On Thu, Jan 15, 2026 at 04:28:51PM +0800, Jianping Li wrote:
> The entire reserved-memory region is now assigned to DSP VMIDs during
> channel setup and stored in cctx->remote_heap. Memory is reclaimed in
> rpmsg_remove by revoking DSP permissions and freeing the buffer, tying
> heap lifecycle to the rpmsg channel.

Why?

> 
> Signed-off-by: Jianping Li <[email protected]>
> ---
>  drivers/misc/fastrpc.c | 95 ++++++++++++++++++++----------------------
>  1 file changed, 45 insertions(+), 50 deletions(-)
> 
> diff --git a/drivers/misc/fastrpc.c b/drivers/misc/fastrpc.c
> index 833c265add5e..f9edca7a8de1 100644
> --- a/drivers/misc/fastrpc.c
> +++ b/drivers/misc/fastrpc.c
> @@ -278,6 +278,8 @@ struct fastrpc_channel_ctx {
>       struct kref refcount;
>       /* Flag if dsp attributes are cached */
>       bool valid_attributes;
> +     /* Flag if audio PD init mem was allocated */
> +     bool audio_init_mem;
>       u32 dsp_attributes[FASTRPC_MAX_DSP_ATTRIBUTES];
>       struct fastrpc_device *secure_fdevice;
>       struct fastrpc_device *fdevice;
> @@ -1304,7 +1306,6 @@ static int fastrpc_init_create_static_process(struct 
> fastrpc_user *fl,
>       struct fastrpc_phy_page pages[1];
>       char *name;
>       int err;
> -     bool scm_done = false;
>       struct {
>               int client_id;
>               u32 namelen;
> @@ -1334,31 +1335,6 @@ static int fastrpc_init_create_static_process(struct 
> fastrpc_user *fl,
>       inbuf.client_id = fl->client_id;
>       inbuf.namelen = init.namelen;
>       inbuf.pageslen = 0;
> -     if (!fl->cctx->remote_heap) {
> -             err = fastrpc_remote_heap_alloc(fl, fl->sctx->dev, init.memlen,
> -                                             &fl->cctx->remote_heap);
> -             if (err)
> -                     goto err_name;
> -
> -             /* Map if we have any heap VMIDs associated with this ADSP 
> Static Process. */
> -             if (fl->cctx->vmcount) {
> -                     u64 src_perms = BIT(QCOM_SCM_VMID_HLOS);
> -
> -                     err = 
> qcom_scm_assign_mem(fl->cctx->remote_heap->dma_addr,
> -                                                     
> (u64)fl->cctx->remote_heap->size,
> -                                                     &src_perms,
> -                                                     fl->cctx->vmperms, 
> fl->cctx->vmcount);
> -                     if (err) {
> -                             dev_err(fl->sctx->dev,
> -                                     "Failed to assign memory with dma_addr 
> %pad size 0x%llx err %d\n",
> -                                     &fl->cctx->remote_heap->dma_addr,
> -                                     fl->cctx->remote_heap->size, err);
> -                             goto err_map;
> -                     }
> -                     scm_done = true;
> -                     inbuf.pageslen = 1;
> -             }
> -     }
>  
>       fl->pd = USER_PD;
>  
> @@ -1370,8 +1346,15 @@ static int fastrpc_init_create_static_process(struct 
> fastrpc_user *fl,
>       args[1].length = inbuf.namelen;
>       args[1].fd = -1;
>  
> -     pages[0].addr = fl->cctx->remote_heap->dma_addr;
> -     pages[0].size = fl->cctx->remote_heap->size;
> +     if (!fl->cctx->audio_init_mem) {
> +             pages[0].addr = fl->cctx->remote_heap->dma_addr;
> +             pages[0].size = fl->cctx->remote_heap->size;

Do we need a flag? Can't we assume that remote_heap is always to be
allocated to the PD?

