diff options
| author | Barry Song <barry.song@analog.com> | 2009-12-02 10:13:36 +0100 |
|---|---|---|
| committer | Mike Frysinger <vapier@gentoo.org> | 2009-12-15 06:15:48 +0100 |
| commit | c45c06596e0d45125d25beb0fe24a68aef1f1046 (patch) | |
| tree | a556caee3f3f14ae9fd0eb5bb9e7053ecd8c63e8 /arch | |
| parent | Blackfin: push BF5Xx configs down into mach-specific Kconfigs (diff) | |
| download | linux-c45c06596e0d45125d25beb0fe24a68aef1f1046.tar.xz linux-c45c06596e0d45125d25beb0fe24a68aef1f1046.zip | |
Blackfin: support smaller uncached DMA chunks for memory constrained systems
When working with 8 meg systems, forcing a 1 meg DMA chunk heavily cuts
into the available resources. So support smaller chunks to better cover
needs for these systems.
Signed-off-by: Barry Song <barry.song@analog.com>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/blackfin/Kconfig | 6 | ||||
| -rw-r--r-- | arch/blackfin/include/asm/bfin-global.h | 6 | ||||
| -rw-r--r-- | arch/blackfin/kernel/cplb-nompu/cplbinit.c | 20 |
3 files changed, 25 insertions, 7 deletions
diff --git a/arch/blackfin/Kconfig b/arch/blackfin/Kconfig index d703247caf20..8141b1e82927 100644 --- a/arch/blackfin/Kconfig +++ b/arch/blackfin/Kconfig @@ -896,6 +896,12 @@ config DMA_UNCACHED_2M bool "Enable 2M DMA region" config DMA_UNCACHED_1M bool "Enable 1M DMA region" +config DMA_UNCACHED_512K + bool "Enable 512K DMA region" +config DMA_UNCACHED_256K + bool "Enable 256K DMA region" +config DMA_UNCACHED_128K + bool "Enable 128K DMA region" config DMA_UNCACHED_NONE bool "Disable DMA region" endchoice diff --git a/arch/blackfin/include/asm/bfin-global.h b/arch/blackfin/include/asm/bfin-global.h index 741c02112c06..e6485c305ea6 100644 --- a/arch/blackfin/include/asm/bfin-global.h +++ b/arch/blackfin/include/asm/bfin-global.h @@ -20,6 +20,12 @@ # define DMA_UNCACHED_REGION (2 * 1024 * 1024) #elif defined(CONFIG_DMA_UNCACHED_1M) # define DMA_UNCACHED_REGION (1024 * 1024) +#elif defined(CONFIG_DMA_UNCACHED_512K) +# define DMA_UNCACHED_REGION (512 * 1024) +#elif defined(CONFIG_DMA_UNCACHED_256K) +# define DMA_UNCACHED_REGION (256 * 1024) +#elif defined(CONFIG_DMA_UNCACHED_128K) +# define DMA_UNCACHED_REGION (128 * 1024) #else # define DMA_UNCACHED_REGION (0) #endif diff --git a/arch/blackfin/kernel/cplb-nompu/cplbinit.c b/arch/blackfin/kernel/cplb-nompu/cplbinit.c index fd9a2f31e686..c9b0a4d53dc1 100644 --- a/arch/blackfin/kernel/cplb-nompu/cplbinit.c +++ b/arch/blackfin/kernel/cplb-nompu/cplbinit.c @@ -89,15 +89,25 @@ void __init generate_cplb_tables_cpu(unsigned int cpu) void __init generate_cplb_tables_all(void) { + unsigned long uncached_end; int i_d, i_i; i_d = 0; /* Normal RAM, including MTD FS. */ #ifdef CONFIG_MTD_UCLINUX - dcplb_bounds[i_d].eaddr = memory_mtd_start + mtd_size; + uncached_end = memory_mtd_start + mtd_size; #else - dcplb_bounds[i_d].eaddr = memory_end; + uncached_end = memory_end; #endif + /* + * if DMA uncached is less than 1MB, mark the 1MB chunk as uncached + * so that we don't have to use 4kB pages and cause CPLB thrashing + */ + if ((DMA_UNCACHED_REGION >= 1 * 1024 * 1024) || !DMA_UNCACHED_REGION || + ((_ramend - uncached_end) >= 1 * 1024 * 1024)) + dcplb_bounds[i_d].eaddr = uncached_end; + else + dcplb_bounds[i_d].eaddr = uncached_end & ~(1 * 1024 * 1024); dcplb_bounds[i_d++].data = SDRAM_DGENERIC; /* DMA uncached region. */ if (DMA_UNCACHED_REGION) { @@ -135,11 +145,7 @@ void __init generate_cplb_tables_all(void) i_i = 0; /* Normal RAM, including MTD FS. */ -#ifdef CONFIG_MTD_UCLINUX - icplb_bounds[i_i].eaddr = memory_mtd_start + mtd_size; -#else - icplb_bounds[i_i].eaddr = memory_end; -#endif + icplb_bounds[i_i].eaddr = uncached_end; icplb_bounds[i_i++].data = SDRAM_IGENERIC; /* DMA uncached region. */ if (DMA_UNCACHED_REGION) { |