Merge branch 'omap-for-v4.1/ocp2scp' into omap-for-v4.1/fixes-not-urgent

3 files changed, 38 insertions, 3 deletions

diff --git a/Documentation/devicetree/bindings/bus/omap-ocp2scp.txt b/Documentation/devicetree/bindings/bus/omap-ocp2scp.txt
index 63dd8051521c..18729f6fe1e5 100644
--- a/Documentation/devicetree/bindings/bus/omap-ocp2scp.txt
+++ b/Documentation/devicetree/bindings/bus/omap-ocp2scp.txt
@@ -1,7 +1,8 @@
 * OMAP OCP2SCP - ocp interface to scp interface
 
 properties:
-- compatible : Should be "ti,omap-ocp2scp"
+- compatible : Should be "ti,am437x-ocp2scp" for AM437x processor
+	       Should be "ti,omap-ocp2scp" for all others
 - reg : Address and length of the register set for the device
 - #address-cells, #size-cells : Must be present if the device has sub-nodes
 - ranges : the child address space are mapped 1:1 onto the parent address space
diff --git a/arch/arm/boot/dts/am4372.dtsi b/arch/arm/boot/dts/am4372.dtsi
index 1943fc333e7c..286e31790e29 100644
--- a/arch/arm/boot/dts/am4372.dtsi
+++ b/arch/arm/boot/dts/am4372.dtsi
@@ -787,7 +787,7 @@
 		};
 
 		ocp2scp0: ocp2scp@483a8000 {
-			compatible = "ti,omap-ocp2scp";
+			compatible = "ti,am437x-ocp2scp", "ti,omap-ocp2scp";
 			#address-cells = <1>;
 			#size-cells = <1>;
 			ranges;
@@ -806,7 +806,7 @@
 		};
 
 		ocp2scp1: ocp2scp@483e8000 {
-			compatible = "ti,omap-ocp2scp";
+			compatible = "ti,am437x-ocp2scp", "ti,omap-ocp2scp";
 			#address-cells = <1>;
 			#size-cells = <1>;
 			ranges;
diff --git a/drivers/bus/omap-ocp2scp.c b/drivers/bus/omap-ocp2scp.c
index 723ec06ad2c8..9f1856948758 100644
--- a/drivers/bus/omap-ocp2scp.c
+++ b/drivers/bus/omap-ocp2scp.c
@@ -16,6 +16,7 @@
  *
  */
 
+#include <linux/io.h>
 #include <linux/module.h>
 #include <linux/platform_device.h>
 #include <linux/err.h>
@@ -23,6 +24,9 @@
 #include <linux/of.h>
 #include <linux/of_platform.h>
 
+#define OCP2SCP_TIMING 0x18
+#define SYNC2_MASK 0xf
+
 static int ocp2scp_remove_devices(struct device *dev, void *c)
 {
 	struct platform_device *pdev = to_platform_device(dev);
@@ -35,6 +39,9 @@ static int ocp2scp_remove_devices(struct device *dev, void *c)
 static int omap_ocp2scp_probe(struct platform_device *pdev)
 {
 	int ret;
+	u32 reg;
+	void __iomem *regs;
+	struct resource *res;
 	struct device_node *np = pdev->dev.of_node;
 
 	if (np) {
@@ -47,6 +54,32 @@ static int omap_ocp2scp_probe(struct platform_device *pdev)
 	}
 
 	pm_runtime_enable(&pdev->dev);
+	/*
+	 * As per AM572x TRM: http://www.ti.com/lit/ug/spruhz6/spruhz6.pdf
+	 * under section 26.3.2.2, table 26-26 OCP2SCP TIMING Caution;
+	 * As per OMAP4430 TRM: http://www.ti.com/lit/ug/swpu231ap/swpu231ap.pdf
+	 * under section 23.12.6.2.2 , Table 23-1213 OCP2SCP TIMING Caution;
+	 * As per OMAP4460 TRM: http://www.ti.com/lit/ug/swpu235ab/swpu235ab.pdf
+	 * under section 23.12.6.2.2, Table 23-1213 OCP2SCP TIMING Caution;
+	 * As per OMAP543x TRM http://www.ti.com/lit/pdf/swpu249
+	 * under section 27.3.2.2, Table 27-27 OCP2SCP TIMING Caution;
+	 *
+	 * Read path of OCP2SCP is not working properly due to low reset value
+	 * of SYNC2 parameter in OCP2SCP. Suggested reset value is 0x6 or more.
+	 */
+	if (!of_device_is_compatible(np, "ti,am437x-ocp2scp")) {
+		res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+		regs = devm_ioremap_resource(&pdev->dev, res);
+		if (IS_ERR(regs))
+			goto err0;
+
+		pm_runtime_get_sync(&pdev->dev);
+		reg = readl_relaxed(regs + OCP2SCP_TIMING);
+		reg &= ~(SYNC2_MASK);
+		reg |= 0x6;
+		writel_relaxed(reg, regs + OCP2SCP_TIMING);
+		pm_runtime_put_sync(&pdev->dev);
+	}
 
 	return 0;
 
@@ -67,6 +100,7 @@ static int omap_ocp2scp_remove(struct platform_device *pdev)
 #ifdef CONFIG_OF
 static const struct of_device_id omap_ocp2scp_id_table[] = {
 	{ .compatible = "ti,omap-ocp2scp" },
+	{ .compatible = "ti,am437x-ocp2scp" },
 	{}
 };
 MODULE_DEVICE_TABLE(of, omap_ocp2scp_id_table);