bus: mhi: ep: Add support for handling SYS_ERR condition

Add support for handling SYS_ERR (System Error) condition in the MHI
endpoint stack. The SYS_ERR flag will be asserted by the endpoint device
when it detects an internal error. The host will then issue reset and
reinitializes MHI to recover from the error state.

Reviewed-by: Alex Elder <elder@linaro.org>
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>

diff --git a/drivers/bus/mhi/ep/internal.h b/drivers/bus/mhi/ep/internal.h
index 4f2e268417021c65435b1a58dad3a66aafd6989d..d201d755560c176fa68b6e79a7e649d99851523a 100644 (file)
--- a/drivers/bus/mhi/ep/internal.h
+++ b/drivers/bus/mhi/ep/internal.h
@@ -211,5 +211,6 @@ int mhi_ep_set_mhi_state(struct mhi_ep_cntrl *mhi_cntrl, enum mhi_state mhi_stat
 int mhi_ep_set_m0_state(struct mhi_ep_cntrl *mhi_cntrl);
 int mhi_ep_set_m3_state(struct mhi_ep_cntrl *mhi_cntrl);
 int mhi_ep_set_ready_state(struct mhi_ep_cntrl *mhi_cntrl);
+void mhi_ep_handle_syserr(struct mhi_ep_cntrl *mhi_cntrl);
 
 #endif

diff --git a/drivers/bus/mhi/ep/main.c b/drivers/bus/mhi/ep/main.c
index d36708d43eb658739dd456f4cd2fe8c9df6673e4..706473ea4918f92aeec4cd5f604a06dbde20b11d 100644 (file)
--- a/drivers/bus/mhi/ep/main.c
+++ b/drivers/bus/mhi/ep/main.c
@@ -516,6 +516,26 @@ static void mhi_ep_reset_worker(struct work_struct *work)
        }
 }
 
+/*
+ * We don't need to do anything special other than setting the MHI SYS_ERR
+ * state. The host will reset all contexts and issue MHI RESET so that we
+ * could also recover from error state.
+ */
+void mhi_ep_handle_syserr(struct mhi_ep_cntrl *mhi_cntrl)
+{
+       struct device *dev = &mhi_cntrl->mhi_dev->dev;
+       int ret;
+
+       ret = mhi_ep_set_mhi_state(mhi_cntrl, MHI_STATE_SYS_ERR);
+       if (ret)
+               return;
+
+       /* Signal host that the device went to SYS_ERR state */
+       ret = mhi_ep_send_state_change_event(mhi_cntrl, MHI_STATE_SYS_ERR);
+       if (ret)
+               dev_err(dev, "Failed sending SYS_ERR state change event: %d\n", ret);
+}
+
 int mhi_ep_power_up(struct mhi_ep_cntrl *mhi_cntrl)
 {
        struct device *dev = &mhi_cntrl->mhi_dev->dev;

diff --git a/drivers/bus/mhi/ep/sm.c b/drivers/bus/mhi/ep/sm.c
index ffc02f5d0a0dbe1cbce5db474a5d8d4a86bc08bf..e3865b85399d115d4122c7e112212b7c7c02bc5a 100644 (file)
--- a/drivers/bus/mhi/ep/sm.c
+++ b/drivers/bus/mhi/ep/sm.c
@@ -68,8 +68,10 @@ int mhi_ep_set_m0_state(struct mhi_ep_cntrl *mhi_cntrl)
        ret = mhi_ep_set_mhi_state(mhi_cntrl, MHI_STATE_M0);
        spin_unlock_bh(&mhi_cntrl->state_lock);
 
-       if (ret)
+       if (ret) {
+               mhi_ep_handle_syserr(mhi_cntrl);
                return ret;
+       }
 
        /* Signal host that the device moved to M0 */
        ret = mhi_ep_send_state_change_event(mhi_cntrl, MHI_STATE_M0);
@@ -99,8 +101,10 @@ int mhi_ep_set_m3_state(struct mhi_ep_cntrl *mhi_cntrl)
        ret = mhi_ep_set_mhi_state(mhi_cntrl, MHI_STATE_M3);
        spin_unlock_bh(&mhi_cntrl->state_lock);
 
-       if (ret)
+       if (ret) {
+               mhi_ep_handle_syserr(mhi_cntrl);
                return ret;
+       }
 
        /* Signal host that the device moved to M3 */
        ret = mhi_ep_send_state_change_event(mhi_cntrl, MHI_STATE_M3);
@@ -132,5 +136,8 @@ int mhi_ep_set_ready_state(struct mhi_ep_cntrl *mhi_cntrl)
        ret = mhi_ep_set_mhi_state(mhi_cntrl, MHI_STATE_READY);
        spin_unlock_bh(&mhi_cntrl->state_lock);
 
+       if (ret)
+               mhi_ep_handle_syserr(mhi_cntrl);
+
        return ret;
 }