Re: [PATCH 4/5] usb: musb: dsps: add support for suspend and resume

[Daniel Mack <zonque@gmail.com>]

On 11/25/2013 08:48 PM, Felipe Balbi wrote:
> On Mon, Nov 25, 2013 at 08:39:52PM +0100, Daniel Mack wrote:
>> The dsps platform needs to save save some registers at suspend time and
>> restore them after resume. This patch adds a struct for these registers,
>> and also lets the musb core know that the core registers need to be
>> saved as well.
>>
>> We also have to call musb_port_reset() for this platform upon resume, so
>> this function has to be made non-static.
>>
>> Signed-off-by: Daniel Mack <zonque@gmail.com>
>> ---
>>  drivers/usb/musb/musb_core.h    |  1 +
>>  drivers/usb/musb/musb_dsps.c    | 59 +++++++++++++++++++++++++++++++++++++++++
>>  drivers/usb/musb/musb_host.h    |  2 ++
>>  drivers/usb/musb/musb_virthub.c |  2 +-
>>  4 files changed, 63 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/usb/musb/musb_core.h b/drivers/usb/musb/musb_core.h
>> index 29f7cd7..a423037 100644
>> --- a/drivers/usb/musb/musb_core.h
>> +++ b/drivers/usb/musb/musb_core.h
>> @@ -295,6 +295,7 @@ struct musb {
>>  
>>  	irqreturn_t		(*isr)(int, void *);
>>  	struct work_struct	irq_work;
>> +
>>  	u16			hwvers;
>>  
>>  	u16			intrrxe;
>> diff --git a/drivers/usb/musb/musb_dsps.c b/drivers/usb/musb/musb_dsps.c
>> index e57d712..361ddf8 100644
>> --- a/drivers/usb/musb/musb_dsps.c
>> +++ b/drivers/usb/musb/musb_dsps.c
>> @@ -112,6 +112,19 @@ struct dsps_musb_wrapper {
>>  	u8		poll_seconds;
>>  };
>>  
>> +/*
>> + * register shadow for suspend
>> + */
>> +struct dsps_context {
>> +	u32 control;
>> +	u32 epintr;
>> +	u32 coreintr;
>> +	u32 phy_utmi;
>> +	u32 mode;
>> +	u32 tx_mode;
>> +	u32 rx_mode;
>> +};
>> +
>>  /**
>>   * DSPS glue structure.
>>   */
>> @@ -121,6 +134,8 @@ struct dsps_glue {
>>  	const struct dsps_musb_wrapper *wrp; /* wrapper register offsets */
>>  	struct timer_list timer;	/* otg_workaround timer */
>>  	unsigned long last_timer;    /* last timer data for each instance */
>> +
>> +	struct dsps_context context;
>>  };
>>  
>>  static void dsps_musb_try_idle(struct musb *musb, unsigned long timeout)
>> @@ -506,6 +521,7 @@ static int dsps_create_musb_pdev(struct dsps_glue *glue,
>>  	}
>>  	pdata.config = config;
>>  	pdata.platform_ops = &dsps_ops;
>> +	pdata.restore_after_suspend = 1;
>>  
>>  	config->num_eps = get_int_prop(dn, "mentor,num-eps");
>>  	config->ram_bits = get_int_prop(dn, "mentor,ram-bits");
>> @@ -632,11 +648,54 @@ static const struct of_device_id musb_dsps_of_match[] = {
>>  };
>>  MODULE_DEVICE_TABLE(of, musb_dsps_of_match);
>>  
>> +#ifdef CONFIG_PM
>> +static int dsps_suspend(struct device *dev)
>> +{
>> +	struct dsps_glue *glue = dev_get_drvdata(dev);
>> +	const struct dsps_musb_wrapper *wrp = glue->wrp;
>> +	struct musb *musb = platform_get_drvdata(glue->musb);
>> +	void __iomem *mbase = musb->ctrl_base;
>> +
>> +	glue->context.control = dsps_readl(mbase, wrp->control);
>> +	glue->context.epintr = dsps_readl(mbase, wrp->epintr_set);
>> +	glue->context.coreintr = dsps_readl(mbase, wrp->coreintr_set);
>> +	glue->context.phy_utmi = dsps_readl(mbase, wrp->phy_utmi);
>> +	glue->context.mode = dsps_readl(mbase, wrp->mode);
