mtd: pxa3xx_nand: issue with command time out

Robert Jarzmik robert.jarzmik at free.fr
Mon Jan 25 12:48:02 PST 2016


Brian Norris <computersforpeace at gmail.com> writes:

> Hi Robert,
>
> On Sun, Jan 17, 2016 at 12:53:06AM +0100, Robert Jarzmik wrote:
> commit 24542257a3b987025d4b998ec2d15e556c98ad3f
> Author: Robert Jarzmik <robert.jarzmik at free.fr>
> Date:   Fri Feb 20 19:36:43 2015 +0100
>
>     mtd: pxa3xx-nand: handle PIO in threaded interrupt
>
>
> And now I'm wondering: when does the completion get triggered? i.e.:
>
> 	complete(&info->cmd_complete);

> It seems to me like you've short-circuited some of the IRQ handling
> code, so that the threaded handler is buggy. AIUI, if the completion
> event ever happens, it's actually happening *before* the full (threaded)
> handler is actually finished, since it occurs in pxa3xx_nand_irq(),
> before pxa3xx_nand_irq_thread() ever runs. Now, I'm not sure if that
> causes a real problem in practice, since you used IRQF_ONESHOT, but I
> would think that's also suspect.

I think you're very right, this "goto NORMAL_IRQ_EXIT" creates a
short-cirtcuit. That makes me think that I should :
 - add
static void pxa3xx_nand_data_finished(struct pxa3xx_nand_info *info)
{
	unsigned int done;

 	cmd_done = info->cs ? NDSR_CS1_CMDD : NDSR_CS0_CMDD;
	nand_writel(info, NDSR, cmd_done);
        complete(&inf0->cmd_complete);
}

 - in pxa3xx_nand_irq_thread(), I should add at the end:
	pxa3xx_nand_data_finished(info);

 - in pxa3xx_nand_data_dma_irq(), I should add at the end:
	pxa3xx_nand_data_finished(info);

Ezequiel, would you have a look at that code snippet and tell me if I'm missing
something in the driver's structure ?

Cheers.

--
Robert



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