> +             fl->cctx->audio_init_mem = true;
> +             inbuf.pageslen = 1;
> +     } else {
> +             pages[0].addr = 0;
> +             pages[0].size = 0;
> +     }
>  
>       args[2].ptr = (u64)(uintptr_t) pages;
>       args[2].length = sizeof(*pages);
> @@ -1389,26 +1372,7 @@ static int fastrpc_init_create_static_process(struct 
> fastrpc_user *fl,
>  
>       return 0;
>  err_invoke:
> -     if (fl->cctx->vmcount && scm_done) {
> -             u64 src_perms = 0;
> -             struct qcom_scm_vmperm dst_perms;
> -             u32 i;
> -
> -             for (i = 0; i < fl->cctx->vmcount; i++)
> -                     src_perms |= BIT(fl->cctx->vmperms[i].vmid);
> -
> -             dst_perms.vmid = QCOM_SCM_VMID_HLOS;
> -             dst_perms.perm = QCOM_SCM_PERM_RWX;
> -             err = qcom_scm_assign_mem(fl->cctx->remote_heap->dma_addr,
> -                                             
> (u64)fl->cctx->remote_heap->size,
> -                                             &src_perms, &dst_perms, 1);
> -             if (err)
> -                     dev_err(fl->sctx->dev, "Failed to assign memory 
> dma_addr %pad size 0x%llx err %d\n",
> -                             &fl->cctx->remote_heap->dma_addr, 
> fl->cctx->remote_heap->size, err);
> -     }
> -err_map:
> -     fastrpc_buf_free(fl->cctx->remote_heap);
> -err_name:
> +     fl->cctx->audio_init_mem = false;
>       kfree(name);
>  err:
>       kfree(args);
> @@ -2396,7 +2360,7 @@ static int fastrpc_rpmsg_probe(struct rpmsg_device 
> *rpdev)
>               }
>       }
>  
> -     if (domain_id == SDSP_DOMAIN_ID) {
> +     if (domain_id == SDSP_DOMAIN_ID || domain_id == ADSP_DOMAIN_ID) {
>               struct resource res;
>               u64 src_perms;
>  
> @@ -2408,6 +2372,15 @@ static int fastrpc_rpmsg_probe(struct rpmsg_device 
> *rpdev)
>                                   data->vmperms, data->vmcount);
>               }
>  
> +             if (domain_id == ADSP_DOMAIN_ID) {
> +                     data->remote_heap =
> +                             kzalloc(sizeof(*data->remote_heap), GFP_KERNEL);
> +                     if (!data->remote_heap)
> +                             return -ENOMEM;
> +
> +                     data->remote_heap->dma_addr = res.start;
> +                     data->remote_heap->size = resource_size(&res);
> +             }
>       }
>  
>       secure_dsp = !(of_property_read_bool(rdev->of_node, 
> "qcom,non-secure-domain"));
> @@ -2488,10 +2461,13 @@ static void fastrpc_rpmsg_remove(struct rpmsg_device 
> *rpdev)
>       struct fastrpc_buf *buf, *b;
>       struct fastrpc_user *user;
>       unsigned long flags;
> +     bool skip_free = false;
> +     int err;
>  
>       /* No invocations past this point */
>       spin_lock_irqsave(&cctx->lock, flags);
>       cctx->rpdev = NULL;
> +     cctx->audio_init_mem = false;
>       list_for_each_entry(user, &cctx->users, user)
>               fastrpc_notify_users(user);
>       spin_unlock_irqrestore(&cctx->lock, flags);
> @@ -2505,7 +2481,26 @@ static void fastrpc_rpmsg_remove(struct rpmsg_device 
> *rpdev)
>       list_for_each_entry_safe(buf, b, &cctx->invoke_interrupted_mmaps, node)
>               list_del(&buf->node);
>  
> -     fastrpc_buf_free(cctx->remote_heap);
> +     if (cctx->remote_heap) {
> +             if (cctx->vmcount) {
> +                     u64 src_perms = 0;
> +                     struct qcom_scm_vmperm dst_perms;
> +
> +                     for (u32 i = 0; i < cctx->vmcount; i++)
> +                             src_perms |= BIT(cctx->vmperms[i].vmid);
> +
> +                     dst_perms.vmid = QCOM_SCM_VMID_HLOS;
> +                     dst_perms.perm = QCOM_SCM_PERM_RWX;
> +
> +                     err = qcom_scm_assign_mem(cctx->remote_heap->dma_addr,
> +                                               cctx->remote_heap->size,
> +                                               &src_perms, &dst_perms, 1);
> +                     if (err)
> +                             skip_free = true;
> +             }
> +             if (!skip_free)
> +                     fastrpc_buf_free(cctx->remote_heap);
> +     }
>  
>       of_platform_depopulate(&rpdev->dev);
>  
> -- 
> 2.43.0
> 

-- 
With best wishes
Dmitry

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