RE: [RFC PATCH v2 11/15] usb:cdns3: Implements ISR functionality.

[Pawel Laszczak <pawell@cadence.com>]

>Hi,
>
>>> Patch adds set of generic functions used for handling interrupts
>>> generated by controller. Interrupt related functions are divided
>>> into three groups. The first is related to ep0 and is placed in ep0.c.
>>> The second is responsible for non-default endpoints and is
>>> implemented in gadget.c file. The last group is not related to
>>> endpoints interrupts and is placed in gadget.c.
>>> All groups have common entry point in cdns3_irq_handler_thread function.
>>>
>>> Signed-off-by: Pawel Laszczak <pawell@cadence.com>
>>> ---
>>>  drivers/usb/cdns3/ep0.c    |  63 +++++++++++
>>>  drivers/usb/cdns3/gadget.c | 224 ++++++++++++++++++++++++++++++++++++-
>>>  drivers/usb/cdns3/gadget.h |   1 +
>>>  3 files changed, 287 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/drivers/usb/cdns3/ep0.c b/drivers/usb/cdns3/ep0.c
>>> index d05169e73631..eb92fd234bd7 100644
>>> --- a/drivers/usb/cdns3/ep0.c
>>> +++ b/drivers/usb/cdns3/ep0.c
>>> @@ -90,6 +90,69 @@ static void cdns3_set_hw_configuration(struct cdns3_device *priv_dev)
>>>  	}
>>>  }
>>>
>>> +static void __pending_setup_status_handler(struct cdns3_device *priv_dev)
>>> +{
>>> +	//TODO: Implements this function
>>> +}
>>> +
>>> +/**
>>> + * cdns3_ep0_setup_phase - Handling setup USB requests
>>> + * @priv_dev: extended gadget object
>>> + */
>>> +static void cdns3_ep0_setup_phase(struct cdns3_device *priv_dev)
>>> +{
>>> +	//TODO: Implements this function.
>>> +}
>>> +
>>> +static void cdns3_transfer_completed(struct cdns3_device *priv_dev)
>>> +{
>>> +	//TODO: Implements this function
>>> +}
>>> +
>>> +/**
>>> + * cdns3_check_ep0_interrupt_proceed - Processes interrupt related to endpoint 0
>>> + * @priv_dev: extended gadget object
>>> + * @dir: 1 for IN direction, 0 for OUT direction
>>> + */
>>> +void cdns3_check_ep0_interrupt_proceed(struct cdns3_device *priv_dev, int dir)
>>> +{
>>> +	struct cdns3_usb_regs __iomem *regs = priv_dev->regs;
>>> +	u32 ep_sts_reg;
>>> +
>>> +	cdns3_select_ep(priv_dev, 0 | (dir ? USB_DIR_IN : USB_DIR_OUT));
>>> +	ep_sts_reg = readl(&regs->ep_sts);
>>> +
>>> +	__pending_setup_status_handler(priv_dev);
>>> +
>>> +	if ((ep_sts_reg & EP_STS_SETUP) && dir == 0) {
>>> +		struct usb_ctrlrequest *setup = priv_dev->setup;
>>> +
>>> +		writel(EP_STS_SETUP | EP_STS_IOC | EP_STS_ISP, &regs->ep_sts);
>>
>>instead you can just clear all events at the end of this function by
>>	writel(ep_sts_reg, &regs->ep_sts);
>
>But I can delete events that can appear during processing this function.
>I think that safer is to add this fragment at the beginning, below line
>ep_sts_reg = readl(&regs->ep_sts);
>
>
>>> +
>>> +		priv_dev->ep0_data_dir = setup->bRequestType & USB_DIR_IN;
>>> +		cdns3_ep0_setup_phase(priv_dev);
>>> +		ep_sts_reg &= ~(EP_STS_SETUP | EP_STS_IOC | EP_STS_ISP);
>>
>>Not required.
>Why not ? I must clear at least EP_STS_IOC | EP_STS_ISP.
>I don't want to handle  the last condition in this function, of course if SETUP was reported.
>
>Of course I can also change the construction of function and then I could delete this statement.
>>
>>> +	}
>>> +
>>> +	if (ep_sts_reg & EP_STS_TRBERR)
>>> +		writel(EP_STS_TRBERR, &priv_dev->regs->ep_sts);
>>
>>Can be omitted.
