[v5,6/8] usb: typec: cros_ec_ucsi: Add netlink

diff --git a/MAINTAINERS b/MAINTAINERS
index d084f32208f0..2afb406a24ce 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -5305,7 +5305,9 @@  M:	Abhishek Pandit-Subedi <abhishekpandit@chromium.org>
 M:	Łukasz Bartosik <ukaszb@chromium.org>
 L:	chrome-platform@lists.linux.dev
 S:	Maintained
-F:	drivers/usb/typec/ucsi/cros_ec_ucsi.c
+F:	drivers/usb/typec/ucsi/cros_ec_ucsi_main.c
+F:	drivers/usb/typec/ucsi/cros_ec_ucsi_nl.c
+F:	drivers/usb/typec/ucsi/cros_ec_ucsi_nl.h
 F:	drivers/usb/typec/ucsi/cros_ec_ucsi_trace.h
 
 CHRONTEL CH7322 CEC DRIVER
diff --git a/drivers/usb/typec/ucsi/Makefile b/drivers/usb/typec/ucsi/Makefile
index be98a879104d..82d960394c39 100644
--- a/drivers/usb/typec/ucsi/Makefile
+++ b/drivers/usb/typec/ucsi/Makefile
@@ -21,5 +21,7 @@  obj-$(CONFIG_UCSI_ACPI)			+= ucsi_acpi.o
 obj-$(CONFIG_UCSI_CCG)			+= ucsi_ccg.o
 obj-$(CONFIG_UCSI_STM32G0)		+= ucsi_stm32g0.o
 obj-$(CONFIG_UCSI_PMIC_GLINK)		+= ucsi_glink.o
-obj-$(CONFIG_CROS_EC_UCSI)		+= cros_ec_ucsi.o
 obj-$(CONFIG_UCSI_LENOVO_YOGA_C630)	+= ucsi_yoga_c630.o
+
+obj-$(CONFIG_CROS_EC_UCSI)		+= cros_ec_ucsi.o
+cros_ec_ucsi-y				:= cros_ec_ucsi_main.o cros_ec_ucsi_nl.o
diff --git a/drivers/usb/typec/ucsi/cros_ec_ucsi.c b/drivers/usb/typec/ucsi/cros_ec_ucsi_main.c
similarity index 79%
rename from drivers/usb/typec/ucsi/cros_ec_ucsi.c
rename to drivers/usb/typec/ucsi/cros_ec_ucsi_main.c
index 6e020b7ed352..85edfa95782a 100644
--- a/drivers/usb/typec/ucsi/cros_ec_ucsi.c
+++ b/drivers/usb/typec/ucsi/cros_ec_ucsi_main.c
@@ -19,6 +19,7 @@ 
 #define CREATE_TRACE_POINTS
 #include "ucsi.h"
 #include "cros_ec_ucsi_trace.h"
+#include "cros_ec_ucsi_nl.h"
 
 /*
  * Maximum size in bytes of a UCSI message between AP and EC
@@ -43,6 +44,43 @@  struct cros_ucsi_data {
 	unsigned long flags;
 };
 
+/*
+ * When set to true the cros_ec_ucsi driver will forward all UCSI messages
+ * exchanged between OPM <-> PPM to userspace through netlink
+ */
+static bool is_ap_sniffer_en;
+
+static ssize_t enable_ap_sniffer_show(struct device *dev,
+				      struct device_attribute *attr,
+				      char *buf)
+{
+	return sprintf(buf, "%d\n", is_ap_sniffer_en);
+}
+
+static ssize_t enable_ap_sniffer_store(struct device *dev,
+				       struct device_attribute *attr,
+				       const char *buf, size_t count)
+{
+	u8 value;
+
+	if (kstrtou8(buf, 0, &value))
+		return -EINVAL;
+
+	is_ap_sniffer_en = value ? 1 : 0;
+	return count;
+}
+
+static DEVICE_ATTR_RW(enable_ap_sniffer);
+
+static struct attribute *cros_ec_ucsi_attrs[] = {
+	&dev_attr_enable_ap_sniffer.attr,
+	NULL
+};
+
+static const struct attribute_group cros_ec_ucsi_attrs_grp = {
+	.attrs = cros_ec_ucsi_attrs,
+};
+
 static int cros_ucsi_read(struct ucsi *ucsi, unsigned int offset, void *val,
 			  size_t val_len)
 {
@@ -65,6 +103,9 @@  static int cros_ucsi_read(struct ucsi *ucsi, unsigned int offset, void *val,
 		return ret;
 	}
 
