fbdev: Move framebuffer I/O helpers into <asm/fb.h>

Implement framebuffer I/O helpers, such as fb_read*() and fb_write*(),
in the architecture's <asm/fb.h> header file or the generic one.

The common case has been the use of regular I/O functions, such as
__raw_readb() or memset_io(). A few architectures used plain system-
memory reads and writes. Sparc used helpers for its SBus.

The architectures that used special cases provide the same code in
their __raw_*() I/O helpers. So the patch replaces this code with the
__raw_*() functions and moves it to <asm-generic/fb.h> for all
architectures.

v8:
	* remove garbage after commit-message tags
v6:
	* fix fb_readq()/fb_writeq() on 64-bit mips (kernel test robot)
v5:
	* include <linux/io.h> in <asm-generic/fb>; fix s390 build
v4:
	* ia64, loongarch, sparc64: add fb_mem*() to arch headers
	  to keep current semantics (Arnd)
v3:
	* implement all architectures with generic helpers
	* support reordering and native byte order (Geert, Arnd)

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Tested-by: Sui Jingfeng <suijingfeng@loongson.cn>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20230512102444.5438-7-tzimmermann@suse.de

6 files changed, 185 insertions, 53 deletions

diff --git a/arch/ia64/include/asm/fb.h b/arch/ia64/include/asm/fb.h
index 0208f64a0da0..bcf982043a5c 100644
--- a/arch/ia64/include/asm/fb.h
+++ b/arch/ia64/include/asm/fb.h
@@ -2,7 +2,9 @@
 #ifndef _ASM_FB_H_
 #define _ASM_FB_H_
 
+#include <linux/compiler.h>
 #include <linux/efi.h>
+#include <linux/string.h>
 
 #include <asm/page.h>
 
@@ -18,6 +20,24 @@ static inline void fb_pgprotect(struct file *file, struct vm_area_struct *vma,
 }
 #define fb_pgprotect fb_pgprotect
 
+static inline void fb_memcpy_fromfb(void *to, const volatile void __iomem *from, size_t n)
+{
+	memcpy(to, (void __force *)from, n);
+}
+#define fb_memcpy_fromfb fb_memcpy_fromfb
+
+static inline void fb_memcpy_tofb(volatile void __iomem *to, const void *from, size_t n)
+{
+	memcpy((void __force *)to, from, n);
+}
+#define fb_memcpy_tofb fb_memcpy_tofb
+
+static inline void fb_memset(volatile void __iomem *addr, int c, size_t n)
+{
+	memset((void __force *)addr, c, n);
+}
+#define fb_memset fb_memset
+
 #include <asm-generic/fb.h>
 
 #endif /* _ASM_FB_H_ */
diff --git a/arch/loongarch/include/asm/fb.h b/arch/loongarch/include/asm/fb.h
index ff82f20685c8..c6fc7ef374a4 100644
--- a/arch/loongarch/include/asm/fb.h
+++ b/arch/loongarch/include/asm/fb.h
@@ -5,6 +5,27 @@
 #ifndef _ASM_FB_H_
 #define _ASM_FB_H_
 
+#include <linux/compiler.h>
+#include <linux/string.h>
+
+static inline void fb_memcpy_fromfb(void *to, const volatile void __iomem *from, size_t n)
+{
+	memcpy(to, (void __force *)from, n);
+}
+#define fb_memcpy_fromfb fb_memcpy_fromfb
+
+static inline void fb_memcpy_tofb(volatile void __iomem *to, const void *from, size_t n)
+{
+	memcpy((void __force *)to, from, n);
+}
+#define fb_memcpy_tofb fb_memcpy_tofb
+
+static inline void fb_memset(volatile void __iomem *addr, int c, size_t n)
+{
+	memset((void __force *)addr, c, n);
+}
+#define fb_memset fb_memset
+
 #include <asm-generic/fb.h>
 
 #endif /* _ASM_FB_H_ */
diff --git a/arch/mips/include/asm/fb.h b/arch/mips/include/asm/fb.h
index 6bda0a81d8ca..18b7226403ba 100644
--- a/arch/mips/include/asm/fb.h
+++ b/arch/mips/include/asm/fb.h
@@ -12,6 +12,28 @@ static inline void fb_pgprotect(struct file *file, struct vm_area_struct *vma,
 }
 #define fb_pgprotect fb_pgprotect
 
