Currently slimbus driver doesn't support stream disable
callback, it only supports stream enable callback.

In slimbus usecase, client is switching to new frequency
with same channel and calling enable stream callback for
new frequency but DSP subsystem is crashing as we are switching
to new frequency with same channel without disabling stream
for older frequency.

Ideally, before switching to another frequency, client should
call disable stream callback and then enable stream for newer frequency.

Hence add support to disable stream via qcom_slim_ngd_disable_stream().

Signed-off-by: Viken Dadhaniya <quic_vdadhani@quicinc.com>
---
 drivers/slimbus/qcom-ngd-ctrl.c | 70 +++++++++++++++++++++++++++++++++
 drivers/slimbus/slimbus.h       | 13 ++++++
 2 files changed, 83 insertions(+)

diff --git a/drivers/slimbus/qcom-ngd-ctrl.c b/drivers/slimbus/qcom-ngd-ctrl.c
index e0b21f0f79c1..d952827d2e12 100644
--- a/drivers/slimbus/qcom-ngd-ctrl.c
+++ b/drivers/slimbus/qcom-ngd-ctrl.c
@@ -1,6 +1,7 @@
 // SPDX-License-Identifier: GPL-2.0
 // Copyright (c) 2011-2017, The Linux Foundation. All rights reserved.
 // Copyright (c) 2018, Linaro Limited
+// Copyright (c) 2024 Qualcomm Innovation Center, Inc. All rights reserved.
 
 #include <linux/irq.h>
 #include <linux/kernel.h>
@@ -1084,6 +1085,74 @@ static int qcom_slim_ngd_enable_stream(struct slim_stream_runtime *rt)
 	return ret;
 }
 
+static int qcom_slim_ngd_disable_stream(struct slim_stream_runtime *rt)
+{
+	struct slim_device *sdev = rt->dev;
+	struct slim_controller *ctrl = sdev->ctrl;
+	struct slim_val_inf msg =  {0};
+	u8 wbuf[SLIM_MSGQ_BUF_LEN];
+	u8 rbuf[SLIM_MSGQ_BUF_LEN];
+	struct slim_msg_txn txn = {0,};
+	int i, ret;
+
+	txn.mt = SLIM_MSG_MT_DEST_REFERRED_USER;
+	txn.dt = SLIM_MSG_DEST_LOGICALADDR;
+	txn.la = SLIM_LA_MGR;
+	txn.ec = 0;
+	txn.msg = &msg;
+	txn.msg->num_bytes = 0;
+	txn.msg->wbuf = wbuf;
+	txn.msg->rbuf = rbuf;
+
+	for (i = 0; i < rt->num_ports; i++) {
+		struct slim_port *port = &rt->ports[i];
+
+		if (txn.msg->num_bytes == 0) {
+			wbuf[txn.msg->num_bytes++] = (u8)(SLIM_CH_REMOVE << 6)
+							| (sdev->laddr & 0x1f);
+
+			ret = slim_alloc_txn_tid(ctrl, &txn);
+			if (ret) {
+				dev_err(&sdev->dev, "Fail to allocate TID\n");
+				return -ENXIO;
+			}
+			wbuf[txn.msg->num_bytes++] = txn.tid;
+		}
+		wbuf[txn.msg->num_bytes++] = port->ch.id;
+	}
+
+	txn.mc = SLIM_USR_MC_CHAN_CTRL;
+	txn.rl = txn.msg->num_bytes + 4;
+	ret = qcom_slim_ngd_xfer_msg_sync(ctrl, &txn);
+	if (ret) {
+		slim_free_txn_tid(ctrl, &txn);
+		dev_err(&sdev->dev, "TX timed out:MC:0x%x,mt:0x%x ret:%d\n",
+			txn.mc,	txn.mt, ret);
+		return ret;
+	}
+
+	txn.mc = SLIM_USR_MC_RECONFIG_NOW;
+	txn.msg->num_bytes = 2;
+	wbuf[1] = sdev->laddr;
+	txn.rl = txn.msg->num_bytes + 4;
+
+	ret = slim_alloc_txn_tid(ctrl, &txn);
+	if (ret) {
+		dev_err(ctrl->dev, "Fail to allocate TID ret:%d\n", ret);
+		return ret;
+	}
+
+	wbuf[0] = txn.tid;
+	ret = qcom_slim_ngd_xfer_msg_sync(ctrl, &txn);
+	if (ret) {
+		slim_free_txn_tid(ctrl, &txn);
+		dev_err(&sdev->dev, "TX timed out:MC:0x%x,mt:0x%x ret:%d\n",
+			txn.mc,	txn.mt, ret);
+	}
+
+	return ret;
+}
+
 static int qcom_slim_ngd_get_laddr(struct slim_controller *ctrl,
 				   struct slim_eaddr *ea, u8 *laddr)
 {
@@ -1642,6 +1711,7 @@ static int qcom_slim_ngd_ctrl_probe(struct platform_device *pdev)
 	ctrl->ctrl.clkgear = SLIM_MAX_CLK_GEAR;
 	ctrl->ctrl.get_laddr = qcom_slim_ngd_get_laddr;
 	ctrl->ctrl.enable_stream = qcom_slim_ngd_enable_stream;
+	ctrl->ctrl.disable_stream = qcom_slim_ngd_disable_stream;
 	ctrl->ctrl.xfer_msg = qcom_slim_ngd_xfer_msg;
 	ctrl->ctrl.wakeup = NULL;
 	ctrl->state = QCOM_SLIM_NGD_CTRL_DOWN;
diff --git a/drivers/slimbus/slimbus.h b/drivers/slimbus/slimbus.h
index 00a7f112574b..21543d125614 100644
--- a/drivers/slimbus/slimbus.h
+++ b/drivers/slimbus/slimbus.h
@@ -1,6 +1,7 @@
 /* SPDX-License-Identifier: GPL-2.0 */
 /*
  * Copyright (c) 2011-2017, The Linux Foundation
+ * Copyright (c) 2024 Qualcomm Innovation Center, Inc. All rights reserved.
  */
 
