Date:	Fri, 23 Feb 2007 01:37:24 +0100
From:	Hoang-Nam Nguyen <hnguyen@...ux.vnet.ibm.com>
To:	paulus@...ba.org, linuxppc-dev@...abs.org,
	linux-kernel@...r.kernel.org, johnrose@...ibm.com
Cc:	pmac@....ibm.com, fenkes@...ibm.com, benh@...nel.crashing.org,
	Sylvain Munaut <tnt@...tnt.com>
Subject: [PATCH 1/2] ibmebus: dynamic addiiton/removal of adapters, uevent, root device based on struct device

From: Joachim Fenkes <fenkes@...ibm.com>

This adds two sysfs attributes to /sys/bus/ibmebus which can
be used to notify the ebus driver of added / removed ebus
devices in the OF device tree.

Echoing the device's location code (as found in the OFDT
"ibm,loc-code" property) into the "probe" attribute will
notify ebus of addition of the device and cause the appropriate
device driver's probe function to be called on the device.

Likewise, echoing the location code into the "remove" attribute
will cause the device to be removed from the system.

The writes will block until the respective operation has
finished and return an error code if the operation failed.

Additionally, uevent is now supported by ibmebus through the
generic of_device_uevent function.

The fake root device used to provide a common parent for all
ebus devices is now based on device instead of of_device - it
had no associated devtree node. This saves several checks
throughout the ebus driver.


Signed-off-by: Joachim Fenkes <fenkes@...ibm.com>
---

I repost this patch because a kind fellow (wave to Paul =)
reminded me of the finer points of patch descriptions - Thanks!

As said before, I deem this ready for inclusion.


 arch/powerpc/kernel/ibmebus.c |  129 ++++++++++++++++++++++++++++++++++--------
 include/asm-powerpc/ibmebus.h |    2 


diff -wurp a/arch/powerpc/kernel/ibmebus.c b/arch/powerpc/kernel/ibmebus.c
--- a/arch/powerpc/kernel/ibmebus.c	2007-02-22 05:26:24.971939672 +0100
+++ b/arch/powerpc/kernel/ibmebus.c	2007-02-20 23:31:39.000000000 +0100
@@ -2,6 +2,7 @@
  * IBM PowerPC IBM eBus Infrastructure Support.
  *
  * Copyright (c) 2005 IBM Corporation
+ *  Joachim Fenkes <fenkes@...ibm.com>
  *  Heiko J Schick <schickhj@...ibm.com>
  *    
  * All rights reserved.
@@ -43,10 +44,8 @@
 #include <asm/ibmebus.h>
 #include <asm/abs_addr.h>
 
-static struct ibmebus_dev ibmebus_bus_device = { /* fake "parent" device */
-	.name = ibmebus_bus_device.ofdev.dev.bus_id,
-	.ofdev.dev.bus_id = "ibmebus",
-	.ofdev.dev.bus    = &ibmebus_bus_type,
+static struct device ibmebus_bus_device = { /* fake "parent" device */
+	.bus_id = "ibmebus",
 };
 
 static void *ibmebus_alloc_coherent(struct device *dev,
@@ -161,18 +160,19 @@ static void __devinit ibmebus_dev_releas
 static ssize_t ibmebusdev_show_name(struct device *dev, 
 				    struct device_attribute *attr, char *buf)
 {
-	return sprintf(buf, "%s\n", to_ibmebus_dev(dev)->name);
+	struct ibmebus_dev *ebus_dev = to_ibmebus_dev(dev);
+	char *name = (char*)get_property(ebus_dev->ofdev.node, "name", NULL);
+	return sprintf(buf, "%s\n", name);
 }
 static DEVICE_ATTR(name, S_IRUSR | S_IRGRP | S_IROTH, ibmebusdev_show_name, 
 		   NULL);
 
-static struct ibmebus_dev* __devinit ibmebus_register_device_common(
+static int __devinit ibmebus_register_device_common(
 	struct ibmebus_dev *dev, const char *name)
 {
 	int err = 0;
 
-	dev->name = name;
-	dev->ofdev.dev.parent  = &ibmebus_bus_device.ofdev.dev;
+	dev->ofdev.dev.parent  = &ibmebus_bus_device;
 	dev->ofdev.dev.bus     = &ibmebus_bus_type;
 	dev->ofdev.dev.release = ibmebus_dev_release;
 
