net: wwan: t7xx: Add debug ports

Add support for userspace to enable/disable the debug ports(ADB,MIPC).
- ADB port: /dev/wwan0adb0
- MIPC port: /dev/wwan0mipc0

Application can use ADB (Android Debug Bridge) port to implement
functions (shell, pull, push ...) by ADB protocol commands.
E.g., ADB commands:
- A_OPEN: OPEN(local-id, 0, "destination")
- A_WRTE: WRITE(local-id, remote-id, "data")
- A_OKEY: READY(local-id, remote-id, "")
- A_CLSE: CLOSE(local-id, remote-id, "")

Link: https://android.googlesource.com/platform/packages/modules/adb/+/refs/heads/main/README.md

Application can use MIPC (Modem Information Process Center) port
to debug antenna tuner or noise profiling through this MTK modem
diagnostic interface.

By default, debug ports are not exposed, so using the command
to enable or disable debug ports.

Enable debug ports:
- enable: 'echo 1 > /sys/bus/pci/devices/${bdf}/t7xx_debug_ports

Disable debug ports:
- disable: 'echo 0 > /sys/bus/pci/devices/${bdf}/t7xx_debug_ports

Signed-off-by: Jinjian Song <[e-mail]>
Reviewed-by: Sergey Ryazanov <[e-mail]>
Signed-off-by: Paolo Abeni <[e-mail]>

Documentation/networking/device_drivers/wwan/t7xx.rst

···
 ::
   $ echo fastboot_switching > /sys/bus/pci/devices/${bdf}/t7xx_mode
 
+t7xx_debug_ports
+----------------
+The sysfs interface provides userspace with access to enable/disable the debug
+ports, this interface supports read and write operations.
+
+Debug port status:
+
+- ``1`` represents enable debug ports
+- ``0`` represents disable debug ports
+
+Currently supported debug ports (ADB/MIPC).
+
+Read from userspace to get the current debug ports status.
+
+::
+  $ cat /sys/bus/pci/devices/${bdf}/t7xx_debug_ports
+
+Write from userspace to set the debug ports status.
+
+::
+  $ echo 1 > /sys/bus/pci/devices/${bdf}/t7xx_debug_ports
+
 Management application development
 ==================================
 The driver and userspace interfaces are described below. The MBIM protocol is
···
 port, because device needs a cold reset after enter ``fastboot_switching``
 mode.
 
+ADB port userspace ABI
+----------------------
+
+/dev/wwan0adb0 character device
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+The driver exposes a ADB protocol interface by implementing ADB WWAN Port.
+The userspace end of the ADB channel pipe is a /dev/wwan0adb0 character device.
+Application shall use this interface for ADB protocol communication.
+
+MIPC port userspace ABI
+-----------------------
+
+/dev/wwan0mipc0 character device
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+The driver exposes a diagnostic interface by implementing MIPC (Modem
+Information Process Center) WWAN Port. The userspace end of the MIPC channel
+pipe is a /dev/wwan0mipc0 character device.
+Application shall use this interface for MTK modem diagnostic communication.
+
 The MediaTek's T700 modem supports the 3GPP TS 27.007 [4] specification.
 
 References
···
 [5] *fastboot "a mechanism for communicating with bootloaders"*
 
 - https://android.googlesource.com/platform/system/core/+/refs/heads/main/fastboot/README.md
+
+[6] *ADB (Android Debug Bridge) "a mechanism to keep track of Android devices
+and emulators instances connected to or running on a given host developer
+machine with ADB protocol"*
+
+- https://android.googlesource.com/platform/packages/modules/adb/+/refs/heads/main/README.md

drivers/net/wwan/t7xx/t7xx_modem_ops.c

···
 	pci_save_state(t7xx_dev->pdev);
 	t7xx_pci_reprobe_early(t7xx_dev);
 	t7xx_mode_update(t7xx_dev, T7XX_RESET);
+	WRITE_ONCE(t7xx_dev->debug_ports_show, false);
 
 	if (type == FLDR) {
 		ret = t7xx_acpi_reset(t7xx_dev, "_RST");

drivers/net/wwan/t7xx/t7xx_pci.c

···
 #include "t7xx_pcie_mac.h"
 #include "t7xx_reg.h"
 #include "t7xx_state_monitor.h"
+#include "t7xx_port_proxy.h"
 
