MHI specification shows a state machine with support for STOP channel command
and the validity of certain state transitions. MHI host currently does not
provide any mechanism to stop a channel and restart it without resetting it.
There are also times when the device moves on to a different execution
environment while client drivers on the host are unaware of it and still
attempt to reset the channels facing unnecessary timeouts.
This series addresses the above areas to provide support for stopping an MHI
channel, resuming it back, improved documentation and improving upon channel
state machine handling in general.
This set of patches was tested on arm64 architecture.
v2:
-Renamed the newly introduced APIs to mhi_start_transfer() / mhi_stop_transfer()
-Added improved documentation to avoid confusion with the new APIs
-Removed the __ prefix from mhi_unprepare_channel() API for consistency.
Bhaumik Bhatt (6):
bus: mhi: core: Allow receiving a STOP channel command response
bus: mhi: core: Improvements to the channel handling state machine
bus: mhi: core: Add support to stop or start channel data transfers
bus: mhi: core: Check execution environment for channel before issuing
reset
bus: mhi: core: Remove __ prefix for MHI channel unprepare function
bus: mhi: Improve documentation on channel transfer setup APIs
drivers/bus/mhi/core/init.c | 11 +-
drivers/bus/mhi/core/internal.h | 12 +++
drivers/bus/mhi/core/main.c | 226 ++++++++++++++++++++++++++++------------
include/linux/mhi.h | 37 ++++++-
4 files changed, 215 insertions(+), 71 deletions(-)
--
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project
Add support to enable sending the stop channel command and
improve the channel handling state machine such that all commands
go through a common function. This can help ensure that the state
machine is not violated in any way and adheres to the MHI
specification.
Signed-off-by: Bhaumik Bhatt <[email protected]>
---
drivers/bus/mhi/core/init.c | 6 ++
drivers/bus/mhi/core/internal.h | 12 +++
drivers/bus/mhi/core/main.c | 163 ++++++++++++++++++++++++----------------
3 files changed, 116 insertions(+), 65 deletions(-)
diff --git a/drivers/bus/mhi/core/init.c b/drivers/bus/mhi/core/init.c
index 4d34d62..c9b1de8 100644
--- a/drivers/bus/mhi/core/init.c
+++ b/drivers/bus/mhi/core/init.c
@@ -51,6 +51,12 @@ const char * const mhi_state_str[MHI_STATE_MAX] = {
[MHI_STATE_SYS_ERR] = "SYS_ERR",
};
+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] = "POR",
diff --git a/drivers/bus/mhi/core/internal.h b/drivers/bus/mhi/core/internal.h
index 2df8de5..f4efb15 100644
--- a/drivers/bus/mhi/core/internal.h
+++ b/drivers/bus/mhi/core/internal.h
@@ -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)
diff --git a/drivers/bus/mhi/core/main.c b/drivers/bus/mhi/core/main.c
index ad881a1..1226933 100644
--- a/drivers/bus/mhi/core/main.c
+++ b/drivers/bus/mhi/core/main.c
@@ -1220,56 +1220,120 @@ int mhi_send_cmd(struct mhi_controller *mhi_cntrl,
return 0;
}
-static void __mhi_unprepare_channel(struct mhi_controller *mhi_cntrl,
- struct mhi_chan *mhi_chan)
+static int mhi_update_channel_state(struct mhi_controller *mhi_cntrl,
+ struct mhi_chan *mhi_chan,
+ enum mhi_ch_state_type to_state)
{
- int ret;
struct device *dev = &mhi_cntrl->mhi_dev->dev;
+ enum mhi_cmd_type cmd = MHI_CMD_NOP;
+ int ret = -EIO;
+
+ dev_dbg(dev, "Updating channel %s(%d) state to: %s\n", mhi_chan->name,
+ 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);
+ goto exit_invalid_state;
+ }
+ mhi_chan->ch_state = MHI_CH_STATE_DISABLED;
+ write_unlock_irq(&mhi_chan->lock);
- dev_dbg(dev, "Entered: unprepare channel:%d\n", mhi_chan->chan);
+ cmd = MHI_CMD_RESET_CHAN;
+ break;
+ case MHI_CH_STATE_TYPE_STOP:
+ if (mhi_chan->ch_state != MHI_CH_STATE_ENABLED)
+ goto exit_invalid_state;
- /* 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;
+ 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)
+ goto exit_invalid_state;
