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authorStefan Richter <stefanr@s5r6.in-berlin.de>2007-08-25 14:08:19 +0200
committerStefan Richter <stefanr@s5r6.in-berlin.de>2007-10-17 00:00:05 +0200
commitee71c2f9ee85117e41ef87357ed8f75d29369b98 (patch)
tree9bb749909370ec732ed730ca80553908913156af /drivers/firewire
parentdf8ec2490fed5dd23316bbb2c2e90e59e7d37126 (diff)
downloadop-kernel-dev-ee71c2f9ee85117e41ef87357ed8f75d29369b98.zip
op-kernel-dev-ee71c2f9ee85117e41ef87357ed8f75d29369b98.tar.gz
firewire: fw-ohci: enforce read order for selfID generation
It seems unlikely, but access to self_id_cpu[0] could at least in theory be deferred until after the loop over self_id_cpu[1..n] or even after the subsequent reg_read. Enforce the desired order by a read barrier. Also prevent the reg_read from being reordered relative to the for loop. This isn't necessary if the loop's conditional printk counts as an implicit barrier, but better make it explicit. (self_id_cpu[] is a coherent DMA buffer.) Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
Diffstat (limited to 'drivers/firewire')
-rw-r--r--drivers/firewire/fw-ohci.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/drivers/firewire/fw-ohci.c b/drivers/firewire/fw-ohci.c
index e14c1ca7..a7947ba 100644
--- a/drivers/firewire/fw-ohci.c
+++ b/drivers/firewire/fw-ohci.c
@@ -30,6 +30,7 @@
#include <asm/uaccess.h>
#include <asm/semaphore.h>
+#include <asm/system.h>
#include "fw-transaction.h"
#include "fw-ohci.h"
@@ -926,12 +927,14 @@ static void bus_reset_tasklet(unsigned long data)
self_id_count = (reg_read(ohci, OHCI1394_SelfIDCount) >> 3) & 0x3ff;
generation = (le32_to_cpu(ohci->self_id_cpu[0]) >> 16) & 0xff;
+ rmb();
for (i = 1, j = 0; j < self_id_count; i += 2, j++) {
if (ohci->self_id_cpu[i] != ~ohci->self_id_cpu[i + 1])
fw_error("inconsistent self IDs\n");
ohci->self_id_buffer[j] = le32_to_cpu(ohci->self_id_cpu[i]);
}
+ rmb();
/*
* Check the consistency of the self IDs we just read. The
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