From ca36c36b7821b573fe06ce6bc34db03b557f3ce4 Mon Sep 17 00:00:00 2001 From: David VomLehn Date: Fri, 21 May 2010 11:25:36 -0700 Subject: 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 To: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/1257/ Signed-off-by: Ralf Baechle --- arch/mips/powertv/asic/asic_devices.c | 18 +++++++++--------- 1 file changed, 9 insertions(+), 9 deletions(-) (limited to 'arch/mips/powertv/asic/asic_devices.c') 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", -- cgit v1.1