misc: fastrpc: Remove kernel-side domain checks from capability ioctl

Domain ID in the uAPI is misleading. Remove checks and log messages
related to 'domain' field in capability structure. Update UAPI to
mark the field as unused.

Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
Reviewed-by: Ekansh Gupta <ekansh.gupta@oss.qualcomm.com>
Signed-off-by: Ling Xu <quic_lxu5@quicinc.com>
Signed-off-by: Srinivas Kandagatla <srini@kernel.org>
Link: https://lore.kernel.org/r/20250912131302.303199-3-srini@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Author: quic-lxu5

drivers/misc/fastrpc.c

@@ -1723,7 +1723,6 @@ 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 +1740,7 @@ 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 +1768,6 @@ 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",

include/uapi/misc/fastrpc.h

@@ -134,7 +134,7 @@ struct fastrpc_mem_unmap {
 };
 
 struct fastrpc_ioctl_capability {
-	__u32 domain;
+	__u32 unused; /* deprecated, ignored by the kernel */
 	__u32 attribute_id;
 	__u32 capability;   /* dsp capability */
 	__u32 reserved[4];