[PATCH 062/379][SRU][OEM-5.6] bus: mhi: core: Add uevent support for module autoloading

[You-Sheng Yang]

From: Manivannan Sadhasivam <manivannan.sadhasivam at linaro.org>

BugLink: https://bugs.launchpad.net/bugs/1879633

Add uevent support to MHI bus so that the client drivers can be autoloaded
by udev when the MHI devices gets created. The client drivers are
expected to provide MODULE_DEVICE_TABLE with the MHI id_table struct so
that the alias can be exported.

Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam at linaro.org>
Reviewed-by: Jeffrey Hugo <jhugo at codeaurora.org>
Tested-by: Jeffrey Hugo <jhugo at codeaurora.org>
Link: https://lore.kernel.org/r/20200220095854.4804-13-manivannan.sadhasivam@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh at linuxfoundation.org>
(cherry picked from commit e6b0de469c5babfe29a86be289408ba2070ea44a)
Signed-off-by: You-Sheng Yang <vicamo.yang at canonical.com>
---
 drivers/bus/mhi/core/init.c       |  9 +++++++++
 include/linux/mod_devicetable.h   |  1 +
 scripts/mod/devicetable-offsets.c |  3 +++
 scripts/mod/file2alias.c          | 10 ++++++++++
 4 files changed, 23 insertions(+)

diff --git a/drivers/bus/mhi/core/init.c b/drivers/bus/mhi/core/init.c
index 7bfffa9a5ad1..5fb756ca335e 100644
--- a/drivers/bus/mhi/core/init.c
+++ b/drivers/bus/mhi/core/init.c
@@ -1210,6 +1210,14 @@ void mhi_driver_unregister(struct mhi_driver *mhi_drv)
 }
 EXPORT_SYMBOL_GPL(mhi_driver_unregister);
 
+static int mhi_uevent(struct device *dev, struct kobj_uevent_env *env)
+{
+	struct mhi_device *mhi_dev = to_mhi_device(dev);
+
+	return add_uevent_var(env, "MODALIAS=" MHI_DEVICE_MODALIAS_FMT,
+					mhi_dev->chan_name);
+}
+
 static int mhi_match(struct device *dev, struct device_driver *drv)
 {
 	struct mhi_device *mhi_dev = to_mhi_device(dev);
@@ -1236,6 +1244,7 @@ struct bus_type mhi_bus_type = {
 	.name = "mhi",
 	.dev_name = "mhi",
 	.match = mhi_match,
+	.uevent = mhi_uevent,
 };
 
 static int __init mhi_init(void)
diff --git a/include/linux/mod_devicetable.h b/include/linux/mod_devicetable.h
index 46f37292a396..1a2c65ebaf4f 100644
--- a/include/linux/mod_devicetable.h
+++ b/include/linux/mod_devicetable.h
@@ -825,6 +825,7 @@ struct wmi_device_id {
 	const void *context;
 };
 
+#define MHI_DEVICE_MODALIAS_FMT "mhi:%s"
 #define MHI_NAME_SIZE 32
 
 /**
diff --git a/scripts/mod/devicetable-offsets.c b/scripts/mod/devicetable-offsets.c
index 054405b90ba4..fe3f4a95cb21 100644
--- a/scripts/mod/devicetable-offsets.c
+++ b/scripts/mod/devicetable-offsets.c
@@ -231,5 +231,8 @@ int main(void)
 	DEVID(wmi_device_id);
 	DEVID_FIELD(wmi_device_id, guid_string);
 
+	DEVID(mhi_device_id);
+	DEVID_FIELD(mhi_device_id, chan);
+
 	return 0;
 }
diff --git a/scripts/mod/file2alias.c b/scripts/mod/file2alias.c
index c91eba751804..cae6a4e471b5 100644
--- a/scripts/mod/file2alias.c
+++ b/scripts/mod/file2alias.c
@@ -1335,6 +1335,15 @@ static int do_wmi_entry(const char *filename, void *symval, char *alias)
 	return 1;
 }
 
+/* Looks like: mhi:S */
+static int do_mhi_entry(const char *filename, void *symval, char *alias)
+{
+	DEF_FIELD_ADDR(symval, mhi_device_id, chan);
+	sprintf(alias, MHI_DEVICE_MODALIAS_FMT, *chan);
+
+	return 1;
+}
+
 /* Does namelen bytes of name exactly match the symbol? */
 static bool sym_is(const char *name, unsigned namelen, const char *symbol)
 {
@@ -1407,6 +1416,7 @@ static const struct devtable devtable[] = {
 	{"typec", SIZE_typec_device_id, do_typec_entry},
 	{"tee", SIZE_tee_client_device_id, do_tee_entry},
 	{"wmi", SIZE_wmi_device_id, do_wmi_entry},
+	{"mhi", SIZE_mhi_device_id, do_mhi_entry},
 };
 
 /* Create MODULE_ALIAS() statements.
-- 
2.29.2