Hi,
On 29-06-15 05:45, Simon Glass wrote:
Hi Hans,
On 17 June 2015 at 13:33, Hans de Goede <hdego...@redhat.com> wrote:
On an usb stop instead of leaving orphan usb devices behind simply remove
On a usb_stop()
or
On a 'usb stop' command ?
My intention was for both, since I was under the assumption that "usb stop"
on the cmdline, was the only caller of usb_stop(), but a quick grep to the
sources show that I'm wrong ...
them. This requires CONFIG_DM_DEVICE_REMOVE to be set, so only build
usb_stop() when that is set.
This seems a little unfortunate. I can see the reasoning, but do you
think this is necessary? I suspect people chasing code size may remove
that option and still want to use USB properly.
This was mostly a result of my thinking that usb_stop() is only used
on "usb stop" at the cmdline, which I know realize is wrong.
However my quick grep has learned that we do really need CONFIG_DM_DEVICE_REMOVE
to properly implement usb_stop():
From common/bootm.c :
#if defined(CONFIG_CMD_USB)
/*
* turn off USB to prevent the host controller from writing to the
* SDRAM while Linux is booting. This could happen (at least for OHCI
* controller), because the HCCA (Host Controller Communication Area)
* lies within the SDRAM and the host controller writes continously to
* this area (as busmaster!). The HccaFrameNumber is for example
* updated every 1 ms within the HCCA structure in SDRAM! For more
* details see the OpenHCI specification.
*/
usb_stop();
#endif
And without CONFIG_DM_DEVICE_REMOVE we end up never calling the hcd's remove
callback and thus do not properly stop the usb controller.
So this problem of usb_stop() needing CONFIG_DM_DEVICE_REMOVE already exists
before this patch. If you want I can split out the adding of the #ifdef
in a separate commit, spelling out why usb_stop() MUST have
CONFIG_DM_DEVICE_REMOVE in the commit message. Or maybe just move this all to
Kconfig and make DM_USB conflict with CONFIG_DM_DEVICE_REMOVE?
The result of this commit is best seen in the output of "dm tree" after
plugging out an usb hub with 2 devices plugges in and plugging in a keyb.
instead, before this commit the output would be:
usb [ + ] `-- sunxi-musb
usb_hub [ ] |-- usb_hub
usb_mass_st [ ] | |-- usb_mass_storage
usb_dev_gen [ ] | `-- generic_bus_0_dev_3
usb_dev_gen [ + ] `-- generic_bus_0_dev_1
Notice the non active usb_hub child and its 2 non active children. The
first child being non-active as in this example also causes usb_get_dev_index
to return NULL when probing the first child, which results in the usb kbd
code not binding to the keyboard.
Although I suspect that could be fixed.
Right, but just removing the children is a much cleaner solution, and also
makes the output of "dm tree" properly reflect reality.
With this commit in place the output after swapping and "usb reset" is:
usb [ + ] `-- sunxi-musb
usb_dev_gen [ + ] `-- generic_bus_0_dev_1
As expected, and usb_get_dev_index works properly and the keyboard works.
After this commit usb_find_child() is only necessary for emulated usb
devices, so make its body #ifdef CONFIG_USB_EMUL.
Signed-off-by: Hans de Goede <hdego...@redhat.com>
---
drivers/usb/host/usb-uclass.c | 10 ++++++++++
1 file changed, 10 insertions(+)
diff --git a/drivers/usb/host/usb-uclass.c b/drivers/usb/host/usb-uclass.c
index bce6cec..8f26e35 100644
--- a/drivers/usb/host/usb-uclass.c
+++ b/drivers/usb/host/usb-uclass.c
@@ -128,6 +128,7 @@ int usb_alloc_device(struct usb_device *udev)
return ops->alloc_device(bus, udev);
}
+#ifdef CONFIG_DM_DEVICE_REMOVE
int usb_stop(void)
{
struct udevice *bus;
@@ -143,6 +144,12 @@ int usb_stop(void)
uc_priv = uc->priv;
uclass_foreach_dev(bus, uc) {
+ ret = device_chld_remove(bus);
+ if (ret && !err)
+ err = ret;
+ ret = device_chld_unbind(bus);
+ if (ret && !err)
+ err = ret;
ret = device_remove(bus);
if (ret && !err)
err = ret;
@@ -166,6 +173,7 @@ int usb_stop(void)
return err;
}
+#endif
static void usb_scan_bus(struct udevice *bus, bool recurse)
{
@@ -491,6 +499,7 @@ static int usb_find_child(struct udevice *parent,
struct usb_interface_descriptor *iface,
struct udevice **devp)
{
+#ifdef CONFIG_USB_EMUL /* Emulated devices are explictily bound */
explicitly
Ack.
Can you add a comment about this? It seems that we should rename this
function to usb_find_emul_child() and have it present only when
CONFIG_USB_EMUL is around?
Renaming it to usb_find_emul_child() and only defining the function when
CONFIG_USB_EMUL works for me I will do that for v2.
Also, why bother with the #ifdef if this function is never called
outside sandbox?
Because its call site does not have a #ifdef, I'll add an #ifdef at its
call site to make it more clear that this is only used for emulated
devices.
struct udevice *dev;
*devp = NULL;
@@ -509,6 +518,7 @@ static int usb_find_child(struct udevice *parent,
return 0;
}
}
+#endif
return -ENOENT;
}
--
2.4.3
Regards,
Simon
Regards,
Hans
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