[PATCH v2 1/5] bus: mhi: core: Handle syserr during power_up

[Jeffrey Hugo]

The MHI device may be in the syserr state when we attempt to init it in
power_up().  Since we have no local state, the handling is simple -
reset the device and wait for it to transition out of the reset state.

Signed-off-by: Jeffrey Hugo <jhugo@xxxxxxxxxxxxxx>
---
 drivers/bus/mhi/core/pm.c | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/drivers/bus/mhi/core/pm.c b/drivers/bus/mhi/core/pm.c
index 52690cb..3285c9e 100644
--- a/drivers/bus/mhi/core/pm.c
+++ b/drivers/bus/mhi/core/pm.c
@@ -9,6 +9,7 @@
 #include <linux/dma-direction.h>
 #include <linux/dma-mapping.h>
 #include <linux/interrupt.h>
+#include <linux/iopoll.h>
 #include <linux/list.h>
 #include <linux/mhi.h>
 #include <linux/module.h>
@@ -760,6 +761,7 @@ static void mhi_deassert_dev_wake(struct mhi_controller *mhi_cntrl,
 
 int mhi_async_power_up(struct mhi_controller *mhi_cntrl)
 {
+	enum mhi_state state;
 	enum mhi_ee_type current_ee;
 	enum dev_st_transition next_state;
 	struct device *dev = &mhi_cntrl->mhi_dev->dev;
@@ -829,6 +831,24 @@ int mhi_async_power_up(struct mhi_controller *mhi_cntrl)
 		goto error_bhi_offset;
 	}
 
+	state = mhi_get_mhi_state(mhi_cntrl);
+	if (state == MHI_STATE_SYS_ERR) {
+		mhi_set_mhi_state(mhi_cntrl, MHI_STATE_RESET);
+		ret = readl_poll_timeout(mhi_cntrl->regs + MHICTRL, val,
+					 !(val & MHICTRL_RESET_MASK), 1000,
+					 mhi_cntrl->timeout_ms * 1000);
+		if (ret) {
+			dev_info(dev, "Failed to reset MHI due to syserr state\n");
+			goto error_bhi_offset;
+		}
+
+		/*
+		 * device cleares INTVEC as part of RESET processing,
+		 * re-program it
+		 */
+		mhi_write_reg(mhi_cntrl, mhi_cntrl->bhi, BHI_INTVEC, 0);
+	}
+
 	/* Transition to next state */
 	next_state = MHI_IN_PBL(current_ee) ?
 		DEV_ST_TRANSITION_PBL : DEV_ST_TRANSITION_READY;
-- 
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