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Subject[PATCH v5 3/3] dmaengine: Create debug directories for DMA devices
Date
Create a placeholder directory for each registered DMA device.

DMA drivers can use the dmaengine_get_debugfs_root() call to get their
debugfs root and can populate with custom files to aim debugging.

Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
---
drivers/dma/dmaengine.c | 28 +++++++++++++++++++++++++++-
drivers/dma/dmaengine.h | 16 ++++++++++++++++
include/linux/dmaengine.h | 1 +
3 files changed, 44 insertions(+), 1 deletion(-)

diff --git a/drivers/dma/dmaengine.c b/drivers/dma/dmaengine.c
index 509abc8e8378..5a442752e07d 100644
--- a/drivers/dma/dmaengine.c
+++ b/drivers/dma/dmaengine.c
@@ -62,6 +62,22 @@ static long dmaengine_ref_count;
#ifdef CONFIG_DEBUG_FS
#include <linux/debugfs.h>

+static struct dentry *rootdir;
+
+static void dmaengine_debug_register(struct dma_device *dma_dev)
+{
+ dma_dev->dbg_dev_root = debugfs_create_dir(dev_name(dma_dev->dev),
+ rootdir);
+ if (IS_ERR(dma_dev->dbg_dev_root))
+ dma_dev->dbg_dev_root = NULL;
+}
+
+static void dmaengine_debug_unregister(struct dma_device *dma_dev)
+{
+ debugfs_remove_recursive(dma_dev->dbg_dev_root);
+ dma_dev->dbg_dev_root = NULL;
+}
+
static void dmaengine_dbg_summary_show(struct seq_file *s,
struct dma_device *dma_dev)
{
@@ -107,7 +123,7 @@ DEFINE_SHOW_ATTRIBUTE(dmaengine_summary);

static void __init dmaengine_debugfs_init(void)
{
- struct dentry *rootdir = debugfs_create_dir("dmaengine", NULL);
+ rootdir = debugfs_create_dir("dmaengine", NULL);

/* /sys/kernel/debug/dmaengine/summary */
debugfs_create_file("summary", 0444, rootdir, NULL,
@@ -115,6 +131,12 @@ static void __init dmaengine_debugfs_init(void)
}
#else
static inline void dmaengine_debugfs_init(void) { }
+static inline int dmaengine_debug_register(struct dma_device *dma_dev)
+{
+ return 0;
+}
+
+static inline void dmaengine_debug_unregister(struct dma_device *dma_dev) { }
#endif /* DEBUG_FS */

/* --- sysfs implementation --- */
@@ -1265,6 +1287,8 @@ int dma_async_device_register(struct dma_device *device)
dma_channel_rebalance();
mutex_unlock(&dma_list_mutex);

+ dmaengine_debug_register(device);
+
return 0;

err_out:
@@ -1298,6 +1322,8 @@ void dma_async_device_unregister(struct dma_device *device)
{
struct dma_chan *chan, *n;

+ dmaengine_debug_unregister(device);
+
list_for_each_entry_safe(chan, n, &device->channels, device_node)
__dma_async_device_channel_unregister(device, chan);

diff --git a/drivers/dma/dmaengine.h b/drivers/dma/dmaengine.h
index e8a320c9e57c..1bfbd64b1371 100644
--- a/drivers/dma/dmaengine.h
+++ b/drivers/dma/dmaengine.h
@@ -182,4 +182,20 @@ dmaengine_desc_callback_valid(struct dmaengine_desc_callback *cb)
struct dma_chan *dma_get_slave_channel(struct dma_chan *chan);
struct dma_chan *dma_get_any_slave_channel(struct dma_device *device);

+#ifdef CONFIG_DEBUG_FS
+#include <linux/debugfs.h>
+
+static inline struct dentry *
+dmaengine_get_debugfs_root(struct dma_device *dma_dev) {
+ return dma_dev->dbg_dev_root;
+}
+#else
+struct dentry;
+static inline struct dentry *
+dmaengine_get_debugfs_root(struct dma_device *dma_dev)
+{
+ return NULL;
+}
+#endif /* CONFIG_DEBUG_FS */
+
#endif
diff --git a/include/linux/dmaengine.h b/include/linux/dmaengine.h
index 72920b5cf2d7..21065c04c4ac 100644
--- a/include/linux/dmaengine.h
+++ b/include/linux/dmaengine.h
@@ -902,6 +902,7 @@ struct dma_device {
/* debugfs support */
#ifdef CONFIG_DEBUG_FS
void (*dbg_summary_show)(struct seq_file *s, struct dma_device *dev);
+ struct dentry *dbg_dev_root;
#endif
};

--
Peter
Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki.
Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki

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