Commit 7a97b6b4 authored by Manivannan Sadhasivam's avatar Manivannan Sadhasivam Committed by Greg Kroah-Hartman
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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: default avatarAlex Elder <elder@linaro.org>
Signed-off-by: default avatarManivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Link: https://lore.kernel.org/r/20220405135754.6622-12-manivannan.sadhasivam@linaro.org


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 5d507ee0

drivers/bus/mhi/ep/main.c

+53 −0
Original line number Diff line number Diff line
@@ -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) {

include/linux/mhi_ep.h

+2 −0
Original line number Diff line number Diff line
@@ -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,