File-copy from v4.4.100

This is the result of 'cp' from a linux-stable tree with the 'v4.4.100'
tag checked out (commit 26d6298789e695c9f627ce49a7bbd2286405798a) on
git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git

Please refer to that tree for all history prior to this point.

Change-Id: I8a9ee2aea93cd29c52c847d0ce33091a73ae6afe
diff --git a/arch/cris/arch-v32/kernel/cache.c b/arch/cris/arch-v32/kernel/cache.c
new file mode 100644
index 0000000..f38433b
--- /dev/null
+++ b/arch/cris/arch-v32/kernel/cache.c
@@ -0,0 +1,33 @@
+#include <linux/module.h>
+#include <asm/io.h>
+#include <arch/cache.h>
+#include <arch/hwregs/dma.h>
+
+/* This file is used to workaround a cache bug, Guinness TR 106. */
+
+inline void flush_dma_descr(struct dma_descr_data *descr, int flush_buf)
+{
+	/* Flush descriptor to make sure we get correct in_eop and after. */
+	asm volatile ("ftagd [%0]" :: "r" (descr));
+	/* Flush buffer pointed out by descriptor. */
+	if (flush_buf)
+		cris_flush_cache_range(phys_to_virt((unsigned)descr->buf),
+				(unsigned)(descr->after - descr->buf));
+}
+EXPORT_SYMBOL(flush_dma_descr);
+
+void flush_dma_list(struct dma_descr_data *descr)
+{
+	while (1) {
+		flush_dma_descr(descr, 1);
+		if (descr->eol)
+			break;
+		descr = phys_to_virt((unsigned)descr->next);
+	}
+}
+EXPORT_SYMBOL(flush_dma_list);
+
+/* From cacheflush.S */
+EXPORT_SYMBOL(cris_flush_cache);
+/* From cacheflush.S */
+EXPORT_SYMBOL(cris_flush_cache_range);