+	if (is_ap_sniffer_en)
+		nl_cros_ec_bcast_msg(NL_CROS_EC_TO_PPM, NL_CROS_EC_RD, offset,
+				     val, val_len);
 	trace_cros_ec_opm_to_ppm_rd(offset, val, val_len);
 	return 0;
 }
@@ -106,6 +147,9 @@  static int cros_ucsi_async_control(struct ucsi *ucsi, u64 cmd)
 		return ret;
 	}
 
+	if (is_ap_sniffer_en)
+		nl_cros_ec_bcast_msg(NL_CROS_EC_TO_PPM, NL_CROS_EC_WR,
+				     req->offset, (u8 *) &cmd, sizeof(cmd));
 	trace_cros_ec_opm_to_ppm_wr(req->offset, &cmd, sizeof(cmd));
 	return 0;
 }
@@ -149,6 +193,8 @@  static void cros_ucsi_work(struct work_struct *work)
 	struct cros_ucsi_data *udata = container_of(work, struct cros_ucsi_data, work);
 	u32 cci;
 
+	if (is_ap_sniffer_en)
+		nl_cros_ec_bcast_msg(NL_CROS_EC_TO_OPM, 0, 0, NULL, 0);
 	trace_cros_ec_ppm_to_opm(0);
 
 	if (cros_ucsi_read(udata->ucsi, UCSI_CCI, &cci, sizeof(cci)))
@@ -234,13 +280,29 @@  static int cros_ucsi_probe(struct platform_device *pdev)
 		return ret;
 	}
 
+	ret = nl_cros_ec_register();
+	if (ret) {
+		dev_err(dev, "failed to register netlink: error=%d", ret);
+		cros_ucsi_destroy(udata);
+		return ret;
+	}
+
+	ret = sysfs_create_group(&dev->kobj, &cros_ec_ucsi_attrs_grp);
+	if (ret) {
+		dev_err(dev, "failed to register sysfs group: error=%d", ret);
+		cros_ucsi_destroy(udata);
+		return ret;
+	}
+
 	return 0;
 }
 
-static void cros_ucsi_remove(struct platform_device *dev)
+static void cros_ucsi_remove(struct platform_device *pdev)
 {
-	struct cros_ucsi_data *udata = platform_get_drvdata(dev);
+	struct cros_ucsi_data *udata = platform_get_drvdata(pdev);
 
