imx6: cache: disable L2 before touching Auxiliary Control Register

According PL310 TRM, Auxiliary Control Register
"
The register must be written to using a secure access, and it can be
read using either a secure or a NS access. If you write to this register
with a NS access, it results in a write response with a DECERR response,
and the register is not updated. Writing to this register with the L2
cache enabled, that is, bit[0] of L2 Control Register set to 1,
results in a SLVERR.
"

So If L2 cache is already enabled by ROM, chaning value of ACR
will cause SLVERR and uboot hang.

Signed-off-by: Peng Fan <[email protected]>
Cc: Stefano Babic <[email protected]>
Cc: Fabio Estevam <[email protected]>

1 files changed, 6 insertions, 3 deletions

diff --git a/arch/arm/imx-common/cache.c b/arch/arm/imx-common/cache.c
index 54b021cfede..b77548821db 100644
--- a/arch/arm/imx-common/cache.c
+++ b/arch/arm/imx-common/cache.c
@@ -43,6 +43,12 @@ void v7_outer_cache_enable(void)
 
 
 	/*
+	 * Must disable the L2 before changing the latency parameters
+	 * and auxiliary control register.
+	 */
+	clrbits_le32(&pl310->pl310_ctrl, L2X0_CTRL_EN);
+
+	/*
 	 * Set bit 22 in the auxiliary control register. If this bit
 	 * is cleared, PL310 treats Normal Shared Non-cacheable
 	 * accesses as Cacheable no-allocate.
@@ -59,9 +65,6 @@ void v7_outer_cache_enable(void)
 	}
 #endif
 
-	/* Must disable the L2 before changing the latency parameters */
-	clrbits_le32(&pl310->pl310_ctrl, L2X0_CTRL_EN);
-
 	writel(0x132, &pl310->pl310_tag_latency_ctrl);
 	writel(0x132, &pl310->pl310_data_latency_ctrl);