+
+ cmd = MHI_CMD_START_CHAN;
+ break;
+ default:
+ goto exit_invalid_state;
}
- mhi_chan->ch_state = MHI_CH_STATE_DISABLED;
- write_unlock_irq(&mhi_chan->lock);
+ /* bring host and device out of suspended states */
+ ret = mhi_device_get_sync(mhi_cntrl->mhi_dev);
+ if (ret)
+ return ret;
+ mhi_cntrl->runtime_get(mhi_cntrl);
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;
+ ret = mhi_send_cmd(mhi_cntrl, mhi_chan, cmd);
+ if (ret) {
+ dev_err(dev, "Failed to send %s(%d) %s command\n",
+ mhi_chan->name, mhi_chan->chan,
+ TO_CH_STATE_TYPE_STR(to_state));
+ goto exit_command_failure;
}
- mhi_cntrl->wake_toggle(mhi_cntrl);
- read_unlock_bh(&mhi_cntrl->pm_lock);
+ 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 %s(%d) %s command completion\n",
+ mhi_chan->name, mhi_chan->chan,
+ TO_CH_STATE_TYPE_STR(to_state));
+ ret = -EIO;
+ goto exit_command_failure;
+ }
- mhi_cntrl->runtime_get(mhi_cntrl);
+ ret = 0;
+
+ 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, "Channel %s(%d) state change to %s successful\n",
+ mhi_chan->name, mhi_chan->chan, TO_CH_STATE_TYPE_STR(to_state));
+
+exit_command_failure:
mhi_cntrl->runtime_put(mhi_cntrl);
- ret = mhi_send_cmd(mhi_cntrl, mhi_chan, MHI_CMD_RESET_CHAN);
- if (ret)
- goto error_invalid_state;
+ mhi_device_put(mhi_cntrl->mhi_dev);
- /* 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");
+ return ret;
+
+exit_invalid_state:
+ dev_err(dev, "Channel %s(%d) update to %s not allowed\n",
+ mhi_chan->name, mhi_chan->chan, TO_CH_STATE_TYPE_STR(to_state));
+
+ return -EINVAL;
+}
+
+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);
+
+ /* no more processing events for this channel */
+ mutex_lock(&mhi_chan->mutex);
+
+ ret = mhi_update_channel_state(mhi_cntrl, mhi_chan,
+ MHI_CH_STATE_TYPE_RESET);
+ if (ret)
+ dev_err(dev, "Failed to reset channel, 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, "chan:%d successfully reset\n", mhi_chan->chan);
+
mutex_unlock(&mhi_chan->mutex);
}
@@ -1291,14 +1355,6 @@ 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);
@@ -1306,34 +1362,11 @@ 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,
--
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project
Add support to receive the response to a STOP channel command to the
MHI bus. If a client would like to STOP a channel instead of issuing
a RESET to it, this would provide support for it.
Signed-off-by: Bhaumik Bhatt <[email protected]>
---
drivers/bus/mhi/core/init.c | 5 +++--
drivers/bus/mhi/core/main.c | 5 +++++
2 files changed, 8 insertions(+), 2 deletions(-)
diff --git a/drivers/bus/mhi/core/init.c b/drivers/bus/mhi/core/init.c
index 8cefa35..4d34d62 100644
--- a/drivers/bus/mhi/core/init.c
+++ b/drivers/bus/mhi/core/init.c
@@ -1267,8 +1267,9 @@ static int mhi_driver_remove(struct device *dev)
mutex_lock(&mhi_chan->mutex);
- if (ch_state[dir] == MHI_CH_STATE_ENABLED &&
- !mhi_chan->offload_ch)
+ if ((ch_state[dir] == MHI_CH_STATE_ENABLED ||
+ ch_state[dir] == MHI_CH_STATE_STOP) &&
+ !mhi_chan->offload_ch)
mhi_deinit_chan_ctxt(mhi_cntrl, mhi_chan);
mhi_chan->ch_state = MHI_CH_STATE_DISABLED;
diff --git a/drivers/bus/mhi/core/main.c b/drivers/bus/mhi/core/main.c
index f953e2a..ad881a1 100644
--- a/drivers/bus/mhi/core/main.c
+++ b/drivers/bus/mhi/core/main.c
@@ -1194,6 +1194,11 @@ int mhi_send_cmd(struct mhi_controller *mhi_cntrl,
cmd_tre->dword[0] = MHI_TRE_CMD_RESET_DWORD0;
cmd_tre->dword[1] = MHI_TRE_CMD_RESET_DWORD1(chan);
break;
+ case MHI_CMD_STOP_CHAN:
+ cmd_tre->ptr = MHI_TRE_CMD_STOP_PTR;
+ cmd_tre->dword[0] = MHI_TRE_CMD_STOP_DWORD0;
+ cmd_tre->dword[1] = MHI_TRE_CMD_STOP_DWORD1(chan);
+ break;
case MHI_CMD_START_CHAN:
cmd_tre->ptr = MHI_TRE_CMD_START_PTR;
cmd_tre->dword[0] = MHI_TRE_CMD_START_DWORD0;
--
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project
A client can attempt to unprepare certain channels for transfer even
after the execution environment they are supposed to run in has changed.
