From: Nicolas Schichan <[email protected]>

Commit a0b5cd4ac2d6 ("bus: mvebu-mbus: use automatic I/O
synchronization barriers") enabled the usage of automatic I/O
synchronization barriers by enabling bit WIN_CTRL_SYNCBARRIER in the
control registers of MBus windows, but on non io-coherent platforms
(orion5x, kirkwood and dove) the WIN_CTRL_SYNCBARRIER bit in
the window control register is either reserved (all windows except 6
and 7) or enables read-only protection (windows 6 and 7).

Signed-off-by: Nicolas Schichan <[email protected]>
Reviewed-by: Thomas Petazzoni <[email protected]>
Cc: <[email protected]> # v4.0+
Fixes: a0b5cd4ac2d6 ("bus: mvebu-mbus: use automatic I/O synchronization 
barriers")
Signed-off-by: Thomas Petazzoni <[email protected]>
---
 drivers/bus/mvebu-mbus.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/bus/mvebu-mbus.c b/drivers/bus/mvebu-mbus.c
index fb9ec62..7fa4510 100644
--- a/drivers/bus/mvebu-mbus.c
+++ b/drivers/bus/mvebu-mbus.c
@@ -70,6 +70,7 @@
  */
 #define WIN_CTRL_OFF           0x0000
 #define   WIN_CTRL_ENABLE       BIT(0)
+/* Only on HW I/O coherency capable platforms */
 #define   WIN_CTRL_SYNCBARRIER  BIT(1)
 #define   WIN_CTRL_TGT_MASK     0xf0
 #define   WIN_CTRL_TGT_SHIFT    4
@@ -323,8 +324,9 @@ static int mvebu_mbus_setup_window(struct mvebu_mbus_state 
*mbus,
        ctrl = ((size - 1) & WIN_CTRL_SIZE_MASK) |
                (attr << WIN_CTRL_ATTR_SHIFT)    |
                (target << WIN_CTRL_TGT_SHIFT)   |
-               WIN_CTRL_SYNCBARRIER             |
                WIN_CTRL_ENABLE;
+       if (mbus->hw_io_coherency)
+               ctrl |= WIN_CTRL_SYNCBARRIER;
 
        writel(base & WIN_BASE_LOW, addr + WIN_BASE_OFF);
        writel(ctrl, addr + WIN_CTRL_OFF);
-- 
2.1.0

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