Re: [MiNT] [PATCH] EHCI driver interrupt checking.

[Hrafnkell Hlodversson <keli@keli.dk>]

Whoops! I just learned that the Coldfire can’t update the stack pointer in the movem instruction, so it would be (although *still* not tested):
> _ehci_int_handle_asm:
> 	subq.l #12, sp
> 	movem.l d0-d1/a1,(sp) // save d0, d1 and a1 to stack
> 	move.l a0,-(sp)		// PCI_BIOS specification: parameter is in a0
> 	jsr _ehci_interrupt_handle
> 	addq.l #4,sp // Clean up argument from stack as per C calling conventions
> 	movem.l (sp),d0-d1/a1 // restore old values of d0, d1 and a1
> 	addq.l #12, sp
> 	rts

> On 10 Dec 2014, at 11:16, Hrafnkell Hlodversson <keli@keli.dk> wrote:
> 
> Hello everyone, I’ve been lurking this list (and watching the CVS commits for a while)
> 
> I did a quick read through this diff, and it seems there is a problem with how you’re saving d0.
>> + move.l d0,-(sp) 
> The above does save it to the stack, but after returning from ehci_interrupt_handle:
>> -	addq.l #4,sp
>> +	addq.l #8,sp
> you simply add 4 more bytes to the stack pointer instead of restoring it.
> Also there is a movem.l instruction already there, maybe you should just add the d0 to the lists of registers to be pushed to that one?
> 
> Something like this (First 68k assembly I’ve written in this century and completely untested, so don’t shoot me ;P )
>> 
>> _ehci_int_handle_asm:
>> 	movem.l d0-d1/a1,-(sp) // save d0, d1 and a1 to stack
>> 	move.l a0,-(sp)		// PCI_BIOS specification: parameter is in a0
>> 	jsr _ehci_interrupt_handle
>> 	addq.l #4,sp // Clean up argument from stack as per C calling conventions
>> 	movem.l (sp)+,d0-d1/a1 // restore old values of d0, d1 and a1
>> 	rts
> 
> 
> With kind regards
> Keli
> 
>> On 02 Dec 2014, at 10:11, David Gálvez <dgalvez75@gmail.com> wrote:
>> 
>> PCI interrupt handlers are put into chain.
>> Check if the interrupt was triggered by the device we're driving.
>> Return d0 register unmodified if the interrupt is not ours.
>> Contributed by David Galvez.
>> <ehci_check_interrupt_20141202.diff>
>