[PATCH v4 08/11] drm/tyr: add BO-related ioctls

[Ke Sun via B4 Relay]

From: Alvin Sun <alvin.sun@xxxxxxxxx>

Implement BO_CREATE and BO_MMAP_OFFSET so userspace can allocate GPU
buffers and obtain a DRM mmap offset for the generic mmap path.
BO_CREATE page-aligns the requested size; BO_MMAP_OFFSET rejects
NO_MMAP objects, which must never be CPU-mapped.

Signed-off-by: Alvin Sun <alvin.sun@xxxxxxxxx>
---
 drivers/gpu/drm/tyr/driver.rs |  2 ++
 drivers/gpu/drm/tyr/file.rs   | 73 +++++++++++++++++++++++++++++++++++++++++++
 drivers/gpu/drm/tyr/gem.rs    | 18 +++++++++--
 3 files changed, 90 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/tyr/driver.rs b/drivers/gpu/drm/tyr/driver.rs
index c0f17bc4ce2c9..f4f31b24180b4 100644
--- a/drivers/gpu/drm/tyr/driver.rs
+++ b/drivers/gpu/drm/tyr/driver.rs
@@ -227,6 +227,8 @@ impl drm::Driver for TyrDrmDriver {
         (PANTHOR_VM_DESTROY, drm_panthor_vm_destroy, ioctl::RENDER_ALLOW, TyrDrmFileData::vm_destroy),
         (PANTHOR_VM_BIND, drm_panthor_vm_bind, ioctl::RENDER_ALLOW, TyrDrmFileData::vm_bind),
         (PANTHOR_VM_GET_STATE, drm_panthor_vm_get_state, ioctl::RENDER_ALLOW, TyrDrmFileData::vm_get_state),
+        (PANTHOR_BO_CREATE, drm_panthor_bo_create, ioctl::RENDER_ALLOW, TyrDrmFileData::bo_create),
+        (PANTHOR_BO_MMAP_OFFSET, drm_panthor_bo_mmap_offset, ioctl::RENDER_ALLOW, TyrDrmFileData::bo_mmap_offset),
     }
 }
 
diff --git a/drivers/gpu/drm/tyr/file.rs b/drivers/gpu/drm/tyr/file.rs
index 22a74b4abf3de..9ffb42f0d8851 100644
--- a/drivers/gpu/drm/tyr/file.rs
+++ b/drivers/gpu/drm/tyr/file.rs
@@ -250,6 +250,79 @@ pub(crate) fn vm_get_state(
             Ok(0)
         })
     }
+
+    pub(crate) fn bo_create(
+        ddev: &TyrDrmDevice<Registered>,
+        _reg_data: &TyrDrmRegistrationData<'_>,
+        bocreate: &mut uapi::drm_panthor_bo_create,
+        file: &TyrDrmFile,
+    ) -> Result<u32> {
+        if bocreate.size == 0
+            || bocreate.pad != 0
+            || bocreate.flags & !uapi::drm_panthor_bo_flags_DRM_PANTHOR_BO_NO_MMAP != 0
+        {
+            dev_dbg!(
+                ddev.as_ref(),
+                "Invalid BO_CREATE params: size={}, pad={}, flags={:#x}\n",
+                bocreate.size,
+                bocreate.pad,
+                bocreate.flags
+            );
+            return Err(EINVAL);
+        }
+
+        if bocreate.exclusive_vm_id != 0 {
+            dev_dbg!(ddev.as_ref(), "BO_CREATE: exclusive_vm_id not supported\n");
+            return Err(EINVAL);
+        }
+
+        let size = usize::try_from(bocreate.size).map_err(|_| {
+            dev_dbg!(
+                ddev.as_ref(),
+                "BO_CREATE size {:#x} too large\n",
+                bocreate.size
+            );
+            EINVAL
+        })?;
+        let bo = crate::gem::new_object(ddev, size, bocreate.flags)?;
+        bocreate.handle = bo.create_handle(file)?;
+        bocreate.size = bo.size() as u64;
+
+        Ok(0)
+    }
+
+    pub(crate) fn bo_mmap_offset(
+        ddev: &TyrDrmDevice<Registered>,
+        _reg_data: &TyrDrmRegistrationData<'_>,
+        bommap: &mut uapi::drm_panthor_bo_mmap_offset,
+        file: &TyrDrmFile,
+    ) -> Result<u32> {
+        if bommap.pad != 0 {
+            dev_dbg!(
+                ddev.as_ref(),
+                "BO mmap offset pad not zero: {}\n",
+                bommap.pad
+            );
+            return Err(EINVAL);
+        }
+
+        let bo = crate::gem::lookup_handle(file, bommap.handle).inspect_err(|_| {
+            dev_dbg!(ddev.as_ref(), "Invalid BO mmap handle: {}\n", bommap.handle);
+        })?;
+        if bo.flags() & uapi::drm_panthor_bo_flags_DRM_PANTHOR_BO_NO_MMAP != 0 {
+            dev_dbg!(ddev.as_ref(), "BO mmap offset on NO_MMAP object\n");
+            return Err(EPERM);
+        }
+        bommap.offset = bo.create_mmap_offset().inspect_err(|_| {
+            dev_err!(
+                ddev.as_ref(),
+                "Failed to create mmap offset for handle {}\n",
+                bommap.handle
+            );
+        })?;
+
+        Ok(0)
+    }
 }
 
