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bus: mhi: core: Improvements to the channel handling state machine 

Improve the channel handling state machine such that all commands
go through a common function and a validation process to ensure
that the state machine is not violated in any way and adheres to
the MHI specification. Using this common function allows MHI to
eliminate some unnecessary debug messages and code duplication.

Signed-off-by: Bhaumik Bhatt <bbhatt@codeaurora.org>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Link: https://lore.kernel.org/r/1617311778-1254-4-git-send-email-bbhatt@codeaurora.org
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
This commit is contained in:
Bhaumik Bhatt 2021-04-01 14:16:12 -07:00 committed by Manivannan Sadhasivam
parent 4e44ae3d6d
commit 3317dc6cea
3 changed files with 105 additions and 74 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

6
drivers/bus/mhi/core/init.c
View File

@ -56,6 +56,12 @@ const char * const mhi_state_str[MHI_STATE_MAX] = {
[MHI_STATE_SYS_ERR] = "SYS ERROR",
};
const char * const mhi_ch_state_type_str[MHI_CH_STATE_TYPE_MAX] = {
[MHI_CH_STATE_TYPE_RESET] = "RESET",
[MHI_CH_STATE_TYPE_STOP] = "STOP",
[MHI_CH_STATE_TYPE_START] = "START",
};
static const char * const mhi_pm_state_str[] = {
[MHI_PM_STATE_DISABLE] = "DISABLE",
[MHI_PM_STATE_POR] = "POWER ON RESET",

12
drivers/bus/mhi/core/internal.h
View File

@ -369,6 +369,18 @@ enum mhi_ch_state {
MHI_CH_STATE_ERROR = 0x5,
};
enum mhi_ch_state_type {
MHI_CH_STATE_TYPE_RESET,
MHI_CH_STATE_TYPE_STOP,
MHI_CH_STATE_TYPE_START,
MHI_CH_STATE_TYPE_MAX,
};
extern const char * const mhi_ch_state_type_str[MHI_CH_STATE_TYPE_MAX];
#define TO_CH_STATE_TYPE_STR(state) (((state) >= MHI_CH_STATE_TYPE_MAX) ? \
"INVALID_STATE" : \
mhi_ch_state_type_str[(state)])
#define MHI_INVALID_BRSTMODE(mode) (mode != MHI_DB_BRST_DISABLE && \
mode != MHI_DB_BRST_ENABLE)

