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>

diff --git a/arch/arm/mach-imx/mach-imx6q.c b/arch/arm/mach-imx/mach-imx6q.c
index d131499be5d302b8948dd5500e05a02c77922810..1e126853847cd2657725fd27ef33b1f10cc6e5a4 100644 (file)
--- 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);