powerpc/macio: Rework hotplug media bay support

The hotplug mediabay has tendrils deep into drivers/ide code
which makes a libata port reather difficult. In addition it's
ugly and could be done better.

This reworks the interface between the mediabay and the rest
of the world so that:

   - Any macio_driver can now have a mediabay_event callback
which will be called when that driver sits on a mediabay and
it's been either plugged or unplugged. The device type is
passed as an argument. We can now move all the IDE cruft
into the IDE driver itself

   - A check_media_bay() function can be used to take a peek
at the type of device currently in the bay if any, a cleaner
variant of the previous function with the same name.

   - A pair of lock/unlock functions are exposed to allow the
IDE driver to block the hotplug callbacks during the initial
setup and probing of the bay in order to avoid nasty race
conditions.

   - The mediabay code no longer needs to spin on the status
register of the IDE interface when it detects an IDE device,
this is done just fine by the IDE code itself

Overall, less code, simpler, and allows for another driver
than our old drivers/ide based one.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

1 files changed, 16 insertions, 23 deletions

diff --git a/drivers/block/swim3.c b/drivers/block/swim3.c
index 6380ad8d91bd..59ca2b77b574 100644
--- a/drivers/block/swim3.c
+++ b/drivers/block/swim3.c
@@ -200,7 +200,7 @@ struct floppy_state {
         int     ejected;
         wait_queue_head_t wait;
         int     wanted;
-        struct device_node*     media_bay; /* NULL when not in bay */
+        struct macio_dev *mdev;
         char    dbdma_cmd_space[5 * sizeof(struct dbdma_cmd)];
 };
 
@@ -303,14 +303,13 @@ static int swim3_readbit(struct floppy_state *fs, int bit)
 static void do_fd_request(struct request_queue * q)
 {
         int i;
-        for(i=0;i<floppy_count;i++)
-        {
-#ifdef CONFIG_PMAC_MEDIABAY
-                if (floppy_states[i].media_bay &&
-                        check_media_bay(floppy_states[i].media_bay, MB_FD))
+
+        for(i=0; i<floppy_count; i++) {
+                struct floppy_state *fs = &floppy_states[i];
+                if (fs->mdev->media_bay &&
+                    check_media_bay(fs->mdev->media_bay) != MB_FD)
                         continue;
-#endif /* CONFIG_PMAC_MEDIABAY */
-                start_request(&floppy_states[i]);
+                start_request(fs);
         }
 }
 
@@ -849,10 +848,9 @@ static int floppy_ioctl(struct block_device *bdev, fmode_t mode,
         if ((cmd & 0x80) && !capable(CAP_SYS_ADMIN))
                 return -EPERM;
 
-#ifdef CONFIG_PMAC_MEDIABAY
-        if (fs->media_bay && check_media_bay(fs->media_bay, MB_FD))
+        if (fs->mdev->media_bay &&
+            check_media_bay(fs->mdev->media_bay) != MB_FD)
                 return -ENXIO;
-#endif
 
         switch (cmd) {
         case FDEJECT:
@@ -876,10 +874,9 @@ static int floppy_open(struct block_device *bdev, fmode_t mode)
         int n, err = 0;
 
         if (fs->ref_count == 0) {
-#ifdef CONFIG_PMAC_MEDIABAY
-                if (fs->media_bay && check_media_bay(fs->media_bay, MB_FD))
+                if (fs->mdev->media_bay &&
+                    check_media_bay(fs->mdev->media_bay) != MB_FD)
                         return -ENXIO;
-#endif
                 out_8(&sw->setup, S_IBM_DRIVE | S_FCLK_DIV2);
                 out_8(&sw->control_bic, 0xff);
                 out_8(&sw->mode, 0x95);
@@ -963,10 +960,9 @@ static int floppy_revalidate(struct gendisk *disk)
         struct swim3 __iomem *sw;
         int ret, n;
 
-#ifdef CONFIG_PMAC_MEDIABAY
-        if (fs->media_bay && check_media_bay(fs->media_bay, MB_FD))
+        if (fs->mdev->media_bay &&
+            check_media_bay(fs->mdev->media_bay) != MB_FD)
                 return -ENXIO;
-#endif
 
         sw = fs->swim3;
         grab_drive(fs, revalidating, 0);
@@ -1009,7 +1005,6 @@ static const struct block_device_operations floppy_fops = {
 static int swim3_add_device(struct macio_dev *mdev, int index)
 {
         struct device_node *swim = mdev->ofdev.node;
-        struct device_node *mediabay;
         struct floppy_state *fs = &floppy_states[index];
         int rc = -EBUSY;
 
@@ -1036,9 +1031,7 @@ static int swim3_add_device(struct macio_dev *mdev, int index)
         }
         dev_set_drvdata(&mdev->ofdev.dev, fs);
 
-        mediabay = (strcasecmp(swim->parent->type, "media-bay") == 0) ?
-                swim->parent : NULL;
-        if (mediabay == NULL)
+        if (mdev->media_bay == NULL)
                 pmac_call_feature(PMAC_FTR_SWIM3_ENABLE, swim, 0, 1);
         
         memset(fs, 0, sizeof(*fs));
@@ -1068,7 +1061,7 @@ static int swim3_add_device(struct macio_dev *mdev, int index)
         fs->secpercyl = 36;
         fs->secpertrack = 18;
         fs->total_secs = 2880;
-        fs->media_bay = mediabay;
+        fs->mdev = mdev;
         init_waitqueue_head(&fs->wait);
 
         fs->dma_cmd = (struct dbdma_cmd *) DBDMA_ALIGN(fs->dbdma_cmd_space);
@@ -1093,7 +1086,7 @@ static int swim3_add_device(struct macio_dev *mdev, int index)
         init_timer(&fs->timeout);
 
         printk(KERN_INFO "fd%d: SWIM3 floppy controller %s\n", floppy_count,
-                mediabay ? "in media bay" : "");
+                mdev->media_bay ? "in media bay" : "");
 
         return 0;