From: Adrian Cox <adrian@humboldt•co.uk>
To: linuxppc-dev@lists•linuxppc.org
Subject: ISA DMA
Date: Wed, 19 Dec 2001 10:21:53 +0000 [thread overview]
Message-ID: <3C206A41.1080501@humboldt.co.uk> (raw)
[-- Attachment #1: Type: text/plain, Size: 452 bytes --]
The current 2.4-devel tree never assigns any memory to the ISA DMA zone,
irrespective of the setting of ISA_DMA_THRESHOLD. As I'm currently
trying to get a floppy working on a platform with 24-bit ISA DMA in its
Southbridge, this looks like a problem.
How do people feel about the attached patch? This should only change
behavior for platforms which set ISA_DMA_THRESHOLD to a value other than
0 or (-1)L.
--
Adrian Cox http://www.humboldt.co.uk/
[-- Attachment #2: isadma.patch --]
[-- Type: text/plain, Size: 819 bytes --]
===== arch/ppc/mm/init.c 1.41 vs edited =====
--- 1.41/arch/ppc/mm/init.c Fri Nov 30 15:07:14 2001
+++ edited/arch/ppc/mm/init.c Wed Dec 19 10:15:44 2001
@@ -440,11 +440,18 @@
kmap_prot = PAGE_KERNEL;
#endif /* CONFIG_HIGHMEM */
- /*
- * All pages are DMA-able so we put them all in the DMA zone.
- */
- zones_size[ZONE_DMA] = total_lowmem >> PAGE_SHIFT;
- for (i = 1; i < MAX_NR_ZONES; i++)
+ if (ISA_DMA_THRESHOLD && ISA_DMA_THRESHOLD < total_lowmem - 1)
+ {
+ zones_size[ZONE_DMA] = (ISA_DMA_THRESHOLD + 1) >> PAGE_SHIFT;
+ zones_size[ZONE_NORMAL] =
+ (total_lowmem - ISA_DMA_THRESHOLD - 1) >> PAGE_SHIFT;
+ }
+ else
+ {
+ zones_size[ZONE_DMA] = total_lowmem >> PAGE_SHIFT;
+ zones_size[ZONE_NORMAL] = 0;
+ }
+ for (i = 2; i < MAX_NR_ZONES; i++)
zones_size[i] = 0;
#ifdef CONFIG_HIGHMEM
next reply other threads:[~2001-12-19 10:21 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2001-12-19 10:21 Adrian Cox [this message]
2001-12-20 8:36 ` ISA DMA David Müller (ELSOFT AG)
2001-12-20 9:50 ` Adrian Cox
2001-12-20 10:09 ` Geert Uytterhoeven
-- strict thread matches above, loose matches on Subject: below --
2001-12-20 16:42 Michael Sokolov
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