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>

1 files changed, 2 insertions, 1 deletions

diff --git a/arch/mips/powertv/Makefile b/arch/mips/powertv/Makefile
index 0a0d73c0564..e9fe1c6efe1 100644
--- a/arch/mips/powertv/Makefile
+++ b/arch/mips/powertv/Makefile
@@ -23,6 +23,7 @@
 # under Linux.
 #
 
-obj-y += init.o memory.o reset.o time.o powertv_setup.o asic/ pci/
+obj-y += init.o ioremap.o memory.o powertv_setup.o reset.o time.o \
+	asic/ pci/
 
 EXTRA_CFLAGS += -Wall -Werror