 fn vm_bind_exec_op(vm: &Vm<'_>, file: &TyrDrmFile, op: &VmBindOp) -> Result {
diff --git a/drivers/gpu/drm/tyr/gem.rs b/drivers/gpu/drm/tyr/gem.rs
index 60f6363995a5a..14f3e182b98e2 100644
--- a/drivers/gpu/drm/tyr/gem.rs
+++ b/drivers/gpu/drm/tyr/gem.rs
@@ -38,6 +38,13 @@ pub(crate) struct BoData {
     flags: u32,
 }
 
+impl BoData {
+    /// Returns the flags the BO was created with.
+    pub(crate) fn flags(&self) -> u32 {
+        self.flags
+    }
+}
+
 /// Provides a way to pass arguments when creating BoData
 /// as required by the gem::DriverObject trait.
 pub(crate) struct BoCreateArgs {
@@ -57,7 +64,6 @@ fn new(_dev: &TyrDrmDevice, _size: usize, args: BoCreateArgs) -> impl PinInit<Se
 pub(crate) type Bo = gem::shmem::Object<BoData>;
 
 /// Create a new GEM buffer object.
-#[expect(dead_code)]
 pub(crate) fn new_object(ddev: &TyrDrmDevice, size: usize, flags: u32) -> Result<ARef<Bo>> {
     if size == 0 {
         return Err(EINVAL);
@@ -65,7 +71,7 @@ pub(crate) fn new_object(ddev: &TyrDrmDevice, size: usize, flags: u32) -> Result
 
     let aligned_size = size.checked_next_multiple_of(PAGE_SIZE).ok_or(EINVAL)?;
 
-    Bo::new(
+    let bo = Bo::new(
         ddev,
         aligned_size,
         shmem::ObjectConfig {
@@ -73,7 +79,13 @@ pub(crate) fn new_object(ddev: &TyrDrmDevice, size: usize, flags: u32) -> Result
             parent_resv_obj: None,
         },
         BoCreateArgs { flags },
-    )
+    )?;
+
+    // SAFETY: `ddev` is bound for the duration of this call.
+    let dev = unsafe { ddev.as_ref().as_ref().as_bound() };
+    bo.sg_table(dev)?;
+
+    Ok(bo)
 }
 
 /// Look up a GEM object by handle for a DRM file.

-- 
2.43.0