[PATCH] Inline ioremap() magic for 32-bit constant addresses

[PATCH] Inline ioremap() magic for 32-bit constant addresses

[Maciej W. Rozycki]

Ralf,

 I'd like to get rid of CKSEG1ADDR() wherever possible from code I am 
looking after as the macro is unportable and has already proven to cause 
maintenance hassle.  I don't want to get rid of its advantages though, so 
here's an update for ioremap() that makes it be expanded inline when 
constant arguments are used and the resulting mapping fits in KSEG1.  
Likewise for iounmap().

 Apparently the generic version is used for all platforms but the Au1000.  
I have only implemented the bare minimum required for the platform to keep 
working.  The platform seems to be maintained though, so I'm leaving the 
decision as to whether to inline the platform-specific variation or not up 
to the maintainer.

 OK to apply?

  Maciej

patch-mips-2.6.12-rc4-20050526-ioremap-constant-1
diff -up --recursive --new-file linux-mips-2.6.12-rc4-20050526.macro/arch/mips/au1000/common/setup.c linux-mips-2.6.12-rc4-20050526/arch/mips/au1000/common/setup.c
--- linux-mips-2.6.12-rc4-20050526.macro/arch/mips/au1000/common/setup.c	2005-04-04 04:56:03.000000000 +0000
+++ linux-mips-2.6.12-rc4-20050526/arch/mips/au1000/common/setup.c	2005-06-25 23:45:43.000000000 +0000
@@ -159,7 +159,7 @@ early_initcall(au1x00_setup);
 
 #if defined(CONFIG_64BIT_PHYS_ADDR)
 /* This routine should be valid for all Au1x based boards */
-phys_t fixup_bigphys_addr(phys_t phys_addr, phys_t size)
+phys_t __fixup_bigphys_addr(phys_t phys_addr, phys_t size)
 {
 	u32 start, end;
 
diff -up --recursive --new-file linux-mips-2.6.12-rc4-20050526.macro/arch/mips/mm/ioremap.c linux-mips-2.6.12-rc4-20050526/arch/mips/mm/ioremap.c
--- linux-mips-2.6.12-rc4-20050526.macro/arch/mips/mm/ioremap.c	2005-02-11 05:56:05.000000000 +0000
+++ linux-mips-2.6.12-rc4-20050526/arch/mips/mm/ioremap.c	2005-06-26 00:00:51.000000000 +0000
@@ -102,15 +102,6 @@ static int remap_area_pages(unsigned lon
 }
 
 /*
- * Allow physical addresses to be fixed up to help 36 bit peripherals.
- */
-phys_t __attribute__ ((weak))
-fixup_bigphys_addr(phys_t phys_addr, phys_t size)
-{
-	return phys_addr;
-}
-
-/*
  * Generic mapping function (not visible outside):
  */
 
diff -up --recursive --new-file linux-mips-2.6.12-rc4-20050526.macro/include/asm-mips/io.h linux-mips-2.6.12-rc4-20050526/include/asm-mips/io.h
--- linux-mips-2.6.12-rc4-20050526.macro/include/asm-mips/io.h	2005-04-19 04:57:17.000000000 +0000
+++ linux-mips-2.6.12-rc4-20050526/include/asm-mips/io.h	2005-06-26 00:27:00.000000000 +0000
@@ -26,6 +26,7 @@
 #include <asm/pgtable-bits.h>
 #include <asm/processor.h>
 
+#include <ioremap.h>
 #include <mangle-port.h>
 
 /*
@@ -208,6 +209,8 @@ extern void __iounmap(volatile void __io
 static inline void * __ioremap_mode(phys_t offset, unsigned long size,
 	unsigned long flags)
 {
+#define __IS_LOW512(addr) (!((phys_t)(addr) & (phys_t) ~0x1fffffffULL))
+
 	if (cpu_has_64bit_addresses) {
 		u64 base = UNCAC_BASE;
 
