Re: [Patch v7 2/4] memory: tegra: Add MC error logging on tegra186 onward

[Ashish Mhetre]

On 4/14/2022 2:43 AM, Dmitry Osipenko wrote:
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>
>
> On 4/13/22 12:40, Ashish Mhetre wrote:
> > +irqreturn_t tegra30_mc_handle_irq(int irq, void *data)
> >   {
> >        struct tegra_mc *mc = data;
> > +     unsigned int bit, channel;
> >        unsigned long status;
> > -     unsigned int bit;
> >
> > -     /* mask all interrupts to avoid flooding */
> > -     status = mc_readl(mc, MC_INTSTATUS) & mc->soc->intmask;
> > +     if (mc->soc->num_channels) {
> > +             u32 global_status;
> > +             int err;
> > +
> > +             global_status = mc_ch_readl(mc, MC_BROADCAST_CHANNEL, MC_GLOBAL_INTSTATUS);
>
> This will crash if mc->bcast_ch_regs = ERR_PTR(-EINVAL) for older dtbs.

Actually interrupts won't occur till we write MC_INTMASK register from
broadcast channel with appropriate intmask value. I have added check in
tegra_mc_probe() while registering irq which will write MC_INTMASK from
broadcast only when mc->bcast_ch_regs is initialized i.e.
!IS_ERR(mc->bcast_ch_regs).
So interrupt handler won't be triggered at all if
mc->bcast_ch_regs = ERR_PTR(-EINVAL).