Using the cache size, number of sets and cache line size we can calculate desired associativity of the L2 cache. This is done by the calculation:
associativity = (cache size / cache sets) / cache line size For most normal cache sizes this will quickly roof out to the maximum associativity of 8 (L2x0 variants) or 16 (PL3x0 variants). While all variants have a hard-coded line size of 32 bytes we also support reading the "cache-line-size" ePAPR binding and complain if it does not match the hardware. Signed-off-by: Linus Walleij <[email protected]> --- arch/arm/mm/cache-l2x0.c | 62 +++++++++++++++++++++++++++++++++++++++++++----- 1 file changed, 56 insertions(+), 6 deletions(-) diff --git a/arch/arm/mm/cache-l2x0.c b/arch/arm/mm/cache-l2x0.c index 61a684c743c6..f275cd4e5151 100644 --- a/arch/arm/mm/cache-l2x0.c +++ b/arch/arm/mm/cache-l2x0.c @@ -947,14 +947,18 @@ static u32 cache_id_part_number_from_dt; static void __init l2x0_cache_size_of_parse(const struct device_node *np, u32 *aux_val, u32 *aux_mask, - u32 max_way_size) + u32 max_way_size, + u32 max_associativity) { u32 mask = 0, val = 0; u32 size = 0, sets = 0; u32 way_size = 0, way_size_bits = 1; + u32 linesize = 0; + u32 assoc = 0; of_property_read_u32(np, "cache-size", &size); of_property_read_u32(np, "cache-sets", &sets); + of_property_read_u32(np, "cache-line-size", &linesize); if (!size || !sets) return; @@ -962,10 +966,56 @@ static void __init l2x0_cache_size_of_parse(const struct device_node *np, way_size = size / sets; if (way_size > max_way_size) { - pr_warn("L2C: way size %dKB is too large\n", way_size >> 10); + pr_warn("L2C OF: way size %dKB is too large\n", way_size >> 10); return; } + /* All these l2 caches have the same line size actually */ + if (!linesize) + linesize = CACHE_LINE_SIZE; + if (linesize != CACHE_LINE_SIZE) + pr_warn("L2C OF: DT supplied line size %d bytes does " + "not match hardware line size of %d bytes\n", + linesize, + CACHE_LINE_SIZE); + + /* + * This cache is set associative. By increasing associativity + * we increase the number of blocks per set. Usually this + * quickly hits the roof at 8 or 16 ways of associativity. + */ + assoc = way_size / linesize; + if (assoc > max_associativity) + assoc = max_associativity; + + mask |= L2X0_AUX_CTRL_ASSOC_MASK; + + /* + * Special checks for the PL310 that only has two settings and + * cannot be set to fully associative. + */ + if (max_associativity == 16) { + if (assoc <= 8) { + assoc = 8; + /* Leave bit 16 in associativity set to 0 */ + } + if (assoc > 8 && assoc <= 16) { + assoc = 16; + val |= L310_AUX_CTRL_ASSOCIATIVITY_16; + } + } else { + if (sets == 1) + /* Direct-mapped cache */ + assoc = 1; + val |= (assoc << L2X0_AUX_CTRL_ASSOC_SHIFT); + } + + pr_info("L2C OF: size: %d bytes (%dKB)\n", size, size >> 10); + pr_info("L2C OF: way_size: %d bytes (%d KB)\n", + way_size, way_size >> 10); + pr_info("L2C OF: associativity: %d ways\n", assoc); + + /* Convert to KB */ way_size >>= 10; switch (way_size) { case 512: @@ -987,7 +1037,7 @@ static void __init l2x0_cache_size_of_parse(const struct device_node *np, way_size_bits = 1; break; default: - pr_err("cache way size: %d KB is not mapped\n", + pr_err("L2C OF: cache way size: %d KB is not mapped\n", way_size); break; } @@ -1029,7 +1079,7 @@ static void __init l2x0_of_parse(const struct device_node *np, val |= (dirty - 1) << L2X0_AUX_CTRL_DIRTY_LATENCY_SHIFT; } - l2x0_cache_size_of_parse(np, aux_val, aux_mask, SZ_256K); + l2x0_cache_size_of_parse(np, aux_val, aux_mask, SZ_256K, 8); *aux_val &= ~mask; *aux_val |= val; @@ -1105,7 +1155,7 @@ static void __init l2c310_of_parse(const struct device_node *np, l2x0_base + L310_ADDR_FILTER_START); } - l2x0_cache_size_of_parse(np, aux_val, aux_mask, SZ_512K); + l2x0_cache_size_of_parse(np, aux_val, aux_mask, SZ_512K, 16); } static const struct l2c_init_data of_l2c310_data __initconst = { @@ -1313,7 +1363,7 @@ static void __init aurora_of_parse(const struct device_node *np, *aux_val |= val; *aux_mask &= ~mask; - l2x0_cache_size_of_parse(np, aux_val, aux_mask, SZ_256K); + l2x0_cache_size_of_parse(np, aux_val, aux_mask, SZ_256K, 8); } static const struct l2c_init_data of_aurora_with_outer_data __initconst = { -- 1.9.3 -- To unsubscribe from this list: send the line "unsubscribe linux-leds" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
