riscv: separate MMIO functions into their own header file

Separate the low-level MMIO static inline functions and macros, such
as {read,write}{b,w,l,q}(), into their own header file under
arch/riscv/include: asm/mmio.h.  This is done to break a header
dependency chain that arises when both asm/pgtable.h and asm/io.h are
included by asm/timex.h.  Since the problem is related to the legacy
I/O port support in asm/io.h, this allows files under arch/riscv that
encounter those issues to simply include asm/mmio.h instead, and
bypass the legacy I/O port functions.  Existing users of asm/io.h
don't need to change anything, since asm/mmio.h is included by
asm/io.h.

While here, clean up some checkpatch.pl-related issues with the
original code.

Signed-off-by: Paul Walmsley <paul.walmsley@sifive.com>

1 files changed, 164 insertions, 0 deletions

diff --git a/arch/riscv/include/asm/mmio.h b/arch/riscv/include/asm/mmio.h
new file mode 100644
index 000000000000..308b98f85753
--- /dev/null
+++ b/arch/riscv/include/asm/mmio.h
@@ -0,0 +1,164 @@
+/* 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_MMIO_H
+#define _ASM_RISCV_MMIO_H
+
+#include <linux/types.h>
+#include <asm/mmiowb.h>
+
+void __iomem *ioremap(phys_addr_t offset, unsigned long size);
+
+/*
+ * The RISC-V ISA doesn't yet specify how to query or modify PMAs, so we can't
+ * change the properties of memory regions.  This should be fixed by the
+ * upcoming platform spec.
+ */
+#define ioremap_nocache(addr, size) ioremap((addr), (size))
+#define ioremap_wc(addr, size) ioremap((addr), (size))
+#define ioremap_wt(addr, size) ioremap((addr), (size))
+
+void iounmap(volatile void __iomem *addr);
+
+/* Generic IO read/write.  These perform native-endian accesses. */
+#define __raw_writeb __raw_writeb
+static inline void __raw_writeb(u8 val, volatile void __iomem *addr)
+{
+	asm volatile("sb %0, 0(%1)" : : "r" (val), "r" (addr));
+}
+
+#define __raw_writew __raw_writew
+static inline void __raw_writew(u16 val, volatile void __iomem *addr)
+{
+	asm volatile("sh %0, 0(%1)" : : "r" (val), "r" (addr));
+}
+
+#define __raw_writel __raw_writel
+static inline void __raw_writel(u32 val, volatile void __iomem *addr)
+{
+	asm volatile("sw %0, 0(%1)" : : "r" (val), "r" (addr));
+}
+
+#ifdef CONFIG_64BIT
+#define __raw_writeq __raw_writeq
+static inline void __raw_writeq(u64 val, volatile void __iomem *addr)
+{
+	asm volatile("sd %0, 0(%1)" : : "r" (val), "r" (addr));
+}
+#endif
+
+#define __raw_readb __raw_readb
+static inline u8 __raw_readb(const volatile void __iomem *addr)
+{
+	u8 val;
+
+	asm volatile("lb %0, 0(%1)" : "=r" (val) : "r" (addr));
+	return val;
+}
+
+#define __raw_readw __raw_readw
+static inline u16 __raw_readw(const volatile void __iomem *addr)
+{
+	u16 val;
+
+	asm volatile("lh %0, 0(%1)" : "=r" (val) : "r" (addr));
+	return val;
+}
+
+#define __raw_readl __raw_readl
+static inline u32 __raw_readl(const volatile void __iomem *addr)
+{
+	u32 val;
+
+	asm volatile("lw %0, 0(%1)" : "=r" (val) : "r" (addr));
+	return val;
+}
+
+#ifdef CONFIG_64BIT
+#define __raw_readq __raw_readq
+static inline u64 __raw_readq(const volatile void __iomem *addr)
+{
+	u64 val;
+
+	asm volatile("ld %0, 0(%1)" : "=r" (val) : "r" (addr));
+	return val;
+}
+#endif
+
+/*
+ * Unordered I/O memory access primitives.  These are even more relaxed than
