zorro: Set up z->dev.dma_mask for the DMA API

The generic DMA API uses dev->dma_mask to check the DMA addressable
memory bitmask, and warns if no mask is set or even allocated.

Set z->dev.dma_coherent_mask on Zorro bus scan, and make z->dev.dma_mask
to point to z->dev.dma_coherent_mask so device drivers that need DMA have
everything set up to avoid warnings from dma_alloc_coherent(). Drivers can
still use dma_set_mask_and_coherent() to explicitly set their DMA bit mask.

Signed-off-by: Michael Schmitz <schmitzmic@gmail.com>
[geert: Handle Zorro II with 24-bit address space]
Acked-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>

drivers/zorro/zorro.c

@@ -16,6 +16,7 @@
 #include <linux/bitops.h>
 #include <linux/string.h>
 #include <linux/platform_device.h>
+#include <linux/dma-mapping.h>
 #include <linux/slab.h>
 
 #include <asm/byteorder.h>
@@ -185,6 +186,17 @@ static int __init amiga_zorro_probe(struct platform_device *pdev)
 		z->dev.parent = &bus->dev;
 		z->dev.bus = &zorro_bus_type;
 		z->dev.id = i;
+		switch (z->rom.er_Type & ERT_TYPEMASK) {
+		case ERT_ZORROIII:
+			z->dev.coherent_dma_mask = DMA_BIT_MASK(32);
+			break;
+
+		case ERT_ZORROII:
+		default:
+			z->dev.coherent_dma_mask = DMA_BIT_MASK(24);
+			break;
+		}
+		z->dev.dma_mask = &z->dev.coherent_dma_mask;
 	}
 
 	/* ... then register them */