In the event that happens, the device need not be notified of the reset
and the host can proceed with clean up for the channel context and
memory allocated for it on the host.
Signed-off-by: Bhaumik Bhatt <[email protected]>
---
drivers/bus/mhi/core/main.c | 13 +++++++++++++
1 file changed, 13 insertions(+)
diff --git a/drivers/bus/mhi/core/main.c b/drivers/bus/mhi/core/main.c
index 1a969f4..e8af85a 100644
--- a/drivers/bus/mhi/core/main.c
+++ b/drivers/bus/mhi/core/main.c
@@ -1323,11 +1323,24 @@ static void __mhi_unprepare_channel(struct mhi_controller *mhi_cntrl,
/* no more processing events for this channel */
mutex_lock(&mhi_chan->mutex);
+ if (!(BIT(mhi_cntrl->ee) & mhi_chan->ee_mask)) {
+ dev_err(dev,
+ "Current EE: %s Required EE Mask: 0x%x for chan: %s\n",
+ TO_MHI_EXEC_STR(mhi_cntrl->ee), mhi_chan->ee_mask,
+ mhi_chan->name);
+ goto exit_unprepare_channel;
+ }
+
ret = mhi_update_channel_state(mhi_cntrl, mhi_chan,
MHI_CH_STATE_TYPE_RESET);
if (ret)
dev_err(dev, "Failed to reset channel, still resetting\n");
+exit_unprepare_channel:
+ write_lock_irq(&mhi_chan->lock);
+ mhi_chan->ch_state = MHI_CH_STATE_DISABLED;
+ write_unlock_irq(&mhi_chan->lock);
+
if (!mhi_chan->offload_ch) {
mhi_reset_chan(mhi_cntrl, mhi_chan);
mhi_deinit_chan_ctxt(mhi_cntrl, mhi_chan);
--
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project
The __mhi_unprepare_channel() API does not require the __ prefix.
Get rid of it and make the internal function consistent with the
other function names.
Signed-off-by: Bhaumik Bhatt <[email protected]>
---
drivers/bus/mhi/core/main.c | 10 +++++-----
1 file changed, 5 insertions(+), 5 deletions(-)
diff --git a/drivers/bus/mhi/core/main.c b/drivers/bus/mhi/core/main.c
index e8af85a..19156d4 100644
--- a/drivers/bus/mhi/core/main.c
+++ b/drivers/bus/mhi/core/main.c
@@ -1312,8 +1312,8 @@ static int mhi_update_channel_state(struct mhi_controller *mhi_cntrl,
return -EINVAL;
}
-static void __mhi_unprepare_channel(struct mhi_controller *mhi_cntrl,
- struct mhi_chan *mhi_chan)
+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;
@@ -1433,7 +1433,7 @@ int mhi_prepare_channel(struct mhi_controller *mhi_cntrl,
error_pre_alloc:
mutex_unlock(&mhi_chan->mutex);
- __mhi_unprepare_channel(mhi_cntrl, mhi_chan);
+ mhi_unprepare_channel(mhi_cntrl, mhi_chan);
return ret;
}
@@ -1550,7 +1550,7 @@ int mhi_prepare_for_transfer(struct mhi_device *mhi_dev)
if (!mhi_chan)
continue;
- __mhi_unprepare_channel(mhi_cntrl, mhi_chan);
+ mhi_unprepare_channel(mhi_cntrl, mhi_chan);
}
return ret;
@@ -1568,7 +1568,7 @@ void mhi_unprepare_from_transfer(struct mhi_device *mhi_dev)
if (!mhi_chan)
continue;
- __mhi_unprepare_channel(mhi_cntrl, mhi_chan);
+ mhi_unprepare_channel(mhi_cntrl, mhi_chan);
}
}
EXPORT_SYMBOL_GPL(mhi_unprepare_from_transfer);
--
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project
The mhi_prepare_for_transfer() and mhi_unprepare_from_transfer()
APIs could use better explanation, especially with the addition
of two new APIs to start and stop the transfers on channels. Add
better set of information for those APIs to avoid confusion going
forward.
Signed-off-by: Bhaumik Bhatt <[email protected]>
---
include/linux/mhi.h | 18 ++++++++++++++++--
1 file changed, 16 insertions(+), 2 deletions(-)
diff --git a/include/linux/mhi.h b/include/linux/mhi.h
index aee8494..ee9537f 100644
--- a/include/linux/mhi.h
+++ b/include/linux/mhi.h
@@ -690,13 +690,27 @@ int mhi_device_get_sync(struct mhi_device *mhi_dev);
void mhi_device_put(struct mhi_device *mhi_dev);
/**
- * mhi_prepare_for_transfer - Setup channel for data transfer
+ * mhi_prepare_for_transfer - Setup UL and DL channels for data transfer.
