net: wwan: t7xx: Add control port

Control Port implements driver control messages such as modem-host
handshaking, controls port enumeration, and handles exception messages.

The handshaking process between the driver and the modem happens during
the init sequence. The process involves the exchange of a list of
supported runtime features to make sure that modem and host are ready
to provide proper feature lists including port enumeration. Further
features can be enabled and controlled in this handshaking process.

Signed-off-by: Haijun Liu <haijun.liu@mediatek.com>
Signed-off-by: Chandrashekar Devegowda <chandrashekar.devegowda@intel.com>
Co-developed-by: Ricardo Martinez <ricardo.martinez@linux.intel.com>
Signed-off-by: Ricardo Martinez <ricardo.martinez@linux.intel.com>
Reviewed-by: Loic Poulain <loic.poulain@linaro.org>
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Reviewed-by: Sergey Ryazanov <ryazanov.s.a@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 273 insertions, 0 deletions

diff --git a/drivers/net/wwan/t7xx/t7xx_port_ctrl_msg.c b/drivers/net/wwan/t7xx/t7xx_port_ctrl_msg.c
new file mode 100644
index 000000000000..68430b130a67
--- /dev/null
+++ b/drivers/net/wwan/t7xx/t7xx_port_ctrl_msg.c
@@ -0,0 +1,273 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (c) 2021, MediaTek Inc.
+ * Copyright (c) 2021-2022, Intel Corporation.
+ *
+ * Authors:
+ *  Haijun Liu <haijun.liu@mediatek.com>
+ *  Ricardo Martinez <ricardo.martinez@linux.intel.com>
+ *  Moises Veleta <moises.veleta@intel.com>
+ *
+ * Contributors:
+ *  Amir Hanania <amir.hanania@intel.com>
+ *  Chiranjeevi Rapolu <chiranjeevi.rapolu@intel.com>
+ *  Eliot Lee <eliot.lee@intel.com>
+ *  Sreehari Kancharla <sreehari.kancharla@intel.com>
+ */
+
+#include <linux/bitfield.h>
+#include <linux/device.h>
+#include <linux/err.h>
+#include <linux/kthread.h>
+#include <linux/netdevice.h>
+#include <linux/skbuff.h>
+#include <linux/spinlock.h>
+
+#include "t7xx_port.h"
+#include "t7xx_port_proxy.h"
+#include "t7xx_state_monitor.h"
+
+#define PORT_MSG_VERSION	GENMASK(31, 16)
+#define PORT_MSG_PRT_CNT	GENMASK(15, 0)
+
+struct port_msg {
+	__le32	head_pattern;
+	__le32	info;
+	__le32	tail_pattern;
+	__le32	data[];
+};
+
+static int port_ctl_send_msg_to_md(struct t7xx_port *port, unsigned int msg, unsigned int ex_msg)
+{
+	struct sk_buff *skb;
+	int ret;
+
+	skb = t7xx_ctrl_alloc_skb(0);
+	if (!skb)
+		return -ENOMEM;
+
+	ret = t7xx_port_send_ctl_skb(port, skb, msg, ex_msg);
+	if (ret)
+		dev_kfree_skb_any(skb);
+
+	return ret;
+}
+
+static int fsm_ee_message_handler(struct t7xx_port *port, struct t7xx_fsm_ctl *ctl,
+				  struct sk_buff *skb)
+{
+	struct ctrl_msg_header *ctrl_msg_h = (struct ctrl_msg_header *)skb->data;
+	struct device *dev = &ctl->md->t7xx_dev->pdev->dev;
+	enum md_state md_state;
+	int ret = -EINVAL;
+
+	md_state = t7xx_fsm_get_md_state(ctl);
