When a USB device is unbound, it causes any bootflows attached to it to be removed, via a call to bootdev_clear_bootflows() from bootdev_pre_unbind(). This obviously makes it impossible to boot the bootflow.
However, when booting a bootflow that relies on USB, usb_stop() is called, which unbinds the device. For EFI, this happens in efi_exit_boot_services() which means that the bootflow disappears before it is finished with.
There is no need to unbind all the USB devices just to quiesce them. Add a new usb_pause() call which removes them but leaves them bound.
This resolves a hang on x86 when booting a distro from USB. This was found using a device with 4 bootflows, the last of which was USB.
Signed-off-by: Simon Glass sjg@chromium.org ---
Changes in v4: - Don't rename the legacy-USB functions - Add a bit more detail to the comment
Changes in v2: - Add new patch to avoid unbinding devices in use by bootflows
boot/bootm.c | 2 +- common/usb.c | 5 +++++ drivers/usb/host/usb-uclass.c | 14 ++++++++++++-- include/usb.h | 21 ++++++++++++++++++++- 4 files changed, 38 insertions(+), 4 deletions(-)
diff --git a/boot/bootm.c b/boot/bootm.c index cb61485c226c..d9c3fa8dad99 100644 --- a/boot/bootm.c +++ b/boot/bootm.c @@ -502,7 +502,7 @@ ulong bootm_disable_interrupts(void) * updated every 1 ms within the HCCA structure in SDRAM! For more * details see the OpenHCI specification. */ - usb_stop(); + usb_pause(); #endif return iflag; } diff --git a/common/usb.c b/common/usb.c index 836506dcd9e9..a486d1c87d4d 100644 --- a/common/usb.c +++ b/common/usb.c @@ -144,6 +144,11 @@ int usb_stop(void) return 0; }
+int usb_pause(void) +{ + return usb_stop(); +} + /****************************************************************************** * Detect if a USB device has been plugged or unplugged. */ diff --git a/drivers/usb/host/usb-uclass.c b/drivers/usb/host/usb-uclass.c index a1cd0ad2d669..c26c65d7986b 100644 --- a/drivers/usb/host/usb-uclass.c +++ b/drivers/usb/host/usb-uclass.c @@ -173,7 +173,7 @@ int usb_get_max_xfer_size(struct usb_device *udev, size_t *size) return ops->get_max_xfer_size(bus, size); }
-int usb_stop(void) +static int usb_finish(bool unbind_all) { struct udevice *bus; struct udevice *rh; @@ -195,7 +195,7 @@ int usb_stop(void)
/* Locate root hub device */ device_find_first_child(bus, &rh); - if (rh) { + if (rh && unbind_all) { /* * All USB devices are children of root hub. * Unbinding root hub will unbind all of its children. @@ -222,6 +222,16 @@ int usb_stop(void) return err; }
+int usb_stop(void) +{ + return usb_finish(true); +} + +int usb_pause(void) +{ + return usb_finish(false); +} + static void usb_scan_bus(struct udevice *bus, bool recurse) { struct usb_bus_priv *priv; diff --git a/include/usb.h b/include/usb.h index 09e3f0cb309c..b964e2e1f6b2 100644 --- a/include/usb.h +++ b/include/usb.h @@ -265,7 +265,26 @@ int usb_kbd_deregister(int force); */ int usb_init(void);
-int usb_stop(void); /* stop the USB Controller */ +/** + * usb_stop() - stop the USB Controller and unbind all USB controllers/devices + * + * This unbinds all devices on the USB buses. + * + * Return: 0 if OK, -ve on error + */ +int usb_stop(void); + +/** + * usb_pause() - stop the USB Controller DMA, etc. + * + * Note that this does not unbind bus devices, so using usb_init() after this + * call is not permitted. This function is only useful just before booting, to + * ensure that devices are dormant. + * + * Return: 0 if OK, -ve on error + */ +int usb_pause(void); + int usb_detect_change(void); /* detect if a USB device has been (un)plugged */