diff options
| author | Thomas Petazzoni <thomas.petazzoni@free-electrons.com> | 2015-01-16 17:11:27 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2015-01-29 17:40:44 -0800 |
| commit | 1f20756ce695ee56c2899e95757497d9c1cc8bbb (patch) | |
| tree | f4b68022f85db74cbfa21103eecf5fae28d813d6 | |
| parent | 7b915d382aa74aa03c1a48296dd74e94e0d1345f (diff) | |
ARM: mvebu: completely disable hardware I/O coherency
commit 8f1e8ee28660018a935c7576b9af8ffe1feab54c upstream.
The current hardware I/O coherency is known to cause problems with DMA
coherent buffers, as it still requires explicit I/O synchronization
barriers, which is not compatible with the semantics expected by the
Linux DMA coherent buffers API.
So, in order to have enough time to validate a new solution based on
automatic I/O synchronization barriers, this commit disables hardware
I/O coherency entirely. Future patches will re-enable it.
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | arch/arm/mach-mvebu/coherency.c | 7 |
1 files changed, 6 insertions, 1 deletions
diff --git a/arch/arm/mach-mvebu/coherency.c b/arch/arm/mach-mvebu/coherency.c index c31f4c00b1fc..1163a3e9accd 100644 --- a/arch/arm/mach-mvebu/coherency.c +++ b/arch/arm/mach-mvebu/coherency.c @@ -398,9 +398,14 @@ static int coherency_type(void) return type; } +/* + * As a precaution, we currently completely disable hardware I/O + * coherency, until enough testing is done with automatic I/O + * synchronization barriers to validate that it is a proper solution. + */ int coherency_available(void) { - return coherency_type() != COHERENCY_FABRIC_TYPE_NONE; + return false; } int __init coherency_init(void) |