>>> +
>>> +	if (ep_sts_reg & EP_STS_DESCMIS) {
>>> +		writel(EP_STS_DESCMIS, &priv_dev->regs->ep_sts);
>>
>>This as well.
>>> +
>>> +		if (dir == 0 && !priv_dev->setup_pending) {
>>> +			priv_dev->ep0_data_dir = 0;
>>> +			cdns3_ep0_run_transfer(priv_dev, priv_dev->setup_dma,
>>> +					       8, 0);
>>> +		}
>>> +	}
>>> +
>>> +	if ((ep_sts_reg & EP_STS_IOC) || (ep_sts_reg & EP_STS_ISP)) {
>>> +		writel(EP_STS_IOC, &priv_dev->regs->ep_sts);
>>
>>this write can be omitted.
>>> +		cdns3_transfer_completed(priv_dev);
>>> +	}
>>
>>here you can do
>>	writel(ep_sts_reg, &regs->ep_sts);
>>> +}
>>> +
>>>  /**
>>>   * cdns3_gadget_ep0_enable
>>>   * Function shouldn't be called by gadget driver,
>>> diff --git a/drivers/usb/cdns3/gadget.c b/drivers/usb/cdns3/gadget.c
>>> index c965da16c0c8..309202474e57 100644
>>> --- a/drivers/usb/cdns3/gadget.c
>>> +++ b/drivers/usb/cdns3/gadget.c
>>> @@ -58,6 +58,18 @@ void cdns3_set_register_bit(void __iomem *ptr, u32 mask)
>>>  	writel(mask, ptr);
>>>  }
>>>
>>> +/**
>>> + * cdns3_ep_reg_pos_to_index - Macro converts bit position of ep_ists register
>>> + * to index of endpoint object in cdns3_device.eps[] container
>>> + * @i: bit position of endpoint for which endpoint object is required
>>> + *
>>> + * Remember that endpoint container doesn't contain default endpoint
>>> + */
>>> +static u8 cdns3_ep_reg_pos_to_index(int i)
>>> +{
>>> +	return ((i / 16) + (((i % 16) - 2) * 2));
>>> +}
>>> +
>>>  /**
>>>   * cdns3_next_request - returns next request from list
>>>   * @list: list containing requests
>>> @@ -188,6 +200,21 @@ static void cdns3_ep_stall_flush(struct cdns3_endpoint *priv_ep)
>>>  	priv_ep->flags |= EP_STALL;
>>>  }
>>>
>>> +/**
>>> + * cdns3_gadget_unconfig - reset device configuration
>>> + * @priv_dev: extended gadget object
>>> + */
>>> +void cdns3_gadget_unconfig(struct cdns3_device *priv_dev)
>>> +{
>>> +	/* RESET CONFIGURATION */
>>> +	writel(USB_CONF_CFGRST, &priv_dev->regs->usb_conf);
>>> +
>>> +	cdns3_enable_l1(priv_dev, 0);
>>> +	priv_dev->hw_configured_flag = 0;
>>> +	priv_dev->onchip_mem_allocated_size = 0;
>>> +	priv_dev->out_mem_is_allocated = 0;
>>> +}
>>> +
>>>  void cdns3_enable_l1(struct cdns3_device *priv_dev, int enable)
>>>  {
>>>  	if (enable)
>>> @@ -196,6 +223,23 @@ void cdns3_enable_l1(struct cdns3_device *priv_dev, int enable)
>>>  		writel(USB_CONF_L1DS, &priv_dev->regs->usb_conf);
>>>  }
>>>
>>> +static enum usb_device_speed cdns3_get_speed(struct cdns3_device *priv_dev)
>>> +{
>>> +	u32 reg;
>>> +
>>> +	reg = readl(&priv_dev->regs->usb_sts);
>>> +
>>> +	if (DEV_SUPERSPEED(reg))
>>> +		return USB_SPEED_SUPER;
>>> +	else if (DEV_HIGHSPEED(reg))
>>> +		return USB_SPEED_HIGH;
>>> +	else if (DEV_FULLSPEED(reg))
>>> +		return USB_SPEED_FULL;
>>> +	else if (DEV_LOWSPEED(reg))
>>> +		return USB_SPEED_LOW;
>>> +	return USB_SPEED_UNKNOWN;
>>> +}
>>> +
>>>  /**
>>>   * cdns3_gadget_giveback - call struct usb_request's ->complete callback
>>>   * @priv_ep: The endpoint to whom the request belongs to
>>> @@ -221,12 +265,136 @@ void cdns3_gadget_giveback(struct cdns3_endpoint *priv_ep,
>>>   */
>>>  int cdns3_ep_run_transfer(struct cdns3_endpoint *priv_ep,
>>>  			  struct usb_request *request)
>>> +{
>>> +	return 0;
>>> +}
>>> +
>>> +static void cdns3_transfer_completed(struct cdns3_device *priv_dev,
>>> +				     struct cdns3_endpoint *priv_ep)
>>>  {
>>>  	//TODO: Implements this function.