@@ -218,9 +221,30 @@ static inline void * __ioremap_mode(phys
 		if (flags == _CACHE_UNCACHED)
 			base = (u64) IO_BASE;
 		return (void *) (unsigned long) (base + offset);
+	} else if (__builtin_constant_p(offset) &&
+		   __builtin_constant_p(size) && __builtin_constant_p(flags)) {
+		phys_t phys_addr, last_addr;
+
+		phys_addr = fixup_bigphys_addr(offset, size);
+
+		/* Don't allow wraparound or zero size. */
+		last_addr = phys_addr + size - 1;
+		if (!size || last_addr < phys_addr)
+			return NULL;
+
+		/*
+		 * Map uncached objects in the low 512MB of address
+		 * space using KSEG1.
+		 */
+		if (__IS_LOW512(phys_addr) && __IS_LOW512(last_addr) &&
+		    flags == _CACHE_UNCACHED)
+			return (void *)CKSEG1ADDR(phys_addr);
+
 	}
 
 	return __ioremap(offset, size, flags);
+
+#undef __IS_LOW512
 }
 
 /*
@@ -272,12 +296,16 @@ static inline void * __ioremap_mode(phys
 
 static inline void iounmap(volatile void __iomem *addr)
 {
-	if (cpu_has_64bit_addresses)
+#define __IS_KSEG1(addr) (((unsigned long)(addr) & ~0x1fffffffUL) == CKSEG1)
+
+	if (cpu_has_64bit_addresses ||
+	    (__builtin_constant_p(addr) && __IS_KSEG1(addr)))
 		return;
 
 	__iounmap(addr);
-}
 
+#undef __IS_KSEG1
+}
 
 #define __BUILD_MEMORY_SINGLE(pfx, bwlq, type, irq)			\
 									\
diff -up --recursive --new-file linux-mips-2.6.12-rc4-20050526.macro/include/asm-mips/mach-au1x00/ioremap.h linux-mips-2.6.12-rc4-20050526/include/asm-mips/mach-au1x00/ioremap.h
--- linux-mips-2.6.12-rc4-20050526.macro/include/asm-mips/mach-au1x00/ioremap.h	1970-01-01 00:00:00.000000000 +0000
+++ linux-mips-2.6.12-rc4-20050526/include/asm-mips/mach-au1x00/ioremap.h	2005-06-26 00:16:26.000000000 +0000
@@ -0,0 +1,29 @@
+/*
+ *	include/asm-mips/mach-au1x00/ioremap.h
+ *
+ *	This program is free software; you can redistribute it and/or
+ *	modify it under the terms of the GNU General Public License
+ *	as published by the Free Software Foundation; either version
+ *	2 of the License, or (at your option) any later version.
+ */
+#ifndef __ASM_MACH_AU1X00_IOREMAP_H
+#define __ASM_MACH_AU1X00_IOREMAP_H
+
+#include <linux/types.h>
+
+#ifndef CONFIG_64BIT_PHYS_ADDR
+static inline phys_t __fixup_bigphys_addr(phys_t phys_addr, phys_t size)
+{
+	return phys_addr;
+}
+#endif
+
+/*
+ * Allow physical addresses to be fixed up to help 36-bit peripherals.
+ */
+static inline phys_t fixup_bigphys_addr(phys_t phys_addr, phys_t size)
+{
+	return __fixup_bigphys_addr(phys_addr, size);
+}
+
+#endif /* __ASM_MACH_AU1X00_IOREMAP_H */
diff -up --recursive --new-file linux-mips-2.6.12-rc4-20050526.macro/include/asm-mips/mach-generic/ioremap.h linux-mips-2.6.12-rc4-20050526/include/asm-mips/mach-generic/ioremap.h
--- linux-mips-2.6.12-rc4-20050526.macro/include/asm-mips/mach-generic/ioremap.h	1970-01-01 00:00:00.000000000 +0000
+++ linux-mips-2.6.12-rc4-20050526/include/asm-mips/mach-generic/ioremap.h	2005-06-26 00:05:42.000000000 +0000
@@ -0,0 +1,23 @@
+/*
+ *	include/asm-mips/mach-generic/ioremap.h
+ *
+ *	This program is free software; you can redistribute it and/or
+ *	modify it under the terms of the GNU General Public License
+ *	as published by the Free Software Foundation; either version
+ *	2 of the License, or (at your option) any later version.
+ */
+#ifndef __ASM_MACH_GENERIC_IOREMAP_H
+#define __ASM_MACH_GENERIC_IOREMAP_H
+
+#include <linux/types.h>
+
+/*
+ * Allow physical addresses to be fixed up to help peripherals located
+ * outside the low 32-bit range -- generic pass-through version.
+ */
+static inline phys_t fixup_bigphys_addr(phys_t phys_addr, phys_t size)
+{
+	return phys_addr;
+}
+
+#endif /* __ASM_MACH_GENERIC_IOREMAP_H */

