ide: add ide-4drives host driver (take 3)

CONFIG_BLK_DEV_4DRIVES deserves its own host driver:

* Add drivers/ide/legacy/ide-4drives.c and move "4drives" support there.

* Add ide-4drives.o in the link order after all other legacy host
  drivers enabled by "ide0=" options (they all are mutually exclusive).

* Make ide-4drives host driver probe itself for IDE devices instead of
  indirectly depending on ide_generic host driver.

* Add "probe" module parameter to ide-4drives and update documentation.

v2:
* s/paramater/parameter/ in ide.txt. (Noticed by Randy Dunlap)

v3:
* s/ide_4drives.probe/ide-4drives.probe/ in help entry.
  (Noticed by Sergei Shtylyov)

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

1 files changed, 3 insertions, 2 deletions

diff --git a/Documentation/ide/ide.txt b/Documentation/ide/ide.txt
index 18c02df2f78f..486c699f4aea 100644
--- a/Documentation/ide/ide.txt
+++ b/Documentation/ide/ide.txt
@@ -222,8 +222,6 @@ Summary of ide driver parameters for kernel command line
                           both the respective primary and secondary channel
                           to take effect.
 
- "idex=four"            : four drives on idex and ide(x^1) share same ports
-
  "idex=reset"           : reset interface after probe
 
  "idex=ata66"           : informs the interface that it has an 80c cable
@@ -250,6 +248,9 @@ Also for legacy CMD640 host driver (cmd640) you need to use "probe_vlb"
 kernel paremeter to enable probing for VLB version of the chipset (PCI ones
 are detected automatically).
 
+You also need to use "probe" kernel parameter for ide-4drives driver
+(support for IDE generic chipset with four drives on one port).
+
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 Some Terminology