[src/trunk]: src/sys/arch/powerpc/booke If allocating lots of VA space for an...

[matt <matt%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/d856a33e6838
branches:  trunk
changeset: 780266:d856a33e6838
user:      matt <matt%NetBSD.org@localhost>
date:      Wed Jul 18 18:51:59 2012 +0000

description:
If allocating lots of VA space for an io device, try to 'reserve' the space
so that the TLB might be able to create a large TLB entry to map it all.

diffstat:

 sys/arch/powerpc/booke/booke_machdep.c |  38 +++++++++++++++++++++++++++++++--
 1 files changed, 35 insertions(+), 3 deletions(-)

diffs (65 lines):

diff -r 3da3e43c8728 -r d856a33e6838 sys/arch/powerpc/booke/booke_machdep.c
--- a/sys/arch/powerpc/booke/booke_machdep.c    Wed Jul 18 18:50:46 2012 +0000
+++ b/sys/arch/powerpc/booke/booke_machdep.c    Wed Jul 18 18:51:59 2012 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: booke_machdep.c,v 1.14 2011/06/30 00:52:58 matt Exp $  */
+/*     $NetBSD: booke_machdep.c,v 1.15 2012/07/18 18:51:59 matt Exp $  */
 /*-
  * Copyright (c) 2010, 2011 The NetBSD Foundation, Inc.
  * All rights reserved.
@@ -38,7 +38,7 @@
 #define        _POWERPC_BUS_DMA_PRIVATE
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: booke_machdep.c,v 1.14 2011/06/30 00:52:58 matt Exp $");
+__KERNEL_RCSID(0, "$NetBSD: booke_machdep.c,v 1.15 2012/07/18 18:51:59 matt Exp $");
 
 #include "opt_modular.h"
 
@@ -329,13 +329,45 @@
                panic("mapiodev: no TLB entry reserved for %llx+%llx",
                    (long long)pa, (long long)len);
 
+       const paddr_t orig_pa = pa;
+       const psize_t orig_len = len;
+       vsize_t align = 0;
        pa = trunc_page(pa);
        len = round_page(off + len);
-       vaddr_t va = uvm_km_alloc(kernel_map, len, 0, UVM_KMF_VAONLY);
+       /*
+        * If we are allocating a large amount (>= 1MB) try to get an
+        * aligned VA region for it so try to do a large mapping for it.
+        */
+       if ((len & (len - 1)) == 0 && len >= 0x100000)
+               align = len;
 
+       vaddr_t va = uvm_km_alloc(kernel_map, len, align, UVM_KMF_VAONLY);
+
+       if (va == 0 && align > 0) {
+               /*
+                * Large aligned request failed.  Let's just get anything.
+                */
+               align = 0;
+               va = uvm_km_alloc(kernel_map, len, align, UVM_KMF_VAONLY);
+       }
        if (va == 0)
                return NULL;
 
+       if (align) {
+               /*
+                * Now try to map that via one big TLB entry.
+                */
+               pt_entry_t pte = pte_make_kenter_pa(pa, NULL,
+                   VM_PROT_READ|VM_PROT_WRITE,
+                   prefetchable ? 0 : PMAP_NOCACHE);
+               if (!tlb_ioreserve(va, len, pte)) {
+                       void * const p0 = tlb_mapiodev(orig_pa, orig_len,
+                           prefetchable);
+                       KASSERT(p0 != NULL);
+                       return p0;
+               }
+       }
+
        for (va += len, pa += len; len > 0; len -= PAGE_SIZE) {
                va -= PAGE_SIZE;
                pa -= PAGE_SIZE;