1 files changed, 143 insertions, 0 deletions
diff --git a/arch/riscv/include/asm/io.h b/arch/riscv/include/asm/io.h
new file mode 100644
index 000000000..42497d487
--- /dev/null
+++ b/arch/riscv/include/asm/io.h
@@ -0,0 +1,143 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * {read,write}{b,w,l,q} based on arch/arm64/include/asm/io.h
+ *   which was based on arch/arm/include/io.h
+ *
+ * Copyright (C) 1996-2000 Russell King
+ * Copyright (C) 2012 ARM Ltd.
+ * Copyright (C) 2014 Regents of the University of California
+ */
+
+#ifndef _ASM_RISCV_IO_H
+#define _ASM_RISCV_IO_H
+
+#include <linux/types.h>
+#include <linux/pgtable.h>
+#include <asm/mmiowb.h>
+#include <asm/early_ioremap.h>
+
+/*
+ * MMIO access functions are separated out to break dependency cycles
+ * when using {read,write}* fns in low-level headers
+ */
+#include <asm/mmio.h>
+
+/*
+ *  I/O port access constants.
+ */
+#ifdef CONFIG_MMU
+#define IO_SPACE_LIMIT		(PCI_IO_SIZE - 1)
+#define PCI_IOBASE		((void __iomem *)PCI_IO_START)
+#endif /* CONFIG_MMU */
+
+/*
+ * Emulation routines for the port-mapped IO space used by some PCI drivers.
+ * These are defined as being "fully synchronous", but also "not guaranteed to
+ * be fully ordered with respect to other memory and I/O operations".  We're
+ * going to be on the safe side here and just make them:
+ *  - Fully ordered WRT each other, by bracketing them with two fences.  The
+ *    outer set contains both I/O so inX is ordered with outX, while the inner just
+ *    needs the type of the access (I for inX and O for outX).
+ *  - Ordered in the same manner as readX/writeX WRT memory by subsuming their
+ *    fences.
+ *  - Ordered WRT timer reads, so udelay and friends don't get elided by the
+ *    implementation.
+ * Note that there is no way to actually enforce that outX is a non-posted
+ * operation on RISC-V, but hopefully the timer ordering constraint is
+ * sufficient to ensure this works sanely on controllers that support I/O
+ * writes.
+ */
+#define __io_pbr()	__asm__ __volatile__ ("fence io,i"  : : : "memory");
+#define __io_par(v)	__asm__ __volatile__ ("fence i,ior" : : : "memory");
+#define __io_pbw()	__asm__ __volatile__ ("fence iow,o" : : : "memory");
+#define __io_paw()	__asm__ __volatile__ ("fence o,io"  : : : "memory");
+
+/*
+ * Accesses from a single hart to a single I/O address must be ordered.  This
+ * allows us to use the raw read macros, but we still need to fence before and
+ * after the block to ensure ordering WRT other macros.  These are defined to
+ * perform host-endian accesses so we use __raw instead of __cpu.
+ */
+#define __io_reads_ins(port, ctype, len, bfence, afence)			\
+	static inline void __ ## port ## len(const volatile void __iomem *addr,	\
+					     void *buffer,			\
+					     unsigned int count)		\
+	{									\
+		bfence;								\
+		if (count) {							\
+			ctype *buf = buffer;					\
+										\
+			do {							\
+				ctype x = __raw_read ## len(addr);		\
+				*buf++ = x;					\
+			} while (--count);					\
+		}								\
+		afence;								\
+	}
+
+#define __io_writes_outs(port, ctype, len, bfence, afence)			\
+	static inline void __ ## port ## len(volatile void __iomem *addr,	\
+					     const void *buffer,		\
+					     unsigned int count)		\
+	{									\
+		bfence;								\
+		if (count) {							\
+			const ctype *buf = buffer;				\
+										\
+			do {							\
+				__raw_write ## len(*buf++, addr);		\
+			} while (--count);					\
+		}								\
+		afence;								\
+	}
+
+__io_reads_ins(reads,  u8, b, __io_br(), __io_ar(addr))
+__io_reads_ins(reads, u16, w, __io_br(), __io_ar(addr))
+__io_reads_ins(reads, u32, l, __io_br(), __io_ar(addr))
+#define readsb(addr, buffer, count) __readsb(addr, buffer, count)
+#define readsw(addr, buffer, count) __readsw(addr, buffer, count)
+#define readsl(addr, buffer, count) __readsl(addr, buffer, count)
+
+__io_reads_ins(ins,  u8, b, __io_pbr(), __io_par(addr))
+__io_reads_ins(ins, u16, w, __io_pbr(), __io_par(addr))
+__io_reads_ins(ins, u32, l, __io_pbr(), __io_par(addr))
+#define insb(addr, buffer, count) __insb(PCI_IOBASE + (addr), buffer, count)
+#define insw(addr, buffer, count) __insw(PCI_IOBASE + (addr), buffer, count)
+#define insl(addr, buffer, count) __insl(PCI_IOBASE + (addr), buffer, count)
+
+__io_writes_outs(writes,  u8, b, __io_bw(), __io_aw())
+__io_writes_outs(writes, u16, w, __io_bw(), __io_aw())
+__io_writes_outs(writes, u32, l, __io_bw(), __io_aw())
+#define writesb(addr, buffer, count) __writesb(addr, buffer, count)
+#define writesw(addr, buffer, count) __writesw(addr, buffer, count)
+#define writesl(addr, buffer, count) __writesl(addr, buffer, count)
+
+__io_writes_outs(outs,  u8, b, __io_pbw(), __io_paw())
+__io_writes_outs(outs, u16, w, __io_pbw(), __io_paw())
+__io_writes_outs(outs, u32, l, __io_pbw(), __io_paw())
+#define outsb(addr, buffer, count) __outsb(PCI_IOBASE + (addr), buffer, count)
+#define outsw(addr, buffer, count) __outsw(PCI_IOBASE + (addr), buffer, count)
+#define outsl(addr, buffer, count) __outsl(PCI_IOBASE + (addr), buffer, count)
+
+#ifdef CONFIG_64BIT
+__io_reads_ins(reads, u64, q, __io_br(), __io_ar(addr))
+#define readsq(addr, buffer, count) __readsq(addr, buffer, count)
+
+__io_reads_ins(ins, u64, q, __io_pbr(), __io_par(addr))
+#define insq(addr, buffer, count) __insq(PCI_IOBASE + (addr), buffer, count)
+
+__io_writes_outs(writes, u64, q, __io_bw(), __io_aw())
+#define writesq(addr, buffer, count) __writesq(addr, buffer, count)
+
+__io_writes_outs(outs, u64, q, __io_pbr(), __io_paw())
+#define outsq(addr, buffer, count) __outsq(PCI_IOBASE + (addr), buffer, count)
+#endif
+
+#include <asm-generic/io.h>
+
+#ifdef CONFIG_MMU
+#define arch_memremap_wb(addr, size)	\
+	((__force void *)ioremap_prot((addr), (size), _PAGE_KERNEL))
+#endif
+
+#endif /* _ASM_RISCV_IO_H */