On Tue, 25 Jul 2023, Michael Schmitz wrote:
Thanks William,
On 24/07/23 23:42, William R Sowerbutts wrote:
I was left with the impression that the Q40 does not actually have the IDE
controller on the ISA bus.
This is mistaken.
IDE is definitely accessed over the ISA bus.
There is some documentation on the Q40/Q60 hardware here:
http://www.q40.de/download/harddoc.pdf
Noted - hadn't seen this one before.
The motherboard integrates the CPU, DRAM, video DRAM and display controller,
audio DACs, RTC, interrupt controller, keyboard controller, and an LED
output.
No disk controller on the main board - that's where my error originated.
Note that this also means that the address hardcoded for IDE may be
incorrect (AFAIR, IDE cards could have their IO base reassigned by
firmware).
There are two ISA slots where all other I/O devices are connected. These are
described (concisely!) on page 7 of the linked manual:
8-bit ISA I/O cycles are performed for CPU byte accesses to 0xFF400001 + 4 *
ISA address
16-bit ISA I/O cycles are performed for CPU word accesses to 0xFF400000 + 4
* ISA address
8-bit ISA memory cycles are performed for CPU byte accesses to 0xFF800001 +
4 * ISA address
16-bit ISA memory cycles are performed for CPU word accesses to 0xFF800000 +
4 * ISA address
Yep, that much is evident from the Q40 address translation scheme. But a
similar sort of scheme is used on other m68k platforms to wire up
peripherals that were originally designed for Intel systems, and these
are not connected through an ISA bus.
I can't figure out why those platforms don't suffer from the same "double
translation" problem that William described on q40.
I understand that the machines originally shipped with a 16-bit ISA card
based on the W83787IF "PC super I/O" chip, integrating a floppy controller,
IDE interface, game port, parallel port, and two 16550A UARTs.
OK.
My Q40 came without this card, so I am using a card based on the similar
W83757 chip (the serial ports are 16450 instead of 16550A, it doesn't
support
the fancy EPP/ECP parallel port modes).
It might be a good idea to verify that IDE works in v5.13
Yes, please do.
It did.
And please also verify it's broken after 44b1fbc0f5f30e66 was applied.
I will try to do that!
Probably just try v5.14 - in my tree, 44b1fbc0f5f30e66 came on top of 5.13-rc2
so 5.14 ought to have it applied (but rather check, just the same).
If git is an obstacle, one may obtain the 44b1fbc0f5f30e66 tree (as
easily as the v5.14 tree) by clicking the 'download' button here:
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=44b1fbc0f5f30e66
