From: Martin Sperl <kernel@xxxxxxxxxxxxxxxx>
Expose all the dma registers via debugfs.
The mapping between linux channels and HW-dma channels is
also exposed via a softlink in debugfs.
Signed-off-by: Martin Sperl <kernel@xxxxxxxxxxxxxxxx>
---
drivers/dma/bcm2835-dma.c | 147 ++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 147 insertions(+)
diff --git a/drivers/dma/bcm2835-dma.c b/drivers/dma/bcm2835-dma.c
index 2884285..e2aea4a 100644
--- a/drivers/dma/bcm2835-dma.c
+++ b/drivers/dma/bcm2835-dma.c
@@ -29,6 +29,7 @@
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*/
+#include <linux/debugfs.h>
#include <linux/dmaengine.h>
#include <linux/dma-mapping.h>
#include <linux/dmapool.h>
@@ -51,6 +52,7 @@ struct bcm2835_dmadev {
spinlock_t lock;
void __iomem *base;
struct device_dma_parameters dma_parms;
+ struct dentry *debugfs_node;
};
struct bcm2835_dma_cb {
@@ -904,6 +906,147 @@ static struct dma_chan *bcm2835_dma_xlate(struct of_phandle_args *spec,
return chan;
}
+#ifdef CONFIG_DEBUG_FS
+static struct debugfs_reg32 bcm2835_dma_debugfs_common_reg32[] = {
+ {
+ .name = "int_status",
+ .offset = BCM2835_DMA_INT_STATUS,
+ },
+ {
+ .name = "enable",
+ .offset = BCM2835_DMA_ENABLE,
+ },
+};
+
+static void bcm2835_dma_debugfs_register_common(struct bcm2835_dmadev *od)
+{
+ struct debugfs_regset32 *regset;
+
+ regset = devm_kzalloc(od->ddev.dev, sizeof(*regset), GFP_KERNEL);
+ if (!regset)
+ return;
+
+ regset->regs = bcm2835_dma_debugfs_common_reg32;
+ regset->nregs = ARRAY_SIZE(bcm2835_dma_debugfs_common_reg32);
+ regset->base = od->base;
+
+ debugfs_create_regset32("common", S_IRUGO, od->debugfs_node, regset);
+}
+
+static struct debugfs_reg32 bcm2835_dma_debugfs_channel_reg32[] = {
+ {
+ .name = "cs ",
+ .offset = BCM2835_DMA_CS,
+ },
+ {
+ .name = "addr ",
+ .offset = BCM2835_DMA_ADDR,
+ },
+ {
+ .name = "ti ",
+ .offset = BCM2835_DMA_TI,
+ },
+ {
+ .name = "source ",
+ .offset = BCM2835_DMA_SOURCE_AD,
+ },
+ {
+ .name = "destination",
+ .offset = BCM2835_DMA_DEST_AD,
+ },
+ {
+ .name = "length ",
+ .offset = BCM2835_DMA_LEN,
+ },
+ {
+ .name = "stride ",
+ .offset = BCM2835_DMA_STRIDE,
+ },
+ {
+ .name = "next ",
+ .offset = BCM2835_DMA_NEXTCB,
+ },
+ {
+ .name = "debug ",
+ .offset = BCM2835_DMA_DEBUG,
+ },
+};
+
+static void bcm2835_dma_debugfs_register_channel(struct bcm2835_dmadev *od,
+ int channel)
+{
+ struct debugfs_regset32 *regset;
+ char *name;
+
+ regset = devm_kzalloc(od->ddev.dev, sizeof(*regset), GFP_KERNEL);
+ if (!regset)
+ return;
+
+ name = devm_kasprintf(od->ddev.dev, GFP_KERNEL, "%02d", channel);
+ if (!name)
+ return;
+
+ regset->regs = bcm2835_dma_debugfs_channel_reg32;
+ regset->nregs = ARRAY_SIZE(bcm2835_dma_debugfs_channel_reg32);
+ regset->base = BCM2835_DMA_CHANIO(od->base, channel);
+
+ /*
+ * expose, but only for the owner (=root)
+ * contains pointers that should not leak
+ */
+ debugfs_create_regset32(name, S_IRUSR, od->debugfs_node, regset);
+}
+
+static void bcm2835_dma_debugfs_register_link(struct bcm2835_dmadev *od,
+ struct dma_chan *chan)
+{
+ struct bcm2835_chan *c = to_bcm2835_dma_chan(chan);
+ char *name;
+
+ name = devm_kasprintf(od->ddev.dev, GFP_KERNEL, "%02d", c->ch);
+ if (!name)
+ return;
+
+ debugfs_create_symlink(dev_name(&chan->dev->device),
+ od->debugfs_node, name);
+}
+
+static void bcm2835_dma_debugfs_register(struct bcm2835_dmadev *od)
+{
+ struct dma_chan *chan;
+ int i;
+
+ od->debugfs_node = debugfs_create_dir(dev_name(od->ddev.dev), NULL);
+ if (!od->debugfs_node)
+ return;
+
+ /* expose the common registers */
+ bcm2835_dma_debugfs_register_common(od);
+
+ /* register all the real channels - not only the mapped ones */
+ for (i = 0; i <= BCM2835_DMA_MAX_CHANNEL_NUMBER; i++)
+ bcm2835_dma_debugfs_register_channel(od, i);
+
+ /* create the softlinks */
+ list_for_each_entry(chan, &od->ddev.channels, device_node) {
+ bcm2835_dma_debugfs_register_link(od, chan);
+ }
+}
+
+static void bcm2835_dma_debugfs_remove(struct bcm2835_dmadev *od)
+{
+ debugfs_remove_recursive(od->debugfs_node);
+
+ od->debugfs_node = NULL;
+}
+
+#else
+static void bcm2835_dma_debugfs_register(struct bcm2835_dmadev *od)
+{ }
+static void bcm2835_dma_debugfs_remove(struct bcm2835_dmadev *od)
+{ }
+#endif
+
static int bcm2835_dma_probe(struct platform_device *pdev)
{
struct bcm2835_dmadev *od;
@@ -1022,6 +1165,8 @@ static int bcm2835_dma_probe(struct platform_device *pdev)
goto err_no_dma;
}
+ bcm2835_dma_debugfs_register(od);
+
dev_dbg(&pdev->dev, "Load BCM2835 DMA engine driver\n");
return 0;
@@ -1035,6 +1180,8 @@ static int bcm2835_dma_remove(struct platform_device *pdev)
{
struct bcm2835_dmadev *od = platform_get_drvdata(pdev);
+ bcm2835_dma_debugfs_remove(od);
+
dma_async_device_unregister(&od->ddev);
bcm2835_dma_free(od);
--
2.1.4
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