sh: fix DMA driver's descriptor chaining and cookie assignment

The SH DMA driver wrongly assigns negative cookies to transfer descriptors,
also, its chaining of partial descriptors is broken. The latter problem is
usually invisible, because maximum transfer size per chunk is 16M, but if you
artificially set this limit lower, the driver fails. Since cookies are also
used in chunk management, both these problems are fixed in one patch. As side
effects a possible memory leak, when descriptors are prepared, but not
submitted, and multiple races have also been fixed.
Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Acked-by: Paul Mundt <lethal@linux-sh.org>
Acked-by: Nobuhiro Iwamatsu <iwamatsu@nigauri.org>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

drivers/dma/shdma.h

@@ -13,9 +13,9 @@
 #ifndef __DMA_SHDMA_H
 #define __DMA_SHDMA_H
 
-#include <linux/device.h>
-#include <linux/dmapool.h>
 #include <linux/dmaengine.h>
+#include <linux/interrupt.h>
+#include <linux/list.h>
 
 #define SH_DMA_TCR_MAX 0x00FFFFFF	/* 16MB */
 
@@ -26,13 +26,16 @@ struct sh_dmae_regs {
 };
 
 struct sh_desc {
-	struct list_head tx_list;
 	struct sh_dmae_regs hw;
 	struct list_head node;
 	struct dma_async_tx_descriptor async_tx;
+	dma_cookie_t cookie;
+	int chunks;
 	int mark;
 };
 
+struct device;
+
 struct sh_dmae_chan {
 	dma_cookie_t completed_cookie;	/* The maximum cookie completed */
 	spinlock_t desc_lock;		/* Descriptor operation lock */