Subject: [PATCH net-next v4 09/13] net: wwan: t7xx: Add WWAN network interface

From: Ricardo Martinez <[email-masked]>
Date: Thu, 13 Jan 2022 18:06:23 -0700

From: Haijun Liu <[email-masked]>

Creates the Cross Core Modem Network Interface (CCMNI) which implements
the wwan_ops for registration with the WWAN framework, CCMNI also
implements the net_device_ops functions used by the network device.
Network device operations include open, close, start transmission, TX
timeout, change MTU, and select queue.

Signed-off-by: Haijun Liu <[email-masked]>
Co-developed-by: Chandrashekar Devegowda <[email-masked]>
Signed-off-by: Chandrashekar Devegowda <[email-masked]>
Co-developed-by: Ricardo Martinez <[email-masked]>
Signed-off-by: Ricardo Martinez <[email-masked]>
---
 drivers/net/wwan/t7xx/Makefile         |   1 +
 drivers/net/wwan/t7xx/t7xx_modem_ops.c |  11 +-
 drivers/net/wwan/t7xx/t7xx_netdev.c    | 433 +++++++++++++++++++++++++
 drivers/net/wwan/t7xx/t7xx_netdev.h    |  61 ++++
 4 files changed, 505 insertions(+), 1 deletion(-)
 create mode 100644 drivers/net/wwan/t7xx/t7xx_netdev.c
 create mode 100644 drivers/net/wwan/t7xx/t7xx_netdev.h

diff --git a/drivers/net/wwan/t7xx/Makefile b/drivers/net/wwan/t7xx/Makefile
index 04a9ba50dc14..dc6a7d682c15 100644
--- a/drivers/net/wwan/t7xx/Makefile
+++ b/drivers/net/wwan/t7xx/Makefile
@@ -17,3 +17,4 @@ mtk_t7xx-y:=	t7xx_pci.o \
 		t7xx_hif_dpmaif_tx.o \
 		t7xx_hif_dpmaif_rx.o  \
 		t7xx_dpmaif.o \
+		t7xx_netdev.o
diff --git a/drivers/net/wwan/t7xx/t7xx_modem_ops.c b/drivers/net/wwan/t7xx/t7xx_modem_ops.c
index ec55845e7ac0..3680b0b8205a 100644
--- a/drivers/net/wwan/t7xx/t7xx_modem_ops.c
+++ b/drivers/net/wwan/t7xx/t7xx_modem_ops.c
@@ -35,6 +35,7 @@
 #include "t7xx_hif_cldma.h"
 #include "t7xx_mhccif.h"
 #include "t7xx_modem_ops.h"
+#include "t7xx_netdev.h"
 #include "t7xx_pci.h"
 #include "t7xx_pcie_mac.h"
 #include "t7xx_port.h"
@@ -652,10 +653,14 @@ int t7xx_md_init(struct t7xx_pci_dev *t7xx_dev)
 	if (ret)
 		goto err_destroy_hswq;
 
-	ret = t7xx_cldma_init(md, md->md_ctrl[ID_CLDMA1]);
+	ret = t7xx_ccmni_init(t7xx_dev);
 	if (ret)
 		goto err_uninit_fsm;
 
+	ret = t7xx_cldma_init(md, md->md_ctrl[ID_CLDMA1]);
+	if (ret)
+		goto err_uninit_ccmni;
+
 	ret = t7xx_port_proxy_init(md);
 	if (ret)
 		goto err_uninit_cldma;
@@ -668,6 +673,9 @@ int t7xx_md_init(struct t7xx_pci_dev *t7xx_dev)
 err_uninit_cldma:
 	t7xx_cldma_exit(md->md_ctrl[ID_CLDMA1]);
 
+err_uninit_ccmni:
+	t7xx_ccmni_exit(t7xx_dev);
+
 err_uninit_fsm:
 	t7xx_fsm_uninit(md);
 
@@ -689,6 +697,7 @@ void t7xx_md_exit(struct t7xx_pci_dev *t7xx_dev)
 	t7xx_fsm_append_cmd(md->fsm_ctl, FSM_CMD_PRE_STOP, FSM_CMD_FLAG_WAIT_FOR_COMPLETION);
 	t7xx_port_proxy_uninit(md->port_prox);
 	t7xx_cldma_exit(md->md_ctrl[ID_CLDMA1]);
+	t7xx_ccmni_exit(t7xx_dev);
 	t7xx_fsm_uninit(md);
 	destroy_workqueue(md->handshake_wq);
 }
diff --git a/drivers/net/wwan/t7xx/t7xx_netdev.c b/drivers/net/wwan/t7xx/t7xx_netdev.c
new file mode 100644
index 000000000000..b4a2ef2c7b17
--- /dev/null
+++ b/drivers/net/wwan/t7xx/t7xx_netdev.c
@@ -0,0 +1,433 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (c) 2021, MediaTek Inc.
