Re: [RFC][PATCH 3/9] usb: otg: add OTG core

[Roger Quadros <rogerq-l0cyMroinI0@public.gmane.org>]

On 19/03/15 05:40, Peter Chen wrote:
> On Wed, Mar 18, 2015 at 03:55:57PM +0200, Roger Quadros wrote:
>> The OTG core instantiates the OTG Finite State Machine
>> per OTG controller and manages starting/stopping the
>> host and gadget controllers based on the bus state.
>>
>> It provides APIs for the following tasks
>>
>> - Registering an OTG capable controller
>> - Registering Host and Gadget controllers to OTG core
>> - Providing inputs to and kicking the OTG state machine
>>
>> TODO:
>> - sysfs interface to allow application inputs to OTG state machine
>> - otg class?
>>
>> Signed-off-by: Roger Quadros <rogerq-l0cyMroinI0@public.gmane.org>
>> ---
>>  drivers/usb/Makefile         |   1 +
>>  drivers/usb/common/Makefile  |   1 +
>>  drivers/usb/common/usb-otg.c | 732 +++++++++++++++++++++++++++++++++++++++++++
>>  drivers/usb/common/usb-otg.h |  71 +++++
>>  drivers/usb/core/Kconfig     |   8 +
>>  include/linux/usb/usb-otg.h  |  86 +++++
>>  6 files changed, 899 insertions(+)
>>  create mode 100644 drivers/usb/common/usb-otg.c
>>  create mode 100644 drivers/usb/common/usb-otg.h
>>  create mode 100644 include/linux/usb/usb-otg.h
>>
>> diff --git a/drivers/usb/Makefile b/drivers/usb/Makefile
>> index 2f1e2aa..07f59a5 100644
>> --- a/drivers/usb/Makefile
>> +++ b/drivers/usb/Makefile
>> @@ -60,5 +60,6 @@ obj-$(CONFIG_USB_RENESAS_USBHS)	+= renesas_usbhs/
>>  obj-$(CONFIG_USB_GADGET)	+= gadget/
>>  
>>  obj-$(CONFIG_USB_COMMON)	+= common/
>> +obj-$(CONFIG_USB_OTG_CORE)	+= common/
>>  
>>  obj-$(CONFIG_USBIP_CORE)	+= usbip/
>> diff --git a/drivers/usb/common/Makefile b/drivers/usb/common/Makefile
>> index ca2f8bd..573fc75 100644
>> --- a/drivers/usb/common/Makefile
>> +++ b/drivers/usb/common/Makefile
>> @@ -7,3 +7,4 @@ usb-common-y			  += common.o
>>  usb-common-$(CONFIG_USB_LED_TRIG) += led.o
>>  
>>  obj-$(CONFIG_USB_OTG_FSM) += usb-otg-fsm.o
>> +obj-$(CONFIG_USB_OTG_CORE) += usb-otg.o
>> diff --git a/drivers/usb/common/usb-otg.c b/drivers/usb/common/usb-otg.c
>> new file mode 100644
>> index 0000000..1433fc9
>> --- /dev/null
>> +++ b/drivers/usb/common/usb-otg.c
>> @@ -0,0 +1,732 @@
>> +/**
>> + * drivers/usb/common/usb-otg.c - USB OTG core
>> + *
>> + * Copyright (C) 2015 Texas Instruments Incorporated - http://www.ti.com
>> + * Author: Roger Quadros <rogerq-l0cyMroinI0@public.gmane.org>
>> + *
>> + * This program is free software; you can redistribute it and/or modify
>> + * it under the terms of the GNU General Public License version 2 as
>> + * published by the Free Software Foundation.
>> + *
>> + * This program is distributed in the hope that it will be useful,
>> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
>> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
>> + * GNU General Public License for more details.
>> + */
>> +
>> +#include <linux/kernel.h>
>> +#include <linux/list.h>
>> +#include <linux/timer.h>
>> +#include <linux/usb/otg.h>
>> +#include <linux/usb/phy.h>	/* enum usb_otg_state */
>> +#include <linux/usb/gadget.h>
>> +#include <linux/usb/usb-otg.h>
>> +#include <linux/workqueue.h>
>> +
>> +#include "usb-otg.h"
>> +
>> +/* to link timer with callback data */
>> +struct otg_timer {
>> +	struct timer_list timer;
>> +	/* callback data */
>> +	int *timeout_bit;
>> +	struct otg_data *otgd;
>> +};
>> +
>> +struct otg_data {
>> +	struct device *dev;	/* HCD & GCD's parent device */
>> +
>> +	struct otg_fsm fsm;
>> +	/* HCD, GCD and usb_otg_state are present in otg_fsm->otg
>> +	 * HCD is bus_to_hcd(fsm->otg->host)
>> +	 * GCD is fsm->otg->gadget
>> +	 */
>> +	struct otg_fsm_ops fsm_ops;	/* private copy for override */
>> +	struct usb_otg otg;
>> +	struct usb_hcd *shared_hcd;	/* if shared HCD registered */
>> +
>> +	/* saved hooks to OTG device */
>> +	int (*start_host)(struct otg_fsm *fsm, int on);
>> +	int (*start_gadget)(struct otg_fsm *fsm, int on);
>> +
>> +	struct list_head list;
>> +
>> +	struct work_struct work;	/* OTG FSM work */
>> +	struct workqueue_struct *wq;
>> +
>> +	struct otg_timer timers[NUM_OTG_FSM_TIMERS];
>> +
>> +	bool fsm_running;
>> +	bool gadget_can_start;		/* OTG FSM says gadget can start */
>> +	bool host_can_start;		/* OTG FSM says host can start */
>> +
>> +	/* use otg->fsm.lock for serializing access */
>> +};
> 
> What's the relationship between struct usb_otg otg and this one?

