arch/x86/include/asm/agp.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 #ifndef _ASM_X86_AGP_H
   3 #define _ASM_X86_AGP_H
   4
   5 #include <linux/pgtable.h>
   6 #include <asm/cacheflush.h>
   7
   8 /*
   9  * Functions to keep the agpgart mappings coherent with the MMU. The
  10  * GART gives the CPU a physical alias of pages in memory. The alias
  11  * region is mapped uncacheable. Make sure there are no conflicting
  12  * mappings with different cachability attributes for the same
  13  * page. This avoids data corruption on some CPUs.
  14  */
  15
  16 #define map_page_into_agp(page) set_pages_uc(page, 1)
  17 #define unmap_page_from_agp(page) set_pages_wb(page, 1)
  18
  19 /*
  20  * Could use CLFLUSH here if the cpu supports it. But then it would
  21  * need to be called for each cacheline of the whole page so it may
  22  * not be worth it. Would need a page for it.
  23  */
  24 #define flush_agp_cache() wbinvd()
  25
  26 /* GATT allocation. Returns/accepts GATT kernel virtual address. */
  27 #define alloc_gatt_pages(order)         \
  28         ((char *)__get_free_pages(GFP_KERNEL, (order)))
  29 #define free_gatt_pages(table, order)   \
  30         free_pages((unsigned long)(table), (order))
  31
  32 #endif /* _ASM_X86_AGP_H */