On Thu, Dec 24, 2015 at 07:10:29PM +0300, Peter Mamonov wrote:
> Let me summarize my efforts:
>
> "Global variable" solution works fine, however it is not elegant enough:
>
> diff --git a/drivers/usb/host/ehci-hcd.c b/drivers/usb/host/ehci-hcd.c
> index 862444b..d06e001 100644
> --- a/drivers/usb/host/ehci-hcd.c
> +++ b/drivers/usb/host/ehci-hcd.c
> @@ -138,0 +139,2 @@ static struct descriptor {
> +int ehci_probed = 0;
> +
> @@ -1346,0 +1349,2 @@ static int ehci_probe(struct device_d *dev)
> + ehci_probed = 1;
> +
> diff --git a/drivers/usb/host/uhci-hcd.c b/drivers/usb/host/uhci-hcd.c
> index 5a5314f..c99426c 100644
> --- a/drivers/usb/host/uhci-hcd.c
> +++ b/drivers/usb/host/uhci-hcd.c
> @@ -81,0 +82,2 @@
> +extern int ehci_probed;
> +
> @@ -1232,0 +1235,4 @@ static int uhci_probe(struct device_d *dev)
> + if (!ehci_probed) {
> + dev_err(dev, "PROBE_DEFER\n");
> + return -EPROBE_DEFER;
> + }
>
>
I think one of the big disadvantages here to this solution is that it
doesn't work when you have multiple ehci/uhci devices.
In linux it would be non-go, but barebox... don't know if barebox can
handle such setup.
>
> "Device tree" solution doesn't work, because of_find_device_by_node()
> returns pointer to the device even though the device probe function
> wasn't called. The question is: how to tell if the device probe
> function was called?
I would say the easiest way is to check on "dev-priv", there you also
could get the "struct ehci_priv" if needed in uhci when companion is
there. The "dev->priv" will be set when running probe.
>
> diff --git a/drivers/usb/host/uhci-hcd.c b/drivers/usb/host/uhci-hcd.c
> index c99426c..44eca36 100644
> --- a/drivers/usb/host/uhci-hcd.c
> +++ b/drivers/usb/host/uhci-hcd.c
> @@ -1234,0 +1235,20 @@ static int uhci_probe(struct device_d *dev)
> + struct device_node *dn = dev->device_node, *companion;
> +
> + if (dn) {
> + companion = of_parse_phandle(dn, "companion", 0);
> + if (companion && !of_find_device_by_node(companion)) {
> + dev_err(dev, "PROBE_DEFER\n");
> + return -EPROBE_DEFER;
> + }
> + }
>
if (dn) {
companion = of_parse_phandle(dn, "companion", 0);
if (companion) {
dev = of_find_device_by_node(companion);
if (!dev || !dev->priv) {
dev_err(dev, "PROBE_DEFER\n");
return -EPROBE_DEFER;
}
}
}
if you need "struct ehci_priv" inside of uhci driver, then I would do
some static inline function for casting and doing:
"!ehci_get_priv(dev))" instead "dev->priv", but the access should be
then readonly only.
Don't know if this is a good and acceptable solution.
- Alex
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