ARM: i.MX6: add i.MX6 specific L2 cache configuration

Commit b3a9c315378ff811bf34393f2f0a6e8b9ffced3b upstream.

To improve the performance and power consumption add an i.MX6
specific L2 cache initialization.

This configuration is taken from Freescale's kernel patch

"ENGR00153601 [MX6]Adjust L2 cache parameter" [1]

with two additional improvements:

a) The L2X0_POWER_CTRL has only the two bits we set. So no need
   to read the register before. Remove the register read done
   in Freescale's patch.

b) In the L2X0_PREFETCH_CTRL register, besides the double linefill (bit[30]),
   additionally enable the instruction and data prefetch (bit[29-28]).

Signed-off-by: Dirk Behme <dirk.behme@de.bosch.com>
Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
Signed-off-by: Shawn Guo <shawn.guo@freescale.com>

[1] http://git.freescale.com/git/cgit.cgi/imx/linux-2.6-imx.git/commit/arch/arm/mach-mx6/mm.c?h=imx_3.0.35_12.09.01&id=814656410b40c67a10b25300e51b0477b2bb96d1

1 files changed, 35 insertions, 1 deletions

diff --git a/arch/arm/mach-imx/mach-imx6q.c b/arch/arm/mach-imx/mach-imx6q.c
index 6421e728f4b4..5ab972567ef6 100644
--- a/arch/arm/mach-imx/mach-imx6q.c
+++ b/arch/arm/mach-imx/mach-imx6q.c
@@ -257,10 +257,44 @@ static void __init imx6q_map_io(void)
         imx_scu_map_io();
 }
 
+#ifdef CONFIG_CACHE_L2X0
+static void __init imx6q_init_l2cache(void)
+{
+        void __iomem *l2x0_base;
+        struct device_node *np;
+        unsigned int val;
+
+        np = of_find_compatible_node(NULL, NULL, "arm,pl310-cache");
+        if (!np)
+                goto out;
+
+        l2x0_base = of_iomap(np, 0);
+        if (!l2x0_base) {
+                of_node_put(np);
+                goto out;
+        }
+
+        /* Configure the L2 PREFETCH and POWER registers */
+        val = readl_relaxed(l2x0_base + L2X0_PREFETCH_CTRL);
+        val |= 0x70800000;
+        writel_relaxed(val, l2x0_base + L2X0_PREFETCH_CTRL);
+        val = L2X0_DYNAMIC_CLK_GATING_EN | L2X0_STNDBY_MODE_EN;
+        writel_relaxed(val, l2x0_base + L2X0_POWER_CTRL);
+
+        iounmap(l2x0_base);
+        of_node_put(np);
+
+out:
+        l2x0_of_init(0, ~0UL);
+}
+#else
+static inline void imx6q_init_l2cache(void) {}
+#endif
+
 static void __init imx6q_init_irq(void)
 {
         imx6q_init_revision();
-        l2x0_of_init(0, ~0UL);
+        imx6q_init_l2cache();
         imx_src_init();
         imx_gpc_init();
         irqchip_init();