 #define T7XX_PCI_IREG_BASE		0
 #define T7XX_PCI_EREG_BASE		2
···
 
 static DEVICE_ATTR_RW(t7xx_mode);
 
-static struct attribute *t7xx_mode_attr[] = {
+static ssize_t t7xx_debug_ports_store(struct device *dev,
+				      struct device_attribute *attr,
+				      const char *buf, size_t count)
+{
+	struct t7xx_pci_dev *t7xx_dev;
+	struct pci_dev *pdev;
+	bool show;
+	int ret;
+
+	pdev = to_pci_dev(dev);
+	t7xx_dev = pci_get_drvdata(pdev);
+	if (!t7xx_dev)
+		return -ENODEV;
+
+	ret = kstrtobool(buf, &show);
+	if (ret < 0)
+		return ret;
+
+	t7xx_proxy_debug_ports_show(t7xx_dev, show);
+	WRITE_ONCE(t7xx_dev->debug_ports_show, show);
+
+	return count;
+};
+
+static ssize_t t7xx_debug_ports_show(struct device *dev,
+				     struct device_attribute *attr,
+				     char *buf)
+{
+	struct t7xx_pci_dev *t7xx_dev;
+	struct pci_dev *pdev;
+	bool show;
+
+	pdev = to_pci_dev(dev);
+	t7xx_dev = pci_get_drvdata(pdev);
+	if (!t7xx_dev)
+		return -ENODEV;
+
+	show = READ_ONCE(t7xx_dev->debug_ports_show);
+
+	return sysfs_emit(buf, "%d\n", show);
+}
+
+static DEVICE_ATTR_RW(t7xx_debug_ports);
+
+static struct attribute *t7xx_attr[] = {
 	&dev_attr_t7xx_mode.attr,
+	&dev_attr_t7xx_debug_ports.attr,
 	NULL
 };
 
-static const struct attribute_group t7xx_mode_attribute_group = {
-	.attrs = t7xx_mode_attr,
+static const struct attribute_group t7xx_attribute_group = {
+	.attrs = t7xx_attr,
 };
 
 void t7xx_mode_update(struct t7xx_pci_dev *t7xx_dev, enum t7xx_mode mode)
···
 	t7xx_pcie_mac_interrupts_dis(t7xx_dev);
 
 	ret = sysfs_create_group(&t7xx_dev->pdev->dev.kobj,
-				 &t7xx_mode_attribute_group);
+				 &t7xx_attribute_group);
 	if (ret)
 		goto err_md_exit;
 
···
 
 err_remove_group:
 	sysfs_remove_group(&t7xx_dev->pdev->dev.kobj,
-			   &t7xx_mode_attribute_group);
+			   &t7xx_attribute_group);
 
 err_md_exit:
 	t7xx_md_exit(t7xx_dev);
···
 	t7xx_dev = pci_get_drvdata(pdev);
 
 	sysfs_remove_group(&t7xx_dev->pdev->dev.kobj,
-			   &t7xx_mode_attribute_group);
+			   &t7xx_attribute_group);
 	t7xx_md_exit(t7xx_dev);
 
 	for (i = 0; i < EXT_INT_NUM; i++) {

drivers/net/wwan/t7xx/t7xx_pci.h

···
 	struct dentry		*debugfs_dir;
 #endif
 	u32			mode;
+	bool			debug_ports_show;
 };
 
 enum t7xx_pm_id {

drivers/net/wwan/t7xx/t7xx_port.h

···
 	/* to AP */
 	PORT_CH_AP_CONTROL_RX = 0x1000,
 	PORT_CH_AP_CONTROL_TX = 0x1001,
+	PORT_CH_AP_ADB_RX = 0x100a,
+	PORT_CH_AP_ADB_TX = 0x100b,
 
 	/* to MD */
 	PORT_CH_CONTROL_RX = 0x2000,
···
 	struct port_ops		*ops;
 	char			*name;
 	enum wwan_port_type	port_type;
+	bool			debug;
 };
 
 struct t7xx_port {

drivers/net/wwan/t7xx/t7xx_port_proxy.c

···
 #include "t7xx_state_monitor.h"
 
 #define Q_IDX_CTRL			0
-#define Q_IDX_MBIM			2
+#define Q_IDX_MBIM_MIPC		2
+#define Q_IDX_ADB			3
 #define Q_IDX_AT_CMD			5
 
