to_phys ) ( unsigned long bus_addr ) {
+	return bus_addr;
+}
+
+/*
+ * MMIO reads and writes up to native word size
+ *
+ */
+
+#define LOONG64_READX( _suffix, _type, _insn_suffix )			      \
+static inline __always_inline _type					      \
+IOAPI_INLINE ( loong64, read ## _suffix ) ( volatile _type *io_addr ) {	      \
+	_type data;							      \
+	__asm__ __volatile__ ( "ld." _insn_suffix " %0, %1"		      \
+			       : "=r" ( data ) : "m" ( *io_addr ) );	      \
+	return data;							      \
+}
+LOONG64_READX ( b, uint8_t, "bu");
+LOONG64_READX ( w, uint16_t, "hu");
+LOONG64_READX ( l, uint32_t, "wu");
+LOONG64_READX ( q, uint64_t, "d");
+
+#define LOONG64_WRITEX( _suffix, _type, _insn_suffix )			      \
+static inline __always_inline void					      \
+IOAPI_INLINE ( loong64, write ## _suffix ) ( _type data,		      \
+					     volatile _type *io_addr ) {      \
+	__asm__ __volatile__ ( "st." _insn_suffix " %0, %1"		      \
+			       : : "r" ( data ), "m" ( *io_addr ) );	      \
+}
+LOONG64_WRITEX ( b, uint8_t, "b");
+LOONG64_WRITEX ( w, uint16_t, "h");
+LOONG64_WRITEX ( l, uint32_t, "w" );
+LOONG64_WRITEX ( q, uint64_t, "d");
+
+/*
+ * Memory barrier
+ *
+ */
+static inline __always_inline void
+IOAPI_INLINE ( loong64, mb ) ( void ) {
+	__asm__ __volatile__ ( "dbar 0" );
+}
+
+/* Dummy PIO */
+DUMMY_PIO ( loong64 );
+
+#endif /* _IPXE_LOONG64_IO_H */