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SubjectRe: [Patch v4 1/2] dmaengine: add Qualcomm BAM dma driver
On Tue, Feb 04, 2014 at 12:58:25PM +0100, Lars-Peter Clausen wrote:
> On 02/04/2014 12:04 AM, Andy Gross wrote:
> [...]
> >+static int bam_dma_remove(struct platform_device *pdev)
> >+{
> >+ struct bam_device *bdev = platform_get_drvdata(pdev);
> >+ u32 i;
> >+
> >+ dma_async_device_unregister(&bdev->common);
> >+ of_dma_controller_free(pdev->dev.of_node);
>
> The controller should first be removed from the of lookup table,
> then free the device.
>
Ah right, had this reversed.

> >+
> >+ /* mask all interrupts for this execution environment */
> >+ writel_relaxed(0, bdev->regs + BAM_IRQ_SRCS_MSK_EE(bdev->ee));
>
> You still need to free the interrupt to make this race free,
> especially on a multi-processor system. free_irq() acts as a
> synchronization point that makes sure that interrupt handler has
> finished running and that no new interrupt handlers are being run
> after this point. Just masking the interrupt in the control register
> does not provide these guarantees.

ok i'll just add in a devm_free_irq(). The only good thing then about using the
devm_request_irq is the cleanup on error paths in the probe.

> >+
> >+ for (i = 0; i < bdev->num_channels; i++) {
> >+ bam_dma_terminate_all(&bdev->channels[i]);
> >+ tasklet_kill(&bdev->channels[i].vc.task);
> >+ }
> >+
> >+ tasklet_kill(&bdev->task);
> >+
> >+ clk_disable_unprepare(bdev->bamclk);
> >+
> >+ return 0;
> >+}
> [...]
>

--
sent by an employee of the Qualcomm Innovation Center, Inc.
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
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