drm/msm-hyp: parse client id from dtsi

Read client id from dtsi, then parse and return it when queried
by user space. This change allows setting different client id
without changing driver code.

Change-Id: I3858ee80748f2a485a115c652608cc484d6f3720
Signed-off-by: Camus Wong <camusw@codeaurora.org>

Documentation/devicetree/bindings/display/msm/sde-hyp.txt

@@ -7,7 +7,14 @@ VBlank and Page Flip events to User Space listeners.
 Required properties
 - compatible: Must be "qcom,sde-kms-hyp"
 
+Optional properties:
+- qcom,client-id:	A four character string that is converted to a u32. It's
+			understood as a hex value, if compatible (i.e. "7816").
+			Otherwise, it is treated as a FourCC sequence code
+			(i.e. "LV01").
+
 Example:
 	sde_kms_hyp: qcom,sde_kms_hyp@900000 {
 		compatible = "qcom,sde-kms-hyp";
+		qcom,client-id = "7816";
 	};

drivers/gpu/drm/msm-hyp/msm_drv_hyp.c

@@ -161,6 +161,7 @@ struct drm_msm_hyp_gem {
 #define DRM_MSM_HYP_GEM_GET            0x1
 #define DRM_MSM_HYP_GEM_PUT            0x2
 #define DRM_MSM_HYP_GEM_QRY            0x3
+#define DRM_MSM_HYP_QRY_CLT_ID         0x4
 
 #define DRM_IOCTL_MSM_HYP_GEM_GET\
 	DRM_IOWR(DRM_COMMAND_BASE + DRM_MSM_HYP_GEM_GET, struct drm_msm_hyp_gem)
@@ -168,6 +169,10 @@ struct drm_msm_hyp_gem {
 	DRM_IOW(DRM_COMMAND_BASE + DRM_MSM_HYP_GEM_PUT, struct drm_msm_hyp_gem)
 #define DRM_IOCTL_MSM_HYP_GEM_QRY\
 	DRM_IOWR(DRM_COMMAND_BASE + DRM_MSM_HYP_GEM_QRY, struct drm_msm_hyp_gem)
+#define DRM_IOCTL_MSM_HYP_QRY_CLT_ID\
+	DRM_IOR(DRM_COMMAND_BASE + DRM_MSM_HYP_QRY_CLT_ID, u32)
+
+#define CLIENT_ID_LEN_IN_CHARS         5
 
 static ssize_t msm_drm_write(struct file *filp, const char __user *buffer,
 				size_t count, loff_t *offset)
@@ -306,6 +311,50 @@ static int msm_ioctl_gem_put(struct drm_device *dev, void *data,
 	return ret;
 }
 
+static int _msm_parse_dt(struct device_node *node, u32 *client_id)
+{
+	int len = 0;
+	int ret = 0;
+	const char *client_id_str;
+
+	client_id_str = of_get_property(node, "qcom,client-id", &len);
+	if (len != CLIENT_ID_LEN_IN_CHARS) {
+		DBG("client_id_str len(%d) is invalid\n", len);
+		ret = -EINVAL;
+	} else {
+		/* Try node as a hex value */
+		ret = kstrtouint(client_id_str, 16, client_id);
+		if (ret) {
+			/* Otherwise, treat at 4cc code */
+			*client_id = fourcc_code(client_id_str[0],
+						client_id_str[1],
+						client_id_str[2],
+						client_id_str[3]);
+
+			ret = 0;
+		}
+	}
+
+	return ret;
+}
+
+static int msm_ioctl_query_client_id(struct drm_device *dev, void *data,
+				 struct drm_file *file_priv)
+{
+	struct platform_device *pdev = dev->platformdev;
+	u32 *arg = (u32 *)data;
+	int ret = 0;
+
+	if (!pdev || !pdev->dev.of_node) {
+		DBG("pdev not found\n");
+		return -ENODEV;
+	}
+
+	ret = _msm_parse_dt(pdev->dev.of_node, arg);
+
+	return ret;
+}
+
 static const struct file_operations fops = {
 	.owner              = THIS_MODULE,
 	.open               = drm_open,
@@ -324,6 +373,8 @@ static const struct drm_ioctl_desc msm_ioctls[] = {
 		DRM_AUTH|DRM_RENDER_ALLOW),
 	DRM_IOCTL_DEF_DRV(MSM_HYP_GEM_QRY,  msm_ioctl_gem_query,
 		DRM_AUTH|DRM_RENDER_ALLOW),
+	DRM_IOCTL_DEF_DRV(MSM_HYP_QRY_CLT_ID,  msm_ioctl_query_client_id,
+		DRM_AUTH|DRM_RENDER_ALLOW),
 };
 
 static struct drm_driver msm_driver = {