+ * Allocate and initialize the channel context and
+ * also issue the START channel command to both
+ * channels. Channels can be started only if both
+ * host and device execution environments match and
+ * channels are in a DISABLED state.
* @mhi_dev: Device associated with the channels
*/
int mhi_prepare_for_transfer(struct mhi_device *mhi_dev);
/**
- * mhi_unprepare_from_transfer - Unprepare the channels
+ * mhi_unprepare_from_transfer - Reset UL and DL channels for data transfer.
+ * Issue the RESET channel command and let the
+ * device clean-up the context so no incoming
+ * transfers are seen on the host. Free memory
+ * associated with the context on host. If device
+ * is unresponsive, only perform a host side
+ * clean-up. Channels can be reset only if both
+ * host and device execution environments match
+ * and channels are in an ENABLED, STOPPED or
+ * SUSPENDED state.
* @mhi_dev: Device associated with the channels
*/
void mhi_unprepare_from_transfer(struct mhi_device *mhi_dev);
--
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project
On Wed, Nov 11, 2020 at 11:21:09AM -0800, Bhaumik Bhatt wrote:
> Add support to enable sending the stop channel command and
> improve the channel handling state machine such that all commands
> go through a common function. This can help ensure that the state
> machine is not violated in any way and adheres to the MHI
> specification.
>
> Signed-off-by: Bhaumik Bhatt <[email protected]>
> ---
> drivers/bus/mhi/core/init.c | 6 ++
> drivers/bus/mhi/core/internal.h | 12 +++
> drivers/bus/mhi/core/main.c | 163 ++++++++++++++++++++++++----------------
> 3 files changed, 116 insertions(+), 65 deletions(-)
>
> diff --git a/drivers/bus/mhi/core/init.c b/drivers/bus/mhi/core/init.c
> index 4d34d62..c9b1de8 100644
> --- a/drivers/bus/mhi/core/init.c
> +++ b/drivers/bus/mhi/core/init.c
> @@ -51,6 +51,12 @@ const char * const mhi_state_str[MHI_STATE_MAX] = {
> [MHI_STATE_SYS_ERR] = "SYS_ERR",
> };
>
> +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] = "POR",
> diff --git a/drivers/bus/mhi/core/internal.h b/drivers/bus/mhi/core/internal.h
> index 2df8de5..f4efb15 100644
> --- a/drivers/bus/mhi/core/internal.h
> +++ b/drivers/bus/mhi/core/internal.h
> @@ -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,
> +};
> +
As said in previous patch, this needs to be moved to a separate one.
> +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)
>
> diff --git a/drivers/bus/mhi/core/main.c b/drivers/bus/mhi/core/main.c
> index ad881a1..1226933 100644
> --- a/drivers/bus/mhi/core/main.c
> +++ b/drivers/bus/mhi/core/main.c
> @@ -1220,56 +1220,120 @@ int mhi_send_cmd(struct mhi_controller *mhi_cntrl,
> 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);
Please get rid of these debug prints. We have some of them right now but they
should be removed at some point. For debugging, use ftrace.
Thanks,
Mani
On Wed, Nov 11, 2020 at 11:21:12AM -0800, Bhaumik Bhatt wrote:
> The __mhi_unprepare_channel() API does not require the __ prefix.
> Get rid of it and make the internal function consistent with the
> other function names.
>
> Signed-off-by: Bhaumik Bhatt <[email protected]>
Reviewed-by: Manivannan Sadhasivam <[email protected]>
Thanks,
Mani
> ---
> drivers/bus/mhi/core/main.c | 10 +++++-----
> 1 file changed, 5 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/bus/mhi/core/main.c b/drivers/bus/mhi/core/main.c
> index e8af85a..19156d4 100644
> --- a/drivers/bus/mhi/core/main.c
> +++ b/drivers/bus/mhi/core/main.c
> @@ -1312,8 +1312,8 @@ static int mhi_update_channel_state(struct mhi_controller *mhi_cntrl,
> return -EINVAL;
> }
>
> -static void __mhi_unprepare_channel(struct mhi_controller *mhi_cntrl,
> - struct mhi_chan *mhi_chan)
> +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;
> @@ -1433,7 +1433,7 @@ int mhi_prepare_channel(struct mhi_controller *mhi_cntrl,
>
> error_pre_alloc:
> mutex_unlock(&mhi_chan->mutex);
> - __mhi_unprepare_channel(mhi_cntrl, mhi_chan);
> + mhi_unprepare_channel(mhi_cntrl, mhi_chan);
>
> return ret;
> }
> @@ -1550,7 +1550,7 @@ int mhi_prepare_for_transfer(struct mhi_device *mhi_dev)
> if (!mhi_chan)
> continue;
>
> - __mhi_unprepare_channel(mhi_cntrl, mhi_chan);
> + mhi_unprepare_channel(mhi_cntrl, mhi_chan);
> }
>
> return ret;
> @@ -1568,7 +1568,7 @@ void mhi_unprepare_from_transfer(struct mhi_device *mhi_dev)
> if (!mhi_chan)
> continue;
>
> - __mhi_unprepare_channel(mhi_cntrl, mhi_chan);
> + mhi_unprepare_channel(mhi_cntrl, mhi_chan);
> }
> }
> EXPORT_SYMBOL_GPL(mhi_unprepare_from_transfer);
> --
> The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
> a Linux Foundation Collaborative Project
>
On Wed, Nov 11, 2020 at 11:21:13AM -0800, Bhaumik Bhatt wrote:
> The mhi_prepare_for_transfer() and mhi_unprepare_from_transfer()
> APIs could use better explanation, especially with the addition
> of two new APIs to start and stop the transfers on channels. Add
> better set of information for those APIs to avoid confusion going
> forward.
