[PATCH v4 7/8] slimbus: qcom-ngd-ctrl: Remove data channels on stream disable

[David Heidelberg via B4 Relay <devnull+david.ixit.cz@kernel.org>]

From: David Heidelberg <david@ixit.cz>

qcom_slim_ngd_xfer_msg() silently returns success for every core
reconfiguration message, so the generic channel removal done by
slim_stream_disable() never reaches the ADSP SLIMbus master. The
master therefore keeps the channels of a closed stream. When the next
stream defines the same channel numbers again, the WCD9340 capture
completes without any error but records only zeros; removing the
channels explicitly when the stream is disabled makes it work again.

Implement the disable_stream controller op with the sequence the
downstream NGD driver sends for channel removal, CHAN_CTRL(REMOVE)
listing the stream's channels followed by RECONFIG_NOW. Like
downstream, treat -EREMOTEIO from the removal as success: it means the
controller is being restarted and the channels are gone anyway.

Based on work done by Casey Tunturi.

Assisted-by: Claude:claude-fable-5-1
Signed-off-by: David Heidelberg <david@ixit.cz>
---
 drivers/slimbus/qcom-ngd-ctrl.c | 81 +++++++++++++++++++++++++++++++++++++++++
 1 file changed, 81 insertions(+)

diff --git a/drivers/slimbus/qcom-ngd-ctrl.c b/drivers/slimbus/qcom-ngd-ctrl.c
index eb0ccb31e9074..0a4859466c82d 100644
--- a/drivers/slimbus/qcom-ngd-ctrl.c
+++ b/drivers/slimbus/qcom-ngd-ctrl.c
@@ -1081,16 +1081,96 @@ static int qcom_slim_ngd_enable_stream(struct slim_stream_runtime *rt)
 		slim_free_txn_tid(ctrl, &txn);
 		dev_err(&sdev->dev, "TX timed out:MC:0x%x,mt:0x%x", txn.mc,
 				txn.mt);
 	}
 
 	return ret;
 }
 
+/* CHAN_CTRL operation, bits [7:6] of the first payload byte */
+#define SLIM_USR_CHAN_CTRL_REMOVE	2
+
+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;
+
+	/*
+	 * The NGD drops the core reconfiguration messages that
+	 * slim_stream_disable() uses to remove channels, so ask the master
+	 * to remove them the way the downstream NGD driver does:
+	 * CHAN_CTRL(REMOVE) listing every channel, then RECONFIG_NOW.
+	 * Without this the master keeps the channels active and a later
+	 * DEF_ACT_CHAN with the same channel numbers is a no-op, so the
+	 * data path is never re-armed and a reopened stream moves no data.
+	 */
+	/* 5-bit client number, operation in bits [7:6] */
+	wbuf[txn.msg->num_bytes++] = (SLIM_USR_CHAN_CTRL_REMOVE << 6) |
+				     (sdev->laddr & 0x1f);
+
+	ret = slim_alloc_txn_tid(ctrl, &txn);
+	if (ret) {
+		dev_err(&sdev->dev, "Fail to allocate TID\n");
+		return ret;
+	}
+	wbuf[txn.msg->num_bytes++] = txn.tid;
+
+	for (i = 0; i < rt->num_ports; i++)
+		wbuf[txn.msg->num_bytes++] = rt->ports[i].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);
+		/* Controller restarting, the channels are gone anyway */
+		if (ret == -EREMOTEIO)
+			return 0;
+		dev_err(&sdev->dev, "TX timed out:MC:0x%x,mt:0x%x", txn.mc,
+				txn.mt);
+		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\n");
+		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", txn.mc,
+				txn.mt);
+	}
+
+	return ret;
+}
+
 static int qcom_slim_ngd_get_laddr(struct slim_controller *ctrl,
 				   struct slim_eaddr *ea, u8 *laddr)
 {
 	struct slim_val_inf msg =  {0};
 	u8 failed_ea[6] = {0, 0, 0, 0, 0, 0};
 	struct slim_msg_txn txn;
 	u8 wbuf[10] = {0};
 	u8 rbuf[10] = {0};
@@ -1620,16 +1700,17 @@ static int qcom_slim_ngd_ctrl_probe(struct platform_device *pdev)
 	ctrl->framer.rootfreq = SLIM_ROOT_FREQ >> 3;
 	ctrl->framer.superfreq =
 		ctrl->framer.rootfreq / SLIM_CL_PER_SUPERFRAME_DIV8;
 
 	ctrl->ctrl.a_framer = &ctrl->framer;
 	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;
 
 	mutex_init(&ctrl->tx_lock);
 	mutex_init(&ctrl->ssr_lock);
 	spin_lock_init(&ctrl->tx_buf_lock);
 	init_completion(&ctrl->reconf);

-- 
2.55.0