accel/rocket: Add IOCTLs for synchronizing memory accesses

The NPU cores have their own access to the memory bus, and this isn't
cache coherent with the CPUs.

Add IOCTLs so userspace can mark when the caches need to be flushed, and
also when a writer job needs to be waited for before the buffer can be
accessed from the CPU.

Initially based on the same IOCTLs from the Etnaviv driver.

v2:
- Don't break UABI by reordering the IOCTL IDs (Jeff Hugo)

v3:
- Check that padding fields in IOCTLs are zero (Jeff Hugo)

v6:
- Fix conversion logic to make sure we use DMA_BIDIRECTIONAL when needed
  (Lucas Stach)

v8:
- Always sync BOs in both directions (Robin Murphy)

Reviewed-by: Jeff Hugo <jeff.hugo@oss.qualcomm.com>
Tested-by: Heiko Stuebner <heiko@sntech.de>
Signed-off-by: Tomeu Vizoso <tomeu@tomeuvizoso.net>
Signed-off-by: Jeff Hugo <jeff.hugo@oss.qualcomm.com>
Link: https://lore.kernel.org/r/20250721-6-10-rocket-v9-5-77ebd484941e@tomeuvizoso.net

1 files changed, 34 insertions, 0 deletions

diff --git a/include/uapi/drm/rocket_accel.h b/include/uapi/drm/rocket_accel.h
index 374f8370ac9d..14b2e12b7c49 100644
--- a/include/uapi/drm/rocket_accel.h
+++ b/include/uapi/drm/rocket_accel.h
@@ -13,9 +13,13 @@ extern "C" {
 
 #define DRM_ROCKET_CREATE_BO			0x00
 #define DRM_ROCKET_SUBMIT			0x01
+#define DRM_ROCKET_PREP_BO			0x02
+#define DRM_ROCKET_FINI_BO			0x03
 
 #define DRM_IOCTL_ROCKET_CREATE_BO		DRM_IOWR(DRM_COMMAND_BASE + DRM_ROCKET_CREATE_BO, struct drm_rocket_create_bo)
 #define DRM_IOCTL_ROCKET_SUBMIT			DRM_IOW(DRM_COMMAND_BASE + DRM_ROCKET_SUBMIT, struct drm_rocket_submit)
+#define DRM_IOCTL_ROCKET_PREP_BO		DRM_IOW(DRM_COMMAND_BASE + DRM_ROCKET_PREP_BO, struct drm_rocket_prep_bo)
+#define DRM_IOCTL_ROCKET_FINI_BO		DRM_IOW(DRM_COMMAND_BASE + DRM_ROCKET_FINI_BO, struct drm_rocket_fini_bo)
 
 /**
  * struct drm_rocket_create_bo - ioctl argument for creating Rocket BOs.
@@ -40,6 +44,36 @@ struct drm_rocket_create_bo {
 };
 
 /**
+ * struct drm_rocket_prep_bo - ioctl argument for starting CPU ownership of the BO.
+ *
+ * Takes care of waiting for any NPU jobs that might still use the NPU and performs cache
+ * synchronization.
+ */
+struct drm_rocket_prep_bo {
+	/** Input: GEM handle of the buffer object. */
+	__u32 handle;
+
+	/** Reserved, must be zero. */
+	__u32 reserved;
+
+	/** Input: Amount of time to wait for NPU jobs. */
+	__s64 timeout_ns;
+};
+
+/**
+ * struct drm_rocket_fini_bo - ioctl argument for finishing CPU ownership of the BO.
+ *
+ * Synchronize caches for NPU access.
+ */
+struct drm_rocket_fini_bo {
+	/** Input: GEM handle of the buffer object. */
+	__u32 handle;
+
+	/** Reserved, must be zero. */
+	__u32 reserved;
+};
+
+/**
  * struct drm_rocket_task - A task to be run on the NPU
  *
  * A task is the smallest unit of work that can be run on the NPU.