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-rw-r--r--drivers/bus/mhi/ep/sm.c154
1 files changed, 154 insertions, 0 deletions
diff --git a/drivers/bus/mhi/ep/sm.c b/drivers/bus/mhi/ep/sm.c
new file mode 100644
index 0000000000..fd200b2ac0
--- /dev/null
+++ b/drivers/bus/mhi/ep/sm.c
@@ -0,0 +1,154 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2022 Linaro Ltd.
+ * Author: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
+ */
+
+#include <linux/errno.h>
+#include <linux/mhi_ep.h>
+#include "internal.h"
+
+bool __must_check mhi_ep_check_mhi_state(struct mhi_ep_cntrl *mhi_cntrl,
+ enum mhi_state cur_mhi_state,
+ enum mhi_state mhi_state)
+{
+ if (mhi_state == MHI_STATE_SYS_ERR)
+ return true; /* Allowed in any state */
+
+ if (mhi_state == MHI_STATE_READY)
+ return cur_mhi_state == MHI_STATE_RESET;
+
+ if (mhi_state == MHI_STATE_M0)
+ return cur_mhi_state == MHI_STATE_M3 || cur_mhi_state == MHI_STATE_READY;
+
+ if (mhi_state == MHI_STATE_M3)
+ return cur_mhi_state == MHI_STATE_M0;
+
+ return false;
+}
+
+int mhi_ep_set_mhi_state(struct mhi_ep_cntrl *mhi_cntrl, enum mhi_state mhi_state)
+{
+ struct device *dev = &mhi_cntrl->mhi_dev->dev;
+
+ if (!mhi_ep_check_mhi_state(mhi_cntrl, mhi_cntrl->mhi_state, mhi_state)) {
+ dev_err(dev, "MHI state change to %s from %s is not allowed!\n",
+ mhi_state_str(mhi_state),
+ mhi_state_str(mhi_cntrl->mhi_state));
+ return -EACCES;
+ }
+
+ /* TODO: Add support for M1 and M2 states */
+ if (mhi_state == MHI_STATE_M1 || mhi_state == MHI_STATE_M2) {
+ dev_err(dev, "MHI state (%s) not supported\n", mhi_state_str(mhi_state));
+ return -EOPNOTSUPP;
+ }
+
+ mhi_ep_mmio_masked_write(mhi_cntrl, EP_MHISTATUS, MHISTATUS_MHISTATE_MASK, mhi_state);
+ mhi_cntrl->mhi_state = mhi_state;
+
+ if (mhi_state == MHI_STATE_READY)
+ mhi_ep_mmio_masked_write(mhi_cntrl, EP_MHISTATUS, MHISTATUS_READY_MASK, 1);
+
+ if (mhi_state == MHI_STATE_SYS_ERR)
+ mhi_ep_mmio_masked_write(mhi_cntrl, EP_MHISTATUS, MHISTATUS_SYSERR_MASK, 1);
+
+ return 0;
+}
+
+int mhi_ep_set_m0_state(struct mhi_ep_cntrl *mhi_cntrl)
+{
+ struct device *dev = &mhi_cntrl->mhi_dev->dev;
+ enum mhi_state old_state;
+ int ret;
+
+ /* If MHI is in M3, resume suspended channels */
+ mutex_lock(&mhi_cntrl->state_lock);
+
+ old_state = mhi_cntrl->mhi_state;
+ if (old_state == MHI_STATE_M3)
+ mhi_ep_resume_channels(mhi_cntrl);
+
+ ret = mhi_ep_set_mhi_state(mhi_cntrl, MHI_STATE_M0);
+ if (ret) {
+ mhi_ep_handle_syserr(mhi_cntrl);
+ goto err_unlock;
+ }
+
+ /* Signal host that the device moved to M0 */
+ ret = mhi_ep_send_state_change_event(mhi_cntrl, MHI_STATE_M0);
+ if (ret) {
+ dev_err(dev, "Failed sending M0 state change event\n");
+ goto err_unlock;
+ }
+
+ if (old_state == MHI_STATE_READY) {
+ /* Send AMSS EE event to host */
+ ret = mhi_ep_send_ee_event(mhi_cntrl, MHI_EE_AMSS);
+ if (ret) {
+ dev_err(dev, "Failed sending AMSS EE event\n");
+ goto err_unlock;
+ }
+ }
+
+err_unlock:
+ mutex_unlock(&mhi_cntrl->state_lock);
+
+ return ret;
+}
+
+int mhi_ep_set_m3_state(struct mhi_ep_cntrl *mhi_cntrl)
+{
+ struct device *dev = &mhi_cntrl->mhi_dev->dev;
+ int ret;
+
+ mutex_lock(&mhi_cntrl->state_lock);
+
+ ret = mhi_ep_set_mhi_state(mhi_cntrl, MHI_STATE_M3);
+ if (ret) {
+ mhi_ep_handle_syserr(mhi_cntrl);
+ goto err_unlock;
+ }
+
+ mhi_ep_suspend_channels(mhi_cntrl);
+
+ /* Signal host that the device moved to M3 */
+ ret = mhi_ep_send_state_change_event(mhi_cntrl, MHI_STATE_M3);
+ if (ret) {
+ dev_err(dev, "Failed sending M3 state change event\n");
+ goto err_unlock;
+ }
+
+err_unlock:
+ mutex_unlock(&mhi_cntrl->state_lock);
+
+ return ret;
+}
+
+int mhi_ep_set_ready_state(struct mhi_ep_cntrl *mhi_cntrl)
+{
+ struct device *dev = &mhi_cntrl->mhi_dev->dev;
+ enum mhi_state mhi_state;
+ int ret, is_ready;
+
+ mutex_lock(&mhi_cntrl->state_lock);
+
+ /* Ensure that the MHISTATUS is set to RESET by host */
+ mhi_state = mhi_ep_mmio_masked_read(mhi_cntrl, EP_MHISTATUS, MHISTATUS_MHISTATE_MASK);
+ is_ready = mhi_ep_mmio_masked_read(mhi_cntrl, EP_MHISTATUS, MHISTATUS_READY_MASK);
+
+ if (mhi_state != MHI_STATE_RESET || is_ready) {
+ dev_err(dev, "READY state transition failed. MHI host not in RESET state\n");
+ ret = -EIO;
+ goto err_unlock;
+ }
+
+ ret = mhi_ep_set_mhi_state(mhi_cntrl, MHI_STATE_READY);
+ if (ret)
+ mhi_ep_handle_syserr(mhi_cntrl);
+
+err_unlock:
+ mutex_unlock(&mhi_cntrl->state_lock);
+
+ return ret;
+}