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Fri, 27 Nov 2020 21:49:51 -0800 (PST) Date: Sat, 28 Nov 2020 11:19:41 +0530 From: Manivannan Sadhasivam To: Loic Poulain Cc: hemantk@codeaurora.org, linux-arm-msm@vger.kernel.org, bbhatt@codeaurora.org Subject: Re: [PATCH v3 5/9] mhi: pci_generic: Add support for reset Message-ID: <20201128054941.GD3077@thinkpad> References: <1606404547-10737-1-git-send-email-loic.poulain@linaro.org> <1606404547-10737-6-git-send-email-loic.poulain@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1606404547-10737-6-git-send-email-loic.poulain@linaro.org> Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@vger.kernel.org On Thu, Nov 26, 2020 at 04:29:03PM +0100, Loic Poulain wrote: > Add support for resetting the device, reset can be triggered in case > of error or manually via sysfs (/sys/bus/pci/devices/*/reset). > > Signed-off-by: Loic Poulain > --- > drivers/bus/mhi/pci_generic.c | 119 +++++++++++++++++++++++++++++++++++++----- > 1 file changed, 106 insertions(+), 13 deletions(-) > > diff --git a/drivers/bus/mhi/pci_generic.c b/drivers/bus/mhi/pci_generic.c > index 6b6e5bf..67fcbcf 100644 > --- a/drivers/bus/mhi/pci_generic.c > +++ b/drivers/bus/mhi/pci_generic.c > @@ -8,6 +8,7 @@ > * Copyright (C) 2020 Linaro Ltd > */ > > +#include > #include > #include > #include > @@ -179,6 +180,16 @@ static const struct pci_device_id mhi_pci_id_table[] = { > }; > MODULE_DEVICE_TABLE(pci, mhi_pci_id_table); > > +enum mhi_pci_device_status { > + MHI_PCI_DEV_STARTED, > +}; > + > +struct mhi_pci_device { > + struct mhi_controller mhi_cntrl; > + struct pci_saved_state *pci_state; > + unsigned long status; > +}; > + > static int mhi_pci_read_reg(struct mhi_controller *mhi_cntrl, > void __iomem *addr, u32 *out) > { > @@ -203,6 +214,20 @@ static inline void mhi_pci_reset(struct mhi_controller *mhi_cntrl) > writel(1, mhi_cntrl->regs + DEV_RESET_REG); > } > > +static bool mhi_pci_is_alive(struct mhi_controller *mhi_cntrl) > +{ > + struct pci_dev *pdev = to_pci_dev(mhi_cntrl->cntrl_dev); > + u16 vendor = 0; > + > + if (pci_read_config_word(pdev, PCI_VENDOR_ID, &vendor)) > + return false; > + > + if (vendor == (u16) ~0 || vendor == 0) > + return false; > + > + return true; > +} > + > static int mhi_pci_claim(struct mhi_controller *mhi_cntrl, > unsigned int bar_num, u64 dma_mask) > { > @@ -298,16 +323,20 @@ static int mhi_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id) > { > const struct mhi_pci_dev_info *info = (struct mhi_pci_dev_info *) id->driver_data; > const struct mhi_controller_config *mhi_cntrl_config; > + struct mhi_pci_device *mhi_pdev; > struct mhi_controller *mhi_cntrl; > int err; > > dev_dbg(&pdev->dev, "MHI PCI device found: %s\n", info->name); > > - mhi_cntrl = mhi_alloc_controller(); > - if (!mhi_cntrl) > + mhi_pdev = devm_kzalloc(&pdev->dev, sizeof(*mhi_pdev), GFP_KERNEL); > + if (!mhi_pdev) > return -ENOMEM; Still not agreeing to use the alloc API? I know that it does only one job but the reason for pushing this API is that the MHI stack will misbehave terribly if a non-initialized structure is passed to it. And the only way to ensure is to provide an API and recommend the users to use it. > > mhi_cntrl_config = info->config; > + mhi_cntrl = &mhi_pdev->mhi_cntrl; > + > + mhi_initialize_controller(mhi_cntrl); No, please just stick to alloc API. Thanks, Mani > mhi_cntrl->cntrl_dev = &pdev->dev; > mhi_cntrl->iova_start = 0; > mhi_cntrl->iova_stop = (dma_addr_t)DMA_BIT_MASK(info->dma_data_width); > @@ -322,17 +351,21 @@ static int mhi_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id) > > err = mhi_pci_claim(mhi_cntrl, info->bar_num, DMA_BIT_MASK(info->dma_data_width)); > if (err) > - goto err_release; > + return err; > > err = mhi_pci_get_irqs(mhi_cntrl, mhi_cntrl_config); > if (err) > - goto err_release; > + return err; > + > + pci_set_drvdata(pdev, mhi_pdev); > > - pci_set_drvdata(pdev, mhi_cntrl); > + /* Have stored pci confspace at hand for restore in sudden PCI error */ > + pci_save_state(pdev); > + mhi_pdev->pci_state = pci_store_saved_state(pdev); > > err = mhi_register_controller(mhi_cntrl, mhi_cntrl_config); > if (err) > - goto err_release; > + return err; > > /* MHI bus does not power up the controller by default */ > err = mhi_prepare_for_power_up(mhi_cntrl); > @@ -347,37 +380,97 @@ static int mhi_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id) > goto err_unprepare; > } > > + set_bit(MHI_PCI_DEV_STARTED, &mhi_pdev->status); > + > return 0; > > err_unprepare: > mhi_unprepare_after_power_down(mhi_cntrl); > err_unregister: > mhi_unregister_controller(mhi_cntrl); > -err_release: > - mhi_free_controller(mhi_cntrl); > > return err; > } > > static void mhi_pci_remove(struct pci_dev *pdev) > { > - struct mhi_controller *mhi_cntrl = pci_get_drvdata(pdev); > + struct mhi_pci_device *mhi_pdev = pci_get_drvdata(pdev); > + struct mhi_controller *mhi_cntrl = &mhi_pdev->mhi_cntrl; > + > + if (test_and_clear_bit(MHI_PCI_DEV_STARTED, &mhi_pdev->status)) { > + mhi_power_down(mhi_cntrl, true); > + mhi_unprepare_after_power_down(mhi_cntrl); > + } > > - mhi_power_down(mhi_cntrl, true); > - mhi_unprepare_after_power_down(mhi_cntrl); > mhi_unregister_controller(mhi_cntrl); > > /* MHI-layer reset could not be enough, always hard-reset the device */ > mhi_pci_reset(mhi_cntrl); > +} > + > +void mhi_pci_reset_prepare(struct pci_dev *pdev) > +{ > + struct mhi_pci_device *mhi_pdev = pci_get_drvdata(pdev); > + struct mhi_controller *mhi_cntrl = &mhi_pdev->mhi_cntrl; > + > + dev_info(&pdev->dev, "reset\n"); > + > + /* Clean up MHI state */ > + if (test_and_clear_bit(MHI_PCI_DEV_STARTED, &mhi_pdev->status)) { > + mhi_power_down(mhi_cntrl, false); > + mhi_unprepare_after_power_down(mhi_cntrl); > + } > + > + /* cause internal device reset */ > + mhi_pci_reset(mhi_cntrl); > + > + /* Be sure device reset has been executed */ > + msleep(500); > +} > + > +void mhi_pci_reset_done(struct pci_dev *pdev) > +{ > + struct mhi_pci_device *mhi_pdev = pci_get_drvdata(pdev); > + struct mhi_controller *mhi_cntrl = &mhi_pdev->mhi_cntrl; > + int err; > + > + /* Restore initial known working PCI state */ > + pci_load_saved_state(pdev, mhi_pdev->pci_state); > + pci_restore_state(pdev); > + > + /* Is device status available ? */ > + if (!mhi_pci_is_alive(mhi_cntrl)) { > + dev_err(&pdev->dev, "reset failed\n"); > + return; > + } > > - mhi_free_controller(mhi_cntrl); > + err = mhi_prepare_for_power_up(mhi_cntrl); > + if (err) { > + dev_err(&pdev->dev, "failed to prepare MHI controller\n"); > + return; > + } > + > + err = mhi_sync_power_up(mhi_cntrl); > + if (err) { > + dev_err(&pdev->dev, "failed to power up MHI controller\n"); > + mhi_unprepare_after_power_down(mhi_cntrl); > + return; > + } > + > + set_bit(MHI_PCI_DEV_STARTED, &mhi_pdev->status); > } > > +static const struct pci_error_handlers mhi_pci_err_handler = { > + .reset_prepare = mhi_pci_reset_prepare, > + .reset_done = mhi_pci_reset_done, > +}; > + > static struct pci_driver mhi_pci_driver = { > .name = "mhi-pci-generic", > .id_table = mhi_pci_id_table, > .probe = mhi_pci_probe, > - .remove = mhi_pci_remove > + .remove = mhi_pci_remove, > + .err_handler = &mhi_pci_err_handler, > }; > module_pci_driver(mhi_pci_driver); > > -- > 2.7.4 >