[net-next v4 4/4] net: wwan: t7xx: Add fastboot WWAN port

[Jinjian Song <songjinjian@hotmail.com>]

From: Jinjian Song <jinjian.song@fibocom.com>

On early detection of wwan device in fastboot mode, driver sets
up CLDMA0 HW tx/rx queues for raw data transfer and then create
fastboot port to userspace.

Application can use this port to flash firmware and collect
core dump by fastboot protocol commands.

Signed-off-by: Jinjian Song <jinjian.song@fibocom.com>
---
v4:
 * change function prefix to t7xx_port_fastboot 
 * change the name 'FASTBOOT' to fastboot in struct t7xx_early_port_conf 
v3:
 * no change
v2:
 * no change
---
 .../networking/device_drivers/wwan/t7xx.rst   |  14 ++
 drivers/net/wwan/t7xx/Makefile                |   1 +
 drivers/net/wwan/t7xx/t7xx_port_fastboot.c    | 155 ++++++++++++++++++
 drivers/net/wwan/t7xx/t7xx_port_proxy.c       |   3 +
 drivers/net/wwan/t7xx/t7xx_port_proxy.h       |   2 +
 drivers/net/wwan/t7xx/t7xx_state_monitor.c    |   4 +
 6 files changed, 179 insertions(+)
 create mode 100644 drivers/net/wwan/t7xx/t7xx_port_fastboot.c

diff --git a/Documentation/networking/device_drivers/wwan/t7xx.rst b/Documentation/networking/device_drivers/wwan/t7xx.rst
index d13624a52d8b..7257ede90152 100644
--- a/Documentation/networking/device_drivers/wwan/t7xx.rst
+++ b/Documentation/networking/device_drivers/wwan/t7xx.rst
@@ -125,6 +125,20 @@ The driver exposes an AT port by implementing AT WWAN Port.
 The userspace end of the control port is a /dev/wwan0at0 character
 device. Application shall use this interface to issue AT commands.
 
+fastboot port userspace ABI
+---------------------------
+
+/dev/wwan0fastboot0 character device
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+The driver exposes a fastboot protocol interface by implementing
+fastboot WWAN Port. The userspace end of the fastboot channel pipe is a
+/dev/wwan0fastboot0 character device. Application shall use this interface for
+fastboot protocol communication.
+
+Please note that driver needs to be reloaded to export /dev/wwan0fastboot0
+port, because device needs a cold reset after enter ``FASTBOOT_DL_SWITCHING``
+mode.
+
 The MediaTek's T700 modem supports the 3GPP TS 27.007 [4] specification.
 
