diff options
| -rw-r--r-- | README | 19 | ||||
| -rw-r--r-- | arch/arm/include/asm/system.h | 5 | ||||
| -rw-r--r-- | arch/arm/lib/cache.c | 44 | ||||
| -rw-r--r-- | common/board_r.c | 11 |
4 files changed, 79 insertions, 0 deletions
@@ -4007,6 +4007,25 @@ Configuration Settings: boards which do not use the full malloc in SPL (which is enabled with CONFIG_SYS_SPL_MALLOC_START). +- CONFIG_SYS_NONCACHED_MEMORY: + Size of non-cached memory area. This area of memory will be + typically located right below the malloc() area and mapped + uncached in the MMU. This is useful for drivers that would + otherwise require a lot of explicit cache maintenance. For + some drivers it's also impossible to properly maintain the + cache. For example if the regions that need to be flushed + are not a multiple of the cache-line size, *and* padding + cannot be allocated between the regions to align them (i.e. + if the HW requires a contiguous array of regions, and the + size of each region is not cache-aligned), then a flush of + one region may result in overwriting data that hardware has + written to another region in the same cache-line. This can + happen for example in network drivers where descriptors for + buffers are typically smaller than the CPU cache-line (e.g. + 16 bytes vs. 32 or 64 bytes). + + Non-cached memory is only supported on 32-bit ARM at present. + - CONFIG_SYS_BOOTM_LEN: Normally compressed uImages are limited to an uncompressed size of 8 MBytes. If this is not enough, diff --git a/arch/arm/include/asm/system.h b/arch/arm/include/asm/system.h index 61e2914d44..89f2294689 100644 --- a/arch/arm/include/asm/system.h +++ b/arch/arm/include/asm/system.h @@ -212,6 +212,11 @@ void mmu_set_region_dcache_behaviour(phys_addr_t start, size_t size, */ void mmu_page_table_flush(unsigned long start, unsigned long stop); +#ifdef CONFIG_SYS_NONCACHED_MEMORY +void noncached_init(void); +phys_addr_t noncached_alloc(size_t size, size_t align); +#endif /* CONFIG_SYS_NONCACHED_MEMORY */ + #endif /* __ASSEMBLY__ */ #define arch_align_stack(x) (x) diff --git a/arch/arm/lib/cache.c b/arch/arm/lib/cache.c index f1c0792ce8..9cedeac6d6 100644 --- a/arch/arm/lib/cache.c +++ b/arch/arm/lib/cache.c @@ -8,6 +8,7 @@ /* for now: just dummy functions to satisfy the linker */ #include <common.h> +#include <malloc.h> __weak void flush_cache(unsigned long start, unsigned long size) { @@ -49,3 +50,46 @@ __weak void enable_caches(void) { puts("WARNING: Caches not enabled\n"); } + +#ifdef CONFIG_SYS_NONCACHED_MEMORY +/* + * Reserve one MMU section worth of address space below the malloc() area that + * will be mapped uncached. + */ +static unsigned long noncached_start; +static unsigned long noncached_end; +static unsigned long noncached_next; + +void noncached_init(void) +{ + phys_addr_t start, end; + size_t size; + + end = ALIGN(mem_malloc_start, MMU_SECTION_SIZE) - MMU_SECTION_SIZE; + size = ALIGN(CONFIG_SYS_NONCACHED_MEMORY, MMU_SECTION_SIZE); + start = end - size; + + debug("mapping memory %pa-%pa non-cached\n", &start, &end); + + noncached_start = start; + noncached_end = end; + noncached_next = start; + +#ifndef CONFIG_SYS_DCACHE_OFF + mmu_set_region_dcache_behaviour(noncached_start, size, DCACHE_OFF); +#endif +} + +phys_addr_t noncached_alloc(size_t size, size_t align) +{ + phys_addr_t next = ALIGN(noncached_next, align); + + if (next >= noncached_end || (noncached_end - next) < size) + return 0; + + debug("allocated %zu bytes of uncached memory @%pa\n", size, &next); + noncached_next = next + size; + + return next; +} +#endif /* CONFIG_SYS_NONCACHED_MEMORY */ diff --git a/common/board_r.c b/common/board_r.c index 4eb7a023d4..a301cc226f 100644 --- a/common/board_r.c +++ b/common/board_r.c @@ -265,6 +265,14 @@ static int initr_malloc(void) return 0; } +#ifdef CONFIG_SYS_NONCACHED_MEMORY +static int initr_noncached(void) +{ + noncached_init(); + return 0; +} +#endif + #ifdef CONFIG_DM static int initr_dm(void) { @@ -687,6 +695,9 @@ init_fnc_t init_sequence_r[] = { #endif initr_barrier, initr_malloc, +#ifdef CONFIG_SYS_NONCACHED_MEMORY + initr_noncached, +#endif bootstage_relocate, #ifdef CONFIG_DM initr_dm, |
