[PATCH v4 3/3] remoteproc: imx_rproc: detect and attach to pre-booted remote cores

[Peng Fan]

> Subject: [PATCH v4 3/3] remoteproc: imx_rproc: detect and attach to
> pre-booted remote cores
> 
> From: Hiago De Franco <hiago.franco at toradex.com>
> 
> When the remote core is started before Linux boots (e.g., by the
> bootloader), the driver currently is not able to attach because it only
> checks for cores running in different partitions. If the core was kicked
> by the bootloader, it is in the same partition as Linux and it is already
> up and running.
> 
> This adds power mode verification through dev_pm_genpd_is_on(),
> enabling the driver to detect when the remote core is already running
> and properly attach to it if all the power domain devices are on.
> 
> To accomplish this, we need to avoid passing any attach_data or flags
> to dev_pm_domain_attach_list(), letting the platform device become a
> consumer of the power domain provider. With that the current power
> state of the genpds will not change, allowing the detection of the
> remote core power state.
> 
> We enable and sync the device runtime PM during probe to make sure
> the power domains are correctly managed when the core is controlled
> by the kernel.
> 
> Suggested-by: Ulf Hansson <ulf.hansson at linaro.org>
> Signed-off-by: Hiago De Franco <hiago.franco at toradex.com>
> ---
> v4: Changed to use the new dev_pm_genpd_is_on() function instead,
> as suggested by Ulf. This will now get the power status of the two
> remote cores power domains to decided if imx_rpoc needs to attach or
> not. In order to do that, pm_runtime_enable() and
> pm_runtime_get_sync() were introduced and pd_data was removed.
> v3: Unchanged.
> v2: Dropped unecessary include. Removed the imx_rproc_is_on
> function, as suggested.
> v1:
> ---
>  drivers/remoteproc/imx_rproc.c | 29 ++++++++++++++++++++++++-----
>  1 file changed, 24 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/remoteproc/imx_rproc.c
> b/drivers/remoteproc/imx_rproc.c index
> 627e57a88db2..6f9680142704 100644
> --- a/drivers/remoteproc/imx_rproc.c
> +++ b/drivers/remoteproc/imx_rproc.c
> @@ -18,6 +18,7 @@
>  #include <linux/of_reserved_mem.h>
>  #include <linux/platform_device.h>
>  #include <linux/pm_domain.h>
> +#include <linux/pm_runtime.h>
>  #include <linux/reboot.h>
>  #include <linux/regmap.h>
>  #include <linux/remoteproc.h>
> @@ -890,10 +891,8 @@ static int imx_rproc_partition_notify(struct
> notifier_block *nb,  static int imx_rproc_attach_pd(struct imx_rproc
> *priv)  {
>  	struct device *dev = priv->dev;
> -	int ret;
> -	struct dev_pm_domain_attach_data pd_data = {
> -		.pd_flags = PD_FLAG_DEV_LINK_ON,
> -	};
> +	int ret, i;
> +	bool detached = true;
> 
>  	/*
>  	 * If there is only one power-domain entry, the platform driver
> framework @@ -902,7 +901,22 @@ static int
> imx_rproc_attach_pd(struct imx_rproc *priv)
>  	if (dev->pm_domain)
>  		return 0;
> 
> -	ret = dev_pm_domain_attach_list(dev, &pd_data, &priv-
> >pd_list);
> +	ret = dev_pm_domain_attach_list(dev, NULL, &priv->pd_list);
> +	/*
> +	 * If all the power domain devices are already turned on, the
> remote
> +	 * core is already up when the kernel booted (e.g. kicked by
> the
> +	 * bootloader). In this case attach to it.
> +	 */
> +	for (i = 0; i < ret; i++) {
> +		if (!dev_pm_genpd_is_on(priv->pd_list->pd_devs[i])) {
> +			detached = false;
> +			break;
> +		}
> +	}
> +
> +	if (detached)
> +		priv->rproc->state = RPROC_DETACHED;
> +
>  	return ret < 0 ? ret : 0;
>  }
> 
> @@ -1146,6 +1160,11 @@ static int imx_rproc_probe(struct
> platform_device *pdev)
>  		}
>  	}
> 
> +	if (dcfg->method == IMX_RPROC_SCU_API) {
> +		pm_runtime_enable(dev);
> +		pm_runtime_get_sync(dev);

Need put and disable in imx_rproc_remove.

BTW: Has this patchset tested with M4 in a separate partition,
saying M4 image packed in flash.bin?

Regards,
Peng
> +	}
> +
>  	ret = rproc_add(rproc);
>  	if (ret) {
>  		dev_err(dev, "rproc_add failed\n");
> --
> 2.39.5
>