 References
diff --git a/drivers/net/wwan/t7xx/Makefile b/drivers/net/wwan/t7xx/Makefile
index 2652cd00504e..ddf03efe388a 100644
--- a/drivers/net/wwan/t7xx/Makefile
+++ b/drivers/net/wwan/t7xx/Makefile
@@ -11,6 +11,7 @@ mtk_t7xx-y:=	t7xx_pci.o \
 		t7xx_port_proxy.o  \
 		t7xx_port_ctrl_msg.o \
 		t7xx_port_wwan.o \
+		t7xx_port_fastboot.o \
 		t7xx_hif_dpmaif.o  \
 		t7xx_hif_dpmaif_tx.o \
 		t7xx_hif_dpmaif_rx.o  \
diff --git a/drivers/net/wwan/t7xx/t7xx_port_fastboot.c b/drivers/net/wwan/t7xx/t7xx_port_fastboot.c
new file mode 100644
index 000000000000..880931af3433
--- /dev/null
+++ b/drivers/net/wwan/t7xx/t7xx_port_fastboot.c
@@ -0,0 +1,155 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (c) 2023, Fibocom Wireless Inc.
+ *
+ * Authors:
+ *  Jinjian Song <jinjian.song@fibocom.com>
+ */
+
+#include <linux/atomic.h>
+#include <linux/dev_printk.h>
+#include <linux/err.h>
+#include <linux/minmax.h>
+#include <linux/skbuff.h>
+#include <linux/spinlock.h>
+#include <linux/wwan.h>
+
+#include "t7xx_port.h"
+#include "t7xx_port_proxy.h"
+#include "t7xx_state_monitor.h"
+
+static int t7xx_port_fastboot_start(struct wwan_port *port)
+{
+	struct t7xx_port *port_mtk = wwan_port_get_drvdata(port);
+
+	if (atomic_read(&port_mtk->usage_cnt))
+		return -EBUSY;
+
+	atomic_inc(&port_mtk->usage_cnt);
+	return 0;
+}
+
+static void t7xx_port_fastboot_stop(struct wwan_port *port)
+{
+	struct t7xx_port *port_mtk = wwan_port_get_drvdata(port);
+
+	atomic_dec(&port_mtk->usage_cnt);
+}
+
+static int t7xx_port_fastboot_tx(struct wwan_port *port, struct sk_buff *skb)
+{
+	struct t7xx_port *port_private = wwan_port_get_drvdata(port);
+	struct sk_buff *cur = skb, *cloned;
+	size_t actual, len, offset = 0;
+	int ret;
+	int txq_mtu;
+
+	if (!port_private->chan_enable)
+		return -EINVAL;
+
+	txq_mtu = t7xx_get_port_mtu(port_private);
+	if (txq_mtu < 0)
+		return -EINVAL;
+
+	actual = cur->len;
+	while (actual) {
+		len = min_t(size_t, actual, txq_mtu);
+		cloned = __dev_alloc_skb(len, GFP_KERNEL);
+		if (!cloned)
+			return -ENOMEM;
+
+		skb_put_data(cloned, cur->data + offset, len);
+
+		ret = t7xx_port_send_raw_skb(port_private, cloned);
+		if (ret) {
+			dev_kfree_skb(cloned);
+			dev_err(port_private->dev, "Write error on fastboot port, %d\n", ret);
+			break;
+		}
+		offset += len;
+		actual -= len;
+	}
+
+	dev_kfree_skb(skb);
+	return 0;
+}
+
+static const struct wwan_port_ops wwan_ops = {
+	.start = t7xx_port_fastboot_start,
+	.stop = t7xx_port_fastboot_stop,
+	.tx = t7xx_port_fastboot_tx,
+};
+
+static int t7xx_port_fastboot_init(struct t7xx_port *port)
+{
+	const struct t7xx_port_conf *port_conf = port->port_conf;
+	unsigned int header_len = sizeof(struct ccci_header), mtu;
+	struct wwan_port_caps caps;
+
+	port->rx_length_th = RX_QUEUE_MAXLEN;
+
+	if (!port->wwan.wwan_port) {
+		mtu = t7xx_get_port_mtu(port);
+		caps.frag_len = mtu - header_len;
+		caps.headroom_len = header_len;
+		port->wwan.wwan_port = wwan_create_port(port->dev, port_conf->port_type,
+							&wwan_ops, &caps, port);
+		if (IS_ERR(port->wwan.wwan_port))
+			dev_err(port->dev, "Unable to create WWWAN port %s", port_conf->name);
+	}
+
+	return 0;
+}
+
+static void t7xx_port_fastboot_uninit(struct t7xx_port *port)
+{
+	if (!port->wwan.wwan_port)
+		return;
+
+	port->rx_length_th = 0;
+	wwan_remove_port(port->wwan.wwan_port);
+	port->wwan.wwan_port = NULL;
+}
+
+static int t7xx_port_fastboot_recv_skb(struct t7xx_port *port, struct sk_buff *skb)
+{
+	if (!atomic_read(&port->usage_cnt) || !port->chan_enable) {
+		const struct t7xx_port_conf *port_conf = port->port_conf;
+
+		dev_kfree_skb_any(skb);
+		dev_err_ratelimited(port->dev, "Port %s is not opened, drop packets\n",
+				    port_conf->name);
+		/* Dropping skb, caller should not access skb.*/
+		return 0;
+	}
+
+	wwan_port_rx(port->wwan.wwan_port, skb);
+
+	return 0;
+}
+
+static int t7xx_port_fastboot_enable_chl(struct t7xx_port *port)
+{
+	spin_lock(&port->port_update_lock);
+	port->chan_enable = true;
+	spin_unlock(&port->port_update_lock);
+
+	return 0;
+}
+
+static int t7xx_port_fastboot_disable_chl(struct t7xx_port *port)
+{
+	spin_lock(&port->port_update_lock);
+	port->chan_enable = false;
+	spin_unlock(&port->port_update_lock);
+
+	return 0;
+}
+
+struct port_ops fastboot_port_ops = {
+	.init = t7xx_port_fastboot_init,
+	.recv_skb = t7xx_port_fastboot_recv_skb,
+	.uninit = t7xx_port_fastboot_uninit,
+	.enable_chl = t7xx_port_fastboot_enable_chl,
+	.disable_chl = t7xx_port_fastboot_disable_chl,
+};
diff --git a/drivers/net/wwan/t7xx/t7xx_port_proxy.c b/drivers/net/wwan/t7xx/t7xx_port_proxy.c
index e53a152faee4..7200d2d210fc 100644
--- a/drivers/net/wwan/t7xx/t7xx_port_proxy.c
+++ b/drivers/net/wwan/t7xx/t7xx_port_proxy.c
@@ -112,6 +112,9 @@ static const struct t7xx_port_conf t7xx_early_port_conf[] = {
 		.txq_exp_index = CLDMA_Q_IDX_DUMP,
 		.rxq_exp_index = CLDMA_Q_IDX_DUMP,
 		.path_id = CLDMA_ID_AP,
+		.ops = &fastboot_port_ops,
+		.name = "fastboot",
+		.port_type = WWAN_PORT_FASTBOOT,
 	},
 };
 
