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From: Bhaumik Bhatt <bbhatt@codeaurora.org>
To: manivannan.sadhasivam@linaro.org
Cc: linux-arm-msm@vger.kernel.org, hemantk@codeaurora.org,
	jhugo@codeaurora.org, linux-kernel@vger.kernel.org,
	carl.yin@quectel.com, naveen.kumar@quectel.com,
	loic.poulain@linaro.org, Bhaumik Bhatt <bbhatt@codeaurora.org>
Subject: [PATCH v8 3/9] bus: mhi: core: Improvements to the channel handling state machine
Date: Thu,  1 Apr 2021 14:16:12 -0700	[thread overview]
Message-ID: <1617311778-1254-4-git-send-email-bbhatt@codeaurora.org> (raw)
In-Reply-To: <1617311778-1254-1-git-send-email-bbhatt@codeaurora.org>

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>
---
 drivers/bus/mhi/core/init.c     |   6 ++
 drivers/bus/mhi/core/internal.h |  12 ++++
 drivers/bus/mhi/core/main.c     | 151 ++++++++++++++++++++++------------------
 3 files changed, 100 insertions(+), 69 deletions(-)

diff --git a/drivers/bus/mhi/core/init.c b/drivers/bus/mhi/core/init.c
index f8ba954..9c2ed92 100644
--- a/drivers/bus/mhi/core/init.c
+++ b/drivers/bus/mhi/core/init.c
@@ -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",
diff --git a/drivers/bus/mhi/core/internal.h b/drivers/bus/mhi/core/internal.h
index e690f15..5b9ea66 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 8c510f1..710ca0f 100644
--- a/drivers/bus/mhi/core/main.c
+++ b/drivers/bus/mhi/core/main.c
@@ -1234,56 +1234,105 @@ 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;
 
-	dev_dbg(dev, "Entered: unprepare channel:%d\n", mhi_chan->chan);
-
-	/* 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) {
+	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);
-		mutex_unlock(&mhi_chan->mutex);
-		return;
-	}
 
-	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;
 
-	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;
+		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);
-	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);
-	if (ret)
-		goto error_invalid_state;
 
-	/* even if it fails we will still reset */
+	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)
+				       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");
+			"%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;
+
+	mutex_lock(&mhi_chan->mutex);
+
+	/* no more processing events for this channel */
+	ret = mhi_update_channel_state(mhi_cntrl, mhi_chan,
+				       MHI_CH_STATE_TYPE_RESET);
+	if (ret)
+		dev_err(dev, "%d: Failed to reset channel, still resetting\n",
+			mhi_chan->chan);
 
-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);
 }
 
@@ -1293,8 +1342,6 @@ 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",
@@ -1305,14 +1352,6 @@ 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);
@@ -1320,34 +1359,11 @@ 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,
@@ -1385,9 +1401,6 @@ 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:
-- 
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project


  parent reply	other threads:[~2021-04-01 21:16 UTC|newest]

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-04-01 21:16 Bhaumik Bhatt
2021-04-01 21:16 ` [PATCH v8 1/9] bus: mhi: core: Allow sending the STOP channel command Bhaumik Bhatt
2021-05-04 17:40   ` Jeffrey Hugo
2021-05-26 19:03   ` patchwork-bot+linux-arm-msm
2021-04-01 21:16 ` [PATCH v8 2/9] bus: mhi: core: Clear context for stopped channels from remove() Bhaumik Bhatt
2021-05-04 17:41   ` Jeffrey Hugo
2021-04-01 21:16 ` Bhaumik Bhatt [this message]
2021-04-07  6:26   ` [PATCH v8 3/9] bus: mhi: core: Improvements to the channel handling state machine Manivannan Sadhasivam
2021-05-04 17:43   ` Jeffrey Hugo
2021-04-01 21:16 ` [PATCH v8 4/9] bus: mhi: core: Update debug messages to use client device Bhaumik Bhatt
2021-04-07  6:27   ` Manivannan Sadhasivam
2021-05-04 17:45   ` Jeffrey Hugo
2021-04-01 21:16 ` [PATCH v8 5/9] bus: mhi: core: Hold device wake for channel update commands Bhaumik Bhatt
2021-04-07  6:31   ` Manivannan Sadhasivam
2021-05-04 17:46   ` Jeffrey Hugo
2021-04-01 21:16 ` [PATCH v8 6/9] bus: mhi: core: Clear configuration from channel context during reset Bhaumik Bhatt
2021-05-04 17:48   ` Jeffrey Hugo
2021-04-01 21:16 ` [PATCH v8 7/9] bus: mhi: core: Check channel execution environment before issuing reset Bhaumik Bhatt
2021-05-04 17:49   ` Jeffrey Hugo
2021-04-01 21:16 ` [PATCH v8 8/9] bus: mhi: core: Remove __ prefix for MHI channel unprepare function Bhaumik Bhatt
2021-05-04 17:50   ` Jeffrey Hugo
2021-04-01 21:16 ` [PATCH v8 9/9] bus: mhi: Improve documentation on channel transfer setup APIs Bhaumik Bhatt
2021-05-04 17:51   ` Jeffrey Hugo
2021-04-07  6:56 ` your mail Manivannan Sadhasivam

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