[PATCH v3 1/6] dma: Introduce dma_get_cfg() interface

[Vignesh Raghavendra]

Sometimes, there would be a need to exchange data between DMA provider
and DMA client which are very specific to DMA driver of the SoC/platform
and are not generic enough to be put into struct dma. Therefore, introduce
dma_get_cfg() interface to get DMA provider specific data from client
device. Clients can use unique configuration ID flags to get different
configuration data from DMA driver.

Signed-off-by: Vignesh Raghavendra <vigneshr at ti.com>
Acked-by: Joe Hershberger <joe.hershberger at ni.com>
Reviewed-by: Grygorii Strashko <grygorii.strashko at ti.com>
---
 drivers/dma/dma-uclass.c | 12 ++++++++++++
 include/dma-uclass.h     | 11 +++++++++++
 include/dma.h            | 11 +++++++++++
 3 files changed, 34 insertions(+)

diff --git a/drivers/dma/dma-uclass.c b/drivers/dma/dma-uclass.c
index 0ff56f7e88c9..5598bca21c5e 100644
--- a/drivers/dma/dma-uclass.c
+++ b/drivers/dma/dma-uclass.c
@@ -187,6 +187,18 @@ int dma_send(struct dma *dma, void *src, size_t len, void *metadata)
 
 	return ops->send(dma, src, len, metadata);
 }
+
+int dma_get_cfg(struct dma *dma, u32 cfg_id, void **cfg_data)
+{
+	struct dma_ops *ops = dma_dev_ops(dma->dev);
+
+	debug("%s(dma=%p)\n", __func__, dma);
+
+	if (!ops->get_cfg)
+		return -ENOSYS;
+
+	return ops->get_cfg(dma, cfg_id, cfg_data);
+}
 #endif /* CONFIG_DMA_CHANNELS */
 
 int dma_get_device(u32 transfer_type, struct udevice **devp)
diff --git a/include/dma-uclass.h b/include/dma-uclass.h
index 31b43fb4b98e..a1d9d26ac56f 100644
--- a/include/dma-uclass.h
+++ b/include/dma-uclass.h
@@ -108,6 +108,17 @@ struct dma_ops {
 	 * @return zero on success, or -ve error code.
 	 */
 	int (*send)(struct dma *dma, void *src, size_t len, void *metadata);
+	/**
+	 * get_cfg() - Get DMA channel configuration for client's use
+	 *
+	 * @dma:    The DMA Channel to manipulate
+	 * @cfg_id: DMA provider specific ID to identify what
+	 *          configuration data client needs
+	 * @data:   Pointer to store pointer to DMA driver specific
+	 *          configuration data for the given cfg_id (output param)
+	 * @return zero on success, or -ve error code.
+	 */
+	int (*get_cfg)(struct dma *dma, u32 cfg_id, void **data);
 #endif /* CONFIG_DMA_CHANNELS */
 	/**
 	 * transfer() - Issue a DMA transfer. The implementation must
diff --git a/include/dma.h b/include/dma.h
index 32885571f7d4..426617b34edf 100644
--- a/include/dma.h
+++ b/include/dma.h
@@ -290,6 +290,17 @@ int dma_receive(struct dma *dma, void **dst, void *metadata);
  * @return zero on success, or -ve error code.
  */
 int dma_send(struct dma *dma, void *src, size_t len, void *metadata);
+/**
+ * dma_get_cfg() - Get DMA channel configuration for client's use
+ *
+ * @dma:      The DMA Channel to manipulate
+ * @cfg_id:   DMA provider specific ID to identify what
+ *            configuration data client needs
+ * @cfg_data: Pointer to store pointer to DMA driver specific
+ *            configuration data for the given cfg_id (output param)
+ * @return zero on success, or -ve error code.
+ */
+int dma_get_cfg(struct dma *dma, u32 cfg_id, void **cfg_data);
 #endif /* CONFIG_DMA_CHANNELS */
 
 #if CONFIG_IS_ENABLED(DMA)
-- 
2.24.0