bus: mhi: core: Add support for downloading RDDM image during panic

MHI protocol supports downloading RDDM (RAM Dump) image from the
device through BHIE. This is useful to debugging as the RDDM image
can capture the firmware state.

This is based on the patch submitted by Sujeev Dias:
https://lkml.org/lkml/2018/7/9/989

Signed-off-by: Sujeev Dias <sdias@codeaurora.org>
Signed-off-by: Siddartha Mohanadoss <smohanad@codeaurora.org>
[mani: splitted the data transfer patch and cleaned up for upstream]
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Reviewed-by: Jeffrey Hugo <jhugo@codeaurora.org>
Tested-by: Jeffrey Hugo <jhugo@codeaurora.org>
Link: https://lore.kernel.org/r/20200220095854.4804-10-manivannan.sadhasivam@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 32 insertions, 0 deletions

diff --git a/drivers/bus/mhi/core/pm.c b/drivers/bus/mhi/core/pm.c
index bfe0371f6e75..2ba2f6aba9d5 100644
--- a/drivers/bus/mhi/core/pm.c
+++ b/drivers/bus/mhi/core/pm.c
@@ -450,6 +450,16 @@ static void mhi_pm_disable_transition(struct mhi_controller *mhi_cntrl,
 
 	/* We must notify MHI control driver so it can clean up first */
 	if (transition_state == MHI_PM_SYS_ERR_PROCESS) {
+		/*
+		 * If controller supports RDDM, we do not process
+		 * SYS error state, instead we will jump directly
+		 * to RDDM state
+		 */
+		if (mhi_cntrl->rddm_image) {
+			dev_dbg(dev,
+				 "Controller supports RDDM, so skip SYS_ERR\n");
+			return;
+		}
 		mhi_cntrl->status_cb(mhi_cntrl, MHI_CB_SYS_ERROR);
 	}
 
@@ -895,3 +905,25 @@ int mhi_sync_power_up(struct mhi_controller *mhi_cntrl)
 	return (MHI_IN_MISSION_MODE(mhi_cntrl->ee)) ? 0 : -EIO;
 }
 EXPORT_SYMBOL(mhi_sync_power_up);
+
+int mhi_force_rddm_mode(struct mhi_controller *mhi_cntrl)
+{
+	struct device *dev = &mhi_cntrl->mhi_dev->dev;
+	int ret;
+
+	/* Check if device is already in RDDM */
+	if (mhi_cntrl->ee == MHI_EE_RDDM)
+		return 0;
+
+	dev_dbg(dev, "Triggering SYS_ERR to force RDDM state\n");
+	mhi_set_mhi_state(mhi_cntrl, MHI_STATE_SYS_ERR);
+
+	/* Wait for RDDM event */
+	ret = wait_event_timeout(mhi_cntrl->state_event,
+				 mhi_cntrl->ee == MHI_EE_RDDM,
+				 msecs_to_jiffies(mhi_cntrl->timeout_ms));
+	ret = ret ? 0 : -EIO;
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(mhi_force_rddm_mode);