[PATCH 2/2] remoteproc: imx_rproc: add start up delay

[Mathieu Poirier]

On Sat, Jul 08, 2023 at 01:24:44AM +0200, Marek Vasut wrote:
> From: Peng Fan <peng.fan at nxp.com>
> 
> There is case that after remoteproc start remote processor[M4], the M4
> runs slow and before M4 finish its own rpmsg framework initialization,
> linux sends out vring kick message, then M4 firmware drops the kick
> message. Some NXP released Cortex-M[x] images has such limitation that
> it requires linux sends out vring kick message after M4 firmware finish
> its rpmsg framework initialization.
> 
> Reviewed-by: Jacky Bai <ping.bai at nxp.com>
> Reviewed-by: Ye Li <ye.li at nxp.com>
> Signed-off-by: Peng Fan <peng.fan at nxp.com>
> ---
> Note: picked from NXP downstream LF-6630-2 remoteproc: imx_rproc: add start up delay
> https://github.com/nxp-imx/linux-imx.git 0b1b91c95b291a3b60d6224b13f6a95a75896abf
> ---
> Note: Literally all of the NXP BSP 2.13.0 firmware builds fail to boot
>       without this being set to something like 50..500 ms , so this is
>       rather useful to have.

My stance on this hasn't changed - hacks such as these do not scale and are a
nightmare to maintain.  The problem should be fixed in the M4's firmware.

> ---
> Cc: Bjorn Andersson <andersson at kernel.org>
> Cc: Conor Dooley <conor+dt at kernel.org>
> Cc: Fabio Estevam <festevam at gmail.com>
> Cc: Krzysztof Kozlowski <krzysztof.kozlowski+dt at linaro.org>
> Cc: Mathieu Poirier <mathieu.poirier at linaro.org>
> Cc: NXP Linux Team <linux-imx at nxp.com>
> Cc: Peng Fan <peng.fan at nxp.com>
> Cc: Pengutronix Kernel Team <kernel at pengutronix.de>
> Cc: Rob Herring <robh+dt at kernel.org>
> Cc: Sascha Hauer <s.hauer at pengutronix.de>
> Cc: Shawn Guo <shawnguo at kernel.org>
> Cc: devicetree at vger.kernel.org
> Cc: linux-arm-kernel at lists.infradead.org
> Cc: linux-remoteproc at vger.kernel.org
> ---
>  drivers/remoteproc/imx_rproc.c | 9 +++++++++
>  1 file changed, 9 insertions(+)
> 
> diff --git a/drivers/remoteproc/imx_rproc.c b/drivers/remoteproc/imx_rproc.c
> index f9874fc5a80ff..d0eb96d6a4fe1 100644
> --- a/drivers/remoteproc/imx_rproc.c
> +++ b/drivers/remoteproc/imx_rproc.c
> @@ -6,6 +6,7 @@
>  #include <dt-bindings/firmware/imx/rsrc.h>
>  #include <linux/arm-smccc.h>
>  #include <linux/clk.h>
> +#include <linux/delay.h>
>  #include <linux/err.h>
>  #include <linux/firmware/imx/sci.h>
>  #include <linux/interrupt.h>
> @@ -110,6 +111,7 @@ struct imx_rproc {
>  	u32				core_index;
>  	struct device                   **pd_dev;
>  	struct device_link              **pd_dev_link;
> +	u32				startup_delay;
>  };
>  
>  static const struct imx_rproc_att imx_rproc_att_imx93[] = {
> @@ -382,6 +384,9 @@ static int imx_rproc_start(struct rproc *rproc)
>  	if (ret)
>  		dev_err(dev, "Failed to enable remote core!\n");
>  
> +	if (priv->startup_delay)
> +		msleep(priv->startup_delay);
> +
>  	return ret;
>  }
>  
> @@ -1090,6 +1095,10 @@ static int imx_rproc_probe(struct platform_device *pdev)
>  	if (rproc->state != RPROC_DETACHED)
>  		rproc->auto_boot = of_property_read_bool(np, "fsl,auto-boot");
>  
> +	ret = of_property_read_u32(dev->of_node, "fsl,startup-delay-ms", &priv->startup_delay);
> +	if (ret)
> +		priv->startup_delay = 0;
> +
>  	ret = rproc_add(rproc);
>  	if (ret) {
>  		dev_err(dev, "rproc_add failed\n");
> -- 
> 2.40.1
>