[PATCH v5 3/4] misc: fastrpc: Refactor domain ID to enforce strict mapping

[Dmitry Baryshkov]

On Wed, Jul 02, 2025 at 08:23:40AM +0530, Ling Xu wrote:
> Currently, domain ids are added for each instance, which is not scalable.
> Strict domain IDs for domain.

What does this mean?

> 
> Co-developed-by: Srinivas Kandagatla <srinivas.kandagatla at linaro.org>
> Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla at linaro.org>
> Signed-off-by: Ling Xu <quic_lxu5 at quicinc.com>
> ---
>  drivers/misc/fastrpc.c      | 51 ++++++++++++++++---------------------
>  include/uapi/misc/fastrpc.h |  2 +-
>  2 files changed, 23 insertions(+), 30 deletions(-)
> 
> diff --git a/drivers/misc/fastrpc.c b/drivers/misc/fastrpc.c
> index 378923594f02..441f5851eb97 100644
> --- a/drivers/misc/fastrpc.c
> +++ b/drivers/misc/fastrpc.c
> @@ -27,8 +27,7 @@
>  #define MDSP_DOMAIN_ID (1)
>  #define SDSP_DOMAIN_ID (2)
>  #define CDSP_DOMAIN_ID (3)
> -#define CDSP1_DOMAIN_ID (4)
> -#define FASTRPC_DEV_MAX		5 /* adsp, mdsp, slpi, cdsp, cdsp1 */
> +#define FASTRPC_DOMAIN_MAX    CDSP_DOMAIN_ID

