linux-kernel - [PATCH 2/2] riscv,mmio: Use the generic implementation for the I/O accesses

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Message-Id: <20230711133348.151383-3-parri.andrea@gmail.com>
Date:   Tue, 11 Jul 2023 15:33:48 +0200
From:   Andrea Parri <parri.andrea@...il.com>
To:     Paul Walmsley <paul.walmsley@...ive.com>,
        Palmer Dabbelt <palmer@...belt.com>,
        Albert Ou <aou@...s.berkeley.edu>
Cc:     linux-riscv@...ts.infradead.org, linux-kernel@...r.kernel.org,
        Andrea Parri <parri.andrea@...il.com>
Subject: [PATCH 2/2] riscv,mmio: Use the generic implementation for the I/O accesses

The current implementation of readX(), writeX() and their "relaxed"
variants, readX_relaxed() and writeX_relaxed(), matches the generic
implementation; remove the redundant code.

No functional change intended.

Signed-off-by: Andrea Parri <parri.andrea@...il.com>
---
 arch/riscv/include/asm/mmio.h | 68 ++++-------------------------------
 1 file changed, 6 insertions(+), 62 deletions(-)

diff --git a/arch/riscv/include/asm/mmio.h b/arch/riscv/include/asm/mmio.h
index 4c58ee7f95ecf..116b898fe969d 100644
--- a/arch/riscv/include/asm/mmio.h
+++ b/arch/riscv/include/asm/mmio.h
@@ -80,72 +80,16 @@ static inline u64 __raw_readq(const volatile void __iomem *addr)
 #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 to the same peripheral. Since the
- * platform specification defines that all I/O regions are strongly ordered on
- * channel 0, 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 read and delay() loop.  Writes are ordered relative to any
- * prior Normal memory write.  The memory barriers here are necessary as RISC-V
- * doesn't define any ordering between the memory space and the I/O space.
+ * I/O barriers
+ *
+ * See Documentation/memory-barriers.txt, "Kernel I/O barrier effects".
+ *
+ * Assume that each I/O region is strongly ordered on channel 0, following the
+ * RISC-V Platform Specification, "OS-A Common Requirements".
  */
 #define __io_br()	do {} while (0)
 #define __io_ar(v)	({ __asm__ __volatile__ ("fence i,ir" : : : "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 */
-- 
2.34.1