>
> Signed-off-by: Bhaumik Bhatt <[email protected]>
> ---
> include/linux/mhi.h | 18 ++++++++++++++++--
> 1 file changed, 16 insertions(+), 2 deletions(-)
>
> diff --git a/include/linux/mhi.h b/include/linux/mhi.h
> index aee8494..ee9537f 100644
> --- a/include/linux/mhi.h
> +++ b/include/linux/mhi.h
> @@ -690,13 +690,27 @@ int mhi_device_get_sync(struct mhi_device *mhi_dev);
> void mhi_device_put(struct mhi_device *mhi_dev);
>
> /**
> - * mhi_prepare_for_transfer - Setup channel for data transfer
> + * mhi_prepare_for_transfer - Setup UL and DL channels for data transfer.
> + * Allocate and initialize the channel context and
> + * also issue the START channel command to both
> + * channels. Channels can be started only if both
> + * host and device execution environments match and
> + * channels are in a DISABLED state.
It'd be good if you can add a note about how this API differs from
mhi_start_transfer() API. The content says the difference but an explicit
comparision would be good.
Thanks,
Mani
> * @mhi_dev: Device associated with the channels
> */
> int mhi_prepare_for_transfer(struct mhi_device *mhi_dev);
>
> /**
> - * mhi_unprepare_from_transfer - Unprepare the channels
> + * mhi_unprepare_from_transfer - Reset UL and DL channels for data transfer.
> + * Issue the RESET channel command and let the
> + * device clean-up the context so no incoming
> + * transfers are seen on the host. Free memory
> + * associated with the context on host. If device
> + * is unresponsive, only perform a host side
> + * clean-up. Channels can be reset only if both
> + * host and device execution environments match
> + * and channels are in an ENABLED, STOPPED or
> + * SUSPENDED state.
> * @mhi_dev: Device associated with the channels
> */
> void mhi_unprepare_from_transfer(struct mhi_device *mhi_dev);
> --
> The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
> a Linux Foundation Collaborative Project
>
Hi Mani,
On 2020-11-15 23:13, Manivannan Sadhasivam wrote:
> On Wed, Nov 11, 2020 at 11:21:08AM -0800, Bhaumik Bhatt wrote:
>> Add support to receive the response to a STOP channel command to the
>> MHI bus. If a client would like to STOP a channel instead of issuing
>> a RESET to it, this would provide support for it.
>>
>> Signed-off-by: Bhaumik Bhatt <[email protected]>
>> ---
>> drivers/bus/mhi/core/init.c | 5 +++--
>> drivers/bus/mhi/core/main.c | 5 +++++
>> 2 files changed, 8 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/bus/mhi/core/init.c b/drivers/bus/mhi/core/init.c
>> index 8cefa35..4d34d62 100644
>> --- a/drivers/bus/mhi/core/init.c
>> +++ b/drivers/bus/mhi/core/init.c
>> @@ -1267,8 +1267,9 @@ static int mhi_driver_remove(struct device *dev)
>>
>> mutex_lock(&mhi_chan->mutex);
>>
>> - if (ch_state[dir] == MHI_CH_STATE_ENABLED &&
>> - !mhi_chan->offload_ch)
>> + if ((ch_state[dir] == MHI_CH_STATE_ENABLED ||
>> + ch_state[dir] == MHI_CH_STATE_STOP) &&
>
> This enum is not defined in this patch so it'll break. Please add a
> separate
> patch which introduces the new state enums alone and then have patches
> 1/2
> as a followup.
>
It is actually already defined and present in internal.h as enum
mhi_ch_state.