>> +	glue->context.tx_mode = dsps_readl(mbase, wrp->tx_mode);
>> +	glue->context.rx_mode = dsps_readl(mbase, wrp->rx_mode);
>> +
>> +	return 0;
>> +}
>> +
>> +static int dsps_resume(struct device *dev)
>> +{
>> +	struct dsps_glue *glue = dev_get_drvdata(dev);
>> +	const struct dsps_musb_wrapper *wrp = glue->wrp;
>> +	struct musb *musb = platform_get_drvdata(glue->musb);
>> +	void __iomem *mbase = musb->ctrl_base;
>> +
>> +	dsps_writel(mbase, wrp->control, glue->context.control);
>> +	dsps_writel(mbase, wrp->epintr_set, glue->context.epintr);
>> +	dsps_writel(mbase, wrp->coreintr_set, glue->context.coreintr);
>> +	dsps_writel(mbase, wrp->phy_utmi, glue->context.phy_utmi);
>> +	dsps_writel(mbase, wrp->mode, glue->context.mode);
>> +	dsps_writel(mbase, wrp->tx_mode, glue->context.tx_mode);
>> +	dsps_writel(mbase, wrp->rx_mode, glue->context.rx_mode);
>> +
>> +	musb_port_reset(musb, false);
>> +
>> +	return 0;
>> +}
>> +#endif
>> +
>> +static SIMPLE_DEV_PM_OPS(dsps_pm_ops, dsps_suspend, dsps_resume);
>> +
>>  static struct platform_driver dsps_usbss_driver = {
>>  	.probe		= dsps_probe,
>>  	.remove         = dsps_remove,
>>  	.driver         = {
>>  		.name   = "musb-dsps",
>> +		.pm	= &dsps_pm_ops,
>>  		.of_match_table	= musb_dsps_of_match,
>>  	},
>>  };
>> diff --git a/drivers/usb/musb/musb_host.h b/drivers/usb/musb/musb_host.h
>> index e660af9..7436c24 100644
>> --- a/drivers/usb/musb/musb_host.h
>> +++ b/drivers/usb/musb/musb_host.h
>> @@ -93,6 +93,7 @@ extern void musb_root_disconnect(struct musb *musb);
>>  extern void musb_host_resume_root_hub(struct musb *musb);
>>  extern void musb_host_poke_root_hub(struct musb *musb);
>>  extern void musb_port_suspend(struct musb *musb, bool do_suspend);
>> +extern void musb_port_reset(struct musb *musb, bool do_reset);
>>  #else
>>  static inline struct musb *hcd_to_musb(struct usb_hcd *hcd)
>>  {
>> @@ -123,6 +124,7 @@ static inline void musb_host_resume_root_hub(struct musb *musb)	{}
>>  static inline void musb_host_poll_rh_status(struct musb *musb)	{}
>>  static inline void musb_host_poke_root_hub(struct musb *musb)	{}
>>  static inline void musb_port_suspend(struct musb *musb, bool do_suspend) {}
>> +static inline void musb_port_reset(struct musb *musb)		{}
>>  #endif
>>  
>>  struct usb_hcd;
>> diff --git a/drivers/usb/musb/musb_virthub.c b/drivers/usb/musb/musb_virthub.c
>> index e977441..24e46c0 100644
>> --- a/drivers/usb/musb/musb_virthub.c
>> +++ b/drivers/usb/musb/musb_virthub.c
>> @@ -109,7 +109,7 @@ void musb_port_suspend(struct musb *musb, bool do_suspend)
>>  	}
>>  }
>>  
>> -static void musb_port_reset(struct musb *musb, bool do_reset)
>> +void musb_port_reset(struct musb *musb, bool do_reset)
> 
> NAK, this should not be called from the glue layers at all. If anything
> call from musb_core's resume callback. That will only be called after
> parent's resume has been called anyway.

Given that this driver is successfully used with suspend/resume on other
platforms without that reset, but it's clearly needed for dsps, I'm
fairly sure this should be a glue-layer specific thing. Hence the change.

I think it'll break things on other platforms if we unconditionally
reset the port after resume, but I can't test it. Anyone?


Thanks,
Daniel