From 7a97b6b47353c60dd1b53ada6180741437e377f2 Mon Sep 17 00:00:00 2001 From: Manivannan Sadhasivam Date: Tue, 5 Apr 2022 19:27:47 +0530 Subject: [PATCH] bus: mhi: ep: Add support for handling MHI_RESET Add support for handling MHI_RESET in MHI endpoint stack. MHI_RESET will be issued by the host during shutdown and during error scenario so that it can recover the endpoint device without restarting the whole device. MHI_RESET handling involves resetting the internal MHI registers, data structures, state machines, resetting all channels/rings and setting MHICTRL.RESET bit to 0. Additionally the device will also move to READY state if the reset was due to SYS_ERR. Reviewed-by: Alex Elder Signed-off-by: Manivannan Sadhasivam Link: https://lore.kernel.org/r/20220405135754.6622-12-manivannan.sadhasivam@linaro.org Signed-off-by: Greg Kroah-Hartman --- drivers/bus/mhi/ep/main.c | 53 +++++++++++++++++++++++++++++++++++++++ include/linux/mhi_ep.h | 2 ++ 2 files changed, 55 insertions(+) diff --git a/drivers/bus/mhi/ep/main.c b/drivers/bus/mhi/ep/main.c index 968025e4d3ac..d36708d43eb6 100644 --- a/drivers/bus/mhi/ep/main.c +++ b/drivers/bus/mhi/ep/main.c @@ -381,6 +381,7 @@ static irqreturn_t mhi_ep_irq(int irq, void *data) struct device *dev = &mhi_cntrl->mhi_dev->dev; enum mhi_state state; u32 int_value; + bool mhi_reset; /* Acknowledge the ctrl interrupt */ int_value = mhi_ep_mmio_read(mhi_cntrl, MHI_CTRL_INT_STATUS); @@ -389,6 +390,14 @@ static irqreturn_t mhi_ep_irq(int irq, void *data) /* Check for ctrl interrupt */ if (FIELD_GET(MHI_CTRL_INT_STATUS_MSK, int_value)) { dev_dbg(dev, "Processing ctrl interrupt\n"); + mhi_ep_mmio_get_mhi_state(mhi_cntrl, &state, &mhi_reset); + if (mhi_reset) { + dev_info(dev, "Host triggered MHI reset!\n"); + disable_irq_nosync(mhi_cntrl->irq); + schedule_work(&mhi_cntrl->reset_work); + return IRQ_HANDLED; + } + mhi_ep_process_ctrl_interrupt(mhi_cntrl, state); } @@ -464,6 +473,49 @@ static void mhi_ep_abort_transfer(struct mhi_ep_cntrl *mhi_cntrl) mhi_cntrl->enabled = false; } +static void mhi_ep_reset_worker(struct work_struct *work) +{ + struct mhi_ep_cntrl *mhi_cntrl = container_of(work, struct mhi_ep_cntrl, reset_work); + struct device *dev = &mhi_cntrl->mhi_dev->dev; + enum mhi_state cur_state; + int ret; + + mhi_ep_abort_transfer(mhi_cntrl); + + spin_lock_bh(&mhi_cntrl->state_lock); + /* Reset MMIO to signal host that the MHI_RESET is completed in endpoint */ + mhi_ep_mmio_reset(mhi_cntrl); + cur_state = mhi_cntrl->mhi_state; + spin_unlock_bh(&mhi_cntrl->state_lock); + + /* + * Only proceed further if the reset is due to SYS_ERR. The host will + * issue reset during shutdown also and we don't need to do re-init in + * that case. + */ + if (cur_state == MHI_STATE_SYS_ERR) { + mhi_ep_mmio_init(mhi_cntrl); + + /* Set AMSS EE before signaling ready state */ + mhi_ep_mmio_set_env(mhi_cntrl, MHI_EE_AMSS); + + /* All set, notify the host that we are ready */ + ret = mhi_ep_set_ready_state(mhi_cntrl); + if (ret) + return; + + dev_dbg(dev, "READY state notification sent to the host\n"); + + ret = mhi_ep_enable(mhi_cntrl); + if (ret) { + dev_err(dev, "Failed to enable MHI endpoint: %d\n", ret); + return; + } + + enable_irq(mhi_cntrl->irq); + } +} + int mhi_ep_power_up(struct mhi_ep_cntrl *mhi_cntrl) { struct device *dev = &mhi_cntrl->mhi_dev->dev; @@ -738,6 +790,7 @@ int mhi_ep_register_controller(struct mhi_ep_cntrl *mhi_cntrl, } INIT_WORK(&mhi_cntrl->state_work, mhi_ep_state_worker); + INIT_WORK(&mhi_cntrl->reset_work, mhi_ep_reset_worker); mhi_cntrl->wq = alloc_workqueue("mhi_ep_wq", 0, 0); if (!mhi_cntrl->wq) { diff --git a/include/linux/mhi_ep.h b/include/linux/mhi_ep.h index 9da683e8302c..2f31a54c205f 100644 --- a/include/linux/mhi_ep.h +++ b/include/linux/mhi_ep.h @@ -76,6 +76,7 @@ struct mhi_ep_db_info { * @ch_db_list: List of queued channel doorbells * @wq: Dedicated workqueue for handling rings and state changes * @state_work: State transition worker + * @reset_work: Worker for MHI Endpoint reset * @raise_irq: CB function for raising IRQ to the host * @alloc_map: CB function for allocating memory in endpoint for storing host context and mapping it * @unmap_free: CB function to unmap and free the allocated memory in endpoint for storing host context @@ -122,6 +123,7 @@ struct mhi_ep_cntrl { struct workqueue_struct *wq; struct work_struct state_work; + struct work_struct reset_work; void (*raise_irq)(struct mhi_ep_cntrl *mhi_cntrl, u32 vector); int (*alloc_map)(struct mhi_ep_cntrl *mhi_cntrl, u64 pci_addr, phys_addr_t *phys_ptr,