OMAP L138 Davinci MMC/SD Controller - Support for SDIO Suspend, Resume and Wakeup Operations

Hi Awais,

Is it possible to support the optional Wakeup, Suspend and Resume operations (as specified in SD specifications)?

Yes, It will support.

Please refer the following location in kernel source tree.

drivers/mmc/host/davinci_mmc.c

Hi Titus,

Thank you. I assume that you are referring to the power management functions  davinci_mmcsd_suspend () and davinci_mmcsd_resume() within the davinci_mmc.c driver.

Regards,

Awais

Hi,

Yes. You are correct.

Could you please elaborate your requirement.

Hi Titus,

My inquiry is regarding the Suspend and Resume protocol described in SDIO specifications.

For reference, please see section 1.6 and 3.12 of the following document:

https://www.sdcard.org/developers/overview/host_controller/simple_spec/Simplified_SD_Host_Controller_Spec.pdf

Regards,

Awais

Hi,

Please refer the location & file for SDIO suspend and resume feature.

drivers/mmc/core/sdio.c

mmc_sdio_suspend() & mmc_sdio_resume()

Hi Stalin,

Are not functions generic ones ?Actually mmcsd controller must also support the functionality of suspend and resume and I see davinci mmcsd controller of omapl138 does not support this functionality.

Thanks

Jam

Hi Jam,

What SDK version are you using ?

No, It would support suspend and resume functions too.

Please refer to my first reply.

static const struct dev_pm_ops davinci_mmcsd_pm = {
	.suspend        = davinci_mmcsd_suspend,
	.resume         = davinci_mmcsd_resume,
};

#define davinci_mmcsd_pm_ops (&davinci_mmcsd_pm)
#else
#define davinci_mmcsd_pm_ops NULL
#endif

static struct platform_driver davinci_mmcsd_driver = {
	.driver		= {
		.name	= "davinci_mmc",
		.owner	= THIS_MODULE,
		.pm	= davinci_mmcsd_pm_ops,
	},
	.remove		= __exit_p(davinci_mmcsd_remove),
};

My inquiry is regarding the Suspend and Resume protocol described in SDIO specifications.

For reference, please see section 1.6 and 3.12 of the following document:

https://www.sdcard.org/developers/overview/host_controller/simple_spec/Simplified_SD_Host_Controller_Spec.pdf

Hi Jam,

Are not functions generic ones ?Actually mmcsd controller must also support the functionality of suspend and resume and I see davinci mmcsd controller of omapl138 does not support this functionality.

Sorry, I'm not sure about this SDIO suspend/resume fns.

Did you know that any other TI processor or any processor has support for SDIO suspend/resume function as you asked ?

You can check the "Capabilities Register" of D23 to check the suspend/resume support.

What do you say about the below answers ?

Have you refered to the location & file for SDIO suspend and resume feature ?

drivers/mmc/core/sdio.c

mmc_sdio_suspend() & mmc_sdio_resume()

Hi Stalin,

Thanks for replying..

1. mmcsdsdio controller of DM8148 Processor supports this functionality of suspend resume

2. I do not find Capabilities Register for Omp-l138 processor

3. I have checked drivers/mmc/core/sdio.c mmc_sdio_suspend() & mmc_sdio_resume(), My understanding is , these are not the desired function as hardware must support suspend resume features as specification dictates.On hardware side the driver functions davinci_mmcsd_suspend(), disabling the clock ,interrupts and releasing the sdio host.

Thanks

Jam

Hi Jam,

1. mmcsdsdio controller of DM8148 Processor supports this functionality of suspend resume

Thanks.

Could you please direct me to file that has support this feature.

Hi Stalin,

please refer to

http://www.ti.com/lit/ug/sprugz8e/sprugz8e.pdf

and see chapter #18 for suspend resume functionality of mmcsdsdio controller.