+/*
+ * MIPS doesn't define __raw_ I/O macros, so the helpers
+ * in <asm-generic/fb.h> don't generate fb_readq() and
+ * fb_write(). We have to provide them here.
+ *
+ * TODO: Convert MIPS to generic I/O. The helpers below can
+ *       then be removed.
+ */
+#ifdef CONFIG_64BIT
+static inline u64 fb_readq(const volatile void __iomem *addr)
+{
+	return __raw_readq(addr);
+}
+#define fb_readq fb_readq
+
+static inline void fb_writeq(u64 b, volatile void __iomem *addr)
+{
+	__raw_writeq(b, addr);
+}
+#define fb_writeq fb_writeq
+#endif
+
 #include <asm-generic/fb.h>
 
 #endif /* _ASM_FB_H_ */
diff --git a/arch/sparc/include/asm/fb.h b/arch/sparc/include/asm/fb.h
index 689ee5c60054..077da91aeba1 100644
--- a/arch/sparc/include/asm/fb.h
+++ b/arch/sparc/include/asm/fb.h
@@ -2,6 +2,8 @@
 #ifndef _SPARC_FB_H_
 #define _SPARC_FB_H_
 
+#include <linux/io.h>
+
 struct fb_info;
 struct file;
 struct vm_area_struct;
@@ -16,6 +18,24 @@ static inline void fb_pgprotect(struct file *file, struct vm_area_struct *vma,
 int fb_is_primary_device(struct fb_info *info);
 #define fb_is_primary_device fb_is_primary_device
 
+static inline void fb_memcpy_fromfb(void *to, const volatile void __iomem *from, size_t n)
+{
+	sbus_memcpy_fromio(to, from, n);
+}
+#define fb_memcpy_fromfb fb_memcpy_fromfb
+
+static inline void fb_memcpy_tofb(volatile void __iomem *to, const void *from, size_t n)
+{
+	sbus_memcpy_toio(to, from, n);
+}
+#define fb_memcpy_tofb fb_memcpy_tofb
+
+static inline void fb_memset(volatile void __iomem *addr, int c, size_t n)
+{
+	sbus_memset_io(addr, c, n);
+}
+#define fb_memset fb_memset
+
 #include <asm-generic/fb.h>
 
 #endif /* _SPARC_FB_H_ */
diff --git a/include/asm-generic/fb.h b/include/asm-generic/fb.h
index c8af99f5a535..0540eccdbeca 100644
--- a/include/asm-generic/fb.h
+++ b/include/asm-generic/fb.h
@@ -7,6 +7,7 @@
  * Only include this header file from your architecture's <asm/fb.h>.
  */
 
+#include <linux/io.h>
 #include <linux/mm_types.h>
 #include <linux/pgtable.h>
 
@@ -30,4 +31,105 @@ static inline int fb_is_primary_device(struct fb_info *info)
 }
 #endif
 
