Linux kernel 2.6.20, PCI and hpt266

["Marco Braga" <marco.braga@gmail.com>]

Hello, I am trying to run kernel 2.6.20 on an Au1500 based board. Versions 2.4.x of the kernel are correctly working.

Problem: on the board there is a HighPoint 371N ATA controller. At the moment the kernel 2.6.20 boots and runs, but the ATA controller does not recognize the IDE disk.

Details:
The driver I use is "drivers/ide/pci/hpt266.c". I've already fixed the timing problems and PLL configuration that afflict this controller, and removed RESOURCE_64BIT to fix problems with the PCI bus on mips and resource_size_t casts.

I've managed to follow the problem to ide-probe.c, in function "actual_try_to_identify". It seems that the values read from the ATA registers through IO ports are not correct. As every ATA controller, it needs 8 bytes in IO port space for Command Block registers, and 4 bytes for the Control Block registers. They are mapped by the kernel at:

1400-1407 (8 bytes) Command block channel 0
1408-140F (8 bytes) Command block channel 1
1410-1413 (4 bytes) Control block channel 0
1414-1417 (4 bytes) Control block channel 1

Notice that Highpoint 371N has registers for 2 channel, but the pinout for only 1 channel. In fact the first channel is disabled by the driver, so the actual registers are in the range 1408-140F and 1414-1417. The first sign of the problem is that INB do not read the correct values for the ALTSTATUS register. In fact the kernel reports:

 ... probing with STATUS(...) instead of ALTSTATUS(...)

[as in ide-probe.c, line 290]

The values read from the ATA registers are completely wrong. The registers are accessed through hwif->INB, that are common "inb" functions. This makes me suspect that "inX" functions are not working, but I don't know how to test this. Notice that the PCI controller configuration space is correctly accessed, as I can confirm reading sys/bus/pci/.../config.

Can you help or suggest me anything?
Thanx!