Peter Chen <peter.c...@freescale.com> writes:

> The main design flow is the same with msm otg driver, that is the id and
> vbus interrupt are handled at core driver, others are handled by
> individual drivers.
>
> - At former design, when switch usb role from device->host, it will call
> udc_stop, it will remove the gadget driver, so when switch role
> from host->device, it can't add gadget driver any more.
> At new design, when role switch occurs, the gadget just calls
> usb_gadget_vbus_disconnect/usb_gadget_vbus_connect as well as
> reset controller, it will not free any device/gadget structure
>
> - Add vbus connect and disconnect to core interrupt handler, it can
> notify udc driver by calling usb_gadget_vbus_disconnect
> /usb_gadget_vbus_connect.
>
> Signed-off-by: Peter Chen <peter.c...@freescale.com>

A few comments below.

> ---
>  drivers/usb/chipidea/bits.h |   10 +++
>  drivers/usb/chipidea/ci.h   |    8 ++-
>  drivers/usb/chipidea/core.c |  177 ++++++++++++++++++++++++++++++++++++++----
>  drivers/usb/chipidea/otg.c  |   28 +++++---
>  drivers/usb/chipidea/otg.h  |    3 +
>  drivers/usb/chipidea/udc.c  |    2 +
>  6 files changed, 200 insertions(+), 28 deletions(-)
>
> diff --git a/drivers/usb/chipidea/bits.h b/drivers/usb/chipidea/bits.h
> index 050de85..ba9c6ef 100644
> --- a/drivers/usb/chipidea/bits.h
> +++ b/drivers/usb/chipidea/bits.h
> @@ -65,11 +65,21 @@
>  #define OTGSC_ASVIS        BIT(18)
>  #define OTGSC_BSVIS        BIT(19)
>  #define OTGSC_BSEIS        BIT(20)
> +#define OTGSC_1MSIS        BIT(21)
> +#define OTGSC_DPIS         BIT(22)
>  #define OTGSC_IDIE         BIT(24)
>  #define OTGSC_AVVIE        BIT(25)
>  #define OTGSC_ASVIE        BIT(26)
>  #define OTGSC_BSVIE        BIT(27)
>  #define OTGSC_BSEIE        BIT(28)
> +#define OTGSC_1MSIE        BIT(29)
> +#define OTGSC_DPIE         BIT(30)
> +#define OTGSC_INT_EN_BITS    (OTGSC_IDIE | OTGSC_AVVIE | OTGSC_ASVIE \
> +                             | OTGSC_BSVIE | OTGSC_BSEIE | OTGSC_1MSIE \
> +                             | OTGSC_DPIE)
> +#define OTGSC_INT_STATUS_BITS        (OTGSC_IDIS | OTGSC_AVVIS | OTGSC_ASVIS 
> \
> +                             | OTGSC_BSVIS | OTGSC_BSEIS | OTGSC_1MSIS \
> +                             | OTGSC_DPIS)
>  
>  /* USBMODE */
>  #define USBMODE_CM            (0x03UL <<  0)
> diff --git a/drivers/usb/chipidea/ci.h b/drivers/usb/chipidea/ci.h
> index 8702871..325d790 100644
> --- a/drivers/usb/chipidea/ci.h
> +++ b/drivers/usb/chipidea/ci.h
> @@ -130,6 +130,7 @@ struct hw_bank {
>   * @transceiver: pointer to USB PHY, if any
>   * @hcd: pointer to usb_hcd for ehci host driver
>   * @otg: for otg support
> + * @events: events for otg, and handled at ci_role_work
>   */
>  struct ci13xxx {
>       struct device                   *dev;
> @@ -140,6 +141,7 @@ struct ci13xxx {
>       enum ci_role                    role;
>       bool                            is_otg;
>       struct work_struct              work;
> +     struct delayed_work             dwork;
>       struct workqueue_struct         *wq;
>  
>       struct dma_pool                 *qh_pool;
> @@ -165,7 +167,9 @@ struct ci13xxx {
>       bool                            global_phy;
>       struct usb_phy                  *transceiver;
>       struct usb_hcd                  *hcd;