 #define INVALID_SEQ_NUM			GENMASK(15, 0)
···
 	}, {
 		.tx_ch = PORT_CH_MBIM_TX,
 		.rx_ch = PORT_CH_MBIM_RX,
-		.txq_index = Q_IDX_MBIM,
-		.rxq_index = Q_IDX_MBIM,
+		.txq_index = Q_IDX_MBIM_MIPC,
+		.rxq_index = Q_IDX_MBIM_MIPC,
 		.path_id = CLDMA_ID_MD,
 		.ops = &wwan_sub_port_ops,
 		.name = "MBIM",
···
 		.path_id = CLDMA_ID_AP,
 		.ops = &ctl_port_ops,
 		.name = "t7xx_ap_ctrl",
-	},
+	}, {
+		.tx_ch = PORT_CH_AP_ADB_TX,
+		.rx_ch = PORT_CH_AP_ADB_RX,
+		.txq_index = Q_IDX_ADB,
+		.rxq_index = Q_IDX_ADB,
+		.path_id = CLDMA_ID_AP,
+		.ops = &wwan_sub_port_ops,
+		.name = "adb",
+		.port_type = WWAN_PORT_ADB,
+		.debug = true,
+	}, {
+		.tx_ch = PORT_CH_MIPC_TX,
+		.rx_ch = PORT_CH_MIPC_RX,
+		.txq_index = Q_IDX_MBIM_MIPC,
+		.rxq_index = Q_IDX_MBIM_MIPC,
+		.path_id = CLDMA_ID_MD,
+		.ops = &wwan_sub_port_ops,
+		.name = "mipc",
+		.port_type = WWAN_PORT_MIPC,
+		.debug = true,
+	}
 };
 
 static const struct t7xx_port_conf t7xx_early_port_conf[] = {
···
 		spin_lock_init(&port->port_update_lock);
 		port->chan_enable = false;
 
-		if (port_conf->ops && port_conf->ops->init)
+		if (!port_conf->debug &&
+		    port_conf->ops &&
+		    port_conf->ops->init)
 			port_conf->ops->init(port);
 	}
 
 	t7xx_proxy_setup_ch_mapping(port_prox);
+}
+
+void t7xx_proxy_debug_ports_show(struct t7xx_pci_dev *t7xx_dev, bool show)
+{
+	struct port_proxy *port_prox = t7xx_dev->md->port_prox;
+	struct t7xx_port *port;
+	int i;
+
+	for_each_proxy_port(i, port, port_prox) {
+		const struct t7xx_port_conf *port_conf = port->port_conf;
+
+		if (port_conf->debug && port_conf->ops) {
+			if (show && port_conf->ops->init)
+				port_conf->ops->init(port);
+			else if (!show && port_conf->ops->uninit)
+				port_conf->ops->uninit(port);
+		}
+	}
 }
 
 void t7xx_port_proxy_set_cfg(struct t7xx_modem *md, enum port_cfg_id cfg_id)

drivers/net/wwan/t7xx/t7xx_port_proxy.h

···
 extern struct port_ops t7xx_trace_port_ops;
 #endif
 
+void t7xx_proxy_debug_ports_show(struct t7xx_pci_dev *t7xx_dev, bool show);
 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);

drivers/net/wwan/t7xx/t7xx_port_wwan.c

···
 {
 	const struct t7xx_port_conf *port_conf = port->port_conf;
 
-	if (port_conf->port_type == WWAN_PORT_FASTBOOT)
+	if (port_conf->port_type == WWAN_PORT_FASTBOOT ||
+	    port_conf->port_type == WWAN_PORT_ADB ||
+	    port_conf->port_type == WWAN_PORT_MIPC)
 		t7xx_port_wwan_create(port);
 
 	port->rx_length_th = RX_QUEUE_MAXLEN;
···
 {
 	const struct t7xx_port_conf *port_conf = port->port_conf;
 
-	if (port_conf->port_type == WWAN_PORT_FASTBOOT)
+	if (port_conf->port_type == WWAN_PORT_FASTBOOT ||
+	    port_conf->port_type == WWAN_PORT_ADB ||
+	    port_conf->port_type == WWAN_PORT_MIPC)
 		return;
 
 	if (state != MD_STATE_READY)