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

[Roger Quadros <rogerq@xxxxxx>]

On 18/11/18 12:09, Pawel Laszczak wrote:
> 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@xxxxxxxxxxx>
> ---
>  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);
> +
> +		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.

> +	}
> +
> +	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.

> +
> +	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?

> +
> +	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?

> +		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?

> +		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);
> 

cheers,
-roger

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