media: platform: raspberrypi: rp1_cfe: Add more debug registers

Dump ISP-FE registers FE_DEBUG_FIFO_FULLNESS and FE_DEBUG_STATUS2.
The latter gives an atomic snapshot of state and frames completed.

Dump a CSI-2 Host register which shows which lanes are in LP11.

Dump some sticky error registers from the D-PHY and CSI-2 Host;
note that they will be cleared on every read. This is harmless,
since they are not used for any purpose other than debug.

Signed-off-by: Nick Hollinghurst <nick.hollinghurst@raspberrypi.com>

Author: njhollinghurst

drivers/media/platform/raspberrypi/rp1_cfe/csi2.c

@@ -574,7 +574,7 @@ int csi2_init(struct csi2_device *csi2, struct dentry *debugfs)
 	spin_lock_init(&csi2->errors_lock);
 
 	csi2->dphy.dev = csi2->v4l2_dev->dev;
-	dphy_probe(&csi2->dphy);
+	dphy_probe(&csi2->dphy, debugfs);
 
 	debugfs_create_file("csi2_regs", 0444, debugfs, csi2, &csi2_regs_fops);
 

drivers/media/platform/raspberrypi/rp1_cfe/dphy.c

@@ -16,7 +16,7 @@
 #define dphy_info(fmt, arg...) dev_info(dphy->dev, fmt, ##arg)
 #define dphy_err(fmt, arg...) dev_err(dphy->dev, fmt, ##arg)
 
-/* DW dphy Host registers */
+/* DW CSI-2 Host registers */
 #define VERSION		0x000
 #define N_LANES		0x004
 #define RESETN		0x008
@@ -29,7 +29,14 @@
 #define PHY2_TST_CTRL0	0x058
 #define PHY2_TST_CTRL1	0x05c
 
-/* DW dphy Host Transactions */
+/* DW CSI-2 Host and PHY debug registers */
+#define INT_ST_PHY_FATAL   0x0e0
+#define INT_ST_PKT_FATAL   0x0f0
+#define INT_ST_FRAME_FATAL 0x100
+#define INT_ST_PHY         0x110
+#define INT_ST_PKT         0x120
+
+/* DW D-PHY transaction codes */
 #define DPHY_HS_RX_CTRL_LANE0_OFFSET	0x44
 #define DPHY_PLL_INPUT_DIV_OFFSET	0x17
 #define DPHY_PLL_LOOP_DIV_OFFSET	0x18
@@ -183,7 +190,37 @@ void dphy_stop(struct dphy_data *dphy)
 	 */
 }
 
-void dphy_probe(struct dphy_data *dphy)
+static int dphy_debug_show(struct seq_file *s, void *data)
+{
+	/*
+	 * Here we expose various error flags in the CSI-2 Host and PHY.
+	 * All these registers apart from PHY_STOPSTATE are read-to-clear.
+	 * The only reliable way to count errors would be to service a
+	 * dedicated interrupt. For now, we'll just read (and clear) them.
+	 */
+	struct dphy_data *dphy = s->private;
+	int ret;
+
+	ret = pm_runtime_resume_and_get(dphy->dev);
+	if (ret)
+		return ret;
+
+#define DUMP(reg) seq_printf(s, #reg " \t0x%08x\n", dw_csi2_host_read(dphy, reg))
+	DUMP(PHY_STOPSTATE);      /* Data lane (bits 0-3) or clock (bit 16) is in stopstate */
+	DUMP(INT_ST_PHY_FATAL);   /* HS start sync error for each data lane (bits 0-3) */
+	DUMP(INT_ST_PKT_FATAL);   /* CRC error on VC (bits 0-3); ECC unrecoverable error (bit 16) */
+	DUMP(INT_ST_FRAME_FATAL); /* FS/FE mismatch (bits 0-3), seq (8-11), CRC error (16-19) */
+	DUMP(INT_ST_PHY);         /* Non-fatal error for each data lane HS (bits 0-3), LP (16-19) */
+	DUMP(INT_ST_PKT);         /* Unknown DT on VC (bits 0-3); ECC corrected error (b16-19) */
+#undef DUMP
+
+	pm_runtime_put(dphy->dev);
+	return 0;
+}
+
+DEFINE_SHOW_ATTRIBUTE(dphy_debug);
+
+void dphy_probe(struct dphy_data *dphy, struct dentry *debugfs)
 {
 	u32 host_ver;
 	u8 host_ver_major, host_ver_minor;
@@ -195,4 +232,7 @@ void dphy_probe(struct dphy_data *dphy)
 	host_ver_minor += (u8)((host_ver >> 8) - '0');
 
 	dphy_info("DW dphy Host HW v%u.%u\n", host_ver_major, host_ver_minor);
+
+	if (debugfs)
+		debugfs_create_file("dphy_debug", 0444, debugfs, dphy, &dphy_debug_fops);
 }

drivers/media/platform/raspberrypi/rp1_cfe/dphy.h

@@ -7,6 +7,7 @@
 #ifndef _RP1_DPHY_
 #define _RP1_DPHY_
 
+#include <linux/debugfs.h>
 #include <linux/io.h>
 #include <linux/types.h>
 #include <media/v4l2-mediabus.h>
@@ -22,7 +23,7 @@ struct dphy_data {
 	bool lane_polarities[1 + V4L2_MBUS_CSI2_MAX_DATA_LANES];
 };
 
-void dphy_probe(struct dphy_data *dphy);
+void dphy_probe(struct dphy_data *dphy, struct dentry *debugfs);
 void dphy_start(struct dphy_data *dphy);
 void dphy_stop(struct dphy_data *dphy);
 

drivers/media/platform/raspberrypi/rp1_cfe/pisp_fe.c

@@ -24,6 +24,8 @@
 #define FE_OUTPUT_STATUS	0x014
 #define FE_INT_EN		0x018
 #define FE_INT_STATUS		0x01c
+#define FE_DEBUG_FIFO_FULLNESS	0x024
+#define FE_DEBUG_STATUS2	0x02c
 
 /* CONTROL */
 #define FE_CONTROL_QUEUE	BIT(0)
@@ -162,6 +164,8 @@ static int pisp_regs_show(struct seq_file *s, void *data)
 	DUMP(FE_OUTPUT_STATUS);
 	DUMP(FE_INT_EN);
 	DUMP(FE_INT_STATUS);
+	DUMP(FE_DEBUG_FIFO_FULLNESS);
+	DUMP(FE_DEBUG_STATUS2);
 #undef DUMP
 
 	pm_runtime_put(fe->v4l2_dev->dev);