ChangeSet 1.2217.6.34, 2005/03/25 21:06:29+00:00, [EMAIL PROTECTED](none)
[ARM PATCH] 2507/1: work around ixp2400 erratum #66
Patch from Lennert Buytenhek
Intel's ixp2400 can occasionally corrupt writes to its on-chip
registers, leading to system crashes. The suggested workaround for
this is to map in those registers using XCB=101 instead of XCB=000.
Patch 2491/1 makes all mappings of ixp2000 on-chip I/O regions use
section mappings. This patch makes all iotable section mappings use
XCB=101. This patch depends on 2491/1.
Kernel iotable mappings that are not 1MB-aligned, ioremap(), and
userspace mappings using mmap() on /dev/mem will still generate
XCB=000 mappings, which can trigger erratum #66 quite easily.
For this, an extra patch (to arch/arm/mm/proc-xscale.S) is needed,
which is maintained out-of-tree because it has been rejected in
the past. See http://ixp2xxx.sourceforge.net/kernel/ and look
for 'ixp2000-erratum66-ptes.diff'.
2.6.11-rc4 with 2491/1 plus this patch survives a week of heavy
testing on my ENP-2611, while 2.6.11-rc4 vanilla doesn't stand a
chance and crashes within 30 minutes under the same workload.
Signed-off-by: Lennert BuytenhekSigned-off-by: Deepak Saxena
Signed-off-by: Russell King
arch/arm/mach-ixp2000/core.c | 16 ++++++++++++++++
arch/arm/mm/mm-armv.c | 9 +++++++++
include/asm-arm/arch-ixp2000/ixp2000-regs.h | 3 ++-
include/asm-arm/mach/map.h | 15 ++++++++-------
4 files changed, 35 insertions(+), 8 deletions(-)
diff -Nru a/arch/arm/mach-ixp2000/core.c b/arch/arm/mach-ixp2000/core.c
--- a/arch/arm/mach-ixp2000/core.c 2005-03-26 11:28:38 -08:00
+++ b/arch/arm/mach-ixp2000/core.c 2005-03-26 11:28:38 -08:00
@@ -133,6 +133,22 @@
void __init ixp2000_map_io(void)
{
+ extern unsigned int processor_id;
+
+ /*
+ * On IXP2400 CPUs we need to use MT_IXP2000_DEVICE for
+ * tweaking the PMDs so XCB=101. On IXP2800s we use the normal
+ * PMD flags.
+ */
+ if ((processor_id & 0xfffffff0) == 0x69054190) {
+ int i;
+
+ printk(KERN_INFO "Enabling IXP2400 erratum #66 workaround\n");
+
+ for(i=0;i<ARRAY_SIZE(ixp2000_io_desc);i++)
+ ixp2000_io_desc[i].type = MT_IXP2000_DEVICE;
+ }
+
iotable_init(ixp2000_io_desc, ARRAY_SIZE(ixp2000_io_desc));
early_serial_setup(&ixp2000_serial_port);
diff -Nru a/arch/arm/mm/mm-armv.c b/arch/arm/mm/mm-armv.c
--- a/arch/arm/mm/mm-armv.c 2005-03-26 11:28:38 -08:00
+++ b/arch/arm/mm/mm-armv.c 2005-03-26 11:28:38 -08:00
@@ -356,6 +356,15 @@
[MT_ROM] = {
.prot_sect = PMD_TYPE_SECT,
.domain = DOMAIN_KERNEL,
+ },
+ [MT_IXP2000_DEVICE] = { /* IXP2400 requires XCB=101 for on-chip I/O */
+ .prot_pte = L_PTE_PRESENT | L_PTE_YOUNG | L_PTE_DIRTY |
+ L_PTE_WRITE,
+ .prot_l1 = PMD_TYPE_TABLE,
+ .prot_sect = PMD_TYPE_SECT | PMD_SECT_UNCACHED |
+ PMD_SECT_AP_WRITE | PMD_SECT_BUFFERABLE |
+ PMD_SECT_TEX(1),
+ .domain = DOMAIN_IO,
}
};
diff -Nru a/include/asm-arm/arch-ixp2000/ixp2000-regs.h
b/include/asm-arm/arch-ixp2000/ixp2000-regs.h
--- a/include/asm-arm/arch-ixp2000/ixp2000-regs.h 2005-03-26 11:28:38
-08:00
+++ b/include/asm-arm/arch-ixp2000/ixp2000-regs.h 2005-03-26 11:28:38
-08:00
@@ -29,7 +29,8 @@
* 1) We use only one TLB entry for large number of on-chip I/O devices.
*
* 2) We can easily set the Section attributes to XCB=101 on the IXP2400
- * as required per erratum #66.
+ * as required per erratum #66. We accomplish this by using a
+ * new MT_IXP2000_DEVICE memory type with the bits set as required.
*
* CAP stands for CSR Access Proxy
*/
diff -Nru a/include/asm-arm/mach/map.h b/include/asm-arm/mach/map.h
--- a/include/asm-arm/mach/map.h 2005-03-26 11:28:38 -08:00
+++ b/include/asm-arm/mach/map.h 2005-03-26 11:28:38 -08:00
@@ -18,13 +18,14 @@
struct meminfo;
-#define MT_DEVICE 0
-#define MT_CACHECLEAN 1
-#define MT_MINICLEAN 2
-#define MT_LOW_VECTORS 3
-#define MT_HIGH_VECTORS 4
-#define MT_MEMORY 5
-#define MT_ROM 6
+#define MT_DEVICE 0
+#define MT_CACHECLEAN 1
+#define MT_MINICLEAN 2
+#define MT_LOW_VECTORS 3
+#define MT_HIGH_VECTORS 4
+#define MT_MEMORY 5
+#define MT_ROM 6
+#define MT_IXP2000_DEVICE 7
extern void create_memmap_holes(struct meminfo *);
extern void memtable_init(struct meminfo *);
-
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