+	sysfs_remove_group(&pdev->dev.kobj, &cros_ec_ucsi_attrs_grp);
+	nl_cros_ec_unregister();
 	ucsi_unregister(udata->ucsi);
 	cros_ucsi_destroy(udata);
 }
diff --git a/drivers/usb/typec/ucsi/cros_ec_ucsi_nl.c b/drivers/usb/typec/ucsi/cros_ec_ucsi_nl.c
new file mode 100644
index 000000000000..360568044891
--- /dev/null
+++ b/drivers/usb/typec/ucsi/cros_ec_ucsi_nl.c
@@ -0,0 +1,87 @@ 
+// SPDX-License-Identifier: GPL-2.0
+
+#include <net/genetlink.h>
+#include "cros_ec_ucsi_nl.h"
+
+static const struct genl_multicast_group nl_mc_grps[] = {
+	{ .name = NL_CROS_EC_MC_GRP_NAME },
+};
+
+static struct genl_family genl_fam = {
+	.name	  = NL_CROS_EC_NAME,
+	.version  = NL_CROS_EC_VER,
+	.maxattr  = NL_CROS_EC_A_MAX,
+	.mcgrps	  = nl_mc_grps,
+	.n_mcgrps = ARRAY_SIZE(nl_mc_grps),
+};
+
+int nl_cros_ec_register(void)
+{
+	return genl_register_family(&genl_fam);
+}
+
+void nl_cros_ec_unregister(void)
+{
+	genl_unregister_family(&genl_fam);
+}
+
+int nl_cros_ec_bcast_msg(enum nl_cros_ec_msg_dir dir,
+			 enum nl_cros_ec_cmd_type cmd_type,
+			 u16 offset, const u8 *payload, size_t msg_size)
+{
+	struct timespec64 ts;
+	struct sk_buff *skb;
+	int ret = -ENOMEM;
+	void *hdr;
+
+	skb = genlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
+	if (!skb)
+		return -ENOMEM;
+
+	hdr = genlmsg_put(skb, 0, 0, &genl_fam, 0, NL_CROS_EC_C_UCSI);
+	if (!hdr)
+		goto free_mem;
+
+	ret = nla_put_u8(skb, NL_CROS_EC_A_SRC, NL_CROS_EC_AP);
+	if (ret)
+		goto cancel;
+
+	ret = nla_put_u8(skb, NL_CROS_EC_A_DIR, dir);
+	if (ret)
+		goto cancel;
+
+	ret = nla_put_u16(skb, NL_CROS_EC_A_OFFSET, offset);
+	if (ret)
+		goto cancel;
+
+	ret = nla_put_u8(skb, NL_CROS_EC_A_CMD_TYPE, cmd_type);
+	if (ret)
+		goto cancel;
+
+	ktime_get_ts64(&ts);
+	ret = nla_put_u32(skb, NL_CROS_EC_A_TSTAMP_SEC, (u32)ts.tv_sec);
+	if (ret)
+		goto cancel;
+
+	ret = nla_put_u32(skb, NL_CROS_EC_A_TSTAMP_USEC,
+			  (u32)(ts.tv_nsec/1000));
+	if (ret)
+		goto cancel;
+
+	ret = nla_put(skb, NL_CROS_EC_A_PAYLOAD, msg_size, payload);
+	if (ret)
+		goto cancel;
+
+	genlmsg_end(skb, hdr);
+
+	ret = genlmsg_multicast(&genl_fam, skb, 0, 0, GFP_KERNEL);
+	if (ret && ret != -ESRCH)
+		goto free_mem;
+
+	return 0;
+cancel:
+	genlmsg_cancel(skb, hdr);
+free_mem:
+	nlmsg_free(skb);
+	return ret;
+}
diff --git a/drivers/usb/typec/ucsi/cros_ec_ucsi_nl.h b/drivers/usb/typec/ucsi/cros_ec_ucsi_nl.h
new file mode 100644
index 000000000000..c6192d8ace56
--- /dev/null
+++ b/drivers/usb/typec/ucsi/cros_ec_ucsi_nl.h
@@ -0,0 +1,52 @@ 
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#ifndef __DRIVER_USB_TYPEC_CROS_EC_UCSI_NL_H
+#define __DRIVER_USB_TYPEC_CROS_EC_UCSI_NL_H
+
+#define NL_CROS_EC_NAME "cros_ec_ucsi"
+#define NL_CROS_EC_VER 1
+#define NL_CROS_EC_MC_GRP_NAME "cros_ec_ucsi_mc"
+
+/* attributes */
+enum nl_cros_ec_attrs {
+	NL_CROS_EC_A_SRC,
+	NL_CROS_EC_A_DIR,
+	NL_CROS_EC_A_OFFSET,
+	NL_CROS_EC_A_CMD_TYPE,
+	NL_CROS_EC_A_TSTAMP_SEC,
+	NL_CROS_EC_A_TSTAMP_USEC,
+	NL_CROS_EC_A_PAYLOAD,
+	NL_CROS_EC_A_MAX
+};
+
+enum nl_cros_ec_cmds {
+	NL_CROS_EC_C_UCSI,
+	NL_CROS_EC_C_MAX
+};
+
+/* where message was captured - EC or AP */
+enum nl_cros_ec_src {
+	NL_CROS_EC_AP,
+	NL_CROS_EC_EC
+};
+
+/* message destination */
+enum nl_cros_ec_msg_dir {
+	NL_CROS_EC_TO_PPM,
+	NL_CROS_EC_TO_OPM,
+	NL_CROS_EC_TO_LPM
+};
+
+/* command type - read or write */
+enum nl_cros_ec_cmd_type {
+	NL_CROS_EC_RD,
+	NL_CROS_EC_WR
+};
+
+int nl_cros_ec_register(void);
+void nl_cros_ec_unregister(void);
+int nl_cros_ec_bcast_msg(enum nl_cros_ec_msg_dir dir,
+			 enum nl_cros_ec_cmd_type cmd_type,
+			 u16 offset, const u8 *payload, size_t msg_size);
+
+#endif /* __DRIVER_USB_TYPEC_CROS_EC_UCSI_NL_H */