Hi,
On Friday 30 January 2009, Benjamin Herrenschmidt wrote:
> On Fri, 2009-01-30 at 16:46 +1100, Benjamin Herrenschmidt wrote:
> > Hi Bart !
> >
> > On a bunch of pmac's, I'm getting lost interrupts when trying to do DMA
> > with ide hard disks (first time at boot when reading the partition
> > table). It then times out, reverts to PIO and boots fine.
> >
> > Haven't had time to fully bisect yet, but it seem to be somewhere in the
> > pile of IDE patches (surprise :-) that went in around that time.
> >
> > I'll dig more next week, but in the meantime, I though you may have a
> > possible candidate in mind.
>
> Smells like the patch that popped up not long ago already (can't find
> the thread now) where you cleaned up the port registration and broke our
> trick of passing a different parent device than the one used for DMA or
> something like that ... that mixed with something not testing the dma
Yeah my bad, though thanks to Andreas Schwab it is fixed in -rc3.
> map results (probably my fault) and I think we are passing crap DMA
> addresses to the device.
>
> I'll sort it out. I should be able to just add working dma ops to the
> macio_device, it's a lot easier now that ppc32 has the same dma ops
> structure in struct device as ppc64.
Would be great as I have completely no idea about this stuff.
While you are at DMA support and will be fixing/testing it anyway
you may try to remove long standing duplication/obfuscation:
/* Those fields are duplicating what is in hwif. We currently
* can't use the hwif ones because of some assumptions that are
* beeing done by the generic code about the kind of dma controller
* and format of the dma table. This will have to be fixed though.
*/
volatile struct dbdma_regs __iomem * dma_regs;
struct dbdma_cmd* dma_table_cpu;
What needs to be done is more-or-less:
- teaching pmac_ide_init_dma() about hwif->prd_max_{nents,size}
and then converting it to use ide_allocate_dma_engine()
- pmif->dma_regs -> hwif->dma_base
- pmif->dma_table_cpu -> hwif->dmatable_cpu
- sticking ide_release_dma_engine() somewhere (it seems that
pmac driver never frees DMA memory allocated currently)
Of course while the above would be a nice cleanup+fixup, making
the driver work comes first..
Thanks,
Bart
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