@@ -186,12 +186,12 @@ static struct ibmebus_dev* __devinit ibm
 	if ((err = of_device_register(&dev->ofdev)) != 0) {
 		printk(KERN_ERR "%s: failed to register device (%d).\n",
 		       __FUNCTION__, err);
-		return NULL;
+		return -ENODEV;
 	}
 	
 	device_create_file(&dev->ofdev.dev, &dev_attr_name);
 	
-	return dev;
+	return 0;
 }
 
 static struct ibmebus_dev* __devinit ibmebus_register_device_node(
@@ -205,18 +205,18 @@ static struct ibmebus_dev* __devinit ibm
 	if (!loc_code) {
                 printk(KERN_WARNING "%s: node %s missing 'ibm,loc-code'\n",
 		       __FUNCTION__, dn->name ? dn->name : "<unknown>");
-		return NULL;
+		return ERR_PTR(-EINVAL);
         }
 	
 	if (strlen(loc_code) == 0) {
 	        printk(KERN_WARNING "%s: 'ibm,loc-code' is invalid\n",
 		       __FUNCTION__);
-		return NULL;
+		return ERR_PTR(-EINVAL);
 	}
 
 	dev = kzalloc(sizeof(struct ibmebus_dev), GFP_KERNEL);
 	if (!dev) {
-		return NULL;
+		return ERR_PTR(-ENOMEM);
 	}
 
 	dev->ofdev.node = of_node_get(dn);
@@ -227,9 +227,9 @@ static struct ibmebus_dev* __devinit ibm
 		min(length, BUS_ID_SIZE - 1));
 
 	/* Register with generic device framework. */
-	if (ibmebus_register_device_common(dev, dn->name) == NULL) {
+	if (ibmebus_register_device_common(dev, dn->name) != 0) {
 		kfree(dev);
-		return NULL;
+		return ERR_PTR(-ENODEV);
 	}
 
 	return dev;
@@ -240,9 +240,8 @@ static void ibmebus_probe_of_nodes(char*
 	struct device_node *dn = NULL;
 	
 	while ((dn = of_find_node_by_name(dn, name))) {
-		if (ibmebus_register_device_node(dn) == NULL) {
+		if (IS_ERR(ibmebus_register_device_node(dn))) {
 			of_node_put(dn);
-			
 			return;
 		}
 	}
@@ -262,9 +261,15 @@ static void ibmebus_add_devices_by_id(st
 	return;
 }
 
-static int ibmebus_match_helper(struct device *dev, void *data)
+static int ibmebus_match_helper_name(struct device *dev, void *data)
 {
-	if (strcmp((char*)data, to_ibmebus_dev(dev)->name) == 0)
+	const struct ibmebus_dev *ebus_dev = to_ibmebus_dev(dev);
+	char *name;
+
+	name = (char*)get_property(
+		ebus_dev->ofdev.node, "name", NULL);
+
+	if (name && (strcmp((char*)data, name) == 0))
 		return 1;
 	
 	return 0;
@@ -285,11 +290,10 @@ static void ibmebus_remove_devices_by_id
 	while (strlen(idt->name) > 0) {
 		while ((dev = bus_find_device(&ibmebus_bus_type, NULL, 
 					      (void*)idt->name,
-					      ibmebus_match_helper))) {
+					      ibmebus_match_helper_name))) {
 			ibmebus_unregister_device(dev);
 		}
 		idt++;
-		
 	}
 	
 	return;
@@ -307,6 +311,9 @@ int ibmebus_register_driver(struct ibmeb
 	if ((err = driver_register(&drv->driver) != 0))
 		return err;
 
+	/* remove all supported devices first, in case someone
+	 * probed them manually before registering the driver */
+	ibmebus_remove_devices_by_id(drv->id_table);
 	ibmebus_add_devices_by_id(drv->id_table);
 	
 	return 0;
@@ -363,10 +370,85 @@ static int ibmebus_bus_match(struct devi
 
 struct bus_type ibmebus_bus_type = {
 	.name = "ibmebus",
+	.uevent = of_device_uevent,
 	.match = ibmebus_bus_match,
 };
 EXPORT_SYMBOL(ibmebus_bus_type);
 