>>> +}
>>> +
>>> +/**
>>> + * cdns3_check_ep_interrupt_proceed - Processes interrupt related to endpoint
>>> + * @priv_ep: endpoint object
>>> + *
>>> + * Returns 0
>>> + */
>>> +static int cdns3_check_ep_interrupt_proceed(struct cdns3_endpoint *priv_ep)
>>> +{
>>> +	struct cdns3_device *priv_dev = priv_ep->cdns3_dev;
>>> +	struct cdns3_usb_regs __iomem *regs;
>>> +	u32 ep_sts_reg;
>>> +
>>> +	regs = priv_dev->regs;
>>> +
>>> +	cdns3_select_ep(priv_dev, priv_ep->endpoint.address);
>>> +	ep_sts_reg = readl(&regs->ep_sts);
>>> +
>>> +	if (ep_sts_reg & EP_STS_TRBERR)
>>> +		writel(EP_STS_TRBERR, &regs->ep_sts);
>>> +
>>> +	if (ep_sts_reg & EP_STS_ISOERR)
>>> +		writel(EP_STS_ISOERR, &regs->ep_sts);
>>> +
>>> +	if (ep_sts_reg & EP_STS_OUTSMM)
>>> +		writel(EP_STS_OUTSMM, &regs->ep_sts);
>>> +
>>> +	if (ep_sts_reg & EP_STS_NRDY)
>>> +		writel(EP_STS_NRDY, &regs->ep_sts);
>>
>>Why check for each bit when you are not doing anything. Instead at the end
>>you could just do
>>	writel(ep_sts_reg, &regs->ep_sts)
>>to clear all pending events.
>
>Some time ago I had in these conditions debug messages, but then
>I created the cdns3_decode_epx_irq and I removed them from there.
>
>I will remove them.
>
>>> +
>>> +	if ((ep_sts_reg & EP_STS_IOC) || (ep_sts_reg & EP_STS_ISP)) {
>>> +		writel(EP_STS_IOC | EP_STS_ISP, &regs->ep_sts);
>>> +		cdns3_transfer_completed(priv_dev, priv_ep);
>>> +	}
>>> +
>>> +	if (ep_sts_reg & EP_STS_DESCMIS)
>>> +		writel(EP_STS_DESCMIS, &regs->ep_sts);
>>>
>>>  	return 0;
>>>  }
>>>
>>> +/**
>>> + * cdns3_check_usb_interrupt_proceed - Processes interrupt related to device
>>> + * @priv_dev: extended gadget object
>>> + * @usb_ists: bitmap representation of device's reported interrupts
>>> + * (usb_ists register value)
>>> + */
>>> +static void cdns3_check_usb_interrupt_proceed(struct cdns3_device *priv_dev,
>>> +					      u32 usb_ists)
>>> +{
>>> +	struct cdns3_usb_regs __iomem *regs;
>>> +	int speed = 0;
>>> +
>>> +	regs = priv_dev->regs;
>>> +
>>> +	/* Connection detected */
>>> +	if (usb_ists & (USB_ISTS_CON2I | USB_ISTS_CONI)) {
>>> +		writel(USB_ISTS_CON2I | USB_ISTS_CONI, &regs->usb_ists);
>>> +		speed = cdns3_get_speed(priv_dev);
>>> +
>>> +		dev_dbg(&priv_dev->dev, "Connection detected at speed: %s %d\n",
>>> +			usb_speed_string(speed), speed);
>>> +
>>> +		priv_dev->gadget.speed = speed;
>>> +		priv_dev->is_connected = 1;
>>> +		usb_gadget_set_state(&priv_dev->gadget, USB_STATE_POWERED);
>>> +		cdns3_ep0_config(priv_dev);
>>> +	}
>>> +
>>> +	/* SS Disconnection detected */
>>> +	if (usb_ists & (USB_ISTS_DIS2I | USB_ISTS_DISI)) {
>>> +		dev_dbg(&priv_dev->dev, "Disconnection detected\n");
>>> +
>>> +		writel(USB_ISTS_DIS2I | USB_ISTS_DISI, &regs->usb_ists);
>>> +		if (priv_dev->gadget_driver &&
>>> +		    priv_dev->gadget_driver->disconnect) {
>>> +			spin_unlock(&priv_dev->lock);
>>> +			priv_dev->gadget_driver->disconnect(&priv_dev->gadget);
>>> +			spin_lock(&priv_dev->lock);
>>> +		}
>>> +		priv_dev->gadget.speed = USB_SPEED_UNKNOWN;
>>> +		usb_gadget_set_state(&priv_dev->gadget, USB_STATE_NOTATTACHED);
>>> +		priv_dev->is_connected = 0;
>>> +		cdns3_gadget_unconfig(priv_dev);
>>> +	}
>>
>>What about non Super-Speed disconnects?
