ARC: dma [IOC] Enable per device io coherency

[linux.git] / arch / arc / mm / cache.c

diff --git a/arch/arc/mm/cache.c b/arch/arc/mm/cache.c
index 25c631942500ffe2802654f6690d9a223e2fbfaf..2d389cab46ba0237f7161d84bd64651399f8c2c0 100644 (file)
--- a/arch/arc/mm/cache.c
+++ b/arch/arc/mm/cache.c
@@ -65,7 +65,7 @@ char *arc_cache_mumbojumbo(int c, char *buf, int len)
 
        n += scnprintf(buf + n, len - n, "Peripherals\t: %#lx%s%s\n",
                       perip_base,
-                      IS_AVAIL3(ioc_exists, ioc_enable, ", IO-Coherency "));
+                      IS_AVAIL3(ioc_exists, ioc_enable, ", IO-Coherency (per-device) "));
 
        return buf;
 }
@@ -896,15 +896,6 @@ static void __dma_cache_wback_slc(phys_addr_t start, unsigned long sz)
        slc_op(start, sz, OP_FLUSH);
 }
 
-/*
- * DMA ops for systems with IOC
- * IOC hardware snoops all DMA traffic keeping the caches consistent with
- * memory - eliding need for any explicit cache maintenance of DMA buffers
- */
-static void __dma_cache_wback_inv_ioc(phys_addr_t start, unsigned long sz) {}
-static void __dma_cache_inv_ioc(phys_addr_t start, unsigned long sz) {}
-static void __dma_cache_wback_ioc(phys_addr_t start, unsigned long sz) {}
-
 /*
  * Exported DMA API
  */
@@ -1264,11 +1255,7 @@ void __init arc_cache_init_master(void)
        if (is_isa_arcv2() && ioc_enable)
                arc_ioc_setup();
 
-       if (is_isa_arcv2() && ioc_enable) {
-               __dma_cache_wback_inv = __dma_cache_wback_inv_ioc;
-               __dma_cache_inv = __dma_cache_inv_ioc;
-               __dma_cache_wback = __dma_cache_wback_ioc;
-       } else if (is_isa_arcv2() && l2_line_sz && slc_enable) {
+       if (is_isa_arcv2() && l2_line_sz && slc_enable) {
                __dma_cache_wback_inv = __dma_cache_wback_inv_slc;
                __dma_cache_inv = __dma_cache_inv_slc;
                __dma_cache_wback = __dma_cache_wback_slc;
@@ -1277,6 +1264,12 @@ void __init arc_cache_init_master(void)
                __dma_cache_inv = __dma_cache_inv_l1;
                __dma_cache_wback = __dma_cache_wback_l1;
        }
+       /*
+        * In case of IOC (say IOC+SLC case), pointers above could still be set
+        * but end up not being relevant as the first function in chain is not
+        * called at all for @dma_direct_ops
+        *     arch_sync_dma_for_cpu() -> dma_cache_*() -> __dma_cache_*()
+        */
 }
 
 void __ref arc_cache_init(void)