Map BUS_SPACE_MAP_PREFETCHABLE to Normal-NC. There are other memory

attributes that could map to what we call write-combining on x86, but
this is what Linux uses.  This speeds up framebuffer access significantly.

ok patrick@

diff --git a/sys/arch/arm64/arm64/machdep.c b/sys/arch/arm64/arm64/machdep.c
index 98437f7..7b53ee1 100644 (file)
--- a/sys/arch/arm64/arm64/machdep.c
+++ b/sys/arch/arm64/arm64/machdep.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: machdep.c,v 1.89 2024/04/29 13:01:54 jsg Exp $ */
+/* $OpenBSD: machdep.c,v 1.90 2024/07/03 21:04:04 kettenis Exp $ */
 /*
  * Copyright (c) 2014 Patrick Wildt <patrick@blueri.se>
  * Copyright (c) 2021 Mark Kettenis <kettenis@openbsd.org>
@@ -1170,6 +1170,10 @@ pmap_bootstrap_bs_map(bus_space_tag_t t, bus_addr_t bpa, bus_size_t size,
 {
        u_long startpa, pa, endpa;
        vaddr_t va;
+       int cache = PMAP_CACHE_DEV_NGNRNE;
+
+       if (flags & BUS_SPACE_MAP_PREFETCHABLE)
+               cache = PMAP_CACHE_CI;
 
        va = virtual_avail;     /* steal memory from virtual avail. */
 
@@ -1179,8 +1183,7 @@ pmap_bootstrap_bs_map(bus_space_tag_t t, bus_addr_t bpa, bus_size_t size,
        *bshp = (bus_space_handle_t)(va + (bpa - startpa));
 
        for (pa = startpa; pa < endpa; pa += PAGE_SIZE, va += PAGE_SIZE)
-               pmap_kenter_cache(va, pa, PROT_READ | PROT_WRITE,
-                   PMAP_CACHE_DEV_NGNRNE);
+               pmap_kenter_cache(va, pa, PROT_READ | PROT_WRITE, cache);
 
        virtual_avail = va;
 

diff --git a/sys/arch/arm64/dev/arm64_bus_space.c b/sys/arch/arm64/dev/arm64_bus_space.c
index e4847cb..f78905f 100644 (file)
--- a/sys/arch/arm64/dev/arm64_bus_space.c
+++ b/sys/arch/arm64/dev/arm64_bus_space.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: arm64_bus_space.c,v 1.8 2021/02/16 12:33:22 kettenis Exp $ */
+/*     $OpenBSD: arm64_bus_space.c,v 1.9 2024/07/03 21:04:04 kettenis Exp $ */
 
 /*
  * Copyright (c) 2001-2003 Opsycon AB  (www.opsycon.se / www.opsycon.com)
@@ -195,6 +195,8 @@ generic_space_map(bus_space_tag_t t, bus_addr_t offs, bus_size_t size,
 
        if (flags & BUS_SPACE_MAP_CACHEABLE)
                cache = PMAP_CACHE_WB;
+       if (flags & BUS_SPACE_MAP_PREFETCHABLE)
+               cache = PMAP_CACHE_CI;
        if (flags & BUS_SPACE_MAP_POSTED)
                cache = PMAP_CACHE_DEV_NGNRE;