>
>I connect 2 conditions and I forgot to change  the comment.
>USB_ISTS_DIS2I - HS/FS disconnection
>USB_ISTS_DISI) - SS disconnection
>
>>
>>> +
>>> +	if (usb_ists & USB_ISTS_L2ENTI) {
>>> +		dev_dbg(&priv_dev->dev, "Device suspended\n");
>>> +		writel(USB_ISTS_L2ENTI, &regs->usb_ists);
>>> +	}
>>> +
>>> +	/* Exit from standby mode on L2 exit (Suspend in HS/FS or SS) */
>>> +	if (usb_ists & USB_ISTS_L2EXTI) {
>>> +		dev_dbg(&priv_dev->dev, "[Interrupt] L2 exit detected\n");
>>> +		writel(USB_ISTS_L2EXTI, &regs->usb_ists);
>>> +	}
>>> +
>>> +	/* Exit from standby mode on U3 exit (Suspend in HS/FS or SS). */
>>> +	if (usb_ists & USB_ISTS_U3EXTI) {
>>> +		dev_dbg(&priv_dev->dev, "U3 exit detected\n");
>>> +		writel(USB_ISTS_U3EXTI, &regs->usb_ists);
>>> +	}
>>> +
>>> +	/* resets cases */
>>> +	if (usb_ists & (USB_ISTS_UWRESI | USB_ISTS_UHRESI | USB_ISTS_U2RESI)) {
>>> +		writel(USB_ISTS_U2RESI | USB_ISTS_UWRESI | USB_ISTS_UHRESI,
>>> +		       &regs->usb_ists);
>>> +
>>> +		/*read again to check the actuall speed*/
>>> +		speed = cdns3_get_speed(priv_dev);
>>> +
>>> +		dev_dbg(&priv_dev->dev, "Reset detected at speed: %s %d\n",
>>> +			usb_speed_string(speed), speed);
>>> +
>>> +		usb_gadget_set_state(&priv_dev->gadget, USB_STATE_DEFAULT);
>>> +		priv_dev->gadget.speed = speed;
>>> +		cdns3_gadget_unconfig(priv_dev);
>>> +		cdns3_ep0_config(priv_dev);
>>> +	}
>>> +}
>>> +
>>>  /**
>>>   * cdns3_irq_handler - irq line interrupt handler
>>>   * @cdns: cdns3 instance
>>> @@ -237,8 +405,62 @@ int cdns3_ep_run_transfer(struct cdns3_endpoint *priv_ep,
>>>   */
>>>  static irqreturn_t cdns3_irq_handler_thread(struct cdns3 *cdns)
>>>  {
>>> +	struct cdns3_device *priv_dev;
>>>  	irqreturn_t ret = IRQ_NONE;
>>> -	//TODO: implements this function
>>> +	unsigned long flags;
>>> +	u32 reg;
>>> +
>>> +	priv_dev = container_of(cdns->gadget_dev, struct cdns3_device, dev);
>>> +	spin_lock_irqsave(&priv_dev->lock, flags);
>>> +
>>> +	/* check USB device interrupt */
>>> +	reg = readl(&priv_dev->regs->usb_ists);
>>> +	if (reg) {
>>> +		dev_dbg(&priv_dev->dev, "IRQ: usb_ists: %08X\n", reg);
>>
>>dev_dbg will be terribly slow to be useful. Tracepoints?
>
>It will be moved to Tracepoint.
