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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: Alex Elder <elder@linaro.org>
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Link: https://lore.kernel.org/r/20220405135754.6622-12-manivannan.sadhasivam@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Manivannan Sadhasivam 2022-04-05 19:27:47 +05:30 committed by Greg Kroah-Hartman
parent 5d507ee048
commit 7a97b6b473
2 changed files with 55 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

53
drivers/bus/mhi/ep/main.c
View File

@ -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) {

2
include/linux/mhi_ep.h
View File

@ -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,