rusticl: return correct error from clCreateSubBuffer

From the OpenCL specification, `clCreateSubBuffer` should return:
`CL_MISALIGNED_SUB_BUFFER_OFFSET` if there are no devices in
`context` associated with `buffer` for which the `origin` field of
the `cl_buffer_region` structure passed in `buffer_create_info` is
aligned to the `CL_DEVICE_MEM_BASE_ADDR_ALIGN` value.

This was previously unhandled in the entrypoint, marked as TODO.

Add two functions to `Device` for querying the address alignment in
both bits and bytes, for convenience. Properly retrieving the
alignment value from the underlying device/screen is still marked as
TODO.

Signed-off-by: Ahmed Hesham <ahmed.hesham@arm.com>
Reviewed-by: Karol Herbst <kherbst@redhat.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/40726>

src/gallium/frontends/rusticl/api/device.rs

@@ -200,8 +200,7 @@ unsafe impl CLInfo<cl_device_info> for cl_device_id {
             CL_DEVICE_MAX_WORK_ITEM_DIMENSIONS => v.write::<cl_uint>(dev.max_grid_dimensions()),
             CL_DEVICE_MAX_WORK_ITEM_SIZES => v.write::<&[usize]>(&dev.max_block_sizes()),
             CL_DEVICE_MAX_WRITE_IMAGE_ARGS => v.write::<cl_uint>(dev.caps.max_write_images),
-            // TODO proper retrival from devices
-            CL_DEVICE_MEM_BASE_ADDR_ALIGN => v.write::<cl_uint>(0x1000),
+            CL_DEVICE_MEM_BASE_ADDR_ALIGN => v.write::<cl_uint>(dev.mem_base_addr_align_bits()),
             CL_DEVICE_MIN_DATA_TYPE_ALIGN_SIZE => {
                 v.write::<cl_uint>(16 * size_of::<cl_ulong>() as cl_uint)
             }

src/gallium/frontends/rusticl/api/memory.rs

@@ -452,10 +452,19 @@ fn create_sub_buffer(
         _ => return Err(CL_INVALID_VALUE),
     };
 
-    Ok(MemBase::new_sub_buffer(b, flags, offset, size).into_cl())
+    // CL_MISALIGNED_SUB_BUFFER_OFFSET if there are no devices in context associated with buffer for
+    // which offset is aligned to CL_DEVICE_MEM_BASE_ADDR_ALIGN.
+    let is_aligned_for_any_dev = b
+        .context
+        .devs
+        .iter()
+        .any(|&dev| offset % dev.mem_base_addr_align_bytes() == 0);
 
-    // TODO
-    // CL_MISALIGNED_SUB_BUFFER_OFFSET if there are no devices in context associated with buffer for which the origin field of the cl_buffer_region structure passed in buffer_create_info is aligned to the CL_DEVICE_MEM_BASE_ADDR_ALIGN value.
+    if !is_aligned_for_any_dev {
+        return Err(CL_MISALIGNED_SUB_BUFFER_OFFSET);
+    }
+
+    Ok(MemBase::new_sub_buffer(b, flags, offset, size).into_cl())
 }
 
 #[cl_entrypoint(clSetMemObjectDestructorCallback)]

src/gallium/frontends/rusticl/core/device.rs

@@ -1362,6 +1362,16 @@ impl DeviceBase {
 }
 
 impl Device {
+    pub fn mem_base_addr_align_bytes(&self) -> usize {
+        // TODO: proper retrieval from the underlying device/screen
+        0x200
+    }
+
+    pub fn mem_base_addr_align_bits(&self) -> u32 {
+        const BITS_PER_BYTE: u32 = 8;
+        (self.mem_base_addr_align_bytes() as u32) * BITS_PER_BYTE
+    }
+
     fn new(screen: PipeScreenWithLdev) -> Option<Device> {
         if !Self::check_valid(&screen) {
             return None;