> -     struct usb_otg      otg;
> +     struct usb_otg                  otg;
> +     bool                            id_event;
> +     bool                            b_sess_valid_event;
>  };
>  
>  static inline struct ci_role_driver *ci_role(struct ci13xxx *ci)
> @@ -314,4 +318,6 @@ int hw_port_test_set(struct ci13xxx *ci, u8 mode);
>  
>  u8 hw_port_test_get(struct ci13xxx *ci);
>  
> +void ci_handle_vbus_change(struct ci13xxx *ci);
> +
>  #endif       /* __DRIVERS_USB_CHIPIDEA_CI_H */
> diff --git a/drivers/usb/chipidea/core.c b/drivers/usb/chipidea/core.c
> index aebf695..f8f8484 100644
> --- a/drivers/usb/chipidea/core.c
> +++ b/drivers/usb/chipidea/core.c
> @@ -73,6 +73,7 @@
>  #include "bits.h"
>  #include "host.h"
>  #include "debug.h"
> +#include "otg.h"
>  
>  /* Controller register map */
>  static uintptr_t ci_regs_nolpm[] = {
> @@ -199,6 +200,14 @@ static int hw_device_init(struct ci13xxx *ci, void 
> __iomem *base)
>       if (ci->hw_ep_max > ENDPT_MAX)
>               return -ENODEV;
>  
> +     /* Disable all interrupts bits */
> +     hw_write(ci, OP_USBINTR, 0xffffffff, 0);
> +     ci_disable_otg_interrupt(ci, OTGSC_INT_EN_BITS);
> +
> +     /* Clear all interrupts status bits*/
> +     hw_write(ci, OP_USBSTS, 0xffffffff, 0xffffffff);
> +     ci_clear_otg_interrupt(ci, OTGSC_INT_STATUS_BITS);
> +
>       dev_dbg(ci->dev, "ChipIdea HDRC found, lpm: %d; cap: %p op: %p\n",
>               ci->hw_bank.lpm, ci->hw_bank.cap, ci->hw_bank.op);
>  
> @@ -265,24 +274,124 @@ static enum ci_role ci_otg_role(struct ci13xxx *ci)
>  }
>  
>  /**
> - * ci_role_work - perform role changing based on ID pin
> - * @work: work struct
> + * hw_wait_reg: wait the register value
> + *
> + * Sometimes, it needs to wait register value before going on.
> + * Eg, when switch to device mode, the vbus value should be lower
> + * than OTGSC_BSV before connects to host.
> + *
> + * @ci: the controller
> + * @reg: register index
> + * @mask: mast bit
> + * @value: the bit value to wait
> + * @timeout: timeout to indicate an error
> + *
> + * This function returns an error code if timeout
>   */
> -static void ci_role_work(struct work_struct *work)
> +static int hw_wait_reg(struct ci13xxx *ci, enum ci13xxx_regs reg, u32 mask,
> +                             u32 value, unsigned long timeout)
> +{
> +     unsigned long elapse = jiffies + timeout;
> +
> +     while (hw_read(ci, reg, mask) != value) {
> +             if (time_after(jiffies, elapse)) {
> +                     dev_err(ci->dev, "timeout waiting for %08x in %d\n",
> +                                     mask, reg);
> +                     return -ETIMEDOUT;
> +             }
> +             msleep(20);
> +     }
> +
> +     return 0;
> +}
> +
> +#define CI_VBUS_STABLE_TIMEOUT 500
> +static void ci_handle_id_switch(struct ci13xxx *ci)
>  {
> -     struct ci13xxx *ci = container_of(work, struct ci13xxx, work);
>       enum ci_role role = ci_otg_role(ci);
>  
>       if (role != ci->role) {
>               dev_dbg(ci->dev, "switching from %s to %s\n",
>                       ci_role(ci)->name, ci->roles[role]->name);
>  
> -             ci_role_stop(ci);
> -             ci_role_start(ci, role);
> -             enable_irq(ci->irq);
> +             /* 1. Finish the current role */
