Allow rebinding of the transport device to force a reload of the HID descriptors

In some cases during firmware update the size of the input reports can change
this commit allows for the unbinding and rebinding of the transport HID device to force
a reload of the HID descriptors so that the new size if read by the HID transport
drivers.

2 files changed, 2 insertions, 116 deletions

diff --git a/rmi4update/main.cpp b/rmi4update/main.cpp
index 2f86068..96b1965 100644
--- a/rmi4update/main.cpp
+++ b/rmi4update/main.cpp
@@ -71,113 +71,6 @@ int UpdateDevice(FirmwareImage & image, bool force, bool performLockdown, const
 	return rc;
 }
 
-int WriteDeviceNameToFile(const char * file, const char * str)
-{
-	int fd;
-	ssize_t size;
-
-	fd = open(file, O_WRONLY);
-	if (fd < 0)
-		return UPDATE_FAIL;
-
-	for (;;) {
-		size = write(fd, str, 19);
-		if (size < 0) {
-			if (errno == EINTR)
-				continue;
-
-			return UPDATE_FAIL;
-		}
-		break;
-	}
-
-	close(fd);
-
-	return UPDATE_SUCCESS;
-}
-
-/*
- * We need to rebind the driver to the device after firmware update because the
- * parameters of the device may have changed in the new firmware and the
- * driver should redo the initialization ensure it is using the new values.
- */
-void RebindDriver(const char * hidraw)
-{
-	int rc;
-	ssize_t size;
-	char bindFile[PATH_MAX];
-	char unbindFile[PATH_MAX];
-	char deviceLink[PATH_MAX];
-	char driverName[PATH_MAX];
-	char driverLink[PATH_MAX];
-	char linkBuf[PATH_MAX];
-	char hidDeviceString[20];
-	int i;
-
-	snprintf(unbindFile, PATH_MAX, "/sys/class/hidraw/%s/device/driver/unbind", hidraw);
-	snprintf(deviceLink, PATH_MAX, "/sys/class/hidraw/%s/device", hidraw);
-
-	size = readlink(deviceLink, linkBuf, PATH_MAX);
-	if (size < 0) {
-		fprintf(stderr, "Failed to find the HID string for this device: %s\n",
-			hidraw);
-		return;
-	}
-	linkBuf[size] = 0;
-
-	strncpy(hidDeviceString, StripPath(linkBuf, size), 20);
-
-	snprintf(driverLink, PATH_MAX, "/sys/class/hidraw/%s/device/driver", hidraw);
-
-	size = readlink(driverLink, linkBuf, PATH_MAX);
-	if (size < 0) {
-		fprintf(stderr, "Failed to find the HID string for this device: %s\n",
-			hidraw);
-		return;
-	}
-	linkBuf[size] = 0;
-
-	strncpy(driverName, StripPath(linkBuf, size), PATH_MAX);
-
-	snprintf(bindFile, PATH_MAX, "/sys/bus/hid/drivers/%s/bind", driverName);
-
-	rc = WriteDeviceNameToFile(unbindFile, hidDeviceString);
-	if (rc != UPDATE_SUCCESS) {
-		fprintf(stderr, "Failed to unbind HID device %s: %s\n",
-			hidDeviceString, strerror(errno));
-		return;
-	}
-
-	for (i = 0;; ++i) {
-		struct timespec req;
-		struct timespec rem;
-
-		rc = WriteDeviceNameToFile(bindFile, hidDeviceString);
-		if (rc == UPDATE_SUCCESS)
-			return;
-
-		if (i <= 4)
-			break;
-
-		/* device might not be ready yet to bind to */
-		req.tv_sec = 0;
-		req.tv_nsec = 100 * 1000 * 1000; /* 100 ms */
-		for (;;) {
-			rc = nanosleep(&req, &rem);
-			if (rc < 0) {
-				if (errno == EINTR) {
-					req = rem;
-					continue;
-				}
-			}
-			break;
-		}
-	}
-
-	fprintf(stderr, "Failed to bind HID device %s: %s\n",
-		hidDeviceString, strerror(errno));
-}
-
 int GetFirmwareProps(const char * deviceFile, std::string &props)
 {
 	HIDDevice rmidevice;
@@ -282,17 +175,10 @@ int main(int argc, char **argv)
 	}
 
 	if (deviceName) {
-		char * rawDevice;
 		rc = UpdateDevice(image, force, performLockdown, deviceName);
-		if (rc)
-			return rc;
 
-		rawDevice = strcasestr(deviceName, "hidraw");
-		if (rawDevice)
-			RebindDriver(rawDevice);
 		return rc;
 	} else {
-		char rawDevice[PATH_MAX];
 		char deviceFile[PATH_MAX];
 		bool found = false;
 
@@ -302,6 +188,7 @@ int main(int argc, char **argv)
 
 		while ((devDirEntry = readdir(devDir)) != NULL) {
 			if (strstr(devDirEntry->d_name, "hidraw")) {
+				char rawDevice[PATH_MAX];
 				strncpy(rawDevice, devDirEntry->d_name, PATH_MAX);
 				snprintf(deviceFile, PATH_MAX, "/dev/%s", devDirEntry->d_name);
 				rc = UpdateDevice(image, force, performLockdown, deviceFile);
@@ -309,7 +196,6 @@ int main(int argc, char **argv)
 					continue;
 				} else {
 					found = true;
-					RebindDriver(rawDevice);
 					break;
 				}
 			}
diff --git a/rmi4update/rmi4update.cpp b/rmi4update/rmi4update.cpp
index 2888e24..7217701 100644
--- a/rmi4update/rmi4update.cpp
+++ b/rmi4update/rmi4update.cpp
@@ -499,4 +499,4 @@ int RMI4Update::WaitForIdle(int timeout_ms)
 	fprintf(stderr, "Idle:    %d\n", !m_f34Command && !m_f34Status);
 
 	return UPDATE_FAIL_NOT_IN_IDLE_STATE;
-}
+}
\ No newline at end of file