[U-Boot] IDE_BUS unconditionally expects 2 devices per bus

[Rogan Dawes]

Hi folks

Since include/ide.h defines IDE_BUS(dev) as (dev >> 1), it ignores the 
values of CONFIG_SYS_IDE_MAXBUS and CONFIG_SYS_MAXDEVICE, and 
unconditionally expects an IDE bus to have two devices.

This expectation falls down with the Orion5x SATA support, which uses 
that SATA controller in IDE compatability mode, but can obviously only 
have one device per bus.

I'm not 100% sure whether the problem is with the IDE code, or with the 
Orion5x code which identifies a drive at both "positions" on the IDE 
bus. i.e. if I define CONFIG_SYS_IDE_MAXDEVICE as 
(CONFIG_SYS_IDE_MAXBUS*2), I get the first drive shown twice, and the 
second drive shown twice.

The following RFC patch works for me, but may well break other boards 
that do not define CONFIG_SYS_IDE_MAXDEVICE and CONFIG_SYS_IDE_MAXBUS 
properly:

diff --git a/include/ide.h b/include/ide.h
index 6a1b7ae..3f81fb1 100644
--- a/include/ide.h
+++ b/include/ide.h
@@ -24,7 +24,7 @@
  #ifndef        _IDE_H
  #define _IDE_H

-#define        IDE_BUS(dev)    (dev >> 1)
+#define        IDE_BUS(dev)    (dev >> (CONFIG_SYS_IDE_MAXDEVICE / 
CONFIG_SYS_IDE_MAXBUS - 1))

  #define        ATA_CURR_BASE(dev) 
(CONFIG_SYS_ATA_BASE_ADDR+ide_bus_offset[IDE_BUS(dev)])

Ok, I'm sure it is line wrapped, tab-damaged, etc, and the line itself 
is too long, but conceptually, would that be acceptable?

Thanks

Rogan