+	if (md_state != MD_STATE_EXCEPTION) {
+		dev_err(dev, "Receive invalid MD_EX %x when MD state is %d\n",
+			ctrl_msg_h->ex_msg, md_state);
+		return -EINVAL;
+	}
+
+	switch (le32_to_cpu(ctrl_msg_h->ctrl_msg_id)) {
+	case CTL_ID_MD_EX:
+		if (le32_to_cpu(ctrl_msg_h->ex_msg) != MD_EX_CHK_ID) {
+			dev_err(dev, "Receive invalid MD_EX %x\n", ctrl_msg_h->ex_msg);
+			break;
+		}
+
+		ret = port_ctl_send_msg_to_md(port, CTL_ID_MD_EX, MD_EX_CHK_ID);
+		if (ret) {
+			dev_err(dev, "Failed to send exception message to modem\n");
+			break;
+		}
+
+		ret = t7xx_fsm_append_event(ctl, FSM_EVENT_MD_EX, NULL, 0);
+		if (ret)
+			dev_err(dev, "Failed to append Modem Exception event");
+
+		break;
+
+	case CTL_ID_MD_EX_ACK:
+		if (le32_to_cpu(ctrl_msg_h->ex_msg) != MD_EX_CHK_ACK_ID) {
+			dev_err(dev, "Receive invalid MD_EX_ACK %x\n", ctrl_msg_h->ex_msg);
+			break;
+		}
+
+		ret = t7xx_fsm_append_event(ctl, FSM_EVENT_MD_EX_REC_OK, NULL, 0);
+		if (ret)
+			dev_err(dev, "Failed to append Modem Exception Received event");
+
+		break;
+
+	case CTL_ID_MD_EX_PASS:
+		ret = t7xx_fsm_append_event(ctl, FSM_EVENT_MD_EX_PASS, NULL, 0);
+		if (ret)
+			dev_err(dev, "Failed to append Modem Exception Passed event");
+
+		break;
+
+	case CTL_ID_DRV_VER_ERROR:
+		dev_err(dev, "AP/MD driver version mismatch\n");
+	}
+
+	return ret;
+}
+
+/**
+ * t7xx_port_enum_msg_handler() - Parse the port enumeration message to create/remove nodes.
+ * @md: Modem context.
+ * @msg: Message.
+ *
+ * Used to control create/remove device node.
+ *
+ * Return:
+ * * 0		- Success.
+ * * -EFAULT	- Message check failure.
+ */
+int t7xx_port_enum_msg_handler(struct t7xx_modem *md, void *msg)
+{
+	struct device *dev = &md->t7xx_dev->pdev->dev;
+	unsigned int version, port_count, i;
+	struct port_msg *port_msg = msg;
+
+	version = FIELD_GET(PORT_MSG_VERSION, le32_to_cpu(port_msg->info));
+	if (version != PORT_ENUM_VER ||
+	    le32_to_cpu(port_msg->head_pattern) != PORT_ENUM_HEAD_PATTERN ||
+	    le32_to_cpu(port_msg->tail_pattern) != PORT_ENUM_TAIL_PATTERN) {
+		dev_err(dev, "Invalid port control message %x:%x:%x\n",
+			version, le32_to_cpu(port_msg->head_pattern),
+			le32_to_cpu(port_msg->tail_pattern));
+		return -EFAULT;
+	}
+
+	port_count = FIELD_GET(PORT_MSG_PRT_CNT, le32_to_cpu(port_msg->info));
+	for (i = 0; i < port_count; i++) {
+		u32 port_info = le32_to_cpu(port_msg->data[i]);
+		unsigned int ch_id;
+		bool en_flag;
+
+		ch_id = FIELD_GET(PORT_INFO_CH_ID, port_info);
+		en_flag = port_info & PORT_INFO_ENFLG;
+		if (t7xx_port_proxy_chl_enable_disable(md->port_prox, ch_id, en_flag))
+			dev_dbg(dev, "Port:%x not found\n", ch_id);
+	}
+
+	return 0;
+}
+
+static int control_msg_handler(struct t7xx_port *port, struct sk_buff *skb)
+{
+	const struct t7xx_port_conf *port_conf = port->port_conf;
+	struct t7xx_fsm_ctl *ctl = port->t7xx_dev->md->fsm_ctl;
+	struct ctrl_msg_header *ctrl_msg_h;
