[PATCH 2/2] ARM: imx: add speed grading check for i.mx6 soc

Right, will improve it in V2, thanks.

Best Regards.
Anson Huang
?
Freescale Semiconductor Shanghai
Tel:021-28937058

-----Original Message-----
From: Shawn Guo [mailto:shawn.guo at linaro.org]
Sent: Wednesday, February 12, 2014 5:39 PM
To: Huang Yongcai-B20788
Cc: kernel at pengutronix.de; devicetree at vger.kernel.org; linux-arm-
kernel at lists.infradead.org
Subject: Re: [PATCH 2/2] ARM: imx: add speed grading check for i.mx6 soc

On Wed, Feb 12, 2014 at 03:56:17PM +0800, Anson Huang wrote:

quoted

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 <redacted>
---
 arch/arm/mach-imx/mach-imx6q.c |   22 ++++++++++++++++++++--
 1 file changed, 20 insertions(+), 2 deletions(-)

diff --git a/arch/arm/mach-imx/mach-imx6q.c

b/arch/arm/mach-imx/mach-imx6q.c index f9cbbf9..ad9da1f 100644

--- a/arch/arm/mach-imx/mach-imx6q.c
+++ b/arch/arm/mach-imx/mach-imx6q.c

@@ -219,8 +219,10 @@ 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;

@@ -238,11 +240,27 @@ static void __init imx6q_opp_check_1p2ghz(struct

device *cpu_dev)

quoted

 		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;

val &= 0x3;

Then you do not need to do it in every if-clause below.

quoted

 	if ((val & 0x3) != OCOTP_CFG3_SPEED_1P2GHZ)
 		if (dev_pm_opp_disable(cpu_dev, 1200000000))
 			pr_warn("failed to disable 1.2 GHz OPP\n");
+	if ((val & 0x3) < 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 & 0x3) != OCOTP_CFG3_SPEED_852MHZ)

if (cpu_is_imx6q() && val != OCOTP_CFG3_SPEED_852MHZ)

Shawn

quoted

+			if (dev_pm_opp_disable(cpu_dev, 852000000))
+				pr_warn("failed to disable 852 MHz OPP\n");
+	}

 put_node:
 	of_node_put(np);

@@ -268,7 +286,7 @@ 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);
--

1.7.9.5