Re: [PATCH 3/8][v2]usb:fsl:otg: Add support to add/remove usb host driver

[Alan Stern]

On Wed, 15 Jul 2015, Ramneek Mehresh wrote:

> Add workqueue to add/remove host driver (outside
> interrupt context) upon each id change.
> 
> Signed-off-by: Li Yang <leoli@xxxxxxxxxxxxx>
> Signed-off-by: Ramneek Mehresh <ramneek.mehresh@xxxxxxxxxxxxx>
> ---
>  drivers/usb/host/ehci-fsl.c | 83 ++++++++++++++++++++++++++++++++++-----------
>  drivers/usb/host/ehci-fsl.h | 20 +++++++++++
>  2 files changed, 84 insertions(+), 19 deletions(-)
> 
> diff --git a/drivers/usb/host/ehci-fsl.c b/drivers/usb/host/ehci-fsl.c
> index 5352e74..81e4bf5 100644
> --- a/drivers/usb/host/ehci-fsl.c
> +++ b/drivers/usb/host/ehci-fsl.c
> @@ -44,6 +44,34 @@
>  
>  static struct hc_driver __read_mostly fsl_ehci_hc_driver;
>  
> +#if defined(CONFIG_FSL_USB2_OTG) || defined(CONFIG_FSL_USB2_OTG_MODULE)

You've got these #if lines all over the place.  They look ugly and make
the code hard to read.  Consider removing them.  Or even if you can't
remove them entirely, removing most of them would help.

Also, instead of testing both CONFIG_FSL_USB2_OTG and
CONFIG_FSL_USB2_OTG_MODULE, how about testing a single symbol?  For 
example:

#if defined(CONFIG_FSL_USB2_OTG) || defined(CONFIG_FSL_USB2_OTG_MODULE)
#define CHANGE_HCD 1
#else
#define CHANGE_HCD 0
#endif

Then all you need later on is "#if CHANGE_HCD".  Or if it's inside a 
code block, just "if (CHANGE_HCD)".

> +static struct ehci_fsl *hcd_to_ehci_fsl(struct usb_hcd *hcd)
> +{
> +	return (struct ehci_fsl *)hcd_to_ehci(hcd)->priv;
> +}
> +
> +static void do_change_hcd(struct work_struct *work)
> +{
> +	struct ehci_fsl *ehci_fsl = container_of(work, struct ehci_fsl,
> +					change_hcd_work);
> +	struct usb_hcd *hcd = ehci_fsl->hcd;
> +	void __iomem *non_ehci = hcd->regs;
> +	int retval;
> +
> +	if (ehci_fsl->hcd_add && !ehci_fsl->have_hcd) {
> +		writel(USBMODE_CM_HOST, non_ehci + FSL_SOC_USB_USBMODE);
> +		/* host, gadget and otg share same int line */
> +		retval = usb_add_hcd(hcd, hcd->irq, IRQF_SHARED);
> +		if (retval == 0)
> +			ehci_fsl->have_hcd = 1;
> +	} else if (!ehci_fsl->hcd_add && ehci_fsl->have_hcd) {
> +		usb_remove_hcd(hcd);
> +		ehci_fsl->have_hcd = 0;

Don't you have to turn off the USBMODE_CM_HOST bit here?  It looks 
strange to turn it on above but not turn it off again.

> +	}
> +}
> +#endif


>  static int ehci_fsl_drv_suspend(struct device *dev)
>  {
>  	struct usb_hcd *hcd = dev_get_drvdata(dev);
> -	struct ehci_fsl *ehci_fsl = hcd_to_ehci_fsl(hcd);
>  	void __iomem *non_ehci = hcd->regs;
> +#if defined(CONFIG_FSL_USB2_OTG) || defined(CONFIG_FSL_USB2_OTG_MODULE)
> +	struct ehci_fsl *ehci_fsl = hcd_to_ehci_fsl(hcd);
> +	struct usb_bus host = hcd->self;
> +#endif
> +
>  
>  	if (of_device_is_compatible(dev->parent->of_node,
>  				    "fsl,mpc5121-usb2-dr")) {
>  		return ehci_fsl_mpc512x_drv_suspend(dev);
>  	}
>  
> +#if defined(CONFIG_FSL_USB2_OTG) || defined(CONFIG_FSL_USB2_OTG_MODULE)
> +	if (host.is_otg) {
> +		/* remove hcd */
> +		ehci_fsl->hcd_add = 0;
> +		schedule_work(&ehci_fsl->change_hcd_work);
> +		host.is_otg = 0;

Why do you set host.is_otg to 0 here?  Why not do it in the work 
routine?

