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SubjectRe: [PATCH v23 09/11] acpi/arm64: Add memory-mapped timer support in GTDT driver
On Fri, Apr 07, 2017 at 12:47:47AM +0800, Fu Wei wrote:
> On 6 April 2017 at 02:38, Mark Rutland <mark.rutland@arm.com> wrote:
> > On Sat, Apr 01, 2017 at 01:51:03AM +0800, fu.wei@linaro.org wrote:
> >> + /*
> >> + * Get the GT timer Frame data for every GT Block Timer
> >> + */
> >> + for (i = 0; i < block->timer_count; i++, gtdt_frame++) {
> >> + if (gtdt_frame->common_flags & ACPI_GTDT_GT_IS_SECURE_TIMER)
> >> + continue;
> >> +
> >> + if (!gtdt_frame->base_address || !gtdt_frame->timer_interrupt)
> >> + goto error;
> >> +
> >> + frame = &timer_mem->frame[gtdt_frame->frame_number];
> >> + frame->phys_irq = map_gt_gsi(gtdt_frame->timer_interrupt,
> >> + gtdt_frame->timer_flags);
> >> + if (frame->phys_irq <= 0) {
> >> + pr_warn("failed to map physical timer irq in frame %d.\n",
> >> + gtdt_frame->frame_number);
> >> + goto error;
> >> + }
> >> +
> >> + if (gtdt_frame->virtual_timer_interrupt) {
> >> + frame->virt_irq =
> >> + map_gt_gsi(gtdt_frame->virtual_timer_interrupt,
> >> + gtdt_frame->virtual_timer_flags);
> >> + if (frame->virt_irq <= 0) {
> >> + pr_warn("failed to map virtual timer irq in frame %d.\n",
> >> + gtdt_frame->frame_number);
> >> + acpi_unregister_gsi(gtdt_frame->timer_interrupt);
> >> + goto error;
> >> + }
> >> + } else {
> >> + frame->virt_irq = 0;
> >> + pr_debug("virtual timer in frame %d not implemented.\n",
> >> + gtdt_frame->frame_number);
> >> + }
> >> +
> >> + frame->cntbase = gtdt_frame->base_address;
> >> + /*
> >> + * The CNTBaseN frame is 4KB (register offsets 0x000 - 0xFFC).
> >> + * See ARM DDI 0487A.k_iss10775, page I1-5130, Table I1-4
> >> + * "CNTBaseN memory map".
> >> + */
> >> + frame->size = SZ_4K;
> >> + frame->valid = true;
> >> + }
> >> +
> >> + return 0;
> >> +
> >> +error:
> >> + for (i = 0; i < ARCH_TIMER_MEM_MAX_FRAMES; i++) {
> >> + frame = &timer_mem->frame[i];
> >> + if (!frame->valid)
> >> + continue;
> >> + irq_dispose_mapping(frame->phys_irq);
> >> + if (frame->virt_irq)
> >> + irq_dispose_mapping(frame->virt_irq);
> >> + }
> >
> > We assign interrupts and may goto error before setting valid, so here we
>
> yes, I mean to do it.(setting valid at the end of loop)
>
> > won't free the interrupts of the last frame we parsed.
>
> that won't be a problem, we may assign two interrupts in a round:
> First of all, if the assignment goes wrong, that means the current
> interrupt haven't been successfully assigned.
> (1)if the first goes wrong, the we goto error to unwind the irqs
> assigned in previous rounds.
> (2)if the second one goes wrong , we acpi_unregister_gsi the first one
> and then goto error to unwind the irqs assigned in previous rounds.
> (3)If the two assignments are successful, set up valid flag
>
> So we won't miss freeing the interrupts of the last frame we parsed.
>
> Did I miss something?

No; you are correct, and I was mistaken.

However, I would prefer to simplify this such that we only free the
IRQs in the error path.

We should be able to iterate over all freams, freeing any non-zero
interrupt, since !valid frames shouldn't have non-zero interrupts.

I can make that update locally; no need to respin.

Thanks,
Mark.

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