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SubjectRe: [RFC][PATCH v2 08/13] usb: otg: hub: Notify OTG fsm when A device sets b_hnp_enable
On 17/04/15 05:28, Peter Chen wrote:
> On Tue, Apr 14, 2015 at 01:41:55PM +0300, Roger Quadros wrote:
>> This is the a_set_b_hnp_enable flag in the OTG state machine
>> diagram and must be set when the A-Host has successfully set
>> the b_hnp_enable feature of the OTG-B-Peripheral attached to it.
>>
>> When this bit changes we kick our OTG FSM to make note of the
>> change and act accordingly.
>>
>> Signed-off-by: Roger Quadros <rogerq@ti.com>
>> ---
>> drivers/usb/core/hub.c | 11 ++++++++++-
>> 1 file changed, 10 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
>> index d7c3d5a..ab0d498 100644
>> --- a/drivers/usb/core/hub.c
>> +++ b/drivers/usb/core/hub.c
>> @@ -22,6 +22,7 @@
>> #include <linux/usb/hcd.h>
>> #include <linux/usb/otg.h>
>> #include <linux/usb/quirks.h>
>> +#include <linux/usb/usb-otg.h>
>> #include <linux/workqueue.h>
>> #include <linux/mutex.h>
>> #include <linux/random.h>
>> @@ -2270,6 +2271,9 @@ static int usb_enumerate_device_otg(struct usb_device *udev)
>> "can't set HNP mode: %d\n",
>> err);
>> bus->b_hnp_enable = 0;
>> + } else {
>> + /* notify OTG fsm about a_set_b_hnp_enable */
>> + usb_otg_kick_fsm(udev->bus->controller);
>> }
>> }
>> }
>> @@ -4244,8 +4248,13 @@ hub_port_init (struct usb_hub *hub, struct usb_device *udev, int port1,
>> */
>> if (!hdev->parent) {
>> delay = HUB_ROOT_RESET_TIME;
>> - if (port1 == hdev->bus->otg_port)
>> + if (port1 == hdev->bus->otg_port) {
>> hdev->bus->b_hnp_enable = 0;
>> +#ifdef CONFIG_USB_OTG
>> + /* notify OTG fsm about a_set_b_hnp_enable change */
>> + usb_otg_kick_fsm(hdev->bus->controller);
>> +#endif
>> + }
>> }
>>
>> /* Some low speed devices have problems with the quick delay, so */
>> --
>> 2.1.0
>>
>
> Since the fsm has already kicked, the only thing we need is update
> fsm.a_set_b_hnp_enable, but this flag is missing at current fsm
> structure.

Every time the input changes, the fsm has to be re-kicked.

Instead of fsm.a_set_b_hnp_enable we use fsm->otg->host->b_hnp_enable
in the fsm.
USB host stack doesn't have access to fsm structure but the OTG state
machine has access to hcd.

cheers,
-roger



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