> +		return 0;
> +	}
> +#endif
> +
>  	ehci_prepare_ports_for_controller_suspend(hcd_to_ehci(hcd),
>  			device_may_wakeup(dev));
>  	if (!fsl_deep_sleep())
> @@ -540,15 +571,29 @@ static int ehci_fsl_drv_suspend(struct device *dev)
>  static int ehci_fsl_drv_resume(struct device *dev)
>  {
>  	struct usb_hcd *hcd = dev_get_drvdata(dev);
> -	struct ehci_fsl *ehci_fsl = hcd_to_ehci_fsl(hcd);
>  	struct ehci_hcd *ehci = hcd_to_ehci(hcd);
>  	void __iomem *non_ehci = hcd->regs;
> +#if defined(CONFIG_FSL_USB2_OTG) || defined(CONFIG_FSL_USB2_OTG_MODULE)
> +	struct ehci_fsl *ehci_fsl = hcd_to_ehci_fsl(hcd);
> +	struct usb_bus host = hcd->self;
> +#endif
>  
>  	if (of_device_is_compatible(dev->parent->of_node,
>  				    "fsl,mpc5121-usb2-dr")) {
>  		return ehci_fsl_mpc512x_drv_resume(dev);
>  	}
>  
> +#if defined(CONFIG_FSL_USB2_OTG) || defined(CONFIG_FSL_USB2_OTG_MODULE)
> +	if (host.is_otg) {
> +		/* add hcd */
> +		ehci_fsl->hcd_add = 1;
> +		schedule_work(&ehci_fsl->change_hcd_work);
> +		usb_hcd_resume_root_hub(hcd);
> +		host.is_otg = 0;

Again, why change host.is_otg here?  And for that matter, where does 
host.is_otg ever get set to 1?

Also, what is the reason for calling usb_hcd_resume_root_hub()?  It 
won't do anything, because it will run before the scheduled work, so 
there won't be a root hub for it to resume.

> +		return 0;
> +	}
> +#endif
> +
>  	ehci_prepare_ports_for_controller_resume(ehci);
>  	if (!fsl_deep_sleep())
>  		return 0;
> diff --git a/drivers/usb/host/ehci-fsl.h b/drivers/usb/host/ehci-fsl.h
> index dbd292e..3fd1fd0 100644
> --- a/drivers/usb/host/ehci-fsl.h
> +++ b/drivers/usb/host/ehci-fsl.h
> @@ -62,4 +62,24 @@
>  #define UTMI_PHY_EN             (1<<9)
>  #define ULPI_PHY_CLK_SEL        (1<<10)
>  #define PHY_CLK_VALID		(1<<17)
> +
> +struct ehci_fsl {
> +#ifdef CONFIG_PM
> +	/* Saved USB PHY settings, need to restore after deep sleep. */
> +	u32 usb_ctrl;
> +#endif
> +	struct usb_hcd *hcd;
> +#if defined(CONFIG_FSL_USB2_OTG) || defined(CONFIG_FSL_USB2_OTG_MODULE)
> +	struct work_struct change_hcd_work;
> +#endif

Again, try to eliminate these #if's.  There really isn't anything wrong 
with allocating the space for these things even in a non-OTG build.

> +	/*
> +	 * store current hcd state for otg;
> +	 * have_hcd is true when host drv al already part of otg framework,
> +	 * otherwise false;
> +	 * hcd_add is true when otg framework wants to add host
> +	 * drv as part of otg;flase when it wants to remove it
> +	 */
> +	unsigned have_hcd:1;
> +	unsigned hcd_add:1;
> +};
>  #endif				/* _EHCI_FSL_H */

Alan Stern

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