Re: [PATCH] Inline ioremap() magic for 32-bit constant addresses

[Ralf Baechle]

On Wed, Jun 29, 2005 at 11:55:55AM +0100, Maciej W. Rozycki wrote:

>  I'd like to get rid of CKSEG1ADDR() wherever possible from code I am 
> looking after as the macro is unportable and has already proven to cause 
> maintenance hassle.  I don't want to get rid of its advantages though, so 
> here's an update for ioremap() that makes it be expanded inline when 
> constant arguments are used and the resulting mapping fits in KSEG1.  
> Likewise for iounmap().

I don't think I'd complain about taking the whole thing out off line.  Last
I checked we had no driver that did substancially benefit from being
initialized a few nanoseconds faster.

>  Apparently the generic version is used for all platforms but the Au1000.  
> I have only implemented the bare minimum required for the platform to keep 
> working.  The platform seems to be maintained though, so I'm leaving the 
> decision as to whether to inline the platform-specific variation or not up 
> to the maintainer.

So I guess your patch leaves getting rid of that indirection of
fixup_bigphys_addr calling into __fixup_bigphys_addr to Pete :-)

>  OK to apply?

Fee free.


  Ralf

> patch-mips-2.6.12-rc4-20050526-ioremap-constant-1
> diff -up --recursive --new-file linux-mips-2.6.12-rc4-20050526.macro/arch/mips/au1000/common/setup.c linux-mips-2.6.12-rc4-20050526/arch/mips/au1000/common/setup.c
> --- linux-mips-2.6.12-rc4-20050526.macro/arch/mips/au1000/common/setup.c	2005-04-04 04:56:03.000000000 +0000
> +++ linux-mips-2.6.12-rc4-20050526/arch/mips/au1000/common/setup.c	2005-06-25 23:45:43.000000000 +0000
> @@ -159,7 +159,7 @@ early_initcall(au1x00_setup);
>  
>  #if defined(CONFIG_64BIT_PHYS_ADDR)
>  /* This routine should be valid for all Au1x based boards */
> -phys_t fixup_bigphys_addr(phys_t phys_addr, phys_t size)
> +phys_t __fixup_bigphys_addr(phys_t phys_addr, phys_t size)
>  {
>  	u32 start, end;
>  
> diff -up --recursive --new-file linux-mips-2.6.12-rc4-20050526.macro/arch/mips/mm/ioremap.c linux-mips-2.6.12-rc4-20050526/arch/mips/mm/ioremap.c
> --- linux-mips-2.6.12-rc4-20050526.macro/arch/mips/mm/ioremap.c	2005-02-11 05:56:05.000000000 +0000
> +++ linux-mips-2.6.12-rc4-20050526/arch/mips/mm/ioremap.c	2005-06-26 00:00:51.000000000 +0000
> @@ -102,15 +102,6 @@ static int remap_area_pages(unsigned lon
>  }
>  
>  /*
> - * Allow physical addresses to be fixed up to help 36 bit peripherals.
> - */
> -phys_t __attribute__ ((weak))
> -fixup_bigphys_addr(phys_t phys_addr, phys_t size)
> -{
> -	return phys_addr;
> -}
> -
> -/*
>   * Generic mapping function (not visible outside):
>   */
>  
> diff -up --recursive --new-file linux-mips-2.6.12-rc4-20050526.macro/include/asm-mips/io.h linux-mips-2.6.12-rc4-20050526/include/asm-mips/io.h
> --- linux-mips-2.6.12-rc4-20050526.macro/include/asm-mips/io.h	2005-04-19 04:57:17.000000000 +0000
> +++ linux-mips-2.6.12-rc4-20050526/include/asm-mips/io.h	2005-06-26 00:27:00.000000000 +0000
> @@ -26,6 +26,7 @@
>  #include <asm/pgtable-bits.h>
>  #include <asm/processor.h>
>  
> +#include <ioremap.h>
>  #include <mangle-port.h>
>  
>  /*
> @@ -208,6 +209,8 @@ extern void __iounmap(volatile void __io
>  static inline void * __ioremap_mode(phys_t offset, unsigned long size,
>  	unsigned long flags)
>  {
> +#define __IS_LOW512(addr) (!((phys_t)(addr) & (phys_t) ~0x1fffffffULL))
> +
>  	if (cpu_has_64bit_addresses) {
>  		u64 base = UNCAC_BASE;
>  
> @@ -218,9 +221,30 @@ static inline void * __ioremap_mode(phys
>  		if (flags == _CACHE_UNCACHED)
>  			base = (u64) IO_BASE;
>  		return (void *) (unsigned long) (base + offset);
