Messages in this thread | | | Subject | Re: [PATCH v2 1/5] bus: mhi: core: Handle syserr during power_up | From | Bhaumik Vasav Bhatt <> | Date | Fri, 10 Apr 2020 13:37:36 -0700 |
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Hi Jeff,
We will always have the mhi_intvec_handler registered and trigger your wake_up state event when you write MHI RESET. BHI INTVEC IRQ using mhi_cntrl->irq[0] is _not_ unregistered once you enter AMSS EE.
So, your below assumption is not true: >>>So, if we are in the PBL EE, we would expect to see the BHI interrupt, but if we are in the AMSS EE, we would expect to see a MHI interrupt.
At the start of mhi_async_power_up(), you've already registered for the BHI interrupt as we do setup for IRQ and it is only unregistered from power down if power up on the same cycle was a success.
On 4/10/20 8:03 AM, Jeffrey Hugo wrote: > On 4/9/2020 6:55 PM, Hemant Kumar wrote: >> >> On 4/7/20 9:50 AM, Jeffrey Hugo wrote: >>> The MHI device may be in the syserr state when we attempt to init it in >>> power_up(). Since we have no local state, the handling is simple - >>> reset the device and wait for it to transition out of the reset state. >>> >>> Signed-off-by: Jeffrey Hugo <jhugo@codeaurora.org> >>> --- >>> drivers/bus/mhi/core/pm.c | 20 ++++++++++++++++++++ >>> 1 file changed, 20 insertions(+) >>> >>> diff --git a/drivers/bus/mhi/core/pm.c b/drivers/bus/mhi/core/pm.c >>> index 52690cb..3285c9e 100644 >>> --- a/drivers/bus/mhi/core/pm.c >>> +++ b/drivers/bus/mhi/core/pm.c >>> @@ -9,6 +9,7 @@ >>> #include <linux/dma-direction.h> >>> #include <linux/dma-mapping.h> >>> #include <linux/interrupt.h> >>> +#include <linux/iopoll.h> >>> #include <linux/list.h> >>> #include <linux/mhi.h> >>> #include <linux/module.h> >>> @@ -760,6 +761,7 @@ static void mhi_deassert_dev_wake(struct >>> mhi_controller *mhi_cntrl, >>> int mhi_async_power_up(struct mhi_controller *mhi_cntrl) >>> { >>> + enum mhi_state state; >>> enum mhi_ee_type current_ee; >>> enum dev_st_transition next_state; >>> struct device *dev = &mhi_cntrl->mhi_dev->dev; >>> @@ -829,6 +831,24 @@ int mhi_async_power_up(struct mhi_controller >>> *mhi_cntrl) >>> goto error_bhi_offset; >>> } >>> + state = mhi_get_mhi_state(mhi_cntrl); >>> + if (state == MHI_STATE_SYS_ERR) { >>> + mhi_set_mhi_state(mhi_cntrl, MHI_STATE_RESET); >>> + ret = readl_poll_timeout(mhi_cntrl->regs + MHICTRL, val, >>> + !(val & MHICTRL_RESET_MASK), 1000, >>> + mhi_cntrl->timeout_ms * 1000); >> can we use this instead of polling because MSI is configures and >> int_vec handler is registered >> >> wait_event_timeout(mhi_cntrl->state_event, >> MHI_PM_IN_FATAL_STATE(mhi_cntrl->pm_state) || >> mhi_read_reg_field(mhi_cntrl, base, MHICTRL, >> MHICTRL_RESET_MASK, >> MHICTRL_RESET_SHIFT, &reset) || !reset , >> msecs_to_jiffies(mhi_cntrl->timeout_ms)); >> >> 1) In case of MHI_PM_IN_FATAL_STATE we would not be accessing MHI reg >> 2) Consistent with current MHI driver code. > > I'm not sure this works in the way you intend. > > state_event is linked to the intvec, which is the BHI interrupt. I > don't see that the state_event is triggered in the MHI interrupt path > (mhi_irq_handler). So, if we are in the PBL EE, we would expect to > see the BHI interrupt, but if we are in the AMSS EE, we would expect > to see a MHI interrupt. > > Now, for my concerned usecase, those two interrupts happen to be the > same interrupt, so both will get triggered, but I don't expect that to > be the same for all usecases. > > So, with the solution I propose, we exit the wait (poll loop) as soon > as we see the register change values. > > With the solution you propose, if we only get the MHI interrupt, we'll > have to wait out the entire timeout value, and then check the > register. In this scenario, we are almost guaranteed to wait for > longer than necessary. > > Did I miss something? > >>> + if (ret) { >>> + dev_info(dev, "Failed to reset MHI due to syserr >>> state\n"); >>> + goto error_bhi_offset; >>> + } >>> + >>> + /* >>> + * device cleares INTVEC as part of RESET processing, >>> + * re-program it >>> + */ >>> + mhi_write_reg(mhi_cntrl, mhi_cntrl->bhi, BHI_INTVEC, 0); >>> + } >>> + >>> /* Transition to next state */ >>> next_state = MHI_IN_PBL(current_ee) ? >>> DEV_ST_TRANSITION_PBL : DEV_ST_TRANSITION_READY; >> > > -- The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project
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