| Message ID | 1292679093-4632-1-git-send-email-holler@ahsoftware.de |
|---|---|
| State | Changes Requested |
| Headers | show |
Hello, Am -10.01.-28163 20:59, schrieb Alexander Holler: > gcc 4.5.1 seems to ignore (at least some) volatile definitions, > avoid that as done in the kernel. > --- > arch/arm/include/asm/io.h | 15 +++++++++------ > 1 files changed, 9 insertions(+), 6 deletions(-) > > diff --git a/arch/arm/include/asm/io.h b/arch/arm/include/asm/io.h > index ff1518e..3b6c1da 100644 > --- a/arch/arm/include/asm/io.h > +++ b/arch/arm/include/asm/io.h > @@ -125,13 +125,16 @@ extern inline void __raw_readsl(unsigned int addr, void *data, int longlen) > #define __raw_readw(a) __arch_getw(a) > #define __raw_readl(a) __arch_getl(a) > > -#define writeb(v,a) __arch_putb(v,a) > -#define writew(v,a) __arch_putw(v,a) > -#define writel(v,a) __arch_putl(v,a) > +#define __iormb() do { } while (0) > +#define __iowmb() do { } while (0) > > -#define readb(a) __arch_getb(a) > -#define readw(a) __arch_getw(a) > -#define readl(a) __arch_getl(a) > +#define writeb(v,c) ({ __iowmb(); __arch_putb(v,c); }) > +#define writew(v,c) ({ __iowmb(); __arch_putw(v,c); }) > +#define writel(v,c) ({ __iowmb(); __arch_putl(v,c); }) > + > +#define readb(c) ({ u8 __v = __arch_getb(c); __iormb(); __v; }) > +#define readw(c) ({ u16 __v = __arch_getw(c); __iormb(); __v; }) > +#define readl(c) ({ u32 __v = __arch_getl(c); __iormb(); __v; }) > > /* > * The compiler seems to be incapable of optimising constants Sorry, but that patch doesn't work. My first version of that used __arch_putb and __arch_getb for all (instead of w and l), therefor the generated asm code looked (somewhat) correct and I've concluded wrongly that the compiler now doesn't do the wrong optimizations. But after I've changed that to use l and w, those (wrong) optimizations where back again and I haven't seen that. Sorry, will look for another solution. Regards, Alexander
diff --git a/arch/arm/include/asm/io.h b/arch/arm/include/asm/io.h index ff1518e..3b6c1da 100644 --- a/arch/arm/include/asm/io.h +++ b/arch/arm/include/asm/io.h @@ -125,13 +125,16 @@ extern inline void __raw_readsl(unsigned int addr, void *data, int longlen) #define __raw_readw(a) __arch_getw(a) #define __raw_readl(a) __arch_getl(a) -#define writeb(v,a) __arch_putb(v,a) -#define writew(v,a) __arch_putw(v,a) -#define writel(v,a) __arch_putl(v,a) +#define __iormb() do { } while (0) +#define __iowmb() do { } while (0) -#define readb(a) __arch_getb(a) -#define readw(a) __arch_getw(a) -#define readl(a) __arch_getl(a) +#define writeb(v,c) ({ __iowmb(); __arch_putb(v,c); }) +#define writew(v,c) ({ __iowmb(); __arch_putw(v,c); }) +#define writel(v,c) ({ __iowmb(); __arch_putl(v,c); }) + +#define readb(c) ({ u8 __v = __arch_getb(c); __iormb(); __v; }) +#define readw(c) ({ u16 __v = __arch_getw(c); __iormb(); __v; }) +#define readl(c) ({ u32 __v = __arch_getl(c); __iormb(); __v; }) /* * The compiler seems to be incapable of optimising constants
gcc 4.5.1 seems to ignore (at least some) volatile definitions, avoid that as done in the kernel. Reading C99 6.7.3 8 and the comment 114) there, I think it is a bug of that gcc version to ignore the volatile type qualifier used e.g. in __arch_getl(). Anyway, using a definition as in the kernel headers avoids such optimizations when gcc 4.5.1 is used. Maybe the headers as used in the current linux-kernel should be used, but to avoid large changes, I've just added a small change to the current headers. I haven't add the definitions which are using a memory barrier because I haven't found a place in the kernel where they were actually enabled (CONFIG_ARM_DMA_MEM_BUFFERABLE). Signed-off-by: Alexander Holler <holler@ahsoftware.de> --- arch/arm/include/asm/io.h | 15 +++++++++------ 1 files changed, 9 insertions(+), 6 deletions(-)