Hi Angelo,
CC commit relations
On Sat, Apr 27, 2019 at 10:22 PM Angelo Dureghello <angelo@xxxxxxxx> wrote:
On Sat, Apr 27, 2019 at 05:32:22PM +0200, Angelo Dureghello wrote:
as you may know, i am working on mcf5441x.
Sorry for not following carefully all the threads, but from a certain
kernel version (likely 4.19 or near there), seems ioread32be
reads the bytes swapped in endianness (mcf-edma dma driver not working
anymore).
Has there been a change about this in the architecture I/O access ?
How should i proceed now ? Fixing the DMA driver read/write, or what ?
looks like the reason of my ioread32be now swapped is:
https://patchwork.kernel.org/patch/10766673/
Trying to figure out what to do now.
This is commit aecc787c06f4300f ("iomap: Use non-raw io functions for
io{read|write}XXbe"):
--- a/lib/iomap.c
+++ b/lib/iomap.c
@@ -65,8 +65,8 @@ static void bad_io_access(unsigned long port, const
char *access)
#endif
#ifndef mmio_read16be
-#define mmio_read16be(addr) be16_to_cpu(__raw_readw(addr))
-#define mmio_read32be(addr) be32_to_cpu(__raw_readl(addr))
+#define mmio_read16be(addr) swab16(readw(addr))
+#define mmio_read32be(addr) swab32(readl(addr))
#endif
unsigned int ioread8(void __iomem *addr)
@@ -106,8 +106,8 @@ EXPORT_SYMBOL(ioread32be);
#endif
#ifndef mmio_write16be
-#define mmio_write16be(val,port) __raw_writew(be16_to_cpu(val),port)
-#define mmio_write32be(val,port) __raw_writel(be32_to_cpu(val),port)
+#define mmio_write16be(val,port) writew(swab16(val),port)
+#define mmio_write32be(val,port) writel(swab32(val),port)
On big endian, the raw accessors are assumed to be non-swapping,
while non-raw accessors are assumed to be swapping.
The latter is not true for Coldfire internal registers, cfr.
arch/m68k/include/asm/io_no.h:
static inline u16 readw(const volatile void __iomem *addr)
{
if (cf_internalio(addr))
return __raw_readw(addr);
return __le16_to_cpu(__raw_readw(addr));
}
Orthogonal to how Coldfire's read[wl]() should be fixed, I find it a bit
questionable to swap data twice on big endian architectures.
Fortunately we can avoid that by defining our own
mmio_{read,write}{16,32}be()...
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