> +	} else if (__builtin_constant_p(offset) &&
> +		   __builtin_constant_p(size) && __builtin_constant_p(flags)) {
> +		phys_t phys_addr, last_addr;
> +
> +		phys_addr = fixup_bigphys_addr(offset, size);
> +
> +		/* Don't allow wraparound or zero size. */
> +		last_addr = phys_addr + size - 1;
> +		if (!size || last_addr < phys_addr)
> +			return NULL;
> +
> +		/*
> +		 * Map uncached objects in the low 512MB of address
> +		 * space using KSEG1.
> +		 */
> +		if (__IS_LOW512(phys_addr) && __IS_LOW512(last_addr) &&
> +		    flags == _CACHE_UNCACHED)
> +			return (void *)CKSEG1ADDR(phys_addr);
> +
>  	}
>  
>  	return __ioremap(offset, size, flags);
> +
> +#undef __IS_LOW512
>  }
>  
>  /*
> @@ -272,12 +296,16 @@ static inline void * __ioremap_mode(phys
>  
>  static inline void iounmap(volatile void __iomem *addr)
>  {
> -	if (cpu_has_64bit_addresses)
> +#define __IS_KSEG1(addr) (((unsigned long)(addr) & ~0x1fffffffUL) == CKSEG1)
> +
> +	if (cpu_has_64bit_addresses ||
> +	    (__builtin_constant_p(addr) && __IS_KSEG1(addr)))
>  		return;
>  
>  	__iounmap(addr);
> -}
>  
> +#undef __IS_KSEG1
> +}
>  
>  #define __BUILD_MEMORY_SINGLE(pfx, bwlq, type, irq)			\
>  									\
> diff -up --recursive --new-file linux-mips-2.6.12-rc4-20050526.macro/include/asm-mips/mach-au1x00/ioremap.h linux-mips-2.6.12-rc4-20050526/include/asm-mips/mach-au1x00/ioremap.h
> --- linux-mips-2.6.12-rc4-20050526.macro/include/asm-mips/mach-au1x00/ioremap.h	1970-01-01 00:00:00.000000000 +0000
> +++ linux-mips-2.6.12-rc4-20050526/include/asm-mips/mach-au1x00/ioremap.h	2005-06-26 00:16:26.000000000 +0000
> @@ -0,0 +1,29 @@
> +/*
> + *	include/asm-mips/mach-au1x00/ioremap.h
> + *
> + *	This program is free software; you can redistribute it and/or
> + *	modify it under the terms of the GNU General Public License
> + *	as published by the Free Software Foundation; either version
> + *	2 of the License, or (at your option) any later version.
> + */
> +#ifndef __ASM_MACH_AU1X00_IOREMAP_H
> +#define __ASM_MACH_AU1X00_IOREMAP_H
> +
> +#include <linux/types.h>
> +
> +#ifndef CONFIG_64BIT_PHYS_ADDR
> +static inline phys_t __fixup_bigphys_addr(phys_t phys_addr, phys_t size)
> +{
> +	return phys_addr;
> +}
> +#endif
> +
> +/*
> + * Allow physical addresses to be fixed up to help 36-bit peripherals.
> + */
> +static inline phys_t fixup_bigphys_addr(phys_t phys_addr, phys_t size)
> +{
> +	return __fixup_bigphys_addr(phys_addr, size);
> +}
> +
> +#endif /* __ASM_MACH_AU1X00_IOREMAP_H */
> diff -up --recursive --new-file linux-mips-2.6.12-rc4-20050526.macro/include/asm-mips/mach-generic/ioremap.h linux-mips-2.6.12-rc4-20050526/include/asm-mips/mach-generic/ioremap.h
> --- linux-mips-2.6.12-rc4-20050526.macro/include/asm-mips/mach-generic/ioremap.h	1970-01-01 00:00:00.000000000 +0000
> +++ linux-mips-2.6.12-rc4-20050526/include/asm-mips/mach-generic/ioremap.h	2005-06-26 00:05:42.000000000 +0000
> @@ -0,0 +1,23 @@
> +/*
> + *	include/asm-mips/mach-generic/ioremap.h
> + *
> + *	This program is free software; you can redistribute it and/or
> + *	modify it under the terms of the GNU General Public License
> + *	as published by the Free Software Foundation; either version
> + *	2 of the License, or (at your option) any later version.
> + */
> +#ifndef __ASM_MACH_GENERIC_IOREMAP_H
> +#define __ASM_MACH_GENERIC_IOREMAP_H
> +
> +#include <linux/types.h>
> +
> +/*
> + * Allow physical addresses to be fixed up to help peripherals located
> + * outside the low 32-bit range -- generic pass-through version.
> + */
> +static inline phys_t fixup_bigphys_addr(phys_t phys_addr, phys_t size)
> +{
> +	return phys_addr;
> +}
> +
> +#endif /* __ASM_MACH_GENERIC_IOREMAP_H */