> +             if (ci->role == CI_ROLE_GADGET) {
> +                     usb_gadget_vbus_disconnect(&ci->gadget);
> +                     /* host doesn't care B_SESSION_VALID event */
> +                     ci_clear_otg_interrupt(ci, OTGSC_BSVIS);
> +                     ci_disable_otg_interrupt(ci, OTGSC_BSVIE);
> +                     ci->role = CI_ROLE_END;
> +                     /* reset controller */
> +                     hw_device_reset(ci, USBMODE_CM_IDLE);
> +             } else if (ci->role == CI_ROLE_HOST) {
> +                     ci_role_stop(ci);
> +                     /* reset controller */
> +                     hw_device_reset(ci, USBMODE_CM_IDLE);
> +             }
> +
> +             /* 2. Turn on/off vbus according to coming role */
> +             if (ci_otg_role(ci) == CI_ROLE_GADGET) {
> +                     otg_set_vbus(&ci->otg, false);
> +                     /* wait vbus lower than OTGSC_BSV */
> +                     hw_wait_reg(ci, OP_OTGSC, OTGSC_BSV, 0,
> +                                     CI_VBUS_STABLE_TIMEOUT);
> +             } else if (ci_otg_role(ci) == CI_ROLE_HOST) {
> +                     otg_set_vbus(&ci->otg, true);
> +                     /* wait vbus higher than OTGSC_AVV */
> +                     hw_wait_reg(ci, OP_OTGSC, OTGSC_AVV, OTGSC_AVV,
> +                                     CI_VBUS_STABLE_TIMEOUT);
> +             }
> +
> +             /* 3. Begin the new role */
> +             if (ci_otg_role(ci) == CI_ROLE_GADGET) {
> +                     ci->role = role;
> +                     ci_clear_otg_interrupt(ci, OTGSC_BSVIS);
> +                     ci_enable_otg_interrupt(ci, OTGSC_BSVIE);
> +             } else if (ci_otg_role(ci) == CI_ROLE_HOST) {
> +                     ci_role_start(ci, role);
> +             }
>       }
>  }
>  
> +void ci_handle_vbus_change(struct ci13xxx *ci)
> +{
> +     u32 otgsc = hw_read(ci, OP_OTGSC, ~0);
> +
> +     if (otgsc & OTGSC_BSV)
> +             usb_gadget_vbus_connect(&ci->gadget);
> +     else
> +             usb_gadget_vbus_disconnect(&ci->gadget);
> +}
> +
> +/**
> + * ci_otg_work - perform otg (vbus/id) event handle
> + * @work: work struct
> + */
> +static void ci_otg_work(struct work_struct *work)
> +{
> +     struct ci13xxx *ci = container_of(work, struct ci13xxx, work);
> +
> +     if (ci->id_event) {
> +             ci->id_event = false;
> +             ci_handle_id_switch(ci);
> +     } else if (ci->b_sess_valid_event) {
> +             ci->b_sess_valid_event = false;
> +             ci_handle_vbus_change(ci);
> +     } else
> +             dev_err(ci->dev, "unexpected event occurs at %s\n", __func__);
> +
> +     enable_irq(ci->irq);
> +}
> +
> +static void ci_delayed_work(struct work_struct *work)
> +{
> +     struct delayed_work *dwork = to_delayed_work(work);
> +     struct ci13xxx *ci = container_of(dwork, struct ci13xxx, dwork);
> +
> +     otg_set_vbus(&ci->otg, true);
> +
> +}
> +
>  static ssize_t show_role(struct device *dev, struct device_attribute *attr,
>                        char *buf)
>  {
> @@ -321,19 +430,36 @@ static irqreturn_t ci_irq(int irq, void *data)
>       irqreturn_t ret = IRQ_NONE;
>       u32 otgsc = 0;
>  
> -     if (ci->is_otg)
> -             otgsc = hw_read(ci, OP_OTGSC, ~0);
> +     otgsc = hw_read(ci, OP_OTGSC, ~0);