161
drivers/bus/mhi/core/main.c
View File

@ -1242,56 +1242,105 @@ int mhi_send_cmd(struct mhi_controller *mhi_cntrl,
return 0;
}
static int mhi_update_channel_state(struct mhi_controller *mhi_cntrl,
struct mhi_chan *mhi_chan,
enum mhi_ch_state_type to_state)
{
struct device *dev = &mhi_cntrl->mhi_dev->dev;
enum mhi_cmd_type cmd = MHI_CMD_NOP;
int ret;
dev_dbg(dev, "%d: Updating channel state to: %s\n", mhi_chan->chan,
TO_CH_STATE_TYPE_STR(to_state));
switch (to_state) {
case MHI_CH_STATE_TYPE_RESET:
write_lock_irq(&mhi_chan->lock);
if (mhi_chan->ch_state != MHI_CH_STATE_STOP &&
mhi_chan->ch_state != MHI_CH_STATE_ENABLED &&
mhi_chan->ch_state != MHI_CH_STATE_SUSPENDED) {
write_unlock_irq(&mhi_chan->lock);
return -EINVAL;
}
mhi_chan->ch_state = MHI_CH_STATE_DISABLED;
write_unlock_irq(&mhi_chan->lock);
cmd = MHI_CMD_RESET_CHAN;
break;
case MHI_CH_STATE_TYPE_STOP:
if (mhi_chan->ch_state != MHI_CH_STATE_ENABLED)
return -EINVAL;
cmd = MHI_CMD_STOP_CHAN;
break;
case MHI_CH_STATE_TYPE_START:
if (mhi_chan->ch_state != MHI_CH_STATE_STOP &&
mhi_chan->ch_state != MHI_CH_STATE_DISABLED)
return -EINVAL;
cmd = MHI_CMD_START_CHAN;
break;
default:
dev_err(dev, "%d: Channel state update to %s not allowed\n",
mhi_chan->chan, TO_CH_STATE_TYPE_STR(to_state));
return -EINVAL;
}
mhi_cntrl->wake_toggle(mhi_cntrl);
mhi_cntrl->runtime_get(mhi_cntrl);
mhi_cntrl->runtime_put(mhi_cntrl);
reinit_completion(&mhi_chan->completion);
ret = mhi_send_cmd(mhi_cntrl, mhi_chan, cmd);
if (ret) {
dev_err(dev, "%d: Failed to send %s channel command\n",
mhi_chan->chan, TO_CH_STATE_TYPE_STR(to_state));
return ret;
}
ret = wait_for_completion_timeout(&mhi_chan->completion,
msecs_to_jiffies(mhi_cntrl->timeout_ms));
if (!ret || mhi_chan->ccs != MHI_EV_CC_SUCCESS) {
dev_err(dev,
"%d: Failed to receive %s channel command completion\n",
mhi_chan->chan, TO_CH_STATE_TYPE_STR(to_state));
return -EIO;
}
if (to_state != MHI_CH_STATE_TYPE_RESET) {
write_lock_irq(&mhi_chan->lock);
mhi_chan->ch_state = (to_state == MHI_CH_STATE_TYPE_START) ?
MHI_CH_STATE_ENABLED : MHI_CH_STATE_STOP;
write_unlock_irq(&mhi_chan->lock);
}
dev_dbg(dev, "%d: Channel state change to %s successful\n",
mhi_chan->chan, TO_CH_STATE_TYPE_STR(to_state));
return 0;
}
static void __mhi_unprepare_channel(struct mhi_controller *mhi_cntrl,
struct mhi_chan *mhi_chan)
{
int ret;
struct device *dev = &mhi_cntrl->mhi_dev->dev;
dev_dbg(dev, "Entered: unprepare channel:%d\n", mhi_chan->chan);
mutex_lock(&mhi_chan->mutex);
/* no more processing events for this channel */
mutex_lock(&mhi_chan->mutex);
write_lock_irq(&mhi_chan->lock);
if (mhi_chan->ch_state != MHI_CH_STATE_ENABLED &&
mhi_chan->ch_state != MHI_CH_STATE_SUSPENDED) {
write_unlock_irq(&mhi_chan->lock);
mutex_unlock(&mhi_chan->mutex);
return;
}
mhi_chan->ch_state = MHI_CH_STATE_DISABLED;
write_unlock_irq(&mhi_chan->lock);
reinit_completion(&mhi_chan->completion);
read_lock_bh(&mhi_cntrl->pm_lock);
if (MHI_PM_IN_ERROR_STATE(mhi_cntrl->pm_state)) {
read_unlock_bh(&mhi_cntrl->pm_lock);
goto error_invalid_state;
}
mhi_cntrl->wake_toggle(mhi_cntrl);
read_unlock_bh(&mhi_cntrl->pm_lock);
mhi_cntrl->runtime_get(mhi_cntrl);
mhi_cntrl->runtime_put(mhi_cntrl);
ret = mhi_send_cmd(mhi_cntrl, mhi_chan, MHI_CMD_RESET_CHAN);
ret = mhi_update_channel_state(mhi_cntrl, mhi_chan,
MHI_CH_STATE_TYPE_RESET);
if (ret)
goto error_invalid_state;
dev_err(dev, "%d: Failed to reset channel, still resetting\n",
mhi_chan->chan);
/* even if it fails we will still reset */
ret = wait_for_completion_timeout(&mhi_chan->completion,
msecs_to_jiffies(mhi_cntrl->timeout_ms));
if (!ret || mhi_chan->ccs != MHI_EV_CC_SUCCESS)
dev_err(dev,
"Failed to receive cmd completion, still resetting\n");
error_invalid_state:
if (!mhi_chan->offload_ch) {
mhi_reset_chan(mhi_cntrl, mhi_chan);
mhi_deinit_chan_ctxt(mhi_cntrl, mhi_chan);
}
dev_dbg(dev, "chan:%d successfully resetted\n", mhi_chan->chan);
dev_dbg(dev, "%d: successfully reset\n", mhi_chan->chan);
mutex_unlock(&mhi_chan->mutex);
}
@ -1301,8 +1350,6 @@ int mhi_prepare_channel(struct mhi_controller *mhi_cntrl,
int ret = 0;
struct device *dev = &mhi_cntrl->mhi_dev->dev;
dev_dbg(dev, "Preparing channel: %d\n", mhi_chan->chan);
if (!(BIT(mhi_cntrl->ee) & mhi_chan->ee_mask)) {
dev_err(dev,
"Current EE: %s Required EE Mask: 0x%x for chan: %s\n",
@ -1313,14 +1360,6 @@ int mhi_prepare_channel(struct mhi_controller *mhi_cntrl,
mutex_lock(&mhi_chan->mutex);
/* If channel is not in disable state, do not allow it to start */
if (mhi_chan->ch_state != MHI_CH_STATE_DISABLED) {
ret = -EIO;
dev_dbg(dev, "channel: %d is not in disabled state\n",
mhi_chan->chan);
goto error_init_chan;
}
/* Check of client manages channel context for offload channels */
if (!mhi_chan->offload_ch) {
ret = mhi_init_chan_ctxt(mhi_cntrl, mhi_chan);
@ -1328,34 +1367,11 @@ int mhi_prepare_channel(struct mhi_controller *mhi_cntrl,
goto error_init_chan;
}
reinit_completion(&mhi_chan->completion);
read_lock_bh(&mhi_cntrl->pm_lock);
if (MHI_PM_IN_ERROR_STATE(mhi_cntrl->pm_state)) {
read_unlock_bh(&mhi_cntrl->pm_lock);
ret = -EIO;
goto error_pm_state;
}
mhi_cntrl->wake_toggle(mhi_cntrl);
read_unlock_bh(&mhi_cntrl->pm_lock);
mhi_cntrl->runtime_get(mhi_cntrl);
mhi_cntrl->runtime_put(mhi_cntrl);
ret = mhi_send_cmd(mhi_cntrl, mhi_chan, MHI_CMD_START_CHAN);
ret = mhi_update_channel_state(mhi_cntrl, mhi_chan,
MHI_CH_STATE_TYPE_START);
if (ret)
goto error_pm_state;
ret = wait_for_completion_timeout(&mhi_chan->completion,
msecs_to_jiffies(mhi_cntrl->timeout_ms));
if (!ret || mhi_chan->ccs != MHI_EV_CC_SUCCESS) {
ret = -EIO;
goto error_pm_state;
}
write_lock_irq(&mhi_chan->lock);
mhi_chan->ch_state = MHI_CH_STATE_ENABLED;
write_unlock_irq(&mhi_chan->lock);
/* Pre-allocate buffer for xfer ring */
if (mhi_chan->pre_alloc) {
int nr_el = get_nr_avail_ring_elements(mhi_cntrl,
@ -1393,9 +1409,6 @@ int mhi_prepare_channel(struct mhi_controller *mhi_cntrl,
mutex_unlock(&mhi_chan->mutex);
dev_dbg(dev, "Chan: %d successfully moved to start state\n",
mhi_chan->chan);
return 0;
error_pm_state: