From: Bhaumik Bhatt <bbhatt@codeaurora.org>
To: Loic Poulain <loic.poulain@linaro.org>
Cc: manivannan.sadhasivam@linaro.org, hemantk@codeaurora.org,
linux-arm-msm@vger.kernel.org
Subject: Re: [PATCH 4/8] mhi: pci_generic: Add support for reset
Date: Fri, 13 Nov 2020 09:12:16 -0800 [thread overview]
Message-ID: <d207bf6fde62bafd217ef7427d7f00c8@codeaurora.org> (raw)
In-Reply-To: <1605279602-18749-5-git-send-email-loic.poulain@linaro.org>
On 2020-11-13 06:59, 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 <loic.poulain@linaro.org>
> ---
> drivers/bus/mhi/pci_generic.c | 117
> +++++++++++++++++++++++++++++++++++++-----
> 1 file changed, 104 insertions(+), 13 deletions(-)
>
> diff --git a/drivers/bus/mhi/pci_generic.c
> b/drivers/bus/mhi/pci_generic.c
> index 0c07cf5..b48c382 100644
> --- a/drivers/bus/mhi/pci_generic.c
> +++ b/drivers/bus/mhi/pci_generic.c
> @@ -8,6 +8,7 @@
> * Copyright (C) 2020 Linaro Ltd <loic.poulain@linaro.org>
> */
>
> +#include <linux/delay.h>
> #include <linux/device.h>
> #include <linux/mhi.h>
> #include <linux/module.h>
> @@ -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 +323,18 @@ 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)
Not recommended.
> + mhi_pdev = devm_kzalloc(&pdev->dev, sizeof(*mhi_pdev), GFP_KERNEL);
> + if (!mhi_pdev)
> return -ENOMEM;
Why move away from the mhi_alloc_controller/mhi_free_controller pair we
recommended for use?
>
> mhi_cntrl_config = info->config;
> + mhi_cntrl = &mhi_pdev->mhi_cntrl;
> mhi_cntrl->cntrl_dev = &pdev->dev;
> mhi_cntrl->iova_start = 0;
> mhi_cntrl->iova_stop = DMA_BIT_MASK(info->dma_data_width);
> @@ -322,17 +349,21 @@ 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 +378,97 @@ 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);
Not recommended.
>
> 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");
>
> - mhi_free_controller(mhi_cntrl);
> + /* 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;
> + }
> +
> + 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);
--
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora
Forum,
a Linux Foundation Collaborative Project
next prev parent reply other threads:[~2020-11-13 17:12 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-13 14:59 [PATCH 0/8] mhi: pci_generic: Misc improvements Loic Poulain
2020-11-13 14:59 ` [PATCH 1/8] mhi: pci-generic: Increase number of hardware events Loic Poulain
2020-11-13 16:56 ` Bhaumik Bhatt
2020-11-18 3:54 ` Hemant Kumar
2020-11-18 8:26 ` Loic Poulain
2020-11-19 1:50 ` Hemant Kumar
2020-11-19 9:42 ` Loic Poulain
2020-11-13 14:59 ` [PATCH 2/8] mhi: pci-generic: Perform hard reset on remove Loic Poulain
2020-11-19 1:46 ` Hemant Kumar
2020-11-19 9:21 ` Loic Poulain
2020-11-25 17:41 ` Jeffrey Hugo
2020-11-27 16:21 ` Loic Poulain
2020-12-02 1:54 ` Bhaumik Bhatt
2020-11-13 14:59 ` [PATCH 3/8] mhi: pci_generic: Enable burst mode for hardware channels Loic Poulain
2020-11-13 17:06 ` Bhaumik Bhatt
2020-11-13 14:59 ` [PATCH 4/8] mhi: pci_generic: Add support for reset Loic Poulain
2020-11-13 17:12 ` Bhaumik Bhatt [this message]
2020-11-13 17:42 ` Loic Poulain
2020-11-13 17:44 ` Bhaumik Bhatt
2020-11-13 14:59 ` [PATCH 5/8] mhi: pci_generic: Add suspend/resume/recovery procedure Loic Poulain
2020-11-19 2:21 ` Hemant Kumar
2020-11-19 9:54 ` Loic Poulain
2020-11-13 15:00 ` [PATCH 6/8] mhi: pci_generic: Add PCI error handlers Loic Poulain
2020-11-13 15:00 ` [PATCH 7/8] mhi: pci_generic: Add health-check Loic Poulain
2020-11-13 15:00 ` [PATCH 8/8] mhi: pci_generic: Increase controller timeout value Loic Poulain
2020-11-13 17:08 ` Bhaumik Bhatt
2020-11-25 20:23 ` Hemant Kumar
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