+ * the relaxed versions, as they don't even order accesses between successive
+ * operations to the I/O regions.
+ */
+#define readb_cpu(c)		({ u8  __r = __raw_readb(c); __r; })
+#define readw_cpu(c)		({ u16 __r = le16_to_cpu((__force __le16)__raw_readw(c)); __r; })
+#define readl_cpu(c)		({ u32 __r = le32_to_cpu((__force __le32)__raw_readl(c)); __r; })
+
+#define writeb_cpu(v, c)	((void)__raw_writeb((v), (c)))
+#define writew_cpu(v, c)	((void)__raw_writew((__force u16)cpu_to_le16(v), (c)))
+#define writel_cpu(v, c)	((void)__raw_writel((__force u32)cpu_to_le32(v), (c)))
+
+#ifdef CONFIG_64BIT
+#define readq_cpu(c)		({ u64 __r = le64_to_cpu((__force __le64)__raw_readq(c)); __r; })
+#define writeq_cpu(v, c)	((void)__raw_writeq((__force u64)cpu_to_le64(v), (c)))
+#endif
+
+/*
+ * Relaxed I/O memory access primitives. These follow the Device memory
+ * ordering rules but do not guarantee any ordering relative to Normal memory
+ * accesses.  These are defined to order the indicated access (either a read or
+ * write) with all other I/O memory accesses. Since the platform specification
+ * defines that all I/O regions are strongly ordered on channel 2, no explicit
+ * fences are required to enforce this ordering.
+ */
+/* FIXME: These are now the same as asm-generic */
+#define __io_rbr()		do {} while (0)
+#define __io_rar()		do {} while (0)
+#define __io_rbw()		do {} while (0)
+#define __io_raw()		do {} while (0)
+
+#define readb_relaxed(c)	({ u8  __v; __io_rbr(); __v = readb_cpu(c); __io_rar(); __v; })
+#define readw_relaxed(c)	({ u16 __v; __io_rbr(); __v = readw_cpu(c); __io_rar(); __v; })
+#define readl_relaxed(c)	({ u32 __v; __io_rbr(); __v = readl_cpu(c); __io_rar(); __v; })
+
+#define writeb_relaxed(v, c)	({ __io_rbw(); writeb_cpu((v), (c)); __io_raw(); })
+#define writew_relaxed(v, c)	({ __io_rbw(); writew_cpu((v), (c)); __io_raw(); })
+#define writel_relaxed(v, c)	({ __io_rbw(); writel_cpu((v), (c)); __io_raw(); })
+
+#ifdef CONFIG_64BIT
+#define readq_relaxed(c)	({ u64 __v; __io_rbr(); __v = readq_cpu(c); __io_rar(); __v; })
+#define writeq_relaxed(v, c)	({ __io_rbw(); writeq_cpu((v), (c)); __io_raw(); })
+#endif
+
+/*
+ * I/O memory access primitives. Reads are ordered relative to any
+ * following Normal memory access. Writes are ordered relative to any prior
+ * Normal memory access.  The memory barriers here are necessary as RISC-V
+ * doesn't define any ordering between the memory space and the I/O space.
+ */
+#define __io_br()	do {} while (0)
+#define __io_ar(v)	__asm__ __volatile__ ("fence i,r" : : : "memory")
+#define __io_bw()	__asm__ __volatile__ ("fence w,o" : : : "memory")
+#define __io_aw()	mmiowb_set_pending()
+
+#define readb(c)	({ u8  __v; __io_br(); __v = readb_cpu(c); __io_ar(__v); __v; })
+#define readw(c)	({ u16 __v; __io_br(); __v = readw_cpu(c); __io_ar(__v); __v; })
+#define readl(c)	({ u32 __v; __io_br(); __v = readl_cpu(c); __io_ar(__v); __v; })
+
+#define writeb(v, c)	({ __io_bw(); writeb_cpu((v), (c)); __io_aw(); })
+#define writew(v, c)	({ __io_bw(); writew_cpu((v), (c)); __io_aw(); })
+#define writel(v, c)	({ __io_bw(); writel_cpu((v), (c)); __io_aw(); })
+
+#ifdef CONFIG_64BIT
+#define readq(c)	({ u64 __v; __io_br(); __v = readq_cpu(c); __io_ar(__v); __v; })
+#define writeq(v, c)	({ __io_bw(); writeq_cpu((v), (c)); __io_aw(); })
+#endif
+
+#endif /* _ASM_RISCV_MMIO_H */