>>
>>> +		cdns3_check_usb_interrupt_proceed(priv_dev, reg);
>>> +		ret = IRQ_HANDLED;
>>> +	}
>>> +
>>> +	/* check endpoint interrupt */
>>> +	reg = readl(&priv_dev->regs->ep_ists);
>>> +	if (reg != 0) {
>>> +		dev_dbg(&priv_dev->dev, "IRQ ep_ists: %08X\n", reg);
>>> +	} else {
>>> +		if (USB_STS_CFGSTS(readl(&priv_dev->regs->usb_sts)))
>>> +			ret = IRQ_HANDLED;
>>
>>Why is this done. We don't seem to be handling anything here.
>>Don't we need to clear the usb_sts?
>
>This check CFGSTS bit. From controller spec:
>Configuration status -
>1 - device is in the configured state
>0 - device is not configured
>This bit set during SET_CONFIGURATION
>request means that status stage of this
>request was finished successfully, thus device
>configuration was finished successfully
>
>And again, the setting related with setting endpoint configuration.
>
>The author did not mention anything about setting alternate setting
>that require reconfiguring endpoints.
>
>I think that this fragment protects against handling epx before setting configuration.
>
>I think that I can omit this fragment, but I need to test it with Command Verifier.
>
>Regarding clearing usb_sts,  it's cleared but in other functions  invoked from this one.
>Maybe it could be better to pass to these other function content of usb_ists and do
>clearing in one place. It could limit access to registers and make the code more readable

Sorry, I am little confused. 
We have ep_sts, usb_ists and  ep_ists 
usb_ists - must be cleared by software 
ep_ists -  we don't have to clear this register. It's RO. I think that clearing it by software could 
 	   cause some racing. 
>>
>>> +		goto irqend;
>>> +	}
>>> +
>>> +	/* handle default endpoint OUT */
>>> +	if (reg & EP_ISTS_EP_OUT0) {
>>> +		cdns3_check_ep0_interrupt_proceed(priv_dev, 0);
>>> +		ret = IRQ_HANDLED;
>>> +	}
>>> +
>>> +	/* handle default endpoint IN */
>>> +	if (reg & EP_ISTS_EP_IN0) {
>>> +		cdns3_check_ep0_interrupt_proceed(priv_dev, 1);
>>> +		ret = IRQ_HANDLED;
>>> +	}
>>> +
>>> +	/* check if interrupt from non default endpoint, if no exit */
>>> +	reg &= ~(EP_ISTS_EP_OUT0 | EP_ISTS_EP_IN0);
>>> +	if (!reg)
>>> +		goto irqend;
>>> +
>>> +	do {
>>> +		unsigned int bit_pos = ffs(reg);
>>> +		u32 bit_mask = 1 << (bit_pos - 1);
>>> +		int index;
>>> +
>>> +		index = cdns3_ep_reg_pos_to_index(bit_pos);
>>> +		cdns3_check_ep_interrupt_proceed(priv_dev->eps[index]);
>>> +		reg &= ~bit_mask;
>>> +		ret = IRQ_HANDLED;
>>> +	} while (reg);
>>> +
>>> +irqend:
>>> +	spin_unlock_irqrestore(&priv_dev->lock, flags);
>>>  	return ret;
>>>  }
>>>
>>> diff --git a/drivers/usb/cdns3/gadget.h b/drivers/usb/cdns3/gadget.h
>>> index 224f6b830bc9..8c2f363f9340 100644
>>> --- a/drivers/usb/cdns3/gadget.h
>>> +++ b/drivers/usb/cdns3/gadget.h
>>> @@ -1072,6 +1072,7 @@ int cdns3_handshake(void __iomem *ptr, u32 mask, u32 done, int usec);
>>>  void cdns3_set_register_bit(void __iomem *ptr, u32 mask);
>>>  int cdns3_init_ep0(struct cdns3_device *priv_dev);
>>>  void cdns3_ep0_config(struct cdns3_device *priv_dev);
>>> +void cdns3_check_ep0_interrupt_proceed(struct cdns3_device *priv_dev, int dir);
>>>  void cdns3_select_ep(struct cdns3_device *priv_dev, u32 ep);
>>>  void cdns3_enable_l1(struct cdns3_device *priv_dev, int enable);
>>>  struct usb_request *cdns3_next_request(struct list_head *list);
>>>
>
>Thanks
>Cheers,
>Pawel