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 <loic.poulain@xxxxxxxxxx>
> ---
> 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 <loic.poulain@xxxxxxxxxx>
> */
>
> +#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 +323,20 @@ 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
>
