Re: [PATCH v8 08/14] usb: otg: add OTG/dual-role core

[Roger Quadros]

On 18/05/16 15:59, Roger Quadros wrote:
> Hi Peter,
> 
> On 18/05/16 10:45, Peter Chen wrote:
>>
>>
>> On Mon, May 16, 2016 at 5:00 PM, Roger Quadros <rogerq@xxxxxx <mailto:rogerq@xxxxxx>> wrote:
>>
>>     On 13/05/16 13:03, Roger Quadros wrote:
>>     > It provides APIs for the following tasks
>>     >
>>     > - Registering an OTG/dual-role capable controller
>>     > - Registering Host and Gadget controllers to OTG core
>>     > - Providing inputs to and kicking the OTG state machine
>>     >
>>     > Provide a dual-role device (DRD) state machine.
>>     > DRD mode is a reduced functionality OTG mode. In this mode
>>     > we don't support SRP, HNP and dynamic role-swap.
>>     >
>>     > In DRD operation, the controller mode (Host or Peripheral)
>>     > is decided based on the ID pin status. Once a cable plug (Type-A
>>     > or Type-B) is attached the controller selects the state
>>     > and doesn't change till the cable in unplugged and a different
>>     > cable type is inserted.
>>     >
>>     > As we don't need most of the complex OTG states and OTG timers
>>     > we implement a lean DRD state machine in usb-otg.c.
>>     > The DRD state machine is only interested in 2 hardware inputs
>>     > 'id' and 'b_sess_vld'.
>>     >
>>     > Signed-off-by: Roger Quadros <rogerq@xxxxxx <mailto:rogerq@xxxxxx>>
>>     > ---
>>     >  drivers/usb/common/Makefile  |    2 +-
>>     >  drivers/usb/common/usb-otg.c | 1042 ++++++++++++++++++++++++++++++++++++++++++
>>     >  drivers/usb/core/Kconfig     |    4 +-
>>     >  include/linux/usb/gadget.h   |    2 +
>>     >  include/linux/usb/hcd.h      |    1 +
>>     >  include/linux/usb/otg-fsm.h  |    7 +
>>     >  include/linux/usb/otg.h      |  154 ++++++-
>>     >  7 files changed, 1206 insertions(+), 6 deletions(-)
>>     >  create mode 100644 drivers/usb/common/usb-otg.c
>>
>>
>>     This patch causes the following build issues when CONFIG_USB_GADGET=m, CONFIG_USB=m,
>>     CONFIG_USB_COMMON=m and CONFIG_USB_OTG=y
>>
>>     ERROR: "usb_otg_register_gadget" [drivers/usb/gadget/udc/udc-core.ko] undefined!
>>     ERROR: "usb_otg_unregister_gadget" [drivers/usb/gadget/udc/udc-core.ko] undefined!
>>     ERROR: "usb_otg_register_hcd" [drivers/usb/core/usbcore.ko] undefined!
>>     ERROR: "usb_otg_unregister_hcd" [drivers/usb/core/usbcore.ko] undefined!
>>     ERROR: "otg_statemachine" [drivers/usb/chipidea/ci_hdrc.ko] undefined!
>>     scripts/Makefile.modpost:91: recipe for target '__modpost' failed
>>     make[1]: *** [__modpost] Error 1
>>     Makefile:1141: recipe for target 'modules' failed
>>     make: *** [modules] Error 2
>>     make: *** Waiting for unfinished jobs....
>>
>>     drivers/built-in.o: In function `drd_set_state':
>>     usb-otg.c:(.text+0x2b4242): undefined reference to `usb_otg_state_string'
>>     drivers/built-in.o: In function `drd_statemachine':
>>     (.text+0x2b4b4c): undefined reference to `usb_otg_state_string'
>>     Makefile:937: recipe for target 'vmlinux' failed
>>
>>     I'll fix it up with the following diff.
>>
>>     diff --git a/drivers/usb/Makefile b/drivers/usb/Makefile
>>     index dca7856..16a5b55 100644
>>     --- a/drivers/usb/Makefile
>>     +++ b/drivers/usb/Makefile
>>     @@ -59,5 +59,6 @@ obj-$(CONFIG_USB_RENESAS_USBHS)       += renesas_usbhs/
>>      obj-$(CONFIG_USB_GADGET)       += gadget/
>>
>>      obj-$(CONFIG_USB_COMMON)       += common/
>>     +obj-$(CONFIG_USB_OTG)          += common/
>>
>>      obj-$(CONFIG_USBIP_CORE)       += usbip/
>>     diff --git a/drivers/usb/common/usb-otg.c b/drivers/usb/common/usb-otg.c
>>     index 77048aa..17e449e 100644
>>     --- a/drivers/usb/common/usb-otg.c
>>     +++ b/drivers/usb/common/usb-otg.c
>>     @@ -56,6 +56,30 @@ static int usb_otg_hcd_is_primary_hcd(struct usb_hcd *hcd)
>>             return hcd == hcd->primary_hcd;
>>      }
>>
>>     +static const char *otg_state_string(enum usb_otg_state state)
>>     +{
>>     +       static const char *const names[] = {
>>     +               [OTG_STATE_A_IDLE] = "a_idle",
>>     +               [OTG_STATE_A_WAIT_VRISE] = "a_wait_vrise",
>>     +               [OTG_STATE_A_WAIT_BCON] = "a_wait_bcon",
>>     +               [OTG_STATE_A_HOST] = "a_host",
>>     +               [OTG_STATE_A_SUSPEND] = "a_suspend",
>>     +               [OTG_STATE_A_PERIPHERAL] = "a_peripheral",
>>     +               [OTG_STATE_A_WAIT_VFALL] = "a_wait_vfall",
>>     +               [OTG_STATE_A_VBUS_ERR] = "a_vbus_err",
>>     +               [OTG_STATE_B_IDLE] = "b_idle",
>>     +               [OTG_STATE_B_SRP_INIT] = "b_srp_init",
>>     +               [OTG_STATE_B_PERIPHERAL] = "b_peripheral",
>>     +               [OTG_STATE_B_WAIT_ACON] = "b_wait_acon",
>>     +               [OTG_STATE_B_HOST] = "b_host",
>>     +       };
>>     +
>>     +       if (state < 0 || state >= ARRAY_SIZE(names))
>>     +               return "UNDEFINED";
>>     +
>>     +       return names[state];
>>     +}
>>     +
>>
>>
>>
>> From my point, make another copy for otg stuff is not a good way,
>> could we make folder under usb/ named otg for dedicated otg stuffs,
>> in that case, build otg stuffs can not depend on USB_COMMON.
> 
> OK. I can try that. I'll delete otg_state_string from usb-common.c and
> move it into usb/otg/usb-otg.c
> 
> I'll also move usb-otg-fsm.c to usb/otg/.

