From: Peng Fan Date: Wed, 4 May 2016 07:27:50 +0000 (+0800) Subject: imx6: cache: disable L2 before touching Auxiliary Control Register X-Git-Tag: v2016.05~9 X-Git-Url: https://git.librecmc.org/?a=commitdiff_plain;h=ad7af5d7e4caf49581c7403d5a8edc0f11a5f652;p=oweals%2Fu-boot.git 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 Cc: Stefano Babic Cc: Fabio Estevam --- diff --git a/arch/arm/imx-common/cache.c b/arch/arm/imx-common/cache.c index 54b021cfed..b77548821d 100644 --- a/arch/arm/imx-common/cache.c +++ b/arch/arm/imx-common/cache.c @@ -42,6 +42,12 @@ void v7_outer_cache_enable(void) unsigned int val; + /* + * 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 @@ -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);