1 /* 2 * Memory subsystem initialization for Hexagon 3 * 4 * Copyright (c) 2010-2011, The Linux Foundation. All rights reserved. 5 * 6 * This program is free software; you can redistribute it and/or modify 7 * it under the terms of the GNU General Public License version 2 and 8 * only version 2 as published by the Free Software Foundation. 9 * 10 * This program is distributed in the hope that it will be useful, 11 * but WITHOUT ANY WARRANTY; without even the implied warranty of 12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 13 * GNU General Public License for more details. 14 * 15 * You should have received a copy of the GNU General Public License 16 * along with this program; if not, write to the Free Software 17 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 18 * 02110-1301, USA. 19 */ 20 21 #include <linux/init.h> 22 #include <linux/mm.h> 23 #include <linux/bootmem.h> 24 #include <asm/atomic.h> 25 #include <linux/highmem.h> 26 #include <asm/tlb.h> 27 #include <asm/sections.h> 28 #include <asm/vm_mmu.h> 29 30 /* 31 * Define a startpg just past the end of the kernel image and a lastpg 32 * that corresponds to the end of real or simulated platform memory. 33 */ 34 #define bootmem_startpg (PFN_UP(((unsigned long) _end) - PAGE_OFFSET)) 35 36 unsigned long bootmem_lastpg; /* Should be set by platform code */ 37 38 /* Set as variable to limit PMD copies */ 39 int max_kernel_seg = 0x303; 40 41 /* think this should be (page_size-1) the way it's used...*/ 42 unsigned long zero_page_mask; 43 44 /* indicate pfn's of high memory */ 45 unsigned long highstart_pfn, highend_pfn; 46 47 /* struct mmu_gather defined in asm-generic.h; */ 48 DEFINE_PER_CPU(struct mmu_gather, mmu_gathers); 49 50 /* Default cache attribute for newly created page tables */ 51 unsigned long _dflt_cache_att = CACHEDEF; 52 53 /* 54 * The current "generation" of kernel map, which should not roll 55 * over until Hell freezes over. Actual bound in years needs to be 56 * calculated to confirm. 57 */ 58 DEFINE_SPINLOCK(kmap_gen_lock); 59 60 /* checkpatch says don't init this to 0. */ 61 unsigned long long kmap_generation; 62 63 /* 64 * mem_init - initializes memory 65 * 66 * Frees up bootmem 67 * Fixes up more stuff for HIGHMEM 68 * Calculates and displays memory available/used 69 */ 70 void __init mem_init(void) 71 { 72 /* No idea where this is actually declared. Seems to evade LXR. */ 73 totalram_pages += free_all_bootmem(); 74 num_physpages = bootmem_lastpg; /* seriously, what? */ 75 76 printk(KERN_INFO "totalram_pages = %ld\n", totalram_pages); 77 78 /* 79 * To-Do: someone somewhere should wipe out the bootmem map 80 * after we're done? 81 */ 82 83 /* 84 * This can be moved to some more virtual-memory-specific 85 * initialization hook at some point. Set the init_mm 86 * descriptors "context" value to point to the initial 87 * kernel segment table's physical address. 88 */ 89 init_mm.context.ptbase = __pa(init_mm.pgd); 90 } 91 92 /* 93 * free_initmem - frees memory used by stuff declared with __init 94 * 95 * Todo: free pages between __init_begin and __init_end; possibly 96 * some devtree related stuff as well. 97 */ 98 void __init_refok free_initmem(void) 99 { 100 } 101 102 /* 103 * free_initrd_mem - frees... initrd memory. 104 * @start - start of init memory 105 * @end - end of init memory 106 * 107 * Apparently has to be passed the address of the initrd memory. 108 * 109 * Wrapped by #ifdef CONFIG_BLKDEV_INITRD 110 */ 111 void free_initrd_mem(unsigned long start, unsigned long end) 112 { 113 } 114 115 void sync_icache_dcache(pte_t pte) 116 { 117 unsigned long addr; 118 struct page *page; 119 120 page = pte_page(pte); 121 addr = (unsigned long) page_address(page); 122 123 __vmcache_idsync(addr, PAGE_SIZE); 124 } 125 126 /* 127 * In order to set up page allocator "nodes", 128 * somebody has to call free_area_init() for UMA. 129 * 130 * In this mode, we only have one pg_data_t 131 * structure: contig_mem_data. 132 */ 133 void __init paging_init(void) 134 { 135 unsigned long zones_sizes[MAX_NR_ZONES] = {0, }; 136 137 /* 138 * This is not particularly well documented anywhere, but 139 * give ZONE_NORMAL all the memory, including the big holes 140 * left by the kernel+bootmem_map which are already left as reserved 141 * in the bootmem_map; free_area_init should see those bits and 142 * adjust accordingly. 