fastboot: Automatically reboot to userspace fastboot.

In order to flash logical partitions, "flashall" must be run against
userspace fastboot. When the bootloader supports the "reboot-fastboot"
command, we now attempt to automatically reboot into userspace fastboot.

We do this by closing the transport, sleeping for one second, and then
polling for a new connection until one is available. FastBootDriver is
then assigned the new transport.

Bug: 78793464
Test: fastboot flashall on device with logical partitions, while booted
      into bootloader fastboot

Change-Id: I6949871b93ab5e352784cabe0963c6ecfc0af36d

1 files changed, 24 insertions, 1 deletions

diff --git a/fastboot/engine.cpp b/fastboot/engine.cpp
index 689064339..6a52b12bb 100644
--- a/fastboot/engine.cpp
+++ b/fastboot/engine.cpp
@@ -79,12 +79,18 @@ struct Action {
 static std::vector<std::unique_ptr<Action>> action_list;
 static fastboot::FastBootDriver* fb = nullptr;
 
+static constexpr char kStatusFormat[] = "%-50s ";
+
 void fb_init(fastboot::FastBootDriver& fbi) {
     fb = &fbi;
     auto cb = [](std::string& info) { fprintf(stderr, "(bootloader) %s\n", info.c_str()); };
     fb->SetInfoCallback(cb);
 }
 
+void fb_reinit(Transport* transport) {
+    fb->set_transport(transport);
+}
+
 const std::string fb_get_error() {
     return fb->Error();
 }
@@ -332,7 +338,7 @@ int64_t fb_execute_queue() {
     for (auto& a : action_list) {
         a->start = now();
         if (!a->msg.empty()) {
-            fprintf(stderr, "%-50s ", a->msg.c_str());
+            fprintf(stderr, kStatusFormat, a->msg.c_str());
             verbose("\n");
         }
         if (a->op == OP_DOWNLOAD) {
@@ -372,3 +378,20 @@ int64_t fb_execute_queue() {
     action_list.clear();
     return status;
 }
+
+bool fb_reboot_to_userspace() {
+    // First ensure that the queue is flushed.
+    fb_execute_queue();
+
+    fprintf(stderr, kStatusFormat, "Rebooting to userspace fastboot");
+    verbose("\n");
+
+    if (fb->RebootTo("fastboot") != fastboot::RetCode::SUCCESS) {
+        fprintf(stderr, "FAILED (%s)\n", fb->Error().c_str());
+        return false;
+    }
+    fprintf(stderr, "OKAY\n");
+
+    fb->set_transport(nullptr);
+    return true;
+}