diff options
Diffstat (limited to 'drivers/bus/mhi/ep/sm.c')
| -rw-r--r-- | drivers/bus/mhi/ep/sm.c | 148 |
1 files changed, 148 insertions, 0 deletions
diff --git a/drivers/bus/mhi/ep/sm.c b/drivers/bus/mhi/ep/sm.c new file mode 100644 index 000000000000..3655c19e23c7 --- /dev/null +++ b/drivers/bus/mhi/ep/sm.c @@ -0,0 +1,148 @@ +// 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 */ + spin_lock_bh(&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); + spin_unlock_bh(&mhi_cntrl->state_lock); + + 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); + if (ret) { + dev_err(dev, "Failed sending M0 state change event\n"); + return ret; + } + + 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"); + return ret; + } + } + + return 0; +} + +int mhi_ep_set_m3_state(struct mhi_ep_cntrl *mhi_cntrl) +{ + struct device *dev = &mhi_cntrl->mhi_dev->dev; + int ret; + + spin_lock_bh(&mhi_cntrl->state_lock); + ret = mhi_ep_set_mhi_state(mhi_cntrl, MHI_STATE_M3); + spin_unlock_bh(&mhi_cntrl->state_lock); + + if (ret) { + mhi_ep_handle_syserr(mhi_cntrl); + return ret; + } + + 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"); + return ret; + } + + return 0; +} + +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; + + spin_lock_bh(&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"); + spin_unlock_bh(&mhi_cntrl->state_lock); + return -EIO; + } + + 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; +} |