| Message ID | 1617215665-19593-3-git-send-email-bbhatt@codeaurora.org (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | 79d056976485baaa6225ff2331b83084051c98a8 |
| Headers | show |
| Series | Polling for MHI ready | expand |
On Wed, Mar 31, 2021 at 11:34:25AM -0700, Bhaumik Bhatt wrote: > In certain devices, it is likely that there is no incoming MHI > interrupt for a transition to MHI READY state. One such example > is the move from Pass Through to an SBL or AMSS execution > environment. In order to facilitate faster bootup times as there > is no need to wait until timeout_ms completes, MHI host can poll > every 25 milliseconds to check if device has entered MHI READY > until a maximum timeout of twice the timeout_ms is reached. > > Signed-off-by: Bhaumik Bhatt <bbhatt@codeaurora.org> > Reviewed-by: Loic Poulain <loic.poulain@linaro.org> Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org> Thanks, Mani > --- > drivers/bus/mhi/core/pm.c | 34 ++++++++++++++++------------------ > 1 file changed, 16 insertions(+), 18 deletions(-) > > diff --git a/drivers/bus/mhi/core/pm.c b/drivers/bus/mhi/core/pm.c > index b6920a5..e4aff77 100644 > --- a/drivers/bus/mhi/core/pm.c > +++ b/drivers/bus/mhi/core/pm.c > @@ -153,35 +153,33 @@ static void mhi_toggle_dev_wake(struct mhi_controller *mhi_cntrl) > /* Handle device ready state transition */ > int mhi_ready_state_transition(struct mhi_controller *mhi_cntrl) > { > - void __iomem *base = mhi_cntrl->regs; > struct mhi_event *mhi_event; > enum mhi_pm_state cur_state; > struct device *dev = &mhi_cntrl->mhi_dev->dev; > - u32 reset = 1, ready = 0; > + u32 interval_us = 25000; /* poll register field every 25 milliseconds */ > int ret, i; > > - /* Wait for RESET to be cleared and READY bit to be set by the device */ > - 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) || > - mhi_read_reg_field(mhi_cntrl, base, MHISTATUS, > - MHISTATUS_READY_MASK, > - MHISTATUS_READY_SHIFT, &ready) || > - (!reset && ready), > - msecs_to_jiffies(mhi_cntrl->timeout_ms)); > - > /* Check if device entered error state */ > if (MHI_PM_IN_FATAL_STATE(mhi_cntrl->pm_state)) { > dev_err(dev, "Device link is not accessible\n"); > return -EIO; > } > > - /* Timeout if device did not transition to ready state */ > - if (reset || !ready) { > - dev_err(dev, "Device Ready timeout\n"); > - return -ETIMEDOUT; > + /* Wait for RESET to be cleared and READY bit to be set by the device */ > + ret = mhi_poll_reg_field(mhi_cntrl, mhi_cntrl->regs, MHICTRL, > + MHICTRL_RESET_MASK, MHICTRL_RESET_SHIFT, 0, > + interval_us); > + if (ret) { > + dev_err(dev, "Device failed to clear MHI Reset\n"); > + return ret; > + } > + > + ret = mhi_poll_reg_field(mhi_cntrl, mhi_cntrl->regs, MHISTATUS, > + MHISTATUS_READY_MASK, MHISTATUS_READY_SHIFT, 1, > + interval_us); > + if (ret) { > + dev_err(dev, "Device failed to enter MHI Ready\n"); > + return ret; > } > > dev_dbg(dev, "Device in READY State\n"); > -- > The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, > a Linux Foundation Collaborative Project >
diff --git a/drivers/bus/mhi/core/pm.c b/drivers/bus/mhi/core/pm.c index b6920a5..e4aff77 100644 --- a/drivers/bus/mhi/core/pm.c +++ b/drivers/bus/mhi/core/pm.c @@ -153,35 +153,33 @@ static void mhi_toggle_dev_wake(struct mhi_controller *mhi_cntrl) /* Handle device ready state transition */ int mhi_ready_state_transition(struct mhi_controller *mhi_cntrl) { - void __iomem *base = mhi_cntrl->regs; struct mhi_event *mhi_event; enum mhi_pm_state cur_state; struct device *dev = &mhi_cntrl->mhi_dev->dev; - u32 reset = 1, ready = 0; + u32 interval_us = 25000; /* poll register field every 25 milliseconds */ int ret, i; - /* Wait for RESET to be cleared and READY bit to be set by the device */ - 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) || - mhi_read_reg_field(mhi_cntrl, base, MHISTATUS, - MHISTATUS_READY_MASK, - MHISTATUS_READY_SHIFT, &ready) || - (!reset && ready), - msecs_to_jiffies(mhi_cntrl->timeout_ms)); - /* Check if device entered error state */ if (MHI_PM_IN_FATAL_STATE(mhi_cntrl->pm_state)) { dev_err(dev, "Device link is not accessible\n"); return -EIO; } - /* Timeout if device did not transition to ready state */ - if (reset || !ready) { - dev_err(dev, "Device Ready timeout\n"); - return -ETIMEDOUT; + /* Wait for RESET to be cleared and READY bit to be set by the device */ + ret = mhi_poll_reg_field(mhi_cntrl, mhi_cntrl->regs, MHICTRL, + MHICTRL_RESET_MASK, MHICTRL_RESET_SHIFT, 0, + interval_us); + if (ret) { + dev_err(dev, "Device failed to clear MHI Reset\n"); + return ret; + } + + ret = mhi_poll_reg_field(mhi_cntrl, mhi_cntrl->regs, MHISTATUS, + MHISTATUS_READY_MASK, MHISTATUS_READY_SHIFT, 1, + interval_us); + if (ret) { + dev_err(dev, "Device failed to enter MHI Ready\n"); + return ret; } dev_dbg(dev, "Device in READY State\n");