My spec says that in non-otg implementations OTGSC is reserved. We
probably shouldn't try any of this for such devices.

>  
> -     if (ci->role != CI_ROLE_END)
> -             ret = ci_role(ci)->irq(ci);
> +     /*
> +      * Handle id change interrupt, it indicates device/host function
> +      * switch.
> +      */
> +     if (ci->is_otg && (otgsc & OTGSC_IDIE) && (otgsc & OTGSC_IDIS)) {
> +             ci->id_event = true;
> +             ci_clear_otg_interrupt(ci, OTGSC_IDIS);
> +             disable_irq_nosync(ci->irq);
> +             queue_work(ci->wq, &ci->work);
> +             return IRQ_HANDLED;
> +     }
>  
> -     if (ci->is_otg && (otgsc & OTGSC_IDIS)) {
> -             hw_write(ci, OP_OTGSC, OTGSC_IDIS, OTGSC_IDIS);
> +     /*
> +      * Handle vbus change interrupt, it indicates device connection
> +      * and disconnection events.
> +      */
> +     if ((otgsc & OTGSC_BSVIE) && (otgsc & OTGSC_BSVIS)) {
> +             ci->b_sess_valid_event = true;
> +             ci_clear_otg_interrupt(ci, OTGSC_BSVIS);
>               disable_irq_nosync(ci->irq);
>               queue_work(ci->wq, &ci->work);
> -             ret = IRQ_HANDLED;
> +             return IRQ_HANDLED;
>       }
>  
> +     /* Handle device/host interrupt */
> +     if (ci->role != CI_ROLE_END)
> +             ret = ci_role(ci)->irq(ci);
> +
>       return ret;
>  }
>  
> @@ -398,6 +524,7 @@ static int ci_hdrc_probe(struct platform_device *pdev)
>       struct resource *res;
>       void __iomem    *base;
>       int             ret;
> +     u32             otgsc;
>  
>       if (!dev->platform_data) {
>               dev_err(dev, "platform data missing\n");
> @@ -443,7 +570,8 @@ static int ci_hdrc_probe(struct platform_device *pdev)
>               return -ENODEV;
>       }
>  
> -     INIT_WORK(&ci->work, ci_role_work);
> +     INIT_WORK(&ci->work, ci_otg_work);
> +     INIT_DELAYED_WORK(&ci->dwork, ci_delayed_work);
>       ci->wq = create_singlethread_workqueue("ci_otg");
>       if (!ci->wq) {
>               dev_err(dev, "can't create workqueue\n");
> @@ -466,7 +594,10 @@ static int ci_hdrc_probe(struct platform_device *pdev)
>       }
>  
>       if (ci->roles[CI_ROLE_HOST] && ci->roles[CI_ROLE_GADGET]) {
> +             dev_dbg(dev, "support otg\n");
>               ci->is_otg = true;
> +             /* if otg is supported, create struct usb_otg */
> +             ci_hdrc_otg_init(ci);
>               /* ID pin needs 1ms debouce time, we delay 2ms for safe */
>               mdelay(2);
>               ci->role = ci_otg_role(ci);
> @@ -483,6 +614,17 @@ static int ci_hdrc_probe(struct platform_device *pdev)
>               goto rm_wq;
>       }
>  
> +     otgsc = hw_read(ci, OP_OTGSC, ~0);
> +     /*
> +      * if it is device mode:
> +      * - Enable vbus detect
> +      * - If it has already connected to host, notify udc
> +      */
> +     if (ci->role == CI_ROLE_GADGET) {
> +             ci_enable_otg_interrupt(ci, OTGSC_BSVIE);

We should only do this for otg capable devices, otherwise OTGSC is
reserved.

> +             ci_handle_vbus_change(ci);

Shouldn't this be part of the gadget role start like I suggested a
couple of months back? Maybe ci_enable_otg_interrupt() can go there too.