The old set of enums has MHI_CH_STATE_STOP from enum mhi_ch_state and
the new
enum I introduced is MHI_CH_STATE_TYPE_STOP from enum enum
mhi_ch_state_type.
If it seems confusing, suggestions to renaming them are welcome.
> Also this change is not belonging to this commit I believe.
>
I included this change here because, a channel can be in "stopped" state
and
a user module could be unloaded or a crash could force a driver remove
leading
us to come this check.
If you think I should move it as a separate patch, let me know.
> Thanks,
> Mani
>
>> + !mhi_chan->offload_ch)
>> mhi_deinit_chan_ctxt(mhi_cntrl, mhi_chan);
>>
>> mhi_chan->ch_state = MHI_CH_STATE_DISABLED;
>> diff --git a/drivers/bus/mhi/core/main.c b/drivers/bus/mhi/core/main.c
>> index f953e2a..ad881a1 100644
>> --- a/drivers/bus/mhi/core/main.c
>> +++ b/drivers/bus/mhi/core/main.c
>> @@ -1194,6 +1194,11 @@ int mhi_send_cmd(struct mhi_controller
>> *mhi_cntrl,
>> cmd_tre->dword[0] = MHI_TRE_CMD_RESET_DWORD0;
>> cmd_tre->dword[1] = MHI_TRE_CMD_RESET_DWORD1(chan);
>> break;
>> + case MHI_CMD_STOP_CHAN:
>> + cmd_tre->ptr = MHI_TRE_CMD_STOP_PTR;
>> + cmd_tre->dword[0] = MHI_TRE_CMD_STOP_DWORD0;
>> + cmd_tre->dword[1] = MHI_TRE_CMD_STOP_DWORD1(chan);
>> + break;
>> case MHI_CMD_START_CHAN:
>> cmd_tre->ptr = MHI_TRE_CMD_START_PTR;
>> cmd_tre->dword[0] = MHI_TRE_CMD_START_DWORD0;
>> --
>> The Qualcomm Innovation Center, Inc. is a member of the Code Aurora
>> Forum,
>> a Linux Foundation Collaborative Project
>>
Thanks,
Bhaumik
--
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora
Forum,
a Linux Foundation Collaborative Project
On Wed, Nov 11, 2020 at 11:21:08AM -0800, Bhaumik Bhatt wrote:
> Add support to receive the response to a STOP channel command to the
> MHI bus. If a client would like to STOP a channel instead of issuing
> a RESET to it, this would provide support for it.
>
> Signed-off-by: Bhaumik Bhatt <[email protected]>
> ---
> drivers/bus/mhi/core/init.c | 5 +++--
> drivers/bus/mhi/core/main.c | 5 +++++
> 2 files changed, 8 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/bus/mhi/core/init.c b/drivers/bus/mhi/core/init.c
> index 8cefa35..4d34d62 100644
> --- a/drivers/bus/mhi/core/init.c
> +++ b/drivers/bus/mhi/core/init.c
> @@ -1267,8 +1267,9 @@ static int mhi_driver_remove(struct device *dev)
>
> mutex_lock(&mhi_chan->mutex);
>
> - if (ch_state[dir] == MHI_CH_STATE_ENABLED &&
> - !mhi_chan->offload_ch)
> + if ((ch_state[dir] == MHI_CH_STATE_ENABLED ||
> + ch_state[dir] == MHI_CH_STATE_STOP) &&
This enum is not defined in this patch so it'll break. Please add a separate
patch which introduces the new state enums alone and then have patches 1/2
as a followup.
Also this change is not belonging to this commit I believe.
Thanks,
Mani
> + !mhi_chan->offload_ch)
> mhi_deinit_chan_ctxt(mhi_cntrl, mhi_chan);
>
> mhi_chan->ch_state = MHI_CH_STATE_DISABLED;
> diff --git a/drivers/bus/mhi/core/main.c b/drivers/bus/mhi/core/main.c
> index f953e2a..ad881a1 100644
> --- a/drivers/bus/mhi/core/main.c
> +++ b/drivers/bus/mhi/core/main.c
> @@ -1194,6 +1194,11 @@ int mhi_send_cmd(struct mhi_controller *mhi_cntrl,
> cmd_tre->dword[0] = MHI_TRE_CMD_RESET_DWORD0;
> cmd_tre->dword[1] = MHI_TRE_CMD_RESET_DWORD1(chan);
> break;
> + case MHI_CMD_STOP_CHAN:
> + cmd_tre->ptr = MHI_TRE_CMD_STOP_PTR;
> + cmd_tre->dword[0] = MHI_TRE_CMD_STOP_DWORD0;
> + cmd_tre->dword[1] = MHI_TRE_CMD_STOP_DWORD1(chan);
> + break;
> case MHI_CMD_START_CHAN:
> cmd_tre->ptr = MHI_TRE_CMD_START_PTR;
> cmd_tre->dword[0] = MHI_TRE_CMD_START_DWORD0;
> --
> The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
> a Linux Foundation Collaborative Project
>
On Mon, Nov 16, 2020 at 09:36:09AM -0800, Bhaumik Bhatt wrote:
> Hi Mani,
>
> On 2020-11-15 23:13, Manivannan Sadhasivam wrote:
> > On Wed, Nov 11, 2020 at 11:21:08AM -0800, Bhaumik Bhatt wrote:
> > > Add support to receive the response to a STOP channel command to the
> > > MHI bus. If a client would like to STOP a channel instead of issuing
> > > a RESET to it, this would provide support for it.
