On 06/01/2022 17:44, Greg KH wrote:

On Thu, Jan 06, 2022 at 05:24:27PM +0000, Bryan O'Donoghue wrote:

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On 03/01/2022 05:51, Manivannan Sadhasivam wrote:

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On Mon, Jan 03, 2022 at 03:03:15AM +0000, Bryan O'Donoghue wrote:

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Interacting with a NAND chip on an IPQ6018 I found that the qcomsmem NAND partition parser was returning -EPROBE_DEFER waiting for the main smem driver to load.

This caused the board to reset. Playing about with the probe() function shows that the problem lies in the core clock being switched off before the nandc_unalloc() routine has completed.

If we look at how qcom_nandc_remove() tears down allocated resources we see the expected order is

qcom_nandc_unalloc(nandc);

clk_disable_unprepare(nandc->aon_clk); clk_disable_unprepare(nandc->core_clk);

dma_unmap_resource(&pdev->dev, nandc->base_dma, resource_size(res), DMA_BIDIRECTIONAL, 0);

Tweaking probe() to both bring up and tear-down in that order removes the reset if we end up deferring elsewhere.

Fixes: c76b78d8ec05 ("mtd: nand: Qualcomm NAND controller driver") Signed-off-by: Bryan O'Donoghue bryan.odonoghue@linaro.org

Reviewed-by: Manivannan Sadhasivam mani@kernel.org

Can you please CC stable list for backporting?

Thanks, Mani

NP.

• cc stable

FWIW I believe Greg's scripts will pick up on Fixes: tags automatically

No, that is NOT the way to ensure that a patch will get picked up, that is a "this might eventually get there".

Please read: https://www.kernel.org/doc/html/latest/process/stable-kernel-rules.html for how to do this properly.

thanks,

greg k-h

Good to know

I've just been using Fixes: for the most part

Thanks

--- bod