bus: mvebu: pass the coherency availability information at init time

commit 5686a1e5aa436c49187a60052d5885fb1f541ce6 upstream.

Until now, the mvebu-mbus was guessing by itself whether hardware I/O
coherency was available or not by poking into the Device Tree to see
if the coherency fabric Device Tree node was present or not.

However, on some upcoming SoCs, the presence or absence of the
coherency fabric DT node isn't sufficient: in CONFIG_SMP, the
coherency can be enabled, but not in !CONFIG_SMP.

In order to clean this up, the mvebu_mbus_dt_init() function is
extended to get a boolean argument telling whether coherency is
enabled or not. Therefore, the logic to decide whether coherency is
available or not now belongs to the core SoC code instead of the
mvebu-mbus driver itself, which is much better.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Link: https://lkml.kernel.org/r/1397483228-25625-4-git-send-email-thomas.petazzoni@free-electrons.com
Signed-off-by: Jason Cooper <jason@lakedaemon.net>

[ Greg Ungerer: back ported to linux-3.10.y
  Back port necessary due to large code differences in affected files.
  This change in combination with commit e553554536 ("ARM: mvebu: disable
  I/O coherency on non-SMP situations on Armada 370/375/38x/XP") is
  critical to the hardware I/O coherency being set correctly by both the
  mbus driver and all peripheral hardware drivers. Without this change
  drivers will incorrectly enable I/O coherency window attributes and
  this causes rare unreliable system behavior including oops. ]

Signed-off-by: Greg Ungerer <gerg@uclinux.org>
Acked-by: Gregory CLEMENT <gregory.clement@free-electrons.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 2 insertions, 3 deletions

diff --git a/drivers/bus/mvebu-mbus.c b/drivers/bus/mvebu-mbus.c
index 711dcf4a0313..7c437826c2f9 100644
--- a/drivers/bus/mvebu-mbus.c
+++ b/drivers/bus/mvebu-mbus.c
@@ -838,7 +838,7 @@ fs_initcall(mvebu_mbus_debugfs_init);
 int __init mvebu_mbus_init(const char *soc, phys_addr_t mbuswins_phys_base,
 			   size_t mbuswins_size,
 			   phys_addr_t sdramwins_phys_base,
-			   size_t sdramwins_size)
+			   size_t sdramwins_size, int is_coherent)
 {
 	struct mvebu_mbus_state *mbus = &mbus_state;
 	const struct of_device_id *of_id;
@@ -865,8 +865,7 @@ int __init mvebu_mbus_init(const char *soc, phys_addr_t mbuswins_phys_base,
 		return -ENOMEM;
 	}
 
-	if (of_find_compatible_node(NULL, NULL, "marvell,coherency-fabric"))
-		mbus->hw_io_coherency = 1;
+	mbus->hw_io_coherency = is_coherent;
 
 	for (win = 0; win < mbus->soc->num_wins; win++)
 		mvebu_mbus_disable_window(mbus, win);