diff --git a/drivers/net/wwan/t7xx/t7xx_port_proxy.h b/drivers/net/wwan/t7xx/t7xx_port_proxy.h
index 7f5706811445..0f40b4884dc0 100644
--- a/drivers/net/wwan/t7xx/t7xx_port_proxy.h
+++ b/drivers/net/wwan/t7xx/t7xx_port_proxy.h
@@ -98,6 +98,8 @@ extern struct port_ops ctl_port_ops;
 extern struct port_ops t7xx_trace_port_ops;
 #endif
 
+extern struct port_ops fastboot_port_ops;
+
 void t7xx_port_proxy_reset(struct port_proxy *port_prox);
 void t7xx_port_proxy_uninit(struct port_proxy *port_prox);
 int t7xx_port_proxy_init(struct t7xx_modem *md);
diff --git a/drivers/net/wwan/t7xx/t7xx_state_monitor.c b/drivers/net/wwan/t7xx/t7xx_state_monitor.c
index 3f5e8759705c..7cec51666f42 100644
--- a/drivers/net/wwan/t7xx/t7xx_state_monitor.c
+++ b/drivers/net/wwan/t7xx/t7xx_state_monitor.c
@@ -229,6 +229,7 @@ static void t7xx_lk_stage_event_handling(struct t7xx_fsm_ctl *ctl, unsigned int
 	struct cldma_ctrl *md_ctrl;
 	enum lk_event_id lk_event;
 	struct device *dev;
+	struct t7xx_port *port;
 
 	dev = &md->t7xx_dev->pdev->dev;
 	lk_event = FIELD_GET(MISC_LK_EVENT_MASK, status);
@@ -244,6 +245,9 @@ static void t7xx_lk_stage_event_handling(struct t7xx_fsm_ctl *ctl, unsigned int
 		t7xx_cldma_stop(md_ctrl);
 		t7xx_cldma_switch_cfg(md_ctrl, CLDMA_DEDICATED_Q_CFG);
 
+		port = &ctl->md->port_prox->ports[0];
+		port->port_conf->ops->enable_chl(port);
+
 		t7xx_cldma_start(md_ctrl);
 
 		if (lk_event == LK_EVENT_CREATE_POST_DL_PORT)
-- 
2.34.1