dmaengine: Revert "drivers/dma: remove unused support for MEMSET operations"

This reverts commit 48a9db462d99494583dad829969616ac90a8df4e.

Some platforms actually need support for the memset operations. Bring it back.

Signed-off-by: Maxime Ripard <[e-mail]>
Signed-off-by: Vinod Koul <[e-mail]>

drivers/dma/dmaengine.c

···
 		!device->device_prep_dma_pq);
 	BUG_ON(dma_has_cap(DMA_PQ_VAL, device->cap_mask) &&
 		!device->device_prep_dma_pq_val);
+	BUG_ON(dma_has_cap(DMA_MEMSET, device->cap_mask) &&
+		!device->device_prep_dma_memset);
 	BUG_ON(dma_has_cap(DMA_INTERRUPT, device->cap_mask) &&
 		!device->device_prep_dma_interrupt);
 	BUG_ON(dma_has_cap(DMA_SG, device->cap_mask) &&

include/linux/dmaengine.h

···
 	DMA_PQ,
 	DMA_XOR_VAL,
 	DMA_PQ_VAL,
+	DMA_MEMSET,
 	DMA_INTERRUPT,
 	DMA_SG,
 	DMA_PRIVATE,
···
  * @copy_align: alignment shift for memcpy operations
  * @xor_align: alignment shift for xor operations
  * @pq_align: alignment shift for pq operations
+ * @fill_align: alignment shift for memset operations
  * @dev_id: unique device ID
  * @dev: struct device reference for dma mapping api
  * @src_addr_widths: bit mask of src addr widths the device supports
···
  * @device_prep_dma_xor_val: prepares a xor validation operation
  * @device_prep_dma_pq: prepares a pq operation
  * @device_prep_dma_pq_val: prepares a pqzero_sum operation
+ * @device_prep_dma_memset: prepares a memset operation
  * @device_prep_dma_interrupt: prepares an end of chain interrupt operation
  * @device_prep_slave_sg: prepares a slave dma operation
  * @device_prep_dma_cyclic: prepare a cyclic dma operation suitable for audio.
···
 	u8 copy_align;
 	u8 xor_align;
 	u8 pq_align;
+	u8 fill_align;
 	#define DMA_HAS_PQ_CONTINUE (1 << 15)
 
 	int dev_id;
···
 		struct dma_chan *chan, dma_addr_t *pq, dma_addr_t *src,
 		unsigned int src_cnt, const unsigned char *scf, size_t len,
 		enum sum_check_flags *pqres, unsigned long flags);
+	struct dma_async_tx_descriptor *(*device_prep_dma_memset)(
+		struct dma_chan *chan, dma_addr_t dest, int value, size_t len,
+		unsigned long flags);
 	struct dma_async_tx_descriptor *(*device_prep_dma_interrupt)(
 		struct dma_chan *chan, unsigned long flags);
 	struct dma_async_tx_descriptor *(*device_prep_dma_sg)(
···
 	return chan->device->device_prep_interleaved_dma(chan, xt, flags);
 }
 
+static inline struct dma_async_tx_descriptor *dmaengine_prep_dma_memset(
+		struct dma_chan *chan, dma_addr_t dest, int value, size_t len,
+		unsigned long flags)
+{
+	if (!chan || !chan->device)
+		return NULL;
+
+	return chan->device->device_prep_dma_memset(chan, dest, value,
+						    len, flags);
+}
+
 static inline struct dma_async_tx_descriptor *dmaengine_prep_dma_sg(
 		struct dma_chan *chan,
 		struct scatterlist *dst_sg, unsigned int dst_nents,
···
 				     size_t off2, size_t len)
 {
 	return dmaengine_check_align(dev->pq_align, off1, off2, len);
+}
+
+static inline bool is_dma_fill_aligned(struct dma_device *dev, size_t off1,
+				       size_t off2, size_t len)
+{
+	return dmaengine_check_align(dev->fill_align, off1, off2, len);
 }
 
 static inline void