+	int ret = 0;
+
+	ctrl_msg_h = (struct ctrl_msg_header *)skb->data;
+	switch (le32_to_cpu(ctrl_msg_h->ctrl_msg_id)) {
+	case CTL_ID_HS2_MSG:
+		skb_pull(skb, sizeof(*ctrl_msg_h));
+
+		if (port_conf->rx_ch == PORT_CH_CONTROL_RX) {
+			ret = t7xx_fsm_append_event(ctl, FSM_EVENT_MD_HS2, skb->data,
+						    le32_to_cpu(ctrl_msg_h->data_length));
+			if (ret)
+				dev_err(port->dev, "Failed to append Handshake 2 event");
+		}
+
+		dev_kfree_skb_any(skb);
+		break;
+
+	case CTL_ID_MD_EX:
+	case CTL_ID_MD_EX_ACK:
+	case CTL_ID_MD_EX_PASS:
+	case CTL_ID_DRV_VER_ERROR:
+		ret = fsm_ee_message_handler(port, ctl, skb);
+		dev_kfree_skb_any(skb);
+		break;
+
+	case CTL_ID_PORT_ENUM:
+		skb_pull(skb, sizeof(*ctrl_msg_h));
+		ret = t7xx_port_enum_msg_handler(ctl->md, (struct port_msg *)skb->data);
+		if (!ret)
+			ret = port_ctl_send_msg_to_md(port, CTL_ID_PORT_ENUM, 0);
+		else
+			ret = port_ctl_send_msg_to_md(port, CTL_ID_PORT_ENUM,
+						      PORT_ENUM_VER_MISMATCH);
+
+		break;
+
+	default:
+		ret = -EINVAL;
+		dev_err(port->dev, "Unknown control message ID to FSM %x\n",
+			le32_to_cpu(ctrl_msg_h->ctrl_msg_id));
+		break;
+	}
+
+	if (ret)
+		dev_err(port->dev, "%s control message handle error: %d\n", port_conf->name, ret);
+
+	return ret;
+}
+
+static int port_ctl_rx_thread(void *arg)
+{
+	while (!kthread_should_stop()) {
+		struct t7xx_port *port = arg;
+		struct sk_buff *skb;
+		unsigned long flags;
+
+		spin_lock_irqsave(&port->rx_wq.lock, flags);
+		if (skb_queue_empty(&port->rx_skb_list) &&
+		    wait_event_interruptible_locked_irq(port->rx_wq,
+							!skb_queue_empty(&port->rx_skb_list) ||
+							kthread_should_stop())) {
+			spin_unlock_irqrestore(&port->rx_wq.lock, flags);
+			continue;
+		}
+		if (kthread_should_stop()) {
+			spin_unlock_irqrestore(&port->rx_wq.lock, flags);
+			break;
+		}
+		skb = __skb_dequeue(&port->rx_skb_list);
+		spin_unlock_irqrestore(&port->rx_wq.lock, flags);
+
+		control_msg_handler(port, skb);
+	}
+
+	return 0;
+}
+
+static int port_ctl_init(struct t7xx_port *port)
+{
+	const struct t7xx_port_conf *port_conf = port->port_conf;
+
+	port->thread = kthread_run(port_ctl_rx_thread, port, "%s", port_conf->name);
+	if (IS_ERR(port->thread)) {
+		dev_err(port->dev, "Failed to start port control thread\n");
+		return PTR_ERR(port->thread);
+	}
+
+	port->rx_length_th = CTRL_QUEUE_MAXLEN;
+	return 0;
+}
+
+static void port_ctl_uninit(struct t7xx_port *port)
+{
+	unsigned long flags;
+	struct sk_buff *skb;
+
+	if (port->thread)
+		kthread_stop(port->thread);
+
+	spin_lock_irqsave(&port->rx_wq.lock, flags);
+	port->rx_length_th = 0;
+	while ((skb = __skb_dequeue(&port->rx_skb_list)) != NULL)
+		dev_kfree_skb_any(skb);
+	spin_unlock_irqrestore(&port->rx_wq.lock, flags);
+}
+
+struct port_ops ctl_port_ops = {
+	.init = port_ctl_init,
+	.recv_skb = t7xx_port_enqueue_skb,
+	.uninit = port_ctl_uninit,
+};