> +     }
> +
>       platform_set_drvdata(pdev, ci);
>       ret = request_irq(ci->irq, ci_irq, IRQF_SHARED, ci->platdata->name,
>                         ci);
> @@ -493,8 +635,9 @@ static int ci_hdrc_probe(struct platform_device *pdev)
>       if (ret)
>               goto rm_attr;
>  
> -     if (ci->is_otg)
> -             hw_write(ci, OP_OTGSC, OTGSC_IDIE, OTGSC_IDIE);
> +     /* Handle the situation that usb device at the MicroB to A cable */
> +     if (ci->is_otg && !(otgsc & OTGSC_ID))
> +             queue_delayed_work(ci->wq, &ci->dwork, msecs_to_jiffies(500));
>  
>       return ret;
>  
> diff --git a/drivers/usb/chipidea/otg.c b/drivers/usb/chipidea/otg.c
> index 7dea3b3..2986d91 100644
> --- a/drivers/usb/chipidea/otg.c
> +++ b/drivers/usb/chipidea/otg.c
> @@ -10,21 +10,28 @@
>   * published by the Free Software Foundation.
>   */
>  
> -#include <linux/platform_device.h>
> -#include <linux/module.h>
> -#include <linux/io.h>
> -#include <linux/irq.h>
> -#include <linux/kernel.h>
> -#include <linux/slab.h>
> -#include <linux/usb/gadget.h>
>  #include <linux/usb/otg.h>
> +#include <linux/usb/gadget.h>
>  #include <linux/usb/chipidea.h>
>  
>  #include "ci.h"
> -#include "udc.h"
>  #include "bits.h"
> -#include "host.h"
> -#include "debug.h"
> +
> +void ci_clear_otg_interrupt(struct ci13xxx *ci, u32 bits)
> +{
> +     /* Only clear request bits */
> +     hw_write(ci, OP_OTGSC, OTGSC_INT_STATUS_BITS, bits);
> +}
> +
> +void ci_enable_otg_interrupt(struct ci13xxx *ci, u32 bits)
> +{
> +     hw_write(ci, OP_OTGSC, bits, bits);
> +}
> +
> +void ci_disable_otg_interrupt(struct ci13xxx *ci, u32 bits)
> +{
> +     hw_write(ci, OP_OTGSC, bits, 0);
> +}
>  
>  static int ci_otg_set_peripheral(struct usb_otg *otg,
>               struct usb_gadget *periph)
> @@ -55,6 +62,7 @@ int ci_hdrc_otg_init(struct ci13xxx *ci)
>       ci->otg.set_host = ci_otg_set_host;
>       if (!IS_ERR_OR_NULL(ci->transceiver))
>               ci->transceiver->otg = &ci->otg;
> +     ci_enable_otg_interrupt(ci, OTGSC_IDIE);
>  
>       return 0;
>  }
> diff --git a/drivers/usb/chipidea/otg.h b/drivers/usb/chipidea/otg.h
> index b4c6b3e..fa30428 100644
> --- a/drivers/usb/chipidea/otg.h
> +++ b/drivers/usb/chipidea/otg.h
> @@ -2,5 +2,8 @@
>  #define __DRIVERS_USB_CHIPIDEA_OTG_H
>  
>  int ci_hdrc_otg_init(struct ci13xxx *ci);
> +void ci_clear_otg_interrupt(struct ci13xxx *ci, u32 bits);
> +void ci_enable_otg_interrupt(struct ci13xxx *ci, u32 bits);
> +void ci_disable_otg_interrupt(struct ci13xxx *ci, u32 bits);
>  
>  #endif /* __DRIVERS_USB_CHIPIDEA_OTG_H */
> diff --git a/drivers/usb/chipidea/udc.c b/drivers/usb/chipidea/udc.c
> index d214448..83e54bb 100644
> --- a/drivers/usb/chipidea/udc.c
> +++ b/drivers/usb/chipidea/udc.c
> @@ -1371,6 +1371,7 @@ static int ci13xxx_vbus_session(struct usb_gadget 
> *_gadget, int is_active)
>                       pm_runtime_get_sync(&_gadget->dev);
>                       hw_device_reset(ci, USBMODE_CM_DC);
>                       hw_device_state(ci, ci->ep0out->qh.dma);
> +                     dev_dbg(ci->dev, "Connected to host\n");
>               } else {
>                       hw_device_state(ci, 0);
>                       if (ci->platdata->notify_event)
> @@ -1378,6 +1379,7 @@ static int ci13xxx_vbus_session(struct usb_gadget 
> *_gadget, int is_active)
>                               CI13XXX_CONTROLLER_STOPPED_EVENT);
>                       _gadget_stop_activity(&ci->gadget);
>                       pm_runtime_put_sync(&_gadget->dev);
> +                     dev_dbg(ci->dev, "Disconnected from host\n");
>               }
>       }
>  
> -- 
> 1.7.0.4
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