[PATCH V4 1/1] drm/amd/amdgpu: Release xcp drm memory after unplug

[Lazar, Lijo]

On 7/7/2025 12:38 PM, Meng Li wrote:
> Add a new API amdgpu_xcp_drm_dev_free().
> After unplug xcp device, need to release xcp drm memory etc.
> 
> Co-developed-by: Jiang Liu <gerry at linux.alibaba.com>
> Signed-off-by: Jiang Liu <gerry at linux.alibaba.com>
> Signed-off-by: Meng Li <li.meng at amd.com>
> Acked-by: Alex Deucher <alexander.deucher at amd.com>
> Reviewed-by: Lijo Lazar <lijo.lazar at amd.com>
> ---
>  drivers/gpu/drm/amd/amdgpu/amdgpu_xcp.c     |  1 +
>  drivers/gpu/drm/amd/amdxcp/amdgpu_xcp_drv.c | 58 +++++++++++++++++----
>  drivers/gpu/drm/amd/amdxcp/amdgpu_xcp_drv.h |  1 +
>  3 files changed, 51 insertions(+), 9 deletions(-)
> 
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_xcp.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_xcp.c
> index c8fcafeb6864..e5717c657fd3 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_xcp.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_xcp.c
> @@ -394,6 +394,7 @@ void amdgpu_xcp_dev_unplug(struct amdgpu_device *adev)
>  		p_ddev->primary->dev = adev->xcp_mgr->xcp[i].pdev;
>  		p_ddev->driver =  adev->xcp_mgr->xcp[i].driver;
>  		p_ddev->vma_offset_manager = adev->xcp_mgr->xcp[i].vma_offset_manager;
> +		amdgpu_xcp_drm_dev_free(p_ddev);
>  	}
>  }
>  
> diff --git a/drivers/gpu/drm/amd/amdxcp/amdgpu_xcp_drv.c b/drivers/gpu/drm/amd/amdxcp/amdgpu_xcp_drv.c
> index 8bc36f04b1b7..447f46c29015 100644
> --- a/drivers/gpu/drm/amd/amdxcp/amdgpu_xcp_drv.c
> +++ b/drivers/gpu/drm/amd/amdxcp/amdgpu_xcp_drv.c
> @@ -46,18 +46,29 @@ static const struct drm_driver amdgpu_xcp_driver = {
>  
>  static int8_t pdev_num;
>  static struct xcp_device *xcp_dev[MAX_XCP_PLATFORM_DEVICE];
> +static DEFINE_MUTEX(xcp_mutex);
>  
>  int amdgpu_xcp_drm_dev_alloc(struct drm_device **ddev)
>  {
>  	struct platform_device *pdev;
>  	struct xcp_device *pxcp_dev;
>  	char dev_name[20];
> -	int ret;
> +	int ret, i;
> +
> +	guard(mutex)(&xcp_mutex);
>  
>  	if (pdev_num >= MAX_XCP_PLATFORM_DEVICE)
>  		return -ENODEV;
>  
> -	snprintf(dev_name, sizeof(dev_name), "amdgpu_xcp_%d", pdev_num);
> +	for (i = 0; i < MAX_XCP_PLATFORM_DEVICE; i++) {
> +		if (!xcp_dev[i])
> +			break;
> +	}
> +
> +	if (i >= MAX_XCP_PLATFORM_DEVICE)
> +		return -ENODEV;
> +
> +	snprintf(dev_name, sizeof(dev_name), "amdgpu_xcp_%d", i);
>  	pdev = platform_device_register_simple(dev_name, -1, NULL, 0);
>  	if (IS_ERR(pdev))
>  		return PTR_ERR(pdev);
> @@ -73,8 +84,8 @@ int amdgpu_xcp_drm_dev_alloc(struct drm_device **ddev)
>  		goto out_devres;
>  	}
>  
> -	xcp_dev[pdev_num] = pxcp_dev;
> -	xcp_dev[pdev_num]->pdev = pdev;
> +	xcp_dev[i] = pxcp_dev;
> +	xcp_dev[i]->pdev = pdev;
>  	*ddev = &pxcp_dev->drm;
>  	pdev_num++;
>  
> @@ -89,16 +100,45 @@ int amdgpu_xcp_drm_dev_alloc(struct drm_device **ddev)
>  }
>  EXPORT_SYMBOL(amdgpu_xcp_drm_dev_alloc);
>  
> -void amdgpu_xcp_drv_release(void)
> +static void free_xcp_dev(int8_t index)
>  {
> -	for (--pdev_num; pdev_num >= 0; --pdev_num) {
> -		struct platform_device *pdev = xcp_dev[pdev_num]->pdev;
> +	if ((index < MAX_XCP_PLATFORM_DEVICE) && (xcp_dev[index])) {
> +		struct platform_device *pdev = xcp_dev[index]->pdev;
>  
>  		devres_release_group(&pdev->dev, NULL);
>  		platform_device_unregister(pdev);
> -		xcp_dev[pdev_num] = NULL;
> +
> +		xcp_dev[index] = NULL;
> +		pdev_num--;
> +	}
> +}
> +
> +void amdgpu_xcp_drm_dev_free(struct drm_device *ddev)
> +{
> +	int8_t i;
> +
> +	guard(mutex)(&xcp_mutex);
> +
> +	for (i = 0; i < MAX_XCP_PLATFORM_DEVICE; i++) {
> +		if ((xcp_dev[i]) && (&xcp_dev[i]->drm == ddev)) {
> +			free_xcp_dev(i);
> +			break;
> +		}
> +	}
> +}
> +EXPORT_SYMBOL(amdgpu_xcp_drm_dev_free);
> +
> +void amdgpu_xcp_drv_release(void)
> +{
> +	int8_t i;
> +
> +	guard(mutex)(&xcp_mutex);
> +
> +	for (i = 0; pdev_num && i < MAX_XCP_PLATFORM_DEVICE; i++) {
> +		free_xcp_dev(i);
> +		if (pdev_num == 0)
> +			break;

This if check is not required. It's already covered in loop exit condition.

Thanks,
Lijo

>  	}
> -	pdev_num = 0;
>  }
>  EXPORT_SYMBOL(amdgpu_xcp_drv_release);
>  
> diff --git a/drivers/gpu/drm/amd/amdxcp/amdgpu_xcp_drv.h b/drivers/gpu/drm/amd/amdxcp/amdgpu_xcp_drv.h
> index c1c4b679bf95..580a1602c8e3 100644
> --- a/drivers/gpu/drm/amd/amdxcp/amdgpu_xcp_drv.h
> +++ b/drivers/gpu/drm/amd/amdxcp/amdgpu_xcp_drv.h
> @@ -25,5 +25,6 @@
>  #define _AMDGPU_XCP_DRV_H_
>  
>  int amdgpu_xcp_drm_dev_alloc(struct drm_device **ddev);
> +void amdgpu_xcp_drm_dev_free(struct drm_device *ddev);
>  void amdgpu_xcp_drv_release(void);
>  #endif /* _AMDGPU_XCP_DRV_H_ */