With release of ARC HS38 v2.1 new IO coherency engine could be built-in ARC core. This hardware module ensures coherency between DMA-ed data from peripherals and L2 cache.

With L2 and IOC enabled there's no overhead for L2 cache manual maintenance which results in significantly improved IO bandwidth.

Signed-off-by: Alexey Brodkin abrodkin@synopsys.com --- arch/arc/include/asm/arcregs.h | 7 +++++ arch/arc/lib/cache.c | 59 ++++++++++++++++++++++++++++++++++++------ 2 files changed, 58 insertions(+), 8 deletions(-)

diff --git a/arch/arc/include/asm/arcregs.h b/arch/arc/include/asm/arcregs.h index 667f218..cf999b0 100644 --- a/arch/arc/include/asm/arcregs.h +++ b/arch/arc/include/asm/arcregs.h @@ -53,6 +53,13 @@ #define ARC_AUX_SLC_INVALIDATE 0x905 #define ARC_AUX_SLC_IVDL 0x910 #define ARC_AUX_SLC_FLDL 0x912 +#define ARC_BCR_CLUSTER 0xcf + +/* IO coherency related auxiliary registers */ +#define ARC_AUX_IO_COH_ENABLE 0x500 +#define ARC_AUX_IO_COH_PARTIAL 0x501 +#define ARC_AUX_IO_COH_AP0_BASE 0x508 +#define ARC_AUX_IO_COH_AP0_SIZE 0x509

#ifndef __ASSEMBLY__ /* Accessors for auxiliary registers */ diff --git a/arch/arc/lib/cache.c b/arch/arc/lib/cache.c index 8089f9d..56988dd 100644 --- a/arch/arc/lib/cache.c +++ b/arch/arc/lib/cache.c @@ -39,6 +39,7 @@ int icache_exists __section(".data"); #ifdef CONFIG_ISA_ARCV2 int slc_line_sz __section(".data"); int slc_exists __section(".data"); +int ioc_exists __section(".data");

static unsigned int __before_slc_op(const int op) { @@ -147,6 +148,21 @@ static void read_decode_cache_bcr_arcv2(void) slc_exists = 1; slc_line_sz = (slc_cfg.fields.lsz == 0) ? 128 : 64; } + + union { + struct bcr_clust_cfg { +#ifdef CONFIG_CPU_BIG_ENDIAN + unsigned int pad:7, c:1, num_entries:8, num_cores:8, ver:8; +#else + unsigned int ver:8, num_cores:8, num_entries:8, c:1, pad:7; +#endif + } fields; + unsigned int word; + } cbcr; + + cbcr.word = read_aux_reg(ARC_BCR_CLUSTER); + if (cbcr.fields.c) + ioc_exists = 1; } #endif

@@ -191,6 +207,17 @@ void cache_init(void)

#ifdef CONFIG_ISA_ARCV2 read_decode_cache_bcr_arcv2(); + + if (ioc_exists) { + /* IO coherency base - 0x8z */ + write_aux_reg(ARC_AUX_IO_COH_AP0_BASE, 0x80000); + /* IO coherency aperture size - 512Mb: 0x8z-0xAz */ + write_aux_reg(ARC_AUX_IO_COH_AP0_SIZE, 0x11); + /* Enable partial writes */ + write_aux_reg(ARC_AUX_IO_COH_PARTIAL, 1); + /* Enable IO coherency */ + write_aux_reg(ARC_AUX_IO_COH_ENABLE, 1); + } #endif }

@@ -359,18 +386,26 @@ static inline void __dc_line_op(unsigned long paddr, unsigned long sz,

void invalidate_dcache_range(unsigned long start, unsigned long end) { - __dc_line_op(start, end - start, OP_INV); #ifdef CONFIG_ISA_ARCV2 - if (slc_exists) + if (!ioc_exists) +#endif + __dc_line_op(start, end - start, OP_INV); + +#ifdef CONFIG_ISA_ARCV2 + if (slc_exists && !ioc_exists) __slc_line_op(start, end - start, OP_INV); #endif }

void flush_dcache_range(unsigned long start, unsigned long end) { - __dc_line_op(start, end - start, OP_FLUSH); #ifdef CONFIG_ISA_ARCV2 - if (slc_exists) + if (!ioc_exists) +#endif + __dc_line_op(start, end - start, OP_FLUSH); + +#ifdef CONFIG_ISA_ARCV2 + if (slc_exists && !ioc_exists) __slc_line_op(start, end - start, OP_FLUSH); #endif } @@ -382,18 +417,26 @@ void flush_cache(unsigned long start, unsigned long size)

void invalidate_dcache_all(void) { - __dc_entire_op(OP_INV); #ifdef CONFIG_ISA_ARCV2 - if (slc_exists) + if (!ioc_exists) +#endif + __dc_entire_op(OP_INV); + +#ifdef CONFIG_ISA_ARCV2 + if (slc_exists && !ioc_exists) __slc_entire_op(OP_INV); #endif }

void flush_dcache_all(void) { - __dc_entire_op(OP_FLUSH); #ifdef CONFIG_ISA_ARCV2 - if (slc_exists) + if (!ioc_exists) +#endif + __dc_entire_op(OP_FLUSH); + +#ifdef CONFIG_ISA_ARCV2 + if (slc_exists && !ioc_exists) __slc_entire_op(OP_FLUSH); #endif }