Re: [PATCH v9 4/4] misc: fastrpc: Add polling mode support for fastRPC driver

[Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>]

On Wed, Apr 22, 2026 at 02:54:09PM +0530, Ekansh Gupta wrote:
> For any remote call to DSP, after sending an invocation message,
> fastRPC driver waits for glink response and during this time the
> CPU can go into low power modes. This adds latency to overall fastrpc
> call as CPU wakeup and scheduling latencies are included. Add polling
> mode support with which fastRPC driver will poll continuously on a
> memory after sending a message to remote subsystem which will eliminate
> CPU wakeup and scheduling latencies and reduce fastRPC overhead. In case
> poll timeout happens, the call will fallback to normal RPC mode.  Poll
> mode can be enabled by user by using FASTRPC_IOCTL_SET_OPTION ioctl
> request with FASTRPC_POLL_MODE request id.
> 
> Signed-off-by: Ekansh Gupta <ekansh.gupta@oss.qualcomm.com>
> ---
>  drivers/misc/fastrpc.c      | 148 ++++++++++++++++++++++++++++++++++--
>  include/uapi/misc/fastrpc.h |  25 ++++++
>  2 files changed, 166 insertions(+), 7 deletions(-)
> 
> @@ -2331,6 +2446,22 @@ static const struct fastrpc_soc_data default_soc_data = {
>  	.dma_addr_bits_default = 32,
>  };
>  
> +/*
> + * Older platforms that use default_soc_data but whose DSP firmware
> + * supports the FastRPC polling mode.

There should be a comment, "don't add more platforms to this list".

> + */
> +static const struct of_device_id fastrpc_poll_supported_machines[] __maybe_unused = {
> +	{ .compatible = "qcom,qcs8300" },
> +	{ .compatible = "qcom,qcs9100" },

Use qcom,sa8775p instead. See sa8775p-ride boards.
What about qcom,sar2130p?
qcom,sc8280xp?
qcom,milos?

> +	{ .compatible = "qcom,sm8450" },
> +	{ .compatible = "qcom,sm8550" },
> +	{ .compatible = "qcom,sm8650" },
> +	{ .compatible = "qcom,sm8750" },
> +	{ .compatible = "qcom,x1e80100" },
> +	{ .compatible = "qcom,x1p42100" },
> +	{},
> +};
> +
>  static int fastrpc_rpmsg_probe(struct rpmsg_device *rpdev)
>  {
>  	struct device *rdev = &rpdev->dev;

-- 
With best wishes
Dmitry