143 */ 144 145 zones_sizes[ZONE_NORMAL] = max_low_pfn; 146 147 free_area_init(zones_sizes); /* sets up the zonelists and mem_map */ 148 149 /* 150 * Start of high memory area. Will probably need something more 151 * fancy if we... get more fancy. 152 */ 153 high_memory = (void *)((bootmem_lastpg + 1) << PAGE_SHIFT); 154 } 155 156 #ifndef DMA_RESERVE 157 #define DMA_RESERVE (4) 158 #endif 159 160 #define DMA_CHUNKSIZE (1<<22) 161 #define DMA_RESERVED_BYTES (DMA_RESERVE * DMA_CHUNKSIZE) 162 163 /* 164 * Pick out the memory size. We look for mem=size, 165 * where size is "size[KkMm]" 166 */ 167 static int __init early_mem(char *p) 168 { 169 unsigned long size; 170 char *endp; 171 172 size = memparse(p, &endp); 173 174 bootmem_lastpg = PFN_DOWN(size); 175 176 return 0; 177 } 178 early_param("mem", early_mem); 179 180 size_t hexagon_coherent_pool_size = (size_t) (DMA_RESERVE << 22); 181 182 void __init setup_arch_memory(void) 183 { 184 int bootmap_size; 185 /* XXX Todo: this probably should be cleaned up */ 186 u32 *segtable = (u32 *) &swapper_pg_dir[0]; 187 u32 *segtable_end; 188 189 /* 190 * Set up boot memory allocator 191 * 192 * The Gorman book also talks about these functions. 193 * This needs to change for highmem setups. 194 */ 195 196 /* Memory size needs to be a multiple of 16M */ 197 bootmem_lastpg = PFN_DOWN((bootmem_lastpg << PAGE_SHIFT) & 198 ~((BIG_KERNEL_PAGE_SIZE) - 1)); 199 200 /* 201 * Reserve the top DMA_RESERVE bytes of RAM for DMA (uncached) 202 * memory allocation 203 */ 204 bootmap_size = init_bootmem(bootmem_startpg, bootmem_lastpg - 205 PFN_DOWN(DMA_RESERVED_BYTES)); 206 207 printk(KERN_INFO "bootmem_startpg: 0x%08lx\n", bootmem_startpg); 208 printk(KERN_INFO "bootmem_lastpg: 0x%08lx\n", bootmem_lastpg); 209 printk(KERN_INFO "bootmap_size: %d\n", bootmap_size); 210 printk(KERN_INFO "max_low_pfn: 0x%08lx\n", max_low_pfn); 211 212 /* 213 * The default VM page tables (will be) populated with 214 * VA=PA+PAGE_OFFSET mapping. We go in and invalidate entries 215 * higher than what we have memory for. 216 */ 217 218 /* this is pointer arithmetic; each entry covers 4MB */ 219 segtable = segtable + (PAGE_OFFSET >> 22); 220 221 /* this actually only goes to the end of the first gig */ 222 segtable_end = segtable + (1<<(30-22)); 223 224 /* Move forward to the start of empty pages */ 225 segtable += bootmem_lastpg >> (22-PAGE_SHIFT); 226 227 { 228 int i; 229 230 for (i = 1 ; i <= DMA_RESERVE ; i++) 231 segtable[-i] = ((segtable[-i] & __HVM_PTE_PGMASK_4MB) 232 | __HVM_PTE_R | __HVM_PTE_W | __HVM_PTE_X 233 | __HEXAGON_C_UNC << 6 234 | __HVM_PDE_S_4MB); 235 } 236 237 printk(KERN_INFO "clearing segtable from %p to %p\n", segtable, 238 segtable_end); 239 while (segtable < (segtable_end-8)) 240 *(segtable++) = __HVM_PDE_S_INVALID; 241 /* stop the pointer at the device I/O 4MB page */ 242 243 printk(KERN_INFO "segtable = %p (should be equal to _K_io_map)\n", 244 segtable); 245 246 #if 0 247 /* Other half of the early device table from vm_init_segtable. */ 248 printk(KERN_INFO "&_K_init_devicetable = 0x%08x\n", 249 (unsigned long) _K_init_devicetable-PAGE_OFFSET); 250 *segtable = ((u32) (unsigned long) _K_init_devicetable-PAGE_OFFSET) | 251 __HVM_PDE_S_4KB; 252 printk(KERN_INFO "*segtable = 0x%08x\n", *segtable); 253 #endif 254 255 /* 256 * Free all the memory that wasn't taken up by the bootmap, the DMA 257 * reserve, or kernel itself. 258 */ 259 free_bootmem(PFN_PHYS(bootmem_startpg)+bootmap_size, 260 PFN_PHYS(bootmem_lastpg - bootmem_startpg) - bootmap_size - 261 DMA_RESERVED_BYTES); 262 263 /* 264 * The bootmem allocator seemingly just lives to feed memory 265 * to the paging system 266 */ 267 printk(KERN_INFO "PAGE_SIZE=%lu\n", PAGE_SIZE); 268 paging_init(); /* See Gorman Book, 2.3 */ 269 270 /* 271 * At this point, the page allocator is kind of initialized, but 272 * apparently no pages are available (just like with the bootmem 273 * allocator), and need to be freed themselves via mem_init(), 274 * which is called by start_kernel() later on in the process 275 */ 276 } 277