| Message ID | 20220103030316.58301-2-bryan.odonoghue@linaro.org |
|---|---|
| State | Accepted |
| Commit | 5c23b3f965bc9ee696bf2ed4bdc54d339dd9a455 |
| Headers | show |
| Series | Two Qcom NAND related fixes. | expand |
On 03/01/2022 05:51, Manivannan Sadhasivam wrote: > On Mon, Jan 03, 2022 at 03:03:15AM +0000, Bryan O'Donoghue wrote: >> 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
On Mon, 2022-01-03 at 03:03:15 UTC, Bryan O'Donoghue wrote: > 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> Applied to https://git.kernel.org/pub/scm/linux/kernel/git/mtd/linux.git mtd/next, thanks. Miquel
miquel.raynal@bootlin.com wrote on Sun, 23 Jan 2022 16:23:26 +0100: > On Mon, 2022-01-03 at 03:03:15 UTC, Bryan O'Donoghue wrote: > > 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> > > Applied to https://git.kernel.org/pub/scm/linux/kernel/git/mtd/linux.git mtd/next, thanks. Both patches pushed to mtd/fixes, actually.
diff --git a/drivers/mtd/nand/raw/qcom_nandc.c b/drivers/mtd/nand/raw/qcom_nandc.c index 04e6f7b267064..0f41a9a421575 100644 --- a/drivers/mtd/nand/raw/qcom_nandc.c +++ b/drivers/mtd/nand/raw/qcom_nandc.c @@ -2,7 +2,6 @@ /* * Copyright (c) 2016, The Linux Foundation. All rights reserved. */ - #include <linux/clk.h> #include <linux/slab.h> #include <linux/bitops.h> @@ -3063,10 +3062,6 @@ static int qcom_nandc_probe(struct platform_device *pdev) if (dma_mapping_error(dev, nandc->base_dma)) return -ENXIO; - ret = qcom_nandc_alloc(nandc); - if (ret) - goto err_nandc_alloc; - ret = clk_prepare_enable(nandc->core_clk); if (ret) goto err_core_clk; @@ -3075,6 +3070,10 @@ static int qcom_nandc_probe(struct platform_device *pdev) if (ret) goto err_aon_clk; + ret = qcom_nandc_alloc(nandc); + if (ret) + goto err_nandc_alloc; + ret = qcom_nandc_setup(nandc); if (ret) goto err_setup; @@ -3086,15 +3085,14 @@ static int qcom_nandc_probe(struct platform_device *pdev) return 0; err_setup: + qcom_nandc_unalloc(nandc); +err_nandc_alloc: clk_disable_unprepare(nandc->aon_clk); err_aon_clk: clk_disable_unprepare(nandc->core_clk); err_core_clk: - qcom_nandc_unalloc(nandc); -err_nandc_alloc: dma_unmap_resource(dev, res->start, resource_size(res), DMA_BIDIRECTIONAL, 0); - return ret; }
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> --- drivers/mtd/nand/raw/qcom_nandc.c | 14 ++++++-------- 1 file changed, 6 insertions(+), 8 deletions(-)