[v5,0/2] Polling for MHI ready

Message

Bhaumik Bhatt March 29, 2021, 7:53 p.m. UTC

v5:
-Use fsleep in place of udelay or usleep_range to accommodate better delay use
-Drop patch for polling during RDDM panic path as new API cannot be used there

v4:
-Added reviewed-by tag
-Return appropriate error code from mhi_poll_reg_field()
-Fixed bug where mhi_poll_reg_field() returns success if polling times out
-Added an interval_us variable in mhi_ready_state_transition()

v3:
-Removed config changes that crept in in the first patch

v2:
-Addressed review comments
-Introduce new patch for to use controller defined read_reg() for polling
-Add usage in RDDM download panic path as well

Use polling instead of interrupt driven approach to wait for MHI ready state.

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.

This patch series has been tested on an arm64 device.

Bhaumik Bhatt (2):
  bus: mhi: core: Introduce internal register poll helper function
  bus: mhi: core: Move to polling method to wait for MHI ready

 drivers/bus/mhi/core/internal.h |  3 +++
 drivers/bus/mhi/core/main.c     | 23 +++++++++++++++++++++++
 drivers/bus/mhi/core/pm.c       | 32 +++++++++++++++-----------------
 3 files changed, 41 insertions(+), 17 deletions(-)