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SubjectRe: [PATCH][PPC32[NEWBIE] enhancement to virt_to_bus/bus_to_virt (try 2)
In 2.6.9 on non-APUS ppc32 platforms, virt_to_bus() will just subtract
KERNELBASE from the the virtual address. bus_to_virt() will perform
the reverse operation.

This patch will make virt_to_bus():

- perform the current operation if the virtual address is between
KERNELBASE and ioremap_bot.

- use iopa() (as on APUS platform) otherwise.

The patch will make bus_to_virt():

- perform the current operation if the bus address is between
PCI_DRAM_OFFSET and (ioremap_bot - KERNELBASE + PCI_DRAM_OFFSET).

- use mm_ptov() (as on APUS platform) otherwise.


The patch also changes virt_to_phys()/phys_to_virt() in a similar way.

-- Linh Dang




--- include/asm-ppc/io.h~2.6.9 2004-11-12 14:24:46.000000000 -0500
+++ include/asm-ppc/io.h 2004-12-02 11:20:21.000000000 -0500
@@ -6,10 +6,11 @@
#include <linux/types.h>

#include <asm/page.h>
#include <asm/byteorder.h>
#include <asm/mmu.h>
+#include <asm/pgtable.h>

#define SIO_CONFIG_RA 0x398
#define SIO_CONFIG_RD 0x399

#define SLOW_DOWN_IO
@@ -222,49 +223,56 @@ extern void io_block_mapping(unsigned lo
* have to be modified [mapped] appropriately.
*/
extern inline unsigned long virt_to_bus(volatile void * address)
{
#ifndef CONFIG_APUS
- if (address == (void *)0)
+ if (unlikely(address == (void *)0))
return 0;
+ if (likely((address >= (void*) KERNELBASE) &&
+ (address < ((void*) ioremap_bot))))
return (unsigned long)address - KERNELBASE + PCI_DRAM_OFFSET;
-#else
- return iopa ((unsigned long) address);
+ else
#endif
+ return iopa ((unsigned long) address);
}

extern inline void * bus_to_virt(unsigned long address)
{
#ifndef CONFIG_APUS
- if (address == 0)
+ if (unlikely (address == 0))
return NULL;
+ if (likely((address >= PCI_DRAM_OFFSET) &&
+ (address < (ioremap_bot - KERNELBASE + PCI_DRAM_OFFSET))))
return (void *)(address - PCI_DRAM_OFFSET + KERNELBASE);
-#else
- return (void*) mm_ptov (address);
+ else
#endif
+ return (void*) mm_ptov (address);
}

/*
* Change virtual addresses to physical addresses and vv, for
* addresses in the area where the kernel has the RAM mapped.
*/
extern inline unsigned long virt_to_phys(volatile void * address)
{
#ifndef CONFIG_APUS
+ if (likely((address >= (void*) KERNELBASE) &&
+ (address < ((void*) ioremap_bot))))
return (unsigned long) address - KERNELBASE;
-#else
- return iopa ((unsigned long) address);
+ else
#endif
+ return iopa ((unsigned long) address);
}

extern inline void * phys_to_virt(unsigned long address)
{
#ifndef CONFIG_APUS
+ if (likely(address < (ioremap_bot - KERNELBASE)))
return (void *) (address + KERNELBASE);
-#else
- return (void*) mm_ptov (address);
+ else
#endif
+ return (void*) mm_ptov (address);
}

/*
* Change "struct page" to physical address.
*/
-
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