arch/hexagon/mm/init.c

   1 /*
   2  * Memory subsystem initialization for Hexagon
   3  *
   4  * Copyright (c) 2010-2011, Code Aurora Forum. 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 }