ARM: imx: add speed grading check for i.mx6 soc

The fuse map of speed_grading[1:0] defines the max speed
of ARM, see below the definition:

2b'11: 1200000000Hz;
2b'10: 996000000Hz;
2b'01: 852000000Hz; -- i.MX6Q Only, exclusive with 996MHz.
2b'00: 792000000Hz;

Need to remove all illegal setpoints according to fuse
map.

Signed-off-by: Anson Huang <b20788@freescale.com>
Signed-off-by: Shawn Guo <shawn.guo@linaro.org>

1 files changed, 23 insertions, 3 deletions

diff --git a/arch/arm/mach-imx/mach-imx6q.c b/arch/arm/mach-imx/mach-imx6q.c
index d131499be5d3..1e126853847c 100644
--- a/arch/arm/mach-imx/mach-imx6q.c
+++ b/arch/arm/mach-imx/mach-imx6q.c
@@ -253,8 +253,10 @@ static void __init imx6q_init_machine(void)
 #define OCOTP_CFG3                      0x440
 #define OCOTP_CFG3_SPEED_SHIFT          16
 #define OCOTP_CFG3_SPEED_1P2GHZ         0x3
+#define OCOTP_CFG3_SPEED_996MHZ         0x2
+#define OCOTP_CFG3_SPEED_852MHZ         0x1
 
-static void __init imx6q_opp_check_1p2ghz(struct device *cpu_dev)
+static void __init imx6q_opp_check_speed_grading(struct device *cpu_dev)
 {
         struct device_node *np;
         void __iomem *base;
@@ -272,11 +274,29 @@ static void __init imx6q_opp_check_1p2ghz(struct device *cpu_dev)
                 goto put_node;
         }
 
+        /*
+         * SPEED_GRADING[1:0] defines the max speed of ARM:
+         * 2b'11: 1200000000Hz;
+         * 2b'10: 996000000Hz;
+         * 2b'01: 852000000Hz; -- i.MX6Q Only, exclusive with 996MHz.
+         * 2b'00: 792000000Hz;
+         * We need to set the max speed of ARM according to fuse map.
+         */
         val = readl_relaxed(base + OCOTP_CFG3);
         val >>= OCOTP_CFG3_SPEED_SHIFT;
-        if ((val & 0x3) != OCOTP_CFG3_SPEED_1P2GHZ)
+        val &= 0x3;
+
+        if (val != OCOTP_CFG3_SPEED_1P2GHZ)
                 if (dev_pm_opp_disable(cpu_dev, 1200000000))
                         pr_warn("failed to disable 1.2 GHz OPP\n");
+        if (val < OCOTP_CFG3_SPEED_996MHZ)
+                if (dev_pm_opp_disable(cpu_dev, 996000000))
+                        pr_warn("failed to disable 996 MHz OPP\n");
+        if (cpu_is_imx6q()) {
+                if (val != OCOTP_CFG3_SPEED_852MHZ)
+                        if (dev_pm_opp_disable(cpu_dev, 852000000))
+                                pr_warn("failed to disable 852 MHz OPP\n");
+        }
 
 put_node:
         of_node_put(np);
@@ -302,7 +322,7 @@ static void __init imx6q_opp_init(void)
                 goto put_node;
         }
 
-        imx6q_opp_check_1p2ghz(cpu_dev);
+        imx6q_opp_check_speed_grading(cpu_dev);
 
 put_node:
         of_node_put(np);