Re: [PATCH] Inline ioremap() magic for 32-bit constant addresses

[Maciej W. Rozycki]

On Wed, 29 Jun 2005, Ralf Baechle wrote:

> >  I'd like to get rid of CKSEG1ADDR() wherever possible from code I am 
> > looking after as the macro is unportable and has already proven to cause 
> > maintenance hassle.  I don't want to get rid of its advantages though, so 
> > here's an update for ioremap() that makes it be expanded inline when 
> > constant arguments are used and the resulting mapping fits in KSEG1.  
> > Likewise for iounmap().
> 
> I don't think I'd complain about taking the whole thing out off line.  Last
> I checked we had no driver that did substancially benefit from being
> initialized a few nanoseconds faster.

 I haven't checked it yet, but it may be possible for my updates to add 
calls to ioremap() from interrupt handlers, which may not necessarily be 
so neutral to performance if calculations are done out of line.  With this 
inline implementation ioremap() expands to at most two instructions for 
qualifying calls and iounmap() expands to nothing.  With an out of line 
version not only the address calculations are done at the run time, but 
you need to add an overhead of two function calls.

 I like the MIPS64 version best, though. ;-)

> >  Apparently the generic version is used for all platforms but the Au1000.  
> > I have only implemented the bare minimum required for the platform to keep 
> > working.  The platform seems to be maintained though, so I'm leaving the 
> > decision as to whether to inline the platform-specific variation or not up 
> > to the maintainer.
> 
> So I guess your patch leaves getting rid of that indirection of
> fixup_bigphys_addr calling into __fixup_bigphys_addr to Pete :-)

 Yes, formally.  Technically, I can probably get convinced to do the dirty 
cut & paste work if asked to appropriately. ;-)

  Maciej