tegra: video: dc: Add sys interface to read display CRC.

- Add attribute in sys to read TEGRA_DC_CRC_CHECKSUM_LATCHED
- Fix some minor formatting issue of dc_sysfs.c

Bug 834332

Change-Id: I48f75fcb1d5403ab40d0da438200a5552ba4e6ff
Reviewed-on: http://git-master/r/37912
Reviewed-by: Varun Colbert <vcolbert@nvidia.com>
Tested-by: Varun Colbert <vcolbert@nvidia.com>

4 files changed, 109 insertions, 9 deletions

diff --git a/drivers/video/tegra/dc/dc.c b/drivers/video/tegra/dc/dc.c
index 5560505fca4f..aa99dce17e0b 100644
--- a/drivers/video/tegra/dc/dc.c
+++ b/drivers/video/tegra/dc/dc.c
@@ -46,6 +46,8 @@
 #include "overlay.h"
 #include "nvsd.h"
 
+#define TEGRA_CRC_LATCHED_DELAY		34
+
 static int no_vsync;
 
 module_param_named(no_vsync, no_vsync, int, S_IRUGO | S_IWUSR);
@@ -1554,6 +1556,46 @@ unsigned tegra_dc_get_out_max_pixclock(const struct tegra_dc *dc)
 }
 EXPORT_SYMBOL(tegra_dc_get_out_max_pixclock);
 
+void tegra_dc_enable_crc(struct tegra_dc *dc)
+{
+	u32 val;
+	tegra_dc_io_start(dc);
+
+	val = CRC_ALWAYS_ENABLE | CRC_INPUT_DATA_ACTIVE_DATA |
+		CRC_ENABLE_ENABLE;
+	tegra_dc_writel(dc, val, DC_COM_CRC_CONTROL);
+	tegra_dc_writel(dc, GENERAL_UPDATE, DC_CMD_STATE_CONTROL);
+	tegra_dc_writel(dc, GENERAL_ACT_REQ, DC_CMD_STATE_CONTROL);
+}
+
+void tegra_dc_disable_crc(struct tegra_dc *dc)
+{
+	tegra_dc_writel(dc, 0x0, DC_COM_CRC_CONTROL);
+	tegra_dc_writel(dc, GENERAL_UPDATE, DC_CMD_STATE_CONTROL);
+	tegra_dc_writel(dc, GENERAL_ACT_REQ, DC_CMD_STATE_CONTROL);
+
+	tegra_dc_io_end(dc);
+}
+
+u32 tegra_dc_read_checksum_latched(struct tegra_dc *dc)
+{
+	int crc = 0;
+	u32 val = 0;
+
+	if(!dc) {
+		dev_err(&dc->ndev->dev, "Failed to get dc.\n");
+		goto crc_error;
+	}
+
+	/* TODO: Replace mdelay with code to sync VBlANK, since
+	 * DC_COM_CRC_CHECKSUM_LATCHED is available after VBLANK */
+	mdelay(TEGRA_CRC_LATCHED_DELAY);
+
+	crc = tegra_dc_readl(dc, DC_COM_CRC_CHECKSUM_LATCHED);
+crc_error:
+	return crc;
+}
+
 static void tegra_dc_vblank(struct work_struct *work)
 {
 	struct tegra_dc *dc = container_of(work, struct tegra_dc, vblank_work);
diff --git a/drivers/video/tegra/dc/dc_priv.h b/drivers/video/tegra/dc/dc_priv.h
index 6a89b09dd4e8..1df5299dafbc 100644
--- a/drivers/video/tegra/dc/dc_priv.h
+++ b/drivers/video/tegra/dc/dc_priv.h
@@ -207,5 +207,10 @@ void tegra_dc_create_sysfs(struct device *dev);
 /* defined in dc.c, used by dc_sysfs.c */
 void tegra_dc_stats_enable(struct tegra_dc *dc, bool enable);
 bool tegra_dc_stats_get(struct tegra_dc *dc);
+
+/* defined in dc.c, used by dc_sysfs.c */
+u32 tegra_dc_read_checksum_latched(struct tegra_dc *dc);
+void tegra_dc_enable_crc(struct tegra_dc *dc);
+void tegra_dc_disable_crc(struct tegra_dc *dc);
 #endif
 
diff --git a/drivers/video/tegra/dc/dc_reg.h b/drivers/video/tegra/dc/dc_reg.h
index a736bc5a1ac5..4419fb514781 100644
--- a/drivers/video/tegra/dc/dc_reg.h
+++ b/drivers/video/tegra/dc/dc_reg.h
@@ -113,6 +113,14 @@
 #define DC_CMD_REG_ACT_CONTROL			0x043
 
