[POWERPC] ibmebus: change probe/remove interface from using loc-code to DT path

In some cases, multiple OFDT nodes might share the same location code, so
the location code is not a unique identifier for an OFDT node. Changed the
ibmebus probe/remove interface to use the DT path of the device node instead
of the location code.

The DT path must be written into probe/remove right as it would appear in
the "devspec" attribute of the ebus device: relative to the DT root, with a
leading slash and without a trailing slash. One trailing newline will not
hurt; multiple newlines will (like perl's chomp()).

Example:

 Add a device "/proc/device-tree/foo@12345678" to ibmebus like this:
    echo /foo@12345678 > /sys/bus/ibmebus/probe

 Remove the device like this:
    echo /foo@12345678 > /sys/bus/ibmebus/remove

Signed-off-by: Joachim Fenkes <fenkes@de.ibm.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>

1 files changed, 60 insertions, 55 deletions

diff --git a/arch/powerpc/kernel/ibmebus.c b/arch/powerpc/kernel/ibmebus.c
index 48446a699ef8..9a8c9af43b22 100644
--- a/arch/powerpc/kernel/ibmebus.c
+++ b/arch/powerpc/kernel/ibmebus.c
@@ -44,8 +44,6 @@
 #include <asm/ibmebus.h>
 #include <asm/abs_addr.h>
 
-#define MAX_LOC_CODE_LENGTH 80
-
 static struct device ibmebus_bus_device = { /* fake "parent" device */
         .bus_id = "ibmebus",
 };
@@ -253,7 +251,7 @@ static void ibmebus_add_devices_by_id(struct of_device_id *idt)
         return;
 }
 
-static int ibmebus_match_helper_name(struct device *dev, void *data)
+static int ibmebus_match_name(struct device *dev, void *data)
 {
         const struct ibmebus_dev *ebus_dev = to_ibmebus_dev(dev);
         const char *name;
@@ -280,7 +278,7 @@ static void ibmebus_remove_devices_by_id(struct of_device_id *idt)
         while (strlen(idt->name) > 0) {
                 while ((dev = bus_find_device(&ibmebus_bus_type, NULL,
                                               (void*)idt->name,
-                                              ibmebus_match_helper_name))) {
+                                              ibmebus_match_name))) {
                         ibmebus_unregister_device(dev);
                 }
                 idt++;
@@ -371,17 +369,30 @@ static struct device_attribute ibmebus_dev_attrs[] = {
         __ATTR_NULL
 };
 
-static int ibmebus_match_helper_loc_code(struct device *dev, void *data)
+static int ibmebus_match_path(struct device *dev, void *data)
 {
-        const struct ibmebus_dev *ebus_dev = to_ibmebus_dev(dev);
-        const char *loc_code;
+        int rc;
+        struct device_node *dn =
+                of_node_get(to_ibmebus_dev(dev)->ofdev.node);
 
-        loc_code = of_get_property(ebus_dev->ofdev.node, "ibm,loc-code", NULL);
+        rc = (dn->full_name && (strcasecmp((char*)data, dn->full_name) == 0));
 
-        if (loc_code && (strcmp(data, loc_code) == 0))
-                return 1;
+        of_node_put(dn);
+        return rc;
+}
 
-        return 0;
+static char *ibmebus_chomp(const char *in, size_t count)
+{
+        char *out = (char*)kmalloc(count + 1, GFP_KERNEL);
+        if (!out)
+                return NULL;
+
+        memcpy(out, in, count);
+        out[count] = '\0';
+        if (out[count - 1] == '\n')
+                out[count - 1] = '\0';
+
+        return out;
 }
 
 static ssize_t ibmebus_store_probe(struct bus_type *bus,
@@ -389,65 +400,59 @@ static ssize_t ibmebus_store_probe(struct bus_type *bus,
 {
         struct device_node *dn = NULL;
         struct ibmebus_dev *dev;
-        const char *loc_code;
-        char parm[MAX_LOC_CODE_LENGTH];
-
-        if (count >= MAX_LOC_CODE_LENGTH)
-                return -EINVAL;
-        memcpy(parm, buf, count);
-        parm[count] = '\0';
-        if (parm[count-1] == '\n')
-                parm[count-1] = '\0';
-
-        if (bus_find_device(&ibmebus_bus_type, NULL, parm,
-                             ibmebus_match_helper_loc_code)) {
-                printk(KERN_WARNING "%s: loc_code %s has already been probed\n",
-                       __FUNCTION__, parm);
-                return -EINVAL;
+        char *path;
+        ssize_t rc;
+
+        path = ibmebus_chomp(buf, count);
+        if (!path)
+                return -ENOMEM;
+
+        if (bus_find_device(&ibmebus_bus_type, NULL, path,
+                             ibmebus_match_path)) {
+                printk(KERN_WARNING "%s: %s has already been probed\n",
+                       __FUNCTION__, path);
+                rc = -EINVAL;
+                goto out;
         }
 
-        while ((dn = of_find_all_nodes(dn))) {
-                loc_code = of_get_property(dn, "ibm,loc-code", NULL);
-                if (loc_code && (strncmp(loc_code, parm, 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 ((dn = of_find_node_by_path(path))) {
+                dev = ibmebus_register_device_node(dn);
+                of_node_put(dn);
+                rc = IS_ERR(dev) ? PTR_ERR(dev) : count;
+        } else {
+                printk(KERN_WARNING "%s: no such device node: %s\n",
+                       __FUNCTION__, path);
+                rc = -ENODEV;
         }
 
-        /* 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__, parm);
-        return -ENODEV;
+out:
+        kfree(path);
+        return rc;
 }
 
 static ssize_t ibmebus_store_remove(struct bus_type *bus,
                                     const char *buf, size_t count)
 {
         struct device *dev;
-        char parm[MAX_LOC_CODE_LENGTH];
+        char *path;
 
-        if (count >= MAX_LOC_CODE_LENGTH)
-                return -EINVAL;
-        memcpy(parm, buf, count);
-        parm[count] = '\0';
-        if (parm[count-1] == '\n')
-                parm[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, parm,
-                                   ibmebus_match_helper_loc_code))) {
+        path = ibmebus_chomp(buf, count);
+        if (!path)
+                return -ENOMEM;
+
+        if ((dev = bus_find_device(&ibmebus_bus_type, NULL, path,
+                                   ibmebus_match_path))) {
                 ibmebus_unregister_device(dev);
+
+                kfree(path);
+                return count;
         } else {
-                printk(KERN_WARNING "%s: loc_code %s not on the bus\n",
-                       __FUNCTION__, parm);
+                printk(KERN_WARNING "%s: %s not on the bus\n",
+                       __FUNCTION__, path);
+
+                kfree(path);
                 return -ENODEV;
         }
-
-        return count;
 }
 
 static struct bus_attribute ibmebus_bus_attrs[] = {