Did you mean why struct usb_otg otg is there in struct otg_data?
Just for easy allocation. fsm_ops only contains the pointer to struct usb_otg.

> 
>> +
>> +/* OTG device list */
>> +LIST_HEAD(otg_list);
>> +static DEFINE_MUTEX(otg_list_mutex);
>> +
>> +/**
>> + * check if device is in our OTG list and return
>> + * otg_data, else NULL.
>> + *
>> + * otg_list_mutex must be held.
>> + */
>> +static struct otg_data *usb_otg_device_get_otgd(struct device *parent_dev)
>> +{
>> +	struct otg_data *otgd;
>> +
>> +	list_for_each_entry(otgd, &otg_list, list) {
>> +		if (otgd->dev == parent_dev)
>> +			return otgd;
>> +	}
>> +
>> +	return NULL;
>> +}
>> +
>> +/**
>> + * timer callback to set timeout bit and kick FSM
>> + */
>> +static void set_tmout(unsigned long data)
>> +{
>> +	struct otg_timer *tmr_data;
>> +
>> +	tmr_data = (struct otg_timer *)data;
>> +
>> +	if (tmr_data->timeout_bit)
>> +		*tmr_data->timeout_bit = 1;
>> +
>> +	usb_otg_sync_inputs(&tmr_data->otgd->fsm);
>> +}
>> +
>> +/**
>> + * Initialize one OTG timer with callback, timeout and timeout bit
>> + */
>> +static void otg_timer_init(enum otg_fsm_timer id, struct otg_data *otgd,
>> +			   void (*callback)(unsigned long),
>> +			   unsigned long expires_ms,
>> +			   int *timeout_bit)
>> +{
>> +	struct otg_timer *otgtimer = &otgd->timers[id];
>> +	struct timer_list *timer = &otgtimer->timer;
>> +
>> +	init_timer(timer);
>> +	timer->function = callback;
>> +	timer->expires = jiffies + msecs_to_jiffies(expires_ms);
>> +	timer->data = (unsigned long)otgtimer;
>> +
> 
> The timer for TB_DATA_PLS is about 10ms or less, it is not suitable
> for using kernel timer, hrtimer is suitable choice.

good catch. I will switch to hrtimer then.

> 
>> +	otgtimer->timeout_bit = timeout_bit;
>> +	otgtimer->otgd = otgd;
>> +}
>> +
>> +/**
>> + * Initialize standard OTG timers
>> + */
>> +static void usb_otg_init_timers(struct otg_data *otgd)
>> +{
>> +	struct otg_fsm *fsm = &otgd->fsm;
>> +
>> +	otg_timer_init(A_WAIT_VRISE, otgd, set_tmout, TA_WAIT_VRISE, &fsm->a_wait_vrise_tmout);
>> +	otg_timer_init(A_WAIT_VFALL, otgd, set_tmout, TA_WAIT_VFALL, &fsm->a_wait_vfall_tmout);
>> +	otg_timer_init(A_WAIT_BCON, otgd, set_tmout, TA_WAIT_BCON, &fsm->a_wait_bcon_tmout);
>> +	otg_timer_init(A_AIDL_BDIS, otgd, set_tmout, TA_AIDL_BDIS, &fsm->a_aidl_bdis_tmout);
>> +	otg_timer_init(A_BIDL_ADIS, otgd, set_tmout, TA_BIDL_ADIS, &fsm->a_bidl_adis_tmout);
>> +	otg_timer_init(B_ASE0_BRST, otgd, set_tmout, TB_ASE0_BRST, &fsm->b_ase0_brst_tmout);
>> +
>> +	otg_timer_init(B_SE0_SRP, otgd, set_tmout, TB_SE0_SRP, &fsm->b_se0_srp);
>> +	otg_timer_init(B_SRP_FAIL, otgd, set_tmout, TB_SRP_FAIL, &fsm->b_srp_done);
>> +
>> +	otg_timer_init(A_WAIT_ENUM, otgd, set_tmout, TB_SRP_FAIL, NULL);
>> +}

<snip>

cheers,
-roger

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