 #define DC_COM_CRC_CONTROL			0x300
+#define  CRC_ALWAYS_ENABLE		(1 << 3)
+#define  CRC_ALWAYS_DISABLE		(0 << 3)
+#define  CRC_INPUT_DATA_ACTIVE_DATA	(1 << 2)
+#define  CRC_INPUT_DATA_FULL_FRAME	(0 << 2)
+#define  CRC_WAIT_TWO_VSYNC		(1 << 1)
+#define  CRC_WAIT_ONE_VSYNC		(0 << 1)
+#define  CRC_ENABLE_ENABLE		(1 << 0)
+#define  CRC_ENABLE_DISABLE		(0 << 0)
 #define DC_COM_CRC_CHECKSUM			0x301
 #define DC_COM_PIN_OUTPUT_ENABLE0		0x302
 #define DC_COM_PIN_OUTPUT_ENABLE1		0x303
diff --git a/drivers/video/tegra/dc/dc_sysfs.c b/drivers/video/tegra/dc/dc_sysfs.c
index 184353d43324..36294c60907f 100644
--- a/drivers/video/tegra/dc/dc_sysfs.c
+++ b/drivers/video/tegra/dc/dc_sysfs.c
@@ -124,6 +124,53 @@ static ssize_t enable_store(struct device *dev,
 
 static DEVICE_ATTR(enable, S_IRUGO|S_IWUSR, enable_show, enable_store);
 
+static ssize_t crc_checksum_latched_show(struct device *device,
+	struct device_attribute *attr, char *buf)
+{
+	struct nvhost_device *ndev = to_nvhost_device(device);
+	struct tegra_dc *dc = nvhost_get_drvdata(ndev);
+
+	u32 crc;
+
+	if (!dc->enabled) {
+		dev_err(&dc->ndev->dev, "Failed to get dc.\n");
+		return -EFAULT;
+	}
+
+	crc = tegra_dc_read_checksum_latched(dc);
+
+	return snprintf(buf, PAGE_SIZE, "%u", crc);
+}
+
+static ssize_t crc_checksum_latched_store(struct device *dev,
+	struct device_attribute *attr, const char *buf, size_t count)
+{
+	struct nvhost_device *ndev = to_nvhost_device(dev);
+	struct tegra_dc *dc = nvhost_get_drvdata(ndev);
+	unsigned long val = 0;
+
+	if (!dc->enabled) {
+		dev_err(&dc->ndev->dev, "Failed to get dc.\n");
+		return -EFAULT;
+	}
+
+	if (strict_strtoul(buf, 10, &val) < 0)
+		return -EINVAL;
+
+	if (val == 1) {
+		tegra_dc_enable_crc(dc);
+		dev_err(&dc->ndev->dev, "crc is enabled.\n");
+	} else if (val == 0) {
+		tegra_dc_disable_crc(dc);
+		dev_err(&dc->ndev->dev, "crc is disabled.\n");
+	} else
+		dev_err(&dc->ndev->dev, "Invalid input.\n");
+
+	return count;
+}
+static DEVICE_ATTR(crc_checksum_latched, S_IRUGO|S_IWUSR|S_IWGRP,
+		crc_checksum_latched_show, crc_checksum_latched_store);
+
 #define ORIENTATION_PORTRAIT	"portrait"
 #define ORIENTATION_LANDSCAPE	"landscape"
 
@@ -235,18 +282,18 @@ void __devexit tegra_dc_remove_sysfs(struct device *dev)
 	struct tegra_dc *dc = nvhost_get_drvdata(ndev);
 	struct tegra_dc_sd_settings *sd_settings = dc->out->sd_settings;
 
-	device_remove_file(dev, &dev_attr_stats_enable);
 	device_remove_file(dev, &dev_attr_mode);
 	device_remove_file(dev, &dev_attr_enable);
+	device_remove_file(dev, &dev_attr_stats_enable);
+	device_remove_file(dev, &dev_attr_crc_checksum_latched);
 
 	if (dc->out->stereo) {
 		device_remove_file(dev, &dev_attr_stereo_orientation);
 		device_remove_file(dev, &dev_attr_stereo_mode);
 	}
 
-	if(sd_settings) {
+	if (sd_settings)
 		nvsd_remove_sysfs(dev);
-	}
 }
 
 void tegra_dc_create_sysfs(struct device *dev)
@@ -259,18 +306,16 @@ void tegra_dc_create_sysfs(struct device *dev)
 	error |= device_create_file(dev, &dev_attr_mode);
 	error |= device_create_file(dev, &dev_attr_enable);
 	error |= device_create_file(dev, &dev_attr_stats_enable);
+	error |= device_create_file(dev, &dev_attr_crc_checksum_latched);
 
 	if (dc->out->stereo) {
 		error |= device_create_file(dev, &dev_attr_stereo_orientation);
 		error |= device_create_file(dev, &dev_attr_stereo_mode);
 	}
 
-	if(sd_settings) {
+	if (sd_settings)
 		error |= nvsd_create_sysfs(dev);
-	}
 
-	if(error) {
-		printk("Failed to create sysfs attributes!\n");
-	}
+	if (error)
+		dev_err(&ndev->dev, "Failed to create sysfs attributes!\n");
 }
-