[PATCH v3 10/14] mips: cdmm: Add mti,mips-cdmm dtb node support

[Serge Semin <Sergey.Semin@baikalelectronics.ru>]

Since having and mapping the CDMM block is platform specific, then
instead of just returning a zero-address, lets make the default CDMM
base address search method (mips_cdmm_phys_base()) to do something
useful. For instance to find the address in a dedicated dtb-node in
order to support of-based platforms by default.

Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Alexey Malahov <Alexey.Malahov@baikalelectronics.ru>
Cc: Paul Burton <paulburton@kernel.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Olof Johansson <olof@lixom.net>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: linux-mips@vger.kernel.org
Cc: devicetree@vger.kernel.org
---
 drivers/bus/mips_cdmm.c | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/drivers/bus/mips_cdmm.c b/drivers/bus/mips_cdmm.c
index 1b14256376d2..7faa8c049f07 100644
--- a/drivers/bus/mips_cdmm.c
+++ b/drivers/bus/mips_cdmm.c
@@ -16,6 +16,8 @@
 #include <linux/platform_device.h>
 #include <linux/slab.h>
 #include <linux/smp.h>
+#include <linux/of_address.h>
+#include <linux/of.h>
 #include <asm/cdmm.h>
 #include <asm/hazards.h>
 #include <asm/mipsregs.h>
@@ -337,9 +339,22 @@ static phys_addr_t mips_cdmm_cur_base(void)
  * Picking a suitable physical address at which to map the CDMM region is
  * platform specific, so this weak function can be overridden by platform
  * code to pick a suitable value if none is configured by the bootloader.
+ * By default this method tries to find a CDMM-specific node in the system
+ * dtb. Note that this won't work for early serial console.
  */
 phys_addr_t __weak mips_cdmm_phys_base(void)
 {
+	struct device_node *np;
+	struct resource res;
+	int err;
+
+	np = of_find_compatible_node(NULL, NULL, "mti,mips-cdmm");
+	if (np) {
+		err = of_address_to_resource(np, 0, &res);
+		if (!err)
+			return res.start;
+	}
+
 	return 0;
 }
 
-- 
2.25.1