ide: add warm-plug support for IDE devices (take 2)

* Add 'struct class ide_port_class' ('ide_port' class) and a 'struct
  device *portdev' ('ide_port' class device) in ide_hwif_t.

* Register 'ide_port' class in ide_init() and unregister it in
  cleanup_module().

* Create ->portdev in ide_register_port () and unregister it in
  ide_unregister().

* Add "delete_devices" class device attribute for unregistering IDE devices
  on a port and "scan" one for probing+registering IDE devices on a port.

* Add ide_sysfs_register_port() helper for registering "delete_devices"
  and "scan" attributes with ->portdev.  Call it in ide_device_add_all().

* Document IDE warm-plug support in Documentation/ide/warm-plug-howto.txt.

v2:
* Convert patch from using 'struct class_device' to use 'struct device'.
  (thanks to Kay Sievers for doing it)

Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>

1 files changed, 69 insertions, 2 deletions

diff --git a/drivers/ide/ide-probe.c b/drivers/ide/ide-probe.c
index 468c4ac4181d..510254ab3c9b 100644
--- a/drivers/ide/ide-probe.c
+++ b/drivers/ide/ide-probe.c
@@ -623,7 +623,7 @@ static void hwif_release_dev (struct device *dev)
         complete(&hwif->gendev_rel_comp);
 }
 
-static void ide_register_port(ide_hwif_t *hwif)
+static int ide_register_port(ide_hwif_t *hwif)
 {
         int ret;
 
@@ -639,9 +639,23 @@ static void ide_register_port(ide_hwif_t *hwif)
         }
         hwif->gendev.release = hwif_release_dev;
         ret = device_register(&hwif->gendev);
-        if (ret < 0)
+        if (ret < 0) {
                 printk(KERN_WARNING "IDE: %s: device_register error: %d\n",
                         __FUNCTION__, ret);
+                goto out;
+        }
+
+        get_device(&hwif->gendev);
+
+        hwif->portdev = device_create(ide_port_class, &hwif->gendev,
+                                      MKDEV(0, 0), hwif->name);
+        if (IS_ERR(hwif->portdev)) {
+                ret = PTR_ERR(hwif->portdev);
+                device_unregister(&hwif->gendev);
+        }
+        dev_set_drvdata(hwif->portdev, hwif);
+out:
+        return ret;
 }
 
 /**
@@ -1378,6 +1392,58 @@ static void ide_port_cable_detect(ide_hwif_t *hwif)
         }
 }
 
+static ssize_t store_delete_devices(struct device *portdev,
+                                    struct device_attribute *attr,
+                                    const char *buf, size_t n)
+{
+        ide_hwif_t *hwif = dev_get_drvdata(portdev);
+
+        if (strncmp(buf, "1", n))
+                return -EINVAL;
+
+        ide_port_unregister_devices(hwif);
+
+        return n;
+};
+
+static DEVICE_ATTR(delete_devices, S_IWUSR, NULL, store_delete_devices);
+
+static ssize_t store_scan(struct device *portdev,
+                          struct device_attribute *attr,
+                          const char *buf, size_t n)
+{
+        ide_hwif_t *hwif = dev_get_drvdata(portdev);
+
+        if (strncmp(buf, "1", n))
+                return -EINVAL;
+
+        ide_port_unregister_devices(hwif);
+        ide_port_scan(hwif);
+
+        return n;
+};
+
+static DEVICE_ATTR(scan, S_IWUSR, NULL, store_scan);
+
+static struct device_attribute *ide_port_attrs[] = {
+        &dev_attr_delete_devices,
+        &dev_attr_scan,
+        NULL
+};
+
+static int ide_sysfs_register_port(ide_hwif_t *hwif)
+{
+        int i, rc;
+
+        for (i = 0; ide_port_attrs[i]; i++) {
+                rc = device_create_file(hwif->portdev, ide_port_attrs[i]);
+                if (rc)
+                        break;
+        }
+
+        return rc;
+}
+
 int ide_device_add_all(u8 *idx, const struct ide_port_info *d)
 {
         ide_hwif_t *hwif, *mate = NULL;
@@ -1474,6 +1540,7 @@ int ide_device_add_all(u8 *idx, const struct ide_port_info *d)
                 hwif = &ide_hwifs[idx[i]];
 
                 if (hwif->present) {
+                        ide_sysfs_register_port(hwif);
                         ide_proc_register_port(hwif);
                         ide_proc_port_register_devices(hwif);
                 }