The MHI specification allows to perform a hard reset of the device
when writing to the SOC_RESET register. It can be used to completely
restart the device (e.g. in case of unrecoverable MHI error).
This is up to the MHI controller driver to determine when this hard
reset should be used, and in case of MHI errors, should be used as
a reset of last resort (after standard MHI stack reset).
This function is prefixed with 'mhi_reg' to highlight that this is
a stateless function, the MHI layer do nothing except triggering the
reset by writing into the right register, this is up to the caller
to ensure right mhi_controller state (e.g. unregister the controller
if necessary).
Signed-off-by: Loic Poulain <loic.poulain@xxxxxxxxxx>
---
drivers/bus/mhi/core/main.c | 7 +++++++
include/linux/mhi.h | 7 +++++++
2 files changed, 14 insertions(+)
diff --git a/drivers/bus/mhi/core/main.c b/drivers/bus/mhi/core/main.c
index a353d1e..9f8ce15 100644
--- a/drivers/bus/mhi/core/main.c
+++ b/drivers/bus/mhi/core/main.c
@@ -142,6 +142,13 @@ enum mhi_state mhi_get_mhi_state(struct mhi_controller *mhi_cntrl)
}
EXPORT_SYMBOL_GPL(mhi_get_mhi_state);
+void mhi_reg_soc_reset(struct mhi_controller *mhi_cntrl)
+{
+ mhi_write_reg(mhi_cntrl, mhi_cntrl->regs, MHI_SOC_RESET_REQ_OFFSET,
+ MHI_SOC_RESET_REQ);
+}
+EXPORT_SYMBOL_GPL(mhi_reg_soc_reset);
+
int mhi_map_single_no_bb(struct mhi_controller *mhi_cntrl,
struct mhi_buf_info *buf_info)
{
diff --git a/include/linux/mhi.h b/include/linux/mhi.h
index 2754742..8b1bf80 100644
--- a/include/linux/mhi.h
+++ b/include/linux/mhi.h
@@ -687,6 +687,13 @@ enum mhi_ee_type mhi_get_exec_env(struct mhi_controller *mhi_cntrl);
enum mhi_state mhi_get_mhi_state(struct mhi_controller *mhi_cntrl);
/**
+ * mhi_reg_soc_reset - Trigger a device reset. This can be used as a last resort
+ * to reset and recover a device.
+ * @mhi_cntrl: MHI controller
+ */
+void mhi_reg_soc_reset(struct mhi_controller *mhi_cntrl);
+
+/**
* mhi_device_get - Disable device low power mode
* @mhi_dev: Device associated with the channel
*/
--
2.7.4
