rapidio: modify mport ID assignment

Changes mport ID and host destination ID assignment to implement unified
method common to all mport drivers.  Makes "riohdid=" kernel command line
parameter common for all architectures with support for more that one host
destination ID assignment.

Signed-off-by: Alexandre Bounine <alexandre.bounine@idt.com>
Cc: Kumar Gala <galak@kernel.crashing.org>
Cc: Matt Porter <mporter@kernel.crashing.org>
Cc: Li Yang <leoli@freescale.com>
Cc: Thomas Moll <thomas.moll@sysgo.com>
Cc: Micha Nelissen <micha@neli.hopto.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/drivers/rapidio/rio.c b/drivers/rapidio/rio.c
index f861b72..9a7b216 100644
--- a/drivers/rapidio/rio.c
+++ b/drivers/rapidio/rio.c
@@ -32,6 +32,7 @@
 #include "rio.h"
 
 static LIST_HEAD(rio_mports);
+static unsigned char next_portid;
 
 /**
  * rio_local_get_device_id - Get the base/extended device id for a port
@@ -1164,8 +1165,33 @@
 
 device_initcall_sync(rio_init_mports);
 
+static int hdids[RIO_MAX_MPORTS + 1];
+
+static int rio_get_hdid(int index)
+{
+	if (!hdids[0] || hdids[0] <= index || index >= RIO_MAX_MPORTS)
+		return -1;
+
+	return hdids[index + 1];
+}
+
+static int rio_hdid_setup(char *str)
+{
+	(void)get_options(str, ARRAY_SIZE(hdids), hdids);
+	return 1;
+}
+
+__setup("riohdid=", rio_hdid_setup);
+
 void rio_register_mport(struct rio_mport *port)
 {
+	if (next_portid >= RIO_MAX_MPORTS) {
+		pr_err("RIO: reached specified max number of mports\n");
+		return;
+	}
+
+	port->id = next_portid++;
+	port->host_deviceid = rio_get_hdid(port->id);
 	list_add_tail(&port->node, &rio_mports);
 }