 #ifndef _DRIVERS_SLIMBUS_H
@@ -316,6 +317,18 @@ enum slim_transport_protocol {
 	SLIM_PROTO_EXT_HALF_DUP,
 };
 
+/*
+ * enum slim_ch_control: Channel control.
+ * Activate will schedule channel and/or group of channels in the TDM frame.
+ * Suspend will keep the schedule but data-transfer won't happen.
+ * Remove will remove the channel/group from the TDM frame.
+ */
+enum slim_ch_control {
+	SLIM_CH_ACTIVATE,
+	SLIM_CH_SUSPEND,
+	SLIM_CH_REMOVE,
+};
+
 /**
  * struct slim_stream_runtime  - SLIMbus stream runtime instance
  *
-- 
2.17.1

On 5/7/24 08:30, Viken Dadhaniya wrote:
> Currently slimbus driver doesn't support stream disable
> callback, it only supports stream enable callback.
> 
> In slimbus usecase, client is switching to new frequency
> with same channel and calling enable stream callback for
> new frequency but DSP subsystem is crashing as we are switching
> to new frequency with same channel without disabling stream
> for older frequency.

This is very difficult to read

but AFAICU comes down to:
"Trying to switch frequencies without closing the channel results
in an attempt to re-enable the channel without a clean shutdown,
which then leads to a crash on the ADSP."

> 
> Ideally, before switching to another frequency, client should
> call disable stream callback and then enable stream for newer frequency.
> 
> Hence add support to disable stream via qcom_slim_ngd_disable_stream().
> 
> Signed-off-by: Viken Dadhaniya <quic_vdadhani@quicinc.com>
> ---
>   drivers/slimbus/qcom-ngd-ctrl.c | 70 +++++++++++++++++++++++++++++++++
>   drivers/slimbus/slimbus.h       | 13 ++++++
>   2 files changed, 83 insertions(+)
> 
> diff --git a/drivers/slimbus/qcom-ngd-ctrl.c b/drivers/slimbus/qcom-ngd-ctrl.c
> index e0b21f0f79c1..d952827d2e12 100644
> --- a/drivers/slimbus/qcom-ngd-ctrl.c
> +++ b/drivers/slimbus/qcom-ngd-ctrl.c
> @@ -1,6 +1,7 @@
>   // SPDX-License-Identifier: GPL-2.0
>   // Copyright (c) 2011-2017, The Linux Foundation. All rights reserved.
>   // Copyright (c) 2018, Linaro Limited
> +// Copyright (c) 2024 Qualcomm Innovation Center, Inc. All rights reserved.
>   
>   #include <linux/irq.h>
>   #include <linux/kernel.h>
> @@ -1084,6 +1085,74 @@ static int qcom_slim_ngd_enable_stream(struct slim_stream_runtime *rt)
>   	return ret;
>   }
>   
> +static int qcom_slim_ngd_disable_stream(struct slim_stream_runtime *rt)
> +{
> +	struct slim_device *sdev = rt->dev;
> +	struct slim_controller *ctrl = sdev->ctrl;
> +	struct slim_val_inf msg =  {0};
> +	u8 wbuf[SLIM_MSGQ_BUF_LEN];
> +	u8 rbuf[SLIM_MSGQ_BUF_LEN];
> +	struct slim_msg_txn txn = {0,};
{ 0 } is enough

Also, reverse-Christmas-tre, please

> +	int i, ret;
> +
> +	txn.mt = SLIM_MSG_MT_DEST_REFERRED_USER;
> +	txn.dt = SLIM_MSG_DEST_LOGICALADDR;
> +	txn.la = SLIM_LA_MGR;
> +	txn.ec = 0;
> +	txn.msg = &msg;
> +	txn.msg->num_bytes = 0;
> +	txn.msg->wbuf = wbuf;
> +	txn.msg->rbuf = rbuf;
> +
> +	for (i = 0; i < rt->num_ports; i++) {
> +		struct slim_port *port = &rt->ports[i];
> +
> +		if (txn.msg->num_bytes == 0) {
> +			wbuf[txn.msg->num_bytes++] = (u8)(SLIM_CH_REMOVE << 6)
> +							| (sdev->laddr & 0x1f);

Add a #define and use FIELD_PREP

> +
> +			ret = slim_alloc_txn_tid(ctrl, &txn);
> +			if (ret) {
> +				dev_err(&sdev->dev, "Fail to allocate TID\n");
> +				return -ENXIO;
> +			}
> +			wbuf[txn.msg->num_bytes++] = txn.tid;
> +		}
> +		wbuf[txn.msg->num_bytes++] = port->ch.id;
> +	}
> +
> +	txn.mc = SLIM_USR_MC_CHAN_CTRL;
> +	txn.rl = txn.msg->num_bytes + 4;

Why +4?

> +	ret = qcom_slim_ngd_xfer_msg_sync(ctrl, &txn);
> +	if (ret) {
> +		slim_free_txn_tid(ctrl, &txn);
> +		dev_err(&sdev->dev, "TX timed out:MC:0x%x,mt:0x%x ret:%d\n",

Please clean this up, add commas to separate all three prints and a
space after each comma

[...]

>   
> +/*
> + * enum slim_ch_control: Channel control.
> + * Activate will schedule channel and/or group of channels in the TDM frame.
> + * Suspend will keep the schedule but data-transfer won't happen.
> + * Remove will remove the channel/group from the TDM frame.

"will" suggests these are not immediate.

Konrad