+static int ibmebus_match_helper_loc_code(struct device *dev, void *data)
+{
+	const struct ibmebus_dev *ebus_dev = to_ibmebus_dev(dev);
+	char *loc_code;
+
+	loc_code = (char*)get_property(
+		ebus_dev->ofdev.node, "ibm,loc-code", NULL);
+
+	if (loc_code && (strcmp((char*)data, loc_code) == 0))
+		return 1;
+
+	return 0;
+}
+
+static ssize_t ibmebus_store_probe(struct bus_type *bus,
+				   const char *buf, size_t count)
+{
+	struct device_node *dn = NULL;
+	struct ibmebus_dev *dev;
+	char *loc_code;
+
+	buf[count] = '\0';
+	if (buf[count-1] == '\n')
+		buf[count-1] = '\0';
+
+	if (bus_find_device(&ibmebus_bus_type, NULL, (char*)buf,
+			     ibmebus_match_helper_loc_code)) {
+		printk(KERN_WARNING "%s: loc_code %s has already been probed\n",
+		       __FUNCTION__, buf);
+		return -EINVAL;
+	}
+
+	while ((dn = of_find_all_nodes(dn))) {
+		loc_code = (char *)get_property(dn, "ibm,loc-code", NULL);
+		if (loc_code && (strncmp(loc_code, buf, count) == 0)) {
+			dev = ibmebus_register_device_node(dn);
+			if (IS_ERR(dev)) {
+				of_node_put(dn);
+				return PTR_ERR(dev);
+			} else
+				return count; /* success */
+		}
+	}
+
+	/* if we drop out of the loop, the loc code was invalid */
+	printk(KERN_WARNING "%s: no device with loc_code %s found\n",
+	       __FUNCTION__, buf);
+	return -ENODEV;
+}
+static BUS_ATTR(probe, S_IWUSR, NULL, ibmebus_store_probe);
+
+static ssize_t ibmebus_store_remove(struct bus_type *bus,
+				    const char *buf, size_t count)
+{
+	struct device *dev;
+
+	buf[count] = '\0';
+	if (buf[count-1] == '\n')
+		buf[count-1] = '\0';
+
+	/* The location code is unique, so we will find one device at most */
+	if ((dev = bus_find_device(&ibmebus_bus_type, NULL, (char*)buf,
+				   ibmebus_match_helper_loc_code))) {
+		ibmebus_unregister_device(dev);
+	} else {
+		printk(KERN_WARNING "%s: loc_code %s not on the bus\n",
+		       __FUNCTION__, buf);
+		return -ENODEV;
+	}
+
+	return count;
+}
+static BUS_ATTR(remove, S_IWUSR, NULL, ibmebus_store_remove);
+
 static int __init ibmebus_bus_init(void)
 {
 	int err;
@@ -380,7 +462,7 @@ static int __init ibmebus_bus_init(void)
 		return err;
 	}
 	
-	err = device_register(&ibmebus_bus_device.ofdev.dev);
+	err = device_register(&ibmebus_bus_device);
 	if (err) {
 		printk(KERN_WARNING "%s: device_register returned %i\n", 
 		       __FUNCTION__, err);
@@ -389,6 +471,9 @@ static int __init ibmebus_bus_init(void)
 		return err;
 	}
 	
+	bus_create_file(&ibmebus_bus_type, &bus_attr_probe);
+	bus_create_file(&ibmebus_bus_type, &bus_attr_remove);
+
 	return 0;
 }
 __initcall(ibmebus_bus_init);
diff -wurp a/include/asm-powerpc/ibmebus.h b/include/asm-powerpc/ibmebus.h
--- a/include/asm-powerpc/ibmebus.h	2007-02-22 05:27:57.392999408 +0100
+++ b/include/asm-powerpc/ibmebus.h	2007-02-22 05:28:09.244928272 +0100
@@ -2,6 +2,7 @@
  * IBM PowerPC eBus Infrastructure Support.
  *
  * Copyright (c) 2005 IBM Corporation
+ *  Joachim Fenkes <fenkes@...ibm.com>
  *  Heiko J Schick <schickhj@...ibm.com>
  *    
  * All rights reserved.
@@ -47,7 +48,6 @@
 extern struct bus_type ibmebus_bus_type;
 
 struct ibmebus_dev {	
-	const char *name;
 	struct of_device ofdev;
 };
 


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