+ * Copyright (c) 2021, Intel Corporation.
+ *
+ * Authors:
+ *  Chandrashekar Devegowda <[email-masked]>
+ *  Haijun Liu <[email-masked]>
+ *  Ricardo Martinez<[email-masked]>
+ *
+ * Contributors:
+ *  Amir Hanania <[email-masked]>
+ *  Andy Shevchenko <[email-masked]>
+ *  Chiranjeevi Rapolu <[email-masked]>
+ *  Eliot Lee <[email-masked]>
+ *  Moises Veleta <[email-masked]>
+ *  Sreehari Kancharla <[email-masked]>
+ */
+
+#include <linux/atomic.h>
+#include <linux/dev_printk.h>
+#include <linux/device.h>
+#include <linux/gfp.h>
+#include <linux/if_arp.h>
+#include <linux/if_ether.h>
+#include <linux/kernel.h>
+#include <linux/list.h>
+#include <linux/netdev_features.h>
+#include <linux/netdevice.h>
+#include <linux/skbuff.h>
+#include <linux/types.h>
+#include <linux/wwan.h>
+#include <net/pkt_sched.h>
+
+#include "t7xx_common.h"
+#include "t7xx_hif_dpmaif_rx.h"
+#include "t7xx_hif_dpmaif_tx.h"
+#include "t7xx_netdev.h"
+#include "t7xx_pci.h"
+#include "t7xx_state_monitor.h"
+
+#define IP_MUX_SESSION_DEFAULT	0
+
+static u16 t7xx_ccmni_select_queue(struct net_device *dev, struct sk_buff *skb,
+				   struct net_device *sb_dev)
+{
+	return TXQ_TYPE_DEFAULT;
+}
+
+static int t7xx_ccmni_open(struct net_device *dev)
+{
+	struct t7xx_ccmni *ccmni = wwan_netdev_drvpriv(dev);
+
+	netif_carrier_on(dev);
+	netif_tx_start_all_queues(dev);
+	atomic_inc(&ccmni->usage);
+	return 0;
+}
+
+static int t7xx_ccmni_close(struct net_device *dev)
+{
+	struct t7xx_ccmni *ccmni = wwan_netdev_drvpriv(dev);
+
+	if (atomic_dec_return(&ccmni->usage) < 0)
+		return -EINVAL;
+
+	netif_carrier_off(dev);
+	netif_tx_disable(dev);
+	return 0;
+}
+
+static int t7xx_ccmni_send_packet(struct t7xx_ccmni *ccmni, struct sk_buff *skb,
+				  unsigned int txqt)
+{
+	struct t7xx_ccmni_ctrl *ctlb = ccmni->ctlb;
+
+	skb->cb[TX_CB_NETIF_IDX] = ccmni->index;
+
+	if (t7xx_dpmaif_tx_send_skb(ctlb->hif_ctrl, txqt, skb))
+		return NETDEV_TX_BUSY;
+
+	return 0;
+}
+
+static int t7xx_ccmni_start_xmit(struct sk_buff *skb, struct net_device *dev)
+{
+	struct t7xx_ccmni *ccmni = wwan_netdev_drvpriv(dev);
+	int skb_len = skb->len;
+
+	/* If MTU is changed or there is no headroom, drop the packet */
+	if (skb->len > dev->mtu || skb_headroom(skb) < sizeof(struct ccci_header)) {
+		dev_kfree_skb(skb);
+		dev->stats.tx_dropped++;
+		return NETDEV_TX_OK;
+	}
+
+	if (t7xx_ccmni_send_packet(ccmni, skb, TXQ_TYPE_DEFAULT))
+		return NETDEV_TX_BUSY;
+
+	dev->stats.tx_packets++;
+	dev->stats.tx_bytes += skb_len;
+
+	return NETDEV_TX_OK;
+}