> > >
> > > Signed-off-by: Bhaumik Bhatt <[email protected]>
> > > ---
> > > drivers/bus/mhi/core/init.c | 5 +++--
> > > drivers/bus/mhi/core/main.c | 5 +++++
> > > 2 files changed, 8 insertions(+), 2 deletions(-)
> > >
> > > diff --git a/drivers/bus/mhi/core/init.c b/drivers/bus/mhi/core/init.c
> > > index 8cefa35..4d34d62 100644
> > > --- a/drivers/bus/mhi/core/init.c
> > > +++ b/drivers/bus/mhi/core/init.c
> > > @@ -1267,8 +1267,9 @@ static int mhi_driver_remove(struct device *dev)
> > >
> > > mutex_lock(&mhi_chan->mutex);
> > >
> > > - if (ch_state[dir] == MHI_CH_STATE_ENABLED &&
> > > - !mhi_chan->offload_ch)
> > > + if ((ch_state[dir] == MHI_CH_STATE_ENABLED ||
> > > + ch_state[dir] == MHI_CH_STATE_STOP) &&
> >
> > This enum is not defined in this patch so it'll break. Please add a
> > separate
> > patch which introduces the new state enums alone and then have patches
> > 1/2
> > as a followup.
> >
> It is actually already defined and present in internal.h as enum
> mhi_ch_state.
>
> The old set of enums has MHI_CH_STATE_STOP from enum mhi_ch_state and the
> new
> enum I introduced is MHI_CH_STATE_TYPE_STOP from enum enum
> mhi_ch_state_type.
>
> If it seems confusing, suggestions to renaming them are welcome.
>
Ah, sorry. I got confused with MHI_CH_STATE_TYPE_STOP and MHI_CH_STATE_STOP.
Ignore my previous comment.
Thanks,
Mani
> > Also this change is not belonging to this commit I believe.
> >
> I included this change here because, a channel can be in "stopped" state and
> a user module could be unloaded or a crash could force a driver remove
> leading
> us to come this check.
>
> If you think I should move it as a separate patch, let me know.
> > Thanks,
> > Mani
> >
> > > + !mhi_chan->offload_ch)
> > > mhi_deinit_chan_ctxt(mhi_cntrl, mhi_chan);
> > >
> > > mhi_chan->ch_state = MHI_CH_STATE_DISABLED;
> > > diff --git a/drivers/bus/mhi/core/main.c b/drivers/bus/mhi/core/main.c
> > > index f953e2a..ad881a1 100644
> > > --- a/drivers/bus/mhi/core/main.c
> > > +++ b/drivers/bus/mhi/core/main.c
> > > @@ -1194,6 +1194,11 @@ int mhi_send_cmd(struct mhi_controller
> > > *mhi_cntrl,
> > > cmd_tre->dword[0] = MHI_TRE_CMD_RESET_DWORD0;
> > > cmd_tre->dword[1] = MHI_TRE_CMD_RESET_DWORD1(chan);
> > > break;
> > > + case MHI_CMD_STOP_CHAN:
> > > + cmd_tre->ptr = MHI_TRE_CMD_STOP_PTR;
> > > + cmd_tre->dword[0] = MHI_TRE_CMD_STOP_DWORD0;
> > > + cmd_tre->dword[1] = MHI_TRE_CMD_STOP_DWORD1(chan);
> > > + break;
> > > case MHI_CMD_START_CHAN:
> > > cmd_tre->ptr = MHI_TRE_CMD_START_PTR;
> > > cmd_tre->dword[0] = MHI_TRE_CMD_START_DWORD0;
> > > --
> > > The Qualcomm Innovation Center, Inc. is a member of the Code Aurora
> > > Forum,
> > > a Linux Foundation Collaborative Project
> > >
>
> Thanks,
> Bhaumik
> --
> The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
> a Linux Foundation Collaborative Project
On 2020-11-21 09:16 AM, Manivannan Sadhasivam wrote:
> On Mon, Nov 16, 2020 at 09:36:09AM -0800, Bhaumik Bhatt wrote:
>> Hi Mani,
>>
>> On 2020-11-15 23:13, Manivannan Sadhasivam wrote:
>> > On Wed, Nov 11, 2020 at 11:21:08AM -0800, Bhaumik Bhatt wrote:
>> > > Add support to receive the response to a STOP channel command to the
>> > > MHI bus. If a client would like to STOP a channel instead of issuing
>> > > a RESET to it, this would provide support for it.
