MIPS: lantiq: dma: add dev pointer

dma_zalloc_coherent() now crashes if no dev pointer is given.
Add a dev pointer to the ltq_dma_channel structure and fill it in the
driver using it.

This fixes a bug introduced in kernel 4.19.

Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

arch/mips/include/asm/mach-lantiq/xway/xway_dma.h

@@ -40,6 +40,7 @@ struct ltq_dma_channel {
 	int desc;			/* the current descriptor */
 	struct ltq_dma_desc *desc_base; /* the descriptor base */
 	int phys;			/* physical addr */
+	struct device *dev;
 };
 
 enum {

arch/mips/lantiq/xway/dma.c

@@ -130,7 +130,7 @@ ltq_dma_alloc(struct ltq_dma_channel *ch)
 	unsigned long flags;
 
 	ch->desc = 0;
-	ch->desc_base = dma_zalloc_coherent(NULL,
+	ch->desc_base = dma_zalloc_coherent(ch->dev,
 				LTQ_DESC_NUM * LTQ_DESC_SIZE,
 				&ch->phys, GFP_ATOMIC);
 
@@ -182,7 +182,7 @@ ltq_dma_free(struct ltq_dma_channel *ch)
 	if (!ch->desc_base)
 		return;
 	ltq_dma_close(ch);
-	dma_free_coherent(NULL, LTQ_DESC_NUM * LTQ_DESC_SIZE,
+	dma_free_coherent(ch->dev, LTQ_DESC_NUM * LTQ_DESC_SIZE,
 		ch->desc_base, ch->phys);
 }
 EXPORT_SYMBOL_GPL(ltq_dma_free);

drivers/net/ethernet/lantiq_etop.c

@@ -274,6 +274,7 @@ ltq_etop_hw_init(struct net_device *dev)
 		struct ltq_etop_chan *ch = &priv->ch[i];
 
 		ch->idx = ch->dma.nr = i;
+		ch->dma.dev = &priv->pdev->dev;
 
 		if (IS_TX(i)) {
 			ltq_dma_alloc_tx(&ch->dma);