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authorDavid VomLehn <dvomlehn@cisco.com>2010-05-21 11:25:36 -0700
committerRalf Baechle <ralf@linux-mips.org>2010-08-05 13:25:40 +0100
commitca36c36b7821b573fe06ce6bc34db03b557f3ce4 (patch)
tree28fe24b5080e29ca62ff4d1b4bbf5afc83084792 /arch/mips/powertv/asic
parent36f217d9df3e6bf8e6ae7647827b485b79dbaf8e (diff)
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MIPS: PowerTV: Use O(1) algorthm for phys_to_dma/dma_to_phys
Replace phys_to_dma()/dma_to_phys() looping algorithm with an O(1) algorithm The approach taken is inspired by the sparse memory implementation: take a certain number of high-order bits off the address them, use this as an index into a table containing an offset to the desired address and add it to the original value. There is a table for mapping physical addresses to DMA addresses and another one for the reverse mapping. The table sizes depend on how fine-grained the mappings need to be; Coarser granularity less to smaller tables. On a processor with 32-bit physical and DMA addresses, with 4 MIB granularity, memory usage is two 2048-byte arrays. Each 32-byte cache line thus covers 64 MiB of address space. Also, renames phys_to_bus() to phys_to_dma() and bus_to_phys() to dma_to_phys() to align with kernel usage. [Ralf: Fixed silly build breakage due to stackoverflow warning caused by huge array on stack.] Signed-off-by: David VomLehn <dvomlehn@cisco.com> To: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/1257/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Diffstat (limited to 'arch/mips/powertv/asic')
-rw-r--r--arch/mips/powertv/asic/asic_devices.c18
1 files changed, 9 insertions, 9 deletions
diff --git a/arch/mips/powertv/asic/asic_devices.c b/arch/mips/powertv/asic/asic_devices.c
index 9ec523e4dd0..c81dd497ed7 100644
--- a/arch/mips/powertv/asic/asic_devices.c
+++ b/arch/mips/powertv/asic/asic_devices.c
@@ -80,8 +80,8 @@ static bool usb_configured;
* Don't recommend to use it directly, it is usually used by kernel internally.
* Portable code should be using interfaces such as ioremp, dma_map_single, etc.
*/
-unsigned long phys_to_bus_offset;
-EXPORT_SYMBOL(phys_to_bus_offset);
+unsigned long phys_to_dma_offset;
+EXPORT_SYMBOL(phys_to_dma_offset);
/*
*
@@ -533,10 +533,10 @@ void __init configure_platform(void)
switch (asic) {
case ASIC_ZEUS:
- phys_to_bus_offset = 0x30000000;
+ phys_to_dma_offset = 0x30000000;
break;
case ASIC_CALLIOPE:
- phys_to_bus_offset = 0x10000000;
+ phys_to_dma_offset = 0x10000000;
break;
case ASIC_CRONUSLITE:
/* Fall through */
@@ -546,10 +546,10 @@ void __init configure_platform(void)
* 0x2XXXXXXX. If 0x10000000 aliases into 0x60000000-
* 0x6XXXXXXX, the offset should be 0x50000000, not 0x10000000.
*/
- phys_to_bus_offset = 0x10000000;
+ phys_to_dma_offset = 0x10000000;
break;
default:
- phys_to_bus_offset = 0x00000000;
+ phys_to_dma_offset = 0x00000000;
break;
}
}
@@ -603,7 +603,7 @@ void __init platform_alloc_bootmem(void)
int size = gp_resources[i].end - gp_resources[i].start + 1;
if ((gp_resources[i].start != 0) &&
((gp_resources[i].flags & IORESOURCE_MEM) != 0)) {
- reserve_bootmem(bus_to_phys(gp_resources[i].start),
+ reserve_bootmem(dma_to_phys(gp_resources[i].start),
size, 0);
total += gp_resources[i].end -
gp_resources[i].start + 1;
@@ -627,7 +627,7 @@ void __init platform_alloc_bootmem(void)
else {
gp_resources[i].start =
- phys_to_bus(virt_to_phys(mem));
+ phys_to_dma(virt_to_phys(mem));
gp_resources[i].end =
gp_resources[i].start + size - 1;
total += size;
@@ -691,7 +691,7 @@ static void __init pmem_setup_resource(void)
if (resource && pmemaddr && pmemlen) {
/* The address provided by bootloader is in kseg0. Convert to
* a bus address. */
- resource->start = phys_to_bus(pmemaddr - 0x80000000);
+ resource->start = phys_to_dma(pmemaddr - 0x80000000);
resource->end = resource->start + pmemlen - 1;
pr_info("persistent memory: start=0x%x end=0x%x\n",