>> > >
>> > > Signed-off-by: Bhaumik Bhatt <[email protected]>
>> > > ---
>> > > drivers/bus/mhi/core/init.c | 5 +++--
>> > > drivers/bus/mhi/core/main.c | 5 +++++
>> > > 2 files changed, 8 insertions(+), 2 deletions(-)
>> > >
>> > > diff --git a/drivers/bus/mhi/core/init.c b/drivers/bus/mhi/core/init.c
>> > > index 8cefa35..4d34d62 100644
>> > > --- a/drivers/bus/mhi/core/init.c
>> > > +++ b/drivers/bus/mhi/core/init.c
>> > > @@ -1267,8 +1267,9 @@ static int mhi_driver_remove(struct device *dev)
>> > >
>> > > mutex_lock(&mhi_chan->mutex);
>> > >
>> > > - if (ch_state[dir] == MHI_CH_STATE_ENABLED &&
>> > > - !mhi_chan->offload_ch)
>> > > + if ((ch_state[dir] == MHI_CH_STATE_ENABLED ||
>> > > + ch_state[dir] == MHI_CH_STATE_STOP) &&
>> >
>> > This enum is not defined in this patch so it'll break. Please add a
>> > separate
>> > patch which introduces the new state enums alone and then have patches
>> > 1/2
>> > as a followup.
>> >
>> It is actually already defined and present in internal.h as enum
>> mhi_ch_state.
>>
>> The old set of enums has MHI_CH_STATE_STOP from enum mhi_ch_state and
>> the
>> new
>> enum I introduced is MHI_CH_STATE_TYPE_STOP from enum enum
>> mhi_ch_state_type.
>>
>> If it seems confusing, suggestions to renaming them are welcome.
>>
>
> Ah, sorry. I got confused with MHI_CH_STATE_TYPE_STOP and
> MHI_CH_STATE_STOP.
> Ignore my previous comment.
>
> Thanks,
> Mani
>
No problem.
>> > Also this change is not belonging to this commit I believe.
>> >
>> I included this change here because, a channel can be in "stopped"
>> state and
>> a user module could be unloaded or a crash could force a driver remove
>> leading
>> us to come this check.
>>
>> If you think I should move it as a separate patch, let me know.
>> > Thanks,
>> > Mani
>> >
>> > > + !mhi_chan->offload_ch)
>> > > mhi_deinit_chan_ctxt(mhi_cntrl, mhi_chan);
>> > >
>> > > mhi_chan->ch_state = MHI_CH_STATE_DISABLED;
>> > > diff --git a/drivers/bus/mhi/core/main.c b/drivers/bus/mhi/core/main.c
>> > > index f953e2a..ad881a1 100644
>> > > --- a/drivers/bus/mhi/core/main.c
>> > > +++ b/drivers/bus/mhi/core/main.c
>> > > @@ -1194,6 +1194,11 @@ int mhi_send_cmd(struct mhi_controller
>> > > *mhi_cntrl,
>> > > cmd_tre->dword[0] = MHI_TRE_CMD_RESET_DWORD0;
>> > > cmd_tre->dword[1] = MHI_TRE_CMD_RESET_DWORD1(chan);
>> > > break;
>> > > + case MHI_CMD_STOP_CHAN:
>> > > + cmd_tre->ptr = MHI_TRE_CMD_STOP_PTR;
>> > > + cmd_tre->dword[0] = MHI_TRE_CMD_STOP_DWORD0;
>> > > + cmd_tre->dword[1] = MHI_TRE_CMD_STOP_DWORD1(chan);
>> > > + break;
>> > > case MHI_CMD_START_CHAN:
>> > > cmd_tre->ptr = MHI_TRE_CMD_START_PTR;
>> > > cmd_tre->dword[0] = MHI_TRE_CMD_START_DWORD0;
>> > > --
>> > > The Qualcomm Innovation Center, Inc. is a member of the Code Aurora
>> > > Forum,
>> > > a Linux Foundation Collaborative Project
>> > >
>>
>> Thanks,
>> Bhaumik
>> --
>> The Qualcomm Innovation Center, Inc. is a member of the Code Aurora
>> Forum,
>> a Linux Foundation Collaborative Project
Thanks,
Bhaumik
---
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora
Forum,
a Linux Foundation Collaborative Project