+/*
+ * I/O helpers for the framebuffer. Prefer these functions over their
+ * regular counterparts. The regular I/O functions provide in-order
+ * access and swap bytes to/from little-endian ordering. Neither is
+ * required for framebuffers. Instead, the helpers read and write
+ * raw framebuffer data. Independent operations can be reordered for
+ * improved performance.
+ */
+
+#ifndef fb_readb
+static inline u8 fb_readb(const volatile void __iomem *addr)
+{
+	return __raw_readb(addr);
+}
+#define fb_readb fb_readb
+#endif
+
+#ifndef fb_readw
+static inline u16 fb_readw(const volatile void __iomem *addr)
+{
+	return __raw_readw(addr);
+}
+#define fb_readw fb_readw
+#endif
+
+#ifndef fb_readl
+static inline u32 fb_readl(const volatile void __iomem *addr)
+{
+	return __raw_readl(addr);
+}
+#define fb_readl fb_readl
+#endif
+
+#ifndef fb_readq
+#if defined(__raw_readq)
+static inline u64 fb_readq(const volatile void __iomem *addr)
+{
+	return __raw_readq(addr);
+}
+#define fb_readq fb_readq
+#endif
+#endif
+
+#ifndef fb_writeb
+static inline void fb_writeb(u8 b, volatile void __iomem *addr)
+{
+	__raw_writeb(b, addr);
+}
+#define fb_writeb fb_writeb
+#endif
+
+#ifndef fb_writew
+static inline void fb_writew(u16 b, volatile void __iomem *addr)
+{
+	__raw_writew(b, addr);
+}
+#define fb_writew fb_writew
+#endif
+
+#ifndef fb_writel
+static inline void fb_writel(u32 b, volatile void __iomem *addr)
+{
+	__raw_writel(b, addr);
+}
+#define fb_writel fb_writel
+#endif
+
+#ifndef fb_writeq
+#if defined(__raw_writeq)
+static inline void fb_writeq(u64 b, volatile void __iomem *addr)
+{
+	__raw_writeq(b, addr);
+}
+#define fb_writeq fb_writeq
+#endif
+#endif
+
+#ifndef fb_memcpy_fromfb
+static inline void fb_memcpy_fromfb(void *to, const volatile void __iomem *from, size_t n)
+{
+	memcpy_fromio(to, from, n);
+}
+#define fb_memcpy_fromfb fb_memcpy_fromfb
+#endif
+
+#ifndef fb_memcpy_tofb
+static inline void fb_memcpy_tofb(volatile void __iomem *to, const void *from, size_t n)
+{
+	memcpy_toio(to, from, n);
+}
+#define fb_memcpy_tofb fb_memcpy_tofb
+#endif
+
+#ifndef fb_memset
+static inline void fb_memset(volatile void __iomem *addr, int c, size_t n)
+{
+	memset_io(addr, c, n);
+}
+#define fb_memset fb_memset
+#endif
+
 #endif /* __ASM_GENERIC_FB_H_ */
diff --git a/include/linux/fb.h b/include/linux/fb.h
index 4b4d9a5d200a..2cf8efcb9e32 100644
--- a/include/linux/fb.h
+++ b/include/linux/fb.h
@@ -17,7 +17,6 @@
 #include <linux/slab.h>
 
 #include <asm/fb.h>
-#include <asm/io.h>
 
 struct vm_area_struct;
 struct fb_info;
@@ -513,58 +512,6 @@ struct fb_info {
  */
 #define STUPID_ACCELF_TEXT_SHIT
 
-// This will go away
-#if defined(__sparc__)
-
-/* We map all of our framebuffers such that big-endian accesses
- * are what we want, so the following is sufficient.
- */
-
-// This will go away
-#define fb_readb sbus_readb
-#define fb_readw sbus_readw
-#define fb_readl sbus_readl
-#define fb_readq sbus_readq
-#define fb_writeb sbus_writeb
-#define fb_writew sbus_writew
-#define fb_writel sbus_writel
-#define fb_writeq sbus_writeq
-#define fb_memset sbus_memset_io
-#define fb_memcpy_fromfb sbus_memcpy_fromio
-#define fb_memcpy_tofb sbus_memcpy_toio
-
-#elif defined(__i386__) || defined(__alpha__) || defined(__x86_64__) ||	\
-	defined(__hppa__) || defined(__sh__) || defined(__powerpc__) ||	\
-	defined(__arm__) || defined(__aarch64__) || defined(__mips__)
-
-#define fb_readb __raw_readb
-#define fb_readw __raw_readw
-#define fb_readl __raw_readl
-#define fb_readq __raw_readq
-#define fb_writeb __raw_writeb
-#define fb_writew __raw_writew
-#define fb_writel __raw_writel
-#define fb_writeq __raw_writeq
-#define fb_memset memset_io
-#define fb_memcpy_fromfb memcpy_fromio
-#define fb_memcpy_tofb memcpy_toio
-
-#else
-
-#define fb_readb(addr) (*(volatile u8 *) (addr))
-#define fb_readw(addr) (*(volatile u16 *) (addr))
-#define fb_readl(addr) (*(volatile u32 *) (addr))
-#define fb_readq(addr) (*(volatile u64 *) (addr))
-#define fb_writeb(b,addr) (*(volatile u8 *) (addr) = (b))
-#define fb_writew(b,addr) (*(volatile u16 *) (addr) = (b))
-#define fb_writel(b,addr) (*(volatile u32 *) (addr) = (b))
-#define fb_writeq(b,addr) (*(volatile u64 *) (addr) = (b))
-#define fb_memset memset
-#define fb_memcpy_fromfb memcpy
-#define fb_memcpy_tofb memcpy
-
-#endif
-
 #define FB_LEFT_POS(p, bpp)          (fb_be_math(p) ? (32 - (bpp)) : 0)
 #define FB_SHIFT_HIGH(p, val, bits)  (fb_be_math(p) ? (val) >> (bits) : \
 						      (val) << (bits))