+
+static void t7xx_ccmni_tx_timeout(struct net_device *dev, unsigned int __always_unused txqueue)
+{
+	struct t7xx_ccmni *ccmni = netdev_priv(dev);
+
+	dev->stats.tx_errors++;
+
+	if (atomic_read(&ccmni->usage) > 0)
+		netif_tx_wake_all_queues(dev);
+}
+
+static const struct net_device_ops ccmni_netdev_ops = {
+	.ndo_open	  = t7xx_ccmni_open,
+	.ndo_stop	  = t7xx_ccmni_close,
+	.ndo_start_xmit   = t7xx_ccmni_start_xmit,
+	.ndo_tx_timeout   = t7xx_ccmni_tx_timeout,
+	.ndo_select_queue = t7xx_ccmni_select_queue,
+};
+
+static void t7xx_ccmni_start(struct t7xx_ccmni_ctrl *ctlb)
+{
+	struct t7xx_ccmni *ccmni;
+	int i;
+
+	for (i = 0; i < ctlb->nic_dev_num; i++) {
+		ccmni = ctlb->ccmni_inst[i];
+		if (!ccmni)
+			continue;
+
+		if (atomic_read(&ccmni->usage) > 0) {
+			netif_tx_start_all_queues(ccmni->dev);
+			netif_carrier_on(ccmni->dev);
+		}
+	}
+}
+
+static void t7xx_ccmni_pre_stop(struct t7xx_ccmni_ctrl *ctlb)
+{
+	struct t7xx_ccmni *ccmni;
+	int i;
+
+	for (i = 0; i < ctlb->nic_dev_num; i++) {
+		ccmni = ctlb->ccmni_inst[i];
+		if (!ccmni)
+			continue;
+
+		if (atomic_read(&ccmni->usage) > 0)
+			netif_tx_disable(ccmni->dev);
+	}
+}
+
+static void t7xx_ccmni_post_stop(struct t7xx_ccmni_ctrl *ctlb)
+{
+	struct t7xx_ccmni *ccmni;
+	int i;
+
+	for (i = 0; i < ctlb->nic_dev_num; i++) {
+		ccmni = ctlb->ccmni_inst[i];
+		if (!ccmni)
+			continue;
+
+		if (atomic_read(&ccmni->usage) > 0)
+			netif_carrier_off(ccmni->dev);
+	}
+}
+
+static void t7xx_ccmni_wwan_setup(struct net_device *dev)
+{
+	dev->header_ops = NULL;
+	dev->hard_header_len += sizeof(struct ccci_header);
+
+	dev->mtu = ETH_DATA_LEN;
+	dev->max_mtu = CCMNI_MTU_MAX;
+	dev->tx_queue_len = DEFAULT_TX_QUEUE_LEN;
+	dev->watchdog_timeo = CCMNI_NETDEV_WDT_TO;
+	/* CCMNI is a pure IP device */
+	dev->flags = IFF_POINTOPOINT | IFF_NOARP;
+
+	/* Not supporting VLAN */
+	dev->features = NETIF_F_VLAN_CHALLENGED;
+
+	dev->features |= NETIF_F_SG;
+	dev->hw_features |= NETIF_F_SG;
+
+	/* Uplink checksum offload */
+	dev->features |= NETIF_F_HW_CSUM;
+	dev->hw_features |= NETIF_F_HW_CSUM;
+
+	/* Downlink checksum offload */
+	dev->features |= NETIF_F_RXCSUM;
+	dev->hw_features |= NETIF_F_RXCSUM;
+
+	/* Use kernel default free_netdev() function */
+	dev->needs_free_netdev = true;
+
+	/* No need to free again because of free_netdev() */
+	dev->priv_destructor = NULL;
+	dev->type = ARPHRD_NONE;
+
+	dev->netdev_ops = &ccmni_netdev_ops;
+}
+
+static int t7xx_ccmni_wwan_newlink(void *ctxt, struct net_device *dev, u32 if_id,
