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| author | David VomLehn <dvomlehn@cisco.com> | 2010-05-21 11:25:36 -0700 |
|---|---|---|
| committer | Ralf Baechle <ralf@linux-mips.org> | 2010-08-05 13:25:40 +0100 |
| commit | ca36c36b7821b573fe06ce6bc34db03b557f3ce4 (patch) | |
| tree | 28fe24b5080e29ca62ff4d1b4bbf5afc83084792 /arch/mips/powertv/asic/asic_devices.c | |
| parent | 36f217d9df3e6bf8e6ae7647827b485b79dbaf8e (diff) | |
| download | kernel_samsung_smdk4412-ca36c36b7821b573fe06ce6bc34db03b557f3ce4.zip kernel_samsung_smdk4412-ca36c36b7821b573fe06ce6bc34db03b557f3ce4.tar.gz kernel_samsung_smdk4412-ca36c36b7821b573fe06ce6bc34db03b557f3ce4.tar.bz2 | |
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/asic_devices.c')
| -rw-r--r-- | arch/mips/powertv/asic/asic_devices.c | 18 |
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 9ec523e..c81dd49 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", |