xref: /openbmc/linux/arch/x86/include/asm/agp.h (revision ae213c44)
1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef _ASM_X86_AGP_H
3 #define _ASM_X86_AGP_H
4 
5 #include <asm/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 */
33