+				   struct netlink_ext_ack *extack)
+{
+	struct t7xx_ccmni_ctrl *ctlb = ctxt;
+	struct t7xx_ccmni *ccmni;
+	int ret;
+
+	if (if_id >= ARRAY_SIZE(ctlb->ccmni_inst))
+		return -EINVAL;
+
+	ccmni = wwan_netdev_drvpriv(dev);
+	ccmni->index = if_id;
+	ccmni->ctlb = ctlb;
+	ccmni->dev = dev;
+	atomic_set(&ccmni->usage, 0);
+	ctlb->ccmni_inst[if_id] = ccmni;
+
+	ret = register_netdevice(dev);
+	if (ret)
+		return ret;
+
+	netif_device_attach(dev);
+	return 0;
+}
+
+static void t7xx_ccmni_wwan_dellink(void *ctxt, struct net_device *dev, struct list_head *head)
+{
+	struct t7xx_ccmni *ccmni = wwan_netdev_drvpriv(dev);
+	struct t7xx_ccmni_ctrl *ctlb = ctxt;
+	u8 if_id = ccmni->index;
+
+	if (if_id >= ARRAY_SIZE(ctlb->ccmni_inst))
+		return;
+
+	if (WARN_ON(ctlb->ccmni_inst[if_id] != ccmni))
+		return;
+
+	unregister_netdevice(dev);
+}
+
+static const struct wwan_ops ccmni_wwan_ops = {
+	.priv_size = sizeof(struct t7xx_ccmni),
+	.setup     = t7xx_ccmni_wwan_setup,
+	.newlink   = t7xx_ccmni_wwan_newlink,
+	.dellink   = t7xx_ccmni_wwan_dellink,
+};
+
+static int t7xx_ccmni_md_state_callback(enum md_state state, void *para)
+{
+	struct t7xx_ccmni_ctrl *ctlb = para;
+	int ret = 0;
+
+	ctlb->md_sta = state;
+
+	switch (state) {
+	case MD_STATE_READY:
+		t7xx_ccmni_start(ctlb);
+		break;
+
+	case MD_STATE_EXCEPTION:
+	case MD_STATE_STOPPED:
+		t7xx_ccmni_pre_stop(ctlb);
+
+		ret = t7xx_dpmaif_md_state_callback(ctlb->hif_ctrl, state);
+		if (ret < 0)
+			dev_err(ctlb->hif_ctrl->dev,
+				"dpmaif md state callback err, md_sta=%d\n", state);
+
+		t7xx_ccmni_post_stop(ctlb);
+		break;
+
+	case MD_STATE_WAITING_FOR_HS1:
+	case MD_STATE_WAITING_TO_STOP:
+		ret = t7xx_dpmaif_md_state_callback(ctlb->hif_ctrl, state);
+		if (ret < 0)
+			dev_err(ctlb->hif_ctrl->dev,
+				"dpmaif md state callback err, md_sta=%d\n", state);
+
+		break;
+
+	default:
+		break;
+	}
+
+	return ret;
+}
+
+static void init_md_status_notifier(struct t7xx_pci_dev *t7xx_dev)
+{
+	struct t7xx_ccmni_ctrl	*ctlb = t7xx_dev->ccmni_ctlb;
+	struct t7xx_fsm_notifier *md_status_notifier;
+
+	md_status_notifier = &ctlb->md_status_notify;
+	INIT_LIST_HEAD(&md_status_notifier->entry);
+	md_status_notifier->notifier_fn = t7xx_ccmni_md_state_callback;
+	md_status_notifier->data = ctlb;
+
+	t7xx_fsm_notifier_register(t7xx_dev->md, md_status_notifier);
+}
+
+static void t7xx_ccmni_recv_skb(struct t7xx_pci_dev *t7xx_dev, struct sk_buff *skb)
+{
+	struct t7xx_ccmni *ccmni;
+	struct net_device *net_dev;
+	int pkt_type, skb_len;
+	u8 netif_id;
+
