On 2023-04-28 10:27, Thomas Zimmermann wrote:
Implement framebuffer I/O helpers, such as fb_read*() and fb_write*()
with Linux' regular I/O functions. Remove all ifdef cases for the
various architectures.
Most of the supported architectures use __raw_() I/O functions or treat
framebuffer memory like regular memory. This is also implemented by the
architectures' I/O function, so we can use them instead.
Sparc uses SBus to connect to framebuffer devices. It provides respective
implementations of the framebuffer I/O helpers. The involved sbus_()
I/O helpers map to the same code as Sparc's regular I/O functions. As
with other platforms, we can use those instead.
We leave a TODO item to replace all fb_() functions with their regular
I/O counterparts throughout the fbdev drivers.
Signed-off-by: Thomas Zimmermann <tzimmermann@xxxxxxx>
---
include/linux/fb.h | 63 +++++++++++-----------------------------------
1 file changed, 15 insertions(+), 48 deletions(-)
diff --git a/include/linux/fb.h b/include/linux/fb.h
index 08cb47da71f8..4aa9e90edd17 100644
--- a/include/linux/fb.h
+++ b/include/linux/fb.h
@@ -15,7 +15,6 @@
#include <linux/list.h>
#include <linux/backlight.h>
#include <linux/slab.h>
-#include <asm/io.h>
struct vm_area_struct;
struct fb_info;
@@ -511,58 +510,26 @@ 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.
+/*
+ * TODO: Update fbdev drivers to call the I/O helpers directly and
+ * remove the fb_() tokens.
*/
-
-// 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
Note that on at least some architectures, the __raw variants are
native-endian, whereas the regular accessors are explicitly
little-endian, so there is a slight risk of inadvertently changing
behaviour on big-endian systems (MIPS most likely, but a few old ARM
platforms run BE as well).
+#define fb_readb readb
+#define fb_readw readw
+#define fb_readl readl
+#if defined(CONFIG_64BIT)
+#define fb_readq readq
+#endif
You probably don't need to bother making these conditional - 32-bit
architectures aren't forbidden from providing readq/writeq if they
really want to, and drivers can also use the io-64-nonatomic headers for
portability. The build will still fail in a sufficiently obvious manner
if neither is true.
Thanks,
Robin.
+#define fb_writeb writeb
+#define fb_writew writew
+#define fb_writel writel
+#if defined(CONFIG_64BIT)
+#define fb_writeq writeq
+#endif
#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))
