urara: add support for DMA coherent memory area

The information about the DMA memory area is further passed
through the coreboot table to the payload.

BUG=chrome-os-partner:31438
TEST=tested on Pistachio FPGA; DMA memory area was used to test the
     functionality of the DWC2 USB controller driver; behavior was
     as expected.
BRANCH=none

Change-Id: I658e32352bd5fab493ffe15ad9340e19d02fd133
Signed-off-by: Stefan Reinauer <reinauer@chromium.org>
Original-Commit-Id: 0debc105b072a37e2a8ae4098a9634d841191d0a
Original-Change-Id: Icf69835dc6a385a59d30092be4ac69bc80245336
Original-Signed-off-by: Ionela Voinescu <ionela.voinescu@imgtec.com>
Original-Reviewed-on: https://chromium-review.googlesource.com/235910
Original-Reviewed-by: Vadim Bendebury <vbendeb@chromium.org>
Original-Commit-Queue: Vadim Bendebury <vbendeb@chromium.org>
Original-Tested-by: Vadim Bendebury <vbendeb@chromium.org>
Reviewed-on: http://review.coreboot.org/9593
Tested-by: build bot (Jenkins)
Reviewed-by: Patrick Georgi <pgeorgi@google.com>

src/arch/mips/include/arch/memlayout.h

@@ -26,6 +26,6 @@
 /* TODO: Double-check that that's the correct alignment for our ABI. */
 #define STACK(addr, size) REGION(stack, addr, size, 8)
 
-/* TODO: Need to add DMA_COHERENT region like on ARM? */
+#define DMA_COHERENT(addr, size) REGION(dma_coherent, addr, size, 4K)
 
 #endif /* __ARCH_MEMLAYOUT_H */

src/mainboard/google/urara/mainboard.c

@@ -18,9 +18,11 @@
  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston,
  * MA 02110-1301 USA
  */
-
+#include <arch/io.h>
+#include <symbols.h>
 #include <console/console.h>
 #include <device/device.h>
+#include <boot/coreboot_tables.h>
 
 static void mainboard_enable(device_t dev)
 {
@@ -31,3 +33,13 @@ struct chip_operations mainboard_ops = {
 	.enable_dev = mainboard_enable,
 };
 
+void lb_board(struct lb_header *header)
+{
+	struct lb_range *dma;
+
+	dma = (struct lb_range *)lb_new_record(header);
+	dma->tag = LB_TAB_DMA;
+	dma->size = sizeof(*dma);
+	dma->range_start = (uintptr_t)_dma_coherent;
+	dma->range_size = _dma_coherent_size;
+}

src/soc/imgtec/pistachio/include/soc/memlayout.ld

@@ -36,4 +36,6 @@ SECTIONS
 
 	/* Let's use SRAM for CBFS cache. */
 	CBFS_CACHE(0x9b000000, 64K)
+	/* DMA coherent area: end of available DRAM, uncached */
+	DMA_COHERENT(0xAFF00000, 1M)
 }