maple: fix device detection

The maple bus driver that went into the kernel mainline in September 2007
contained some bugs which were revealed by the update of the kobj code
for the current release series. Unfortunately those bugs also helped
ensure maple devices were properly detected. This patch (against the
current git) now ensures that devices are properly detected again.

(A previous attempt to fix this by delaying initialisation only partially
 fixed this - as became apparent when the bus was fully loaded)

Signed-off-by: Adrian McMenamin <adrian@mcmen.demon.co.uk>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>

drivers/sh/maple/maple.c

@@ -1,7 +1,7 @@
 /*
  * Core maple bus functionality
  *
- *  Copyright (C) 2007 Adrian McMenamin
+ *  Copyright (C) 2007, 2008 Adrian McMenamin
  *
  * Based on 2.4 code by:
  *
@@ -18,7 +18,6 @@
 #include <linux/init.h>
 #include <linux/kernel.h>
 #include <linux/device.h>
-#include <linux/module.h>
 #include <linux/interrupt.h>
 #include <linux/list.h>
 #include <linux/io.h>
@@ -54,14 +53,17 @@ static struct device maple_bus;
 static int subdevice_map[MAPLE_PORTS];
 static unsigned long *maple_sendbuf, *maple_sendptr, *maple_lastptr;
 static unsigned long maple_pnp_time;
-static int started, scanning, liststatus, realscan;
+static int started, scanning, liststatus, fullscan;
 static struct kmem_cache *maple_queue_cache;
 
 struct maple_device_specify {
 	int port;
 	int unit;
 };
 
+static bool checked[4];
+static struct maple_device *baseunits[4];
+
 /**
  *  maple_driver_register - register a device driver
  *  automatically makes the driver bus a maple bus
@@ -309,11 +311,9 @@ static void maple_attach_driver(struct maple_device *mdev)
 		else
 			break;
 
-	if (realscan) {
-		printk(KERN_INFO "Maple device detected: %s\n",
-			mdev->product_name);
-		printk(KERN_INFO "Maple device: %s\n", mdev->product_licence);
-	}
+	printk(KERN_INFO "Maple device detected: %s\n",
+		mdev->product_name);
+	printk(KERN_INFO "Maple device: %s\n", mdev->product_licence);
 
 	function = be32_to_cpu(mdev->devinfo.function);
 
@@ -323,20 +323,18 @@ static void maple_attach_driver(struct maple_device *mdev)
 		mdev->driver = &maple_dummy_driver;
 		sprintf(mdev->dev.bus_id, "%d:0.port", mdev->port);
 	} else {
-		if (realscan)
-			printk(KERN_INFO
-				"Maple bus at (%d, %d): Function 0x%lX\n",
-				mdev->port, mdev->unit, function);
+		printk(KERN_INFO
+			"Maple bus at (%d, %d): Function 0x%lX\n",
+			mdev->port, mdev->unit, function);
 
 		matched =
 		    bus_for_each_drv(&maple_bus_type, NULL, mdev,
 				     attach_matching_maple_driver);
 
 		if (matched == 0) {
 			/* Driver does not exist yet */
-			if (realscan)
-				printk(KERN_INFO
-					"No maple driver found.\n");
+			printk(KERN_INFO
+				"No maple driver found.\n");
 			mdev->driver = &maple_dummy_driver;
 		}
 		sprintf(mdev->dev.bus_id, "%d:0%d.%lX", mdev->port,
@@ -472,9 +470,12 @@ static void maple_response_none(struct maple_device *mdev,
 		maple_detach_driver(mdev);
 		return;
 	}
-	if (!started) {
-		printk(KERN_INFO "No maple devices attached to port %d\n",
-		       mdev->port);
+	if (!started || !fullscan) {
+		if (checked[mdev->port] == false) {
+			checked[mdev->port] = true;
+			printk(KERN_INFO "No maple devices attached"
+				" to port %d\n", mdev->port);
+		}
 		return;
 	}
 	maple_clean_submap(mdev);
@@ -485,8 +486,14 @@ static void maple_response_devinfo(struct maple_device *mdev,
 				   char *recvbuf)
 {
 	char submask;
-	if ((!started) || (scanning == 2)) {
-		maple_attach_driver(mdev);
+	if (!started || (scanning == 2) || !fullscan) {
+		if ((mdev->unit == 0) && (checked[mdev->port] == false)) {
+			checked[mdev->port] = true;
+			maple_attach_driver(mdev);
+		} else {
+			if (mdev->unit != 0)
+				maple_attach_driver(mdev);
+		}
 		return;
 	}
 	if (mdev->unit == 0) {
@@ -505,6 +512,7 @@ static void maple_dma_handler(struct work_struct *work)
 	struct maple_device *dev;
 	char *recvbuf;
 	enum maple_code code;
+	int i;
 
 	if (!maple_dma_done())
 		return;
@@ -557,6 +565,19 @@ static void maple_dma_handler(struct work_struct *work)
 		} else
 			scanning = 0;
 
+		if (!fullscan) {
+			fullscan = 1;
+			for (i = 0; i < MAPLE_PORTS; i++) {
+				if (checked[i] == false) {
+					fullscan = 0;
+					dev = baseunits[i];
+					dev->mq->command =
+						MAPLE_COMMAND_DEVINFO;
+					dev->mq->length = 0;
+					maple_add_packet(dev->mq);
+				}
+			}
+		}
 		if (started == 0)
 			started = 1;
 	}
@@ -694,7 +715,9 @@ static int __init maple_bus_init(void)
 
 	/* setup maple ports */
 	for (i = 0; i < MAPLE_PORTS; i++) {
+		checked[i] = false;
 		mdev[i] = maple_alloc_dev(i, 0);
+		baseunits[i] = mdev[i];
 		if (!mdev[i]) {
 			while (i-- > 0)
 				maple_free_dev(mdev[i]);
@@ -703,12 +726,9 @@ static int __init maple_bus_init(void)
 		mdev[i]->mq->command = MAPLE_COMMAND_DEVINFO;
 		mdev[i]->mq->length = 0;
 		maple_add_packet(mdev[i]->mq);
-		/* delay aids hardware detection */
-		mdelay(5);
 		subdevice_map[i] = 0;
 	}
 
-	realscan = 1;
 	/* setup maplebus hardware */
 	maplebus_dma_reset();
 	/* initial detection */