[PATCH 3/4] DW DMAC: add hw-llp property to device tree

[Eugeniy Paltsev]

Several versions of DW DMAC have multi block transfers hardware
support. Hardware support of multi block transfers is disabled
by default if we use DT to configure DMAC and software emulation
of multi block transfers used instead.
Add hw-llp property, so it is possible to enable hardware
multi block transfers (if present) via DT.

Signed-off-by: Eugeniy Paltsev <Eugeniy.Paltsev@xxxxxxxxxxxx>
---
 drivers/dma/dw/core.c                | 2 +-
 drivers/dma/dw/platform.c            | 5 +++++
 include/linux/platform_data/dma-dw.h | 4 ++--
 3 files changed, 8 insertions(+), 3 deletions(-)

diff --git a/drivers/dma/dw/core.c b/drivers/dma/dw/core.c
index c2c0a61..e3ff4ea 100644
--- a/drivers/dma/dw/core.c
+++ b/drivers/dma/dw/core.c
@@ -1569,7 +1569,7 @@ int dw_dma_probe(struct dw_dma_chip *chip)
 				(dwc_params >> DWC_PARAMS_MBLK_EN & 0x1) == 0;
 		} else {
 			dwc->block_size = pdata->block_size;
-			dwc->nollp = pdata->is_nollp;
+			dwc->nollp = pdata->hw_llp[i];
 		}
 	}
 
diff --git a/drivers/dma/dw/platform.c b/drivers/dma/dw/platform.c
index daeceac..2722e60 100644
--- a/drivers/dma/dw/platform.c
+++ b/drivers/dma/dw/platform.c
@@ -151,6 +151,11 @@ dw_dma_parse_dt(struct platform_device *pdev)
 			pdata->data_width[tmp] = BIT(arr[tmp] & 0x07);
 	}
 
+	if (!of_property_read_u32_array(np, "hw-llp", arr, nr_masters)) {
+		for (tmp = 0; tmp < nr_masters; tmp++)
+			pdata->hw_llp[tmp] = arr[tmp];
+	}
+
 	return pdata;
 }
 #else
diff --git a/include/linux/platform_data/dma-dw.h b/include/linux/platform_data/dma-dw.h
index 5f0e11e..5bc8124 100644
--- a/include/linux/platform_data/dma-dw.h
+++ b/include/linux/platform_data/dma-dw.h
@@ -40,19 +40,18 @@ struct dw_dma_slave {
  * @is_private: The device channels should be marked as private and not for
  *	by the general purpose DMA channel allocator.
  * @is_memcpy: The device channels do support memory-to-memory transfers.
- * @is_nollp: The device channels does not support multi block transfers.
  * @chan_allocation_order: Allocate channels starting from 0 or 7
  * @chan_priority: Set channel priority increasing from 0 to 7 or 7 to 0.
  * @block_size: Maximum block size supported by the controller
  * @nr_masters: Number of AHB masters supported by the controller
  * @data_width: Maximum data width supported by hardware per AHB master
  *		(in bytes, power of 2)
+ * @hw_llp: Multi block transfers supported by hardware per AHB master.
  */
 struct dw_dma_platform_data {
 	unsigned int	nr_channels;
 	bool		is_private;
 	bool		is_memcpy;
-	bool		is_nollp;
 #define CHAN_ALLOCATION_ASCENDING	0	/* zero to seven */
 #define CHAN_ALLOCATION_DESCENDING	1	/* seven to zero */
 	unsigned char	chan_allocation_order;
@@ -62,6 +61,7 @@ struct dw_dma_platform_data {
 	unsigned int	block_size;
 	unsigned char	nr_masters;
 	unsigned char	data_width[DW_DMA_MAX_NR_MASTERS];
+	unsigned char	hw_llp[DW_DMA_MAX_NR_MASTERS];
 };
 
 #endif /* _PLATFORM_DATA_DMA_DW_H */
-- 
2.5.5