Unused

>  #define FASTRPC_MAX_SESSIONS	14
>  #define FASTRPC_MAX_VMIDS	16
>  #define FASTRPC_ALIGN		128
> @@ -106,8 +105,6 @@
>  
>  #define miscdev_to_fdevice(d) container_of(d, struct fastrpc_device, miscdev)
>  
> -static const char *domains[FASTRPC_DEV_MAX] = { "adsp", "mdsp",
> -						"sdsp", "cdsp", "cdsp1" };
>  struct fastrpc_phy_page {
>  	u64 addr;		/* physical address */
>  	u64 size;		/* size of contiguous region */
> @@ -1723,7 +1720,6 @@ static int fastrpc_get_info_from_kernel(struct fastrpc_ioctl_capability *cap,
>  	uint32_t attribute_id = cap->attribute_id;
>  	uint32_t *dsp_attributes;
>  	unsigned long flags;
> -	uint32_t domain = cap->domain;
>  	int err;
>  
>  	spin_lock_irqsave(&cctx->lock, flags);
> @@ -1741,7 +1737,7 @@ static int fastrpc_get_info_from_kernel(struct fastrpc_ioctl_capability *cap,
>  	err = fastrpc_get_info_from_dsp(fl, dsp_attributes, FASTRPC_MAX_DSP_ATTRIBUTES);
>  	if (err == DSP_UNSUPPORTED_API) {
>  		dev_info(&cctx->rpdev->dev,
> -			 "Warning: DSP capabilities not supported on domain: %d\n", domain);
> +			 "Warning: DSP capabilities not supported\n");
>  		kfree(dsp_attributes);
>  		return -EOPNOTSUPP;
>  	} else if (err) {
> @@ -1769,17 +1765,6 @@ static int fastrpc_get_dsp_info(struct fastrpc_user *fl, char __user *argp)
>  		return  -EFAULT;
>  
>  	cap.capability = 0;
> -	if (cap.domain >= FASTRPC_DEV_MAX) {
> -		dev_err(&fl->cctx->rpdev->dev, "Error: Invalid domain id:%d, err:%d\n",
> -			cap.domain, err);
> -		return -ECHRNG;
> -	}
> -
> -	/* Fastrpc Capablities does not support modem domain */
> -	if (cap.domain == MDSP_DOMAIN_ID) {
> -		dev_err(&fl->cctx->rpdev->dev, "Error: modem not supported %d\n", err);
> -		return -ECHRNG;
> -	}
>  
>  	if (cap.attribute_id >= FASTRPC_MAX_DSP_ATTRIBUTES) {
>  		dev_err(&fl->cctx->rpdev->dev, "Error: invalid attribute: %d, err: %d\n",
> @@ -2255,6 +2240,20 @@ static int fastrpc_device_register(struct device *dev, struct fastrpc_channel_ct
>  	return err;
>  }
>  
> +static int fastrpc_get_domain_id(const char *domain)
> +{
> +	if (!strncmp(domain, "adsp", 4))
> +		return ADSP_DOMAIN_ID;
> +	else if (!strncmp(domain, "cdsp", 4))
> +		return CDSP_DOMAIN_ID;
> +	else if (!strncmp(domain, "mdsp", 4))
> +		return MDSP_DOMAIN_ID;
> +	else if (!strncmp(domain, "sdsp", 4))
> +		return SDSP_DOMAIN_ID;
> +
> +	return -EINVAL;
> +}
> +
>  static int fastrpc_rpmsg_probe(struct rpmsg_device *rpdev)
>  {
>  	struct device *rdev = &rpdev->dev;
> @@ -2272,15 +2271,10 @@ static int fastrpc_rpmsg_probe(struct rpmsg_device *rpdev)
>  		return err;
>  	}
>  
> -	for (i = 0; i < FASTRPC_DEV_MAX; i++) {
> -		if (!strcmp(domains[i], domain)) {
> -			domain_id = i;
> -			break;
> -		}
> -	}
> +	domain_id = fastrpc_get_domain_id(domain);
>  
>  	if (domain_id < 0) {
> -		dev_info(rdev, "FastRPC Invalid Domain ID %d\n", domain_id);
> +		dev_info(rdev, "FastRPC Domain %s not supported\n", domain);
>  		return -EINVAL;
>  	}
>  
> @@ -2330,21 +2324,20 @@ static int fastrpc_rpmsg_probe(struct rpmsg_device *rpdev)
>  	case ADSP_DOMAIN_ID:
>  	case MDSP_DOMAIN_ID:
>  	case SDSP_DOMAIN_ID:
> -		/* Unsigned PD offloading is only supported on CDSP and CDSP1 */
> +		/* Unsigned PD offloading is only supported on CDSP */
>  		data->unsigned_support = false;
> -		err = fastrpc_device_register(rdev, data, secure_dsp, domains[domain_id]);
> +		err = fastrpc_device_register(rdev, data, secure_dsp, domain);
>  		if (err)
>  			goto err_free_data;
>  		break;
>  	case CDSP_DOMAIN_ID:
> -	case CDSP1_DOMAIN_ID:
>  		data->unsigned_support = true;
>  		/* Create both device nodes so that we can allow both Signed and Unsigned PD */
> -		err = fastrpc_device_register(rdev, data, true, domains[domain_id]);
> +		err = fastrpc_device_register(rdev, data, true, domain);
>  		if (err)
>  			goto err_free_data;
>  
> -		err = fastrpc_device_register(rdev, data, false, domains[domain_id]);
> +		err = fastrpc_device_register(rdev, data, false, domain);
>  		if (err)
>  			goto err_deregister_fdev;
>  		break;
> diff --git a/include/uapi/misc/fastrpc.h b/include/uapi/misc/fastrpc.h
> index f33d914d8f46..27b892b546f6 100644
> --- a/include/uapi/misc/fastrpc.h
> +++ b/include/uapi/misc/fastrpc.h
> @@ -134,7 +134,7 @@ struct fastrpc_mem_unmap {
>  };
>  
>  struct fastrpc_ioctl_capability {
> -	__u32 domain;
> +	__u32 domain; /* deprecated, ignored by the kernel */

reserved1 or unused

>  	__u32 attribute_id;
>  	__u32 capability;   /* dsp capability */
>  	__u32 reserved[4];
> -- 
> 2.34.1
> 

-- 
With best wishes
Dmitry