+	netif_id = skb->cb[RX_CB_NETIF_IDX];
+	ccmni = t7xx_dev->ccmni_ctlb->ccmni_inst[netif_id];
+	if (!ccmni) {
+		dev_kfree_skb(skb);
+		return;
+	}
+
+	net_dev = ccmni->dev;
+	skb->dev = net_dev;
+
+	pkt_type = skb->cb[RX_CB_PKT_TYPE];
+	if (pkt_type == PKT_TYPE_IP6)
+		skb->protocol = htons(ETH_P_IPV6);
+	else
+		skb->protocol = htons(ETH_P_IP);
+
+	skb_len = skb->len;
+	netif_rx_any_context(skb);
+	net_dev->stats.rx_packets++;
+	net_dev->stats.rx_bytes += skb_len;
+}
+
+static void t7xx_ccmni_queue_tx_irq_notify(struct t7xx_ccmni_ctrl *ctlb, int qno)
+{
+	struct t7xx_ccmni *ccmni = ctlb->ccmni_inst[0];
+	struct netdev_queue *net_queue;
+
+	if (netif_running(ccmni->dev) && atomic_read(&ccmni->usage) > 0) {
+		if (ctlb->capability & NIC_CAP_CCMNI_MQ) {
+			net_queue = netdev_get_tx_queue(ccmni->dev, qno);
+			if (netif_tx_queue_stopped(net_queue))
+				netif_tx_wake_queue(net_queue);
+		} else if (netif_queue_stopped(ccmni->dev)) {
+			netif_wake_queue(ccmni->dev);
+		}
+	}
+}
+
+static void t7xx_ccmni_queue_tx_full_notify(struct t7xx_ccmni_ctrl *ctlb, int qno)
+{
+	struct t7xx_ccmni *ccmni = ctlb->ccmni_inst[0];
+	struct netdev_queue *net_queue;
+
+	if (atomic_read(&ccmni->usage) > 0) {
+		netdev_err(ccmni->dev, "TX queue %d is full\n", qno);
+
+		if (ctlb->capability & NIC_CAP_CCMNI_MQ) {
+			net_queue = netdev_get_tx_queue(ccmni->dev, qno);
+			netif_tx_stop_queue(net_queue);
+		} else {
+			netif_stop_queue(ccmni->dev);
+		}
+	}
+}
+
+static void t7xx_ccmni_queue_state_notify(struct t7xx_pci_dev *t7xx_dev,
+					  enum dpmaif_txq_state state, int qno)
+{
+	struct t7xx_ccmni_ctrl *ctlb = t7xx_dev->ccmni_ctlb;
+
+	if (!(ctlb->capability & NIC_CAP_TXBUSY_STOP) ||
+	    ctlb->md_sta != MD_STATE_READY)
+		return;
+
+	if (!ctlb->ccmni_inst[0]) {
+		dev_warn(&t7xx_dev->pdev->dev, "No netdev registered yet\n");
+		return;
+	}
+
+	if (state == DMPAIF_TXQ_STATE_IRQ)
+		t7xx_ccmni_queue_tx_irq_notify(ctlb, qno);
+	else if (state == DMPAIF_TXQ_STATE_FULL)
+		t7xx_ccmni_queue_tx_full_notify(ctlb, qno);
+}
+
+int t7xx_ccmni_init(struct t7xx_pci_dev *t7xx_dev)
+{
+	struct device *dev = &t7xx_dev->pdev->dev;
+	struct t7xx_ccmni_ctrl *ctlb;
+	int ret;
+
+	ctlb = devm_kzalloc(dev, sizeof(*ctlb), GFP_KERNEL);
+	if (!ctlb)
+		return -ENOMEM;
+
+	t7xx_dev->ccmni_ctlb = ctlb;
+	ctlb->t7xx_dev = t7xx_dev;
+	ctlb->callbacks.state_notify = t7xx_ccmni_queue_state_notify;
+	ctlb->callbacks.recv_skb = t7xx_ccmni_recv_skb;
+	ctlb->nic_dev_num = NIC_DEV_DEFAULT;
+	ctlb->capability = NIC_CAP_TXBUSY_STOP | NIC_CAP_SGIO |
