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Embedded Linux Audio
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/* * linux/include/asm-arm/arch-rpc/mmap.h * * Copyright (C) 1996 Russell King */ #define HAVE_MAP_VID_MEM unsigned long map_screen_mem(unsigned long log_start, unsigned long kmem, int update) { static int updated = 0; unsigned long address; pgd_t *pgd; if (updated) return 0; updated = update; address = SCREEN_START | PMD_TYPE_SECT | PMD_DOMAIN(DOMAIN_KERNEL) | PMD_SECT_AP_WRITE; pgd = swapper_pg_dir + (SCREEN2_BASE >> PGDIR_SHIFT); pgd_val(pgd[0]) = address; pgd_val(pgd[1]) = address + (1 << PGDIR_SHIFT); if (update) { unsigned long pgtable = PAGE_ALIGN(kmem), *p; int i; memzero ((void *)pgtable, 4096); pgd_val(pgd[-2]) = __virt_to_phys(pgtable) | PMD_TYPE_TABLE | PMD_DOMAIN(DOMAIN_KERNEL); pgd_val(pgd[-1]) = __virt_to_phys(pgtable + PTRS_PER_PTE*4) | PMD_TYPE_TABLE | PMD_DOMAIN(DOMAIN_KERNEL); p = (unsigned long *)pgtable; i = PTRS_PER_PTE * 2 - ((SCREEN1_END - log_start) >> PAGE_SHIFT); address = SCREEN_START | PTE_TYPE_SMALL | PTE_AP_WRITE; while (i < PTRS_PER_PTE * 2) { p[i++] = address; address += PAGE_SIZE; } flush_page_to_ram(pgtable); kmem = pgtable + PAGE_SIZE; } return kmem; }