drm: omapdrm: dss: Support passing private data to debugfs show handlers

To simplify implementation of debugfs seq_file show handlers, the driver
passes the pointer to the show function through the debugfs_create_file
data pointer. This prevents using the pointer to pass driver private
data to the show handler, and requires all handlers to use global
variables to access private data.

To prepare for the removal of global private data in the driver, rework
the debugfs infrastructure to allow passing a private data pointer to
show handlers.

The price to pay is explicit removal of debugfs files to free the
internally allocated memory. This is desirable anyway as debugfs entries
should be removed when a component driver is unbound, otherwise crashes
will occur due to access to freed memory when the components will be
dynamically allocated instead of stored in global variables.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Sebastian Reichel <sebastian.reichel@collabora.co.uk>

1 files changed, 29 insertions, 11 deletions

diff --git a/drivers/gpu/drm/omapdrm/dss/dsi.c b/drivers/gpu/drm/omapdrm/dss/dsi.c
index 26f4122f6784..a676d27dd479 100644
--- a/drivers/gpu/drm/omapdrm/dss/dsi.c
+++ b/drivers/gpu/drm/omapdrm/dss/dsi.c
@@ -401,6 +401,10 @@ struct dsi_data {
 #endif
 	int debug_read;
 	int debug_write;
+	struct {
+		struct dss_debugfs_entry *irqs;
+		struct dss_debugfs_entry *regs;
+	} debugfs;
 
 #ifdef CONFIG_OMAP2_DSS_COLLECT_IRQ_STATS
 	spinlock_t irq_stats_lock;
@@ -1660,18 +1664,20 @@ static void dsi_dump_dsidev_irqs(struct platform_device *dsidev,
 #undef PIS
 }
 
-static void dsi1_dump_irqs(struct seq_file *s)
+static int dsi1_dump_irqs(struct seq_file *s, void *p)
 {
 	struct platform_device *dsidev = dsi_get_dsidev_from_id(0);
 
 	dsi_dump_dsidev_irqs(dsidev, s);
+	return 0;
 }
 
-static void dsi2_dump_irqs(struct seq_file *s)
+static int dsi2_dump_irqs(struct seq_file *s, void *p)
 {
 	struct platform_device *dsidev = dsi_get_dsidev_from_id(1);
 
 	dsi_dump_dsidev_irqs(dsidev, s);
+	return 0;
 }
 #endif
 
@@ -1759,18 +1765,20 @@ static void dsi_dump_dsidev_regs(struct platform_device *dsidev,
 #undef DUMPREG
 }
 
-static void dsi1_dump_regs(struct seq_file *s)
+static int dsi1_dump_regs(struct seq_file *s, void *p)
 {
 	struct platform_device *dsidev = dsi_get_dsidev_from_id(0);
 
 	dsi_dump_dsidev_regs(dsidev, s);
+	return 0;
 }
 
-static void dsi2_dump_regs(struct seq_file *s)
+static int dsi2_dump_regs(struct seq_file *s, void *p)
 {
 	struct platform_device *dsidev = dsi_get_dsidev_from_id(1);
 
 	dsi_dump_dsidev_regs(dsidev, s);
+	return 0;
 }
 
 enum dsi_cio_power_state {
@@ -5569,15 +5577,22 @@ static int dsi_bind(struct device *dev, struct device *master, void *data)
 	dsi_runtime_put(dsidev);
 
 	if (dsi->module_id == 0)
-		dss_debugfs_create_file("dsi1_regs", dsi1_dump_regs);
-	else if (dsi->module_id == 1)
-		dss_debugfs_create_file("dsi2_regs", dsi2_dump_regs);
-
+		dsi->debugfs.regs = dss_debugfs_create_file("dsi1_regs",
+							    dsi1_dump_regs,
+							    &dsi);
+	else
+		dsi->debugfs.regs = dss_debugfs_create_file("dsi2_regs",
+							    dsi2_dump_regs,
+							    &dsi);
 #ifdef CONFIG_OMAP2_DSS_COLLECT_IRQ_STATS
 	if (dsi->module_id == 0)
-		dss_debugfs_create_file("dsi1_irqs", dsi1_dump_irqs);
-	else if (dsi->module_id == 1)
-		dss_debugfs_create_file("dsi2_irqs", dsi2_dump_irqs);
+		dsi->debugfs.irqs = dss_debugfs_create_file("dsi1_irqs",
+							    dsi1_dump_irqs,
+							    &dsi);
+	else
+		dsi->debugfs.irqs = dss_debugfs_create_file("dsi2_irqs",
+							    dsi2_dump_irqs,
+							    &dsi);
 #endif
 
 	return 0;
@@ -5596,6 +5611,9 @@ static void dsi_unbind(struct device *dev, struct device *master, void *data)
 	struct platform_device *dsidev = to_platform_device(dev);
 	struct dsi_data *dsi = dsi_get_dsidrv_data(dsidev);
 
+	dss_debugfs_remove_file(dsi->debugfs.irqs);
+	dss_debugfs_remove_file(dsi->debugfs.regs);
+
 	of_platform_depopulate(&dsidev->dev);
 
 	WARN_ON(dsi->scp_clk_refcount > 0);