On Thu, 22 Nov 2007 11:36:29 -0700
Grant Likely wrote:
> > +int cpm_command(u32 command, u8 opcode)
> > +{
> > + int i;
> > +
> > + if (command & 0xffffff0f)
> > + return -EINVAL;
> > +
> > + out_be16(&cpmp->cp_cpcr, command | CPM_CR_FLG | (opcode <<
> > 8));
> > + for (i = 0; i < MAX_CR_CMD_LOOPS; i++)
> > + if ((in_be16(&cpmp->cp_cpcr) & CPM_CR_FLG) == 0)
> > + return 0;
> > +
> > + printk(KERN_ERR "%s(): Not able to issue CPM command\n",
> > + __FUNCTION__);
> > + return -EIO;
>
> Do these need to be protected with a spin lock?
Even that might be not enough - we may have simultaneous call of this func in
non-smp case...
I was thinking of some kind of refcount, so one that is going to issue CPM
command, must do say pq_cpmp_get()
and another driver won't be able to mangle with cpcr while it's not done with
previous request.
Yet I am not telling it was better the way it used to be - this approach looks
okay but needs some efforts to defend against
deadlocks while we are at it.
--
Sincerely, Vitaly
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