But we can't delete usb_otg_state_string() from usb-common.c. That is used at a
number of places whether OTG is enabled or not. 

One option is to make usb-common built in when otg is enabled. What do you say?

cheers,
-roger

>>      /**
>>       * Check if the OTG device is in our wait list and return
>>       * otg_wait_data, else NULL.
>>     @@ -433,7 +457,7 @@ static void drd_set_state(struct otg_fsm *fsm, enum usb_otg_state new_state)
>>
>>             fsm->state_changed = 1;
>>             dev_dbg(otg->dev, "otg: set state: %s\n",
>>     -               usb_otg_state_string(new_state));
>>     +               otg_state_string(new_state));
>>             switch (new_state) {
>>             case OTG_STATE_B_IDLE:
>>                     drd_set_protocol(fsm, PROTO_UNDEF);
>>     @@ -449,7 +473,7 @@ static void drd_set_state(struct otg_fsm *fsm, enum usb_otg_state new_state)
>>                     break;
>>             default:
>>                     dev_warn(otg->dev, "%s: otg: invalid state: %s\n",
>>     -                        __func__, usb_otg_state_string(new_state));
>>     +                        __func__, otg_state_string(new_state));
>>                     break;
>>             }
>>
>>     @@ -507,7 +531,7 @@ int drd_statemachine(struct usb_otg *otg)
>>
>>             default:
>>                     dev_err(otg->dev, "%s: otg: invalid usb-drd state: %s\n",
>>     -                       __func__, usb_otg_state_string(state));
>>     +                       __func__, otg_state_string(state));
>>                     break;
>>             }
>>
>>     --
>>     cheers,
>>     -roger
>>     --
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>>
>>
>>
>> -- 
>> BR,
>> Peter Chen
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