From 79d056976485baaa6225ff2331b83084051c98a8 Mon Sep 17 00:00:00 2001 From: Bhaumik Bhatt Date: Wed, 31 Mar 2021 11:34:25 -0700 Subject: bus: mhi: core: Move to polling method to wait for MHI ready 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 Reviewed-by: Loic Poulain Reviewed-by: Manivannan Sadhasivam Link: https://lore.kernel.org/r/1617215665-19593-3-git-send-email-bbhatt@codeaurora.org Signed-off-by: Manivannan Sadhasivam --- 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 b6920a5369a0..e4aff777d74b 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"); -- cgit v1.2.3