489  * DOC: Flat-CCS - Memory compression for Local memory
491  * On Xe-HP and later devices, we use dedicated compression control state (CCS)
495  * The memory required for the CCS of the entire local memory is 1/256 of the
497  * for the CCS data and a secure register will be programmed with the CCS base
500  * Flat CCS data needs to be cleared when a lmem object is allocated.
501  * And CCS data can be copied in and out of CCS region through
502  * XY_CTRL_SURF_COPY_BLT. CPU can't access the CCS data directly.
504  * I915 supports Flat-CCS on lmem only objects. When an objects has smem in
506  * content into smem. If the lmem object is Flat-CCS compressed by userspace,
508  * for such decompression. Hence I915 supports Flat-CCS only on lmem only objects.
510  * When we exhaust the lmem, Flat-CCS capable objects' lmem backing memory can
511  * be temporarily evicted to smem, along with the auxiliary CCS state, where
514  * the backing memory back to lmem, which includes restoring the saved CCS state,
518  * {lmem, smem}, objects are treated as non Flat-CCS capable objects.
549 	 * The XY_CTRL_SURF_COPY_BLT instruction is used to copy the CCS  in emit_copy_ccs()
550 	 * data in and out of the CCS region.  in emit_copy_ccs()
558 	 * 1024 blocks of 256 bytes of CCS represent a total 256KB of CCS.  in emit_copy_ccs()
560 	 * 256 KB of CCS represents 256 * 256 KB = 64 MB of LMEM.  in emit_copy_ccs()
647 		 * will be taken for the blt. in Flat-ccs supported  in calculate_chunk_sz()
725 		 * When there is a eviction of ccs needed smem will have the  in intel_context_migrate_copy()
726 		 * extra pages for the ccs data  in intel_context_migrate_copy()
851 				 * should be safe to directly copy the CCS  in intel_context_migrate_copy()
853 				 * initialised the CCS aux state when first  in intel_context_migrate_copy()
857 				 * need to copy the CCS state as-is.  in intel_context_migrate_copy()
865 				 * While we can't always restore/manage the CCS  in intel_context_migrate_copy()
867 				 * the CCS state from the previous user, so make  in intel_context_migrate_copy()
1052 			 * ccs surface  in intel_context_migrate_clear()