Re: [PATCH v1 6/7] bus: mhi: core: Wait for MHI READY state in most scenarios
From: Manivannan Sadhasivam
Date: Wed Mar 31 2021 - 07:14:32 EST
On Mon, Mar 29, 2021 at 06:28:23PM -0700, Bhaumik Bhatt wrote:
> When moving from SYS_ERROR transition to a different execution
> environment, MHI host relies on the BHI register read to spawn
> the next image download or wait for READY -> M0 states. The
> device can at times move the execution environment to mission
> mode when a pass through is expected, which can result in a
> stall. Initiate a wait for MHI READY and write M0 such that the
> device can proceed with state change event updates for any new
> execution environment being entered. This allows us to remove
> conditionals in handling firmware load for PBL modes and keeps
> the execution environment out of the picture as it can change at
> any time.
>
> Signed-off-by: Bhaumik Bhatt <bbhatt@xxxxxxxxxxxxxx>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@xxxxxxxxxx>
Thanks,
Mani
> ---
> drivers/bus/mhi/core/boot.c | 4 ++--
> drivers/bus/mhi/core/pm.c | 3 +--
> 2 files changed, 3 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/bus/mhi/core/boot.c b/drivers/bus/mhi/core/boot.c
> index 0f0ae88..8100cf5 100644
> --- a/drivers/bus/mhi/core/boot.c
> +++ b/drivers/bus/mhi/core/boot.c
> @@ -416,8 +416,8 @@ void mhi_fw_load_handler(struct mhi_controller *mhi_cntrl)
> }
> }
>
> - /* If device is in pass through, do reset to ready state transition */
> - if (mhi_cntrl->ee == MHI_EE_PTHRU)
> + /* wait for ready on pass through or any other execution environment */
> + if (mhi_cntrl->ee != MHI_EE_EDL && mhi_cntrl->ee != MHI_EE_PBL)
> goto fw_load_ready_state;
>
> fw_name = (mhi_cntrl->ee == MHI_EE_EDL) ?
> diff --git a/drivers/bus/mhi/core/pm.c b/drivers/bus/mhi/core/pm.c
> index 7ac9dfe..b6920a5 100644
> --- a/drivers/bus/mhi/core/pm.c
> +++ b/drivers/bus/mhi/core/pm.c
> @@ -763,8 +763,7 @@ void mhi_pm_st_worker(struct work_struct *work)
> if (MHI_REG_ACCESS_VALID(mhi_cntrl->pm_state))
> mhi_cntrl->ee = mhi_get_exec_env(mhi_cntrl);
> write_unlock_irq(&mhi_cntrl->pm_lock);
> - if (MHI_IN_PBL(mhi_cntrl->ee))
> - mhi_fw_load_handler(mhi_cntrl);
> + mhi_fw_load_handler(mhi_cntrl);
> break;
> case DEV_ST_TRANSITION_SBL:
> write_lock_irq(&mhi_cntrl->pm_lock);
> --
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