+			   NIC_CAP_DATA_ACK_DVD | NIC_CAP_CCMNI_MQ;
+
+	ctlb->hif_ctrl = t7xx_dpmaif_hif_init(t7xx_dev, &ctlb->callbacks);
+	if (!ctlb->hif_ctrl)
+		return -ENOMEM;
+
+	/* WWAN core will create a netdev for the default IP MUX channel */
+	ret = wwan_register_ops(dev, &ccmni_wwan_ops, ctlb, IP_MUX_SESSION_DEFAULT);
+	if (ret)
+		goto err_unregister_ops;
+
+	init_md_status_notifier(t7xx_dev);
+
+	return 0;
+
+err_unregister_ops:
+	wwan_unregister_ops(dev);
+
+	return ret;
+}
+
+void t7xx_ccmni_exit(struct t7xx_pci_dev *t7xx_dev)
+{
+	struct t7xx_ccmni_ctrl *ctlb = t7xx_dev->ccmni_ctlb;
+
+	t7xx_fsm_notifier_unregister(t7xx_dev->md, &ctlb->md_status_notify);
+	wwan_unregister_ops(&t7xx_dev->pdev->dev);
+	t7xx_dpmaif_hif_exit(ctlb->hif_ctrl);
+}
diff --git a/drivers/net/wwan/t7xx/t7xx_netdev.h b/drivers/net/wwan/t7xx/t7xx_netdev.h
new file mode 100644
index 000000000000..2553c050fca4
--- /dev/null
+++ b/drivers/net/wwan/t7xx/t7xx_netdev.h
@@ -0,0 +1,61 @@
+/* SPDX-License-Identifier: GPL-2.0-only
+ *
+ * Copyright (c) 2021, MediaTek Inc.
+ * Copyright (c) 2021, Intel Corporation.
+ *
+ * Authors:
+ *  Haijun Liu <[email-masked]>
+ *  Moises Veleta <[email-masked]>
+ *
+ * Contributors:
+ *  Amir Hanania <[email-masked]>
+ *  Chiranjeevi Rapolu <[email-masked]>
+ *  Ricardo Martinez<[email-masked]>
+ */
+
+#ifndef __T7XX_NETDEV_H__
+#define __T7XX_NETDEV_H__
+
+#include <linux/bits.h>
+#include <linux/netdevice.h>
+#include <linux/types.h>
+
+#include "t7xx_common.h"
+#include "t7xx_hif_dpmaif.h"
+#include "t7xx_pci.h"
+#include "t7xx_state_monitor.h"
+
+#define RXQ_NUM				DPMAIF_RXQ_NUM
+#define NIC_DEV_MAX			21
+#define NIC_DEV_DEFAULT			2
+#define NIC_CAP_TXBUSY_STOP		BIT(0)
+#define NIC_CAP_SGIO			BIT(1)
+#define NIC_CAP_DATA_ACK_DVD		BIT(2)
+#define NIC_CAP_CCMNI_MQ		BIT(3)
+
+/* Must be less than DPMAIF_HW_MTU_SIZE (3*1024 + 8) */
+#define CCMNI_MTU_MAX			3000
+#define CCMNI_NETDEV_WDT_TO		(1 * HZ)
+
+struct t7xx_ccmni {
+	u8				index;
+	atomic_t			usage;
+	struct net_device		*dev;
+	struct t7xx_ccmni_ctrl		*ctlb;
+};
+
+struct t7xx_ccmni_ctrl {
+	struct t7xx_pci_dev		*t7xx_dev;
+	struct dpmaif_ctrl		*hif_ctrl;
+	struct t7xx_ccmni		*ccmni_inst[NIC_DEV_MAX];
+	struct dpmaif_callbacks		callbacks;
+	unsigned int			nic_dev_num;
+	unsigned int			md_sta;
+	unsigned int			capability;
+	struct t7xx_fsm_notifier	md_status_notify;
+};
+
+int t7xx_ccmni_init(struct t7xx_pci_dev *t7xx_dev);
+void t7xx_ccmni_exit(struct t7xx_pci_dev *t7xx_dev);
+
+#endif /* __T7XX_NETDEV_H__ */
-- 
2.17.1