arch/hexagon/mm/init.c

   1 /*
   2  * Memory subsystem initialization for Hexagon
   3  *
   4  * Copyright (c) 2010-2013, 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 + PHYS_OFFSET))
  35
  36 unsigned long bootmem_lastpg;   /*  Should be set by platform code  */
  37 unsigned long __phys_offset;    /*  physical kernel offset >> 12  */
  38
  39 /*  Set as variable to limit PMD copies  */
  40 int max_kernel_seg = 0x303;
  41
  42 /*  think this should be (page_size-1) the way it's used...*/
  43 unsigned long zero_page_mask;
  44
  45 /*  indicate pfn's of high memory  */
  46 unsigned long highstart_pfn, highend_pfn;
  47
  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         free_all_bootmem();
  74         mem_init_print_info(NULL);
  75
  76         /*
  77          *  To-Do:  someone somewhere should wipe out the bootmem map
  78          *  after we're done?
  79          */
  80
  81         /*
  82          * This can be moved to some more virtual-memory-specific
  83          * initialization hook at some point.  Set the init_mm
  84          * descriptors "context" value to point to the initial
  85          * kernel segment table's physical address.
  86          */
  87         init_mm.context.ptbase = __pa(init_mm.pgd);
  88 }
  89
  90 /*
  91  * free_initmem - frees memory used by stuff declared with __init
  92  *
  93  * Todo:  free pages between __init_begin and __init_end; possibly
  94  * some devtree related stuff as well.
  95  */
  96 void __ref free_initmem(void)
  97 {
  98 }
  99
 100 /*
 101  * free_initrd_mem - frees...  initrd memory.
 102  * @start - start of init memory
 103  * @end - end of init memory
 104  *
 105  * Apparently has to be passed the address of the initrd memory.
 106  *
 107  * Wrapped by #ifdef CONFIG_BLKDEV_INITRD
 108  */
 109 void free_initrd_mem(unsigned long start, unsigned long end)
 110 {
 111 }
 112
 113 void sync_icache_dcache(pte_t pte)
 114 {
 115         unsigned long addr;
 116         struct page *page;
 117
 118         page = pte_page(pte);
 119         addr = (unsigned long) page_address(page);
 120
 121         __vmcache_idsync(addr, PAGE_SIZE);
 122 }
 123
 124 /*
 125  * In order to set up page allocator "nodes",
 126  * somebody has to call free_area_init() for UMA.
 127  *
 128  * In this mode, we only have one pg_data_t
 129  * structure: contig_mem_data.
 130  */
 131 void __init paging_init(void)
 132 {
 133         unsigned long zones_sizes[MAX_NR_ZONES] = {0, };
 134
 135         /*
 136          *  This is not particularly well documented anywhere, but
 137          *  give ZONE_NORMAL all the memory, including the big holes
 138          *  left by the kernel+bootmem_map which are already left as reserved
 139          *  in the bootmem_map; free_area_init should see those bits and
 140          *  adjust accordingly.
 141          */
 142
 143         zones_sizes[ZONE_NORMAL] = max_low_pfn;
 144
 145         free_area_init(zones_sizes);  /*  sets up the zonelists and mem_map  */
 146
 147         /*
 148          * Start of high memory area.  Will probably need something more
 149          * fancy if we...  get more fancy.
 150          */
 151         high_memory = (void *)((bootmem_lastpg + 1) << PAGE_SHIFT);
 152 }
 153
 154 #ifndef DMA_RESERVE
 155 #define DMA_RESERVE             (4)
 156 #endif
 157
 158 #define DMA_CHUNKSIZE           (1<<22)
 159 #define DMA_RESERVED_BYTES      (DMA_RESERVE * DMA_CHUNKSIZE)
 160
 161 /*
 162  * Pick out the memory size.  We look for mem=size,
 163  * where size is "size[KkMm]"
 164  */
 165 static int __init early_mem(char *p)
 166 {
 167         unsigned long size;
 168         char *endp;
 169
 170         size = memparse(p, &endp);
 171
 172         bootmem_lastpg = PFN_DOWN(size);
 173
 174         return 0;
 175 }
 176 early_param("mem", early_mem);
 177
 178 size_t hexagon_coherent_pool_size = (size_t) (DMA_RESERVE << 22);
 179
 180 void __init setup_arch_memory(void)
 181 {
 182         int bootmap_size;
 183         /*  XXX Todo: this probably should be cleaned up  */
 184         u32 *segtable = (u32 *) &swapper_pg_dir[0];
 185         u32 *segtable_end;
 186
 187         /*
 188          * Set up boot memory allocator
 189          *
 190          * The Gorman book also talks about these functions.
 191          * This needs to change for highmem setups.
 192          */
 193
 194         /*  Prior to this, bootmem_lastpg is actually mem size  */
 195         bootmem_lastpg += ARCH_PFN_OFFSET;
 196
 197         /* Memory size needs to be a multiple of 16M */
 198         bootmem_lastpg = PFN_DOWN((bootmem_lastpg << PAGE_SHIFT) &
 199                 ~((BIG_KERNEL_PAGE_SIZE) - 1));
 200
 201         /*
 202          * Reserve the top DMA_RESERVE bytes of RAM for DMA (uncached)
 203          * memory allocation
 204          */
 205
 206         max_low_pfn = bootmem_lastpg - PFN_DOWN(DMA_RESERVED_BYTES);
 207         min_low_pfn = ARCH_PFN_OFFSET;
 208         bootmap_size =  init_bootmem_node(NODE_DATA(0), bootmem_startpg, min_low_pfn, max_low_pfn);
 209
 210         printk(KERN_INFO "bootmem_startpg:  0x%08lx\n", bootmem_startpg);
 211         printk(KERN_INFO "bootmem_lastpg:  0x%08lx\n", bootmem_lastpg);
 212         printk(KERN_INFO "bootmap_size:  %d\n", bootmap_size);
 213         printk(KERN_INFO "min_low_pfn:  0x%08lx\n", min_low_pfn);
 214         printk(KERN_INFO "max_low_pfn:  0x%08lx\n", max_low_pfn);
 215
 216         /*
 217          * The default VM page tables (will be) populated with
 218          * VA=PA+PAGE_OFFSET mapping.  We go in and invalidate entries
 219          * higher than what we have memory for.
 220          */
 221
 222         /*  this is pointer arithmetic; each entry covers 4MB  */
 223         segtable = segtable + (PAGE_OFFSET >> 22);
 224
 225         /*  this actually only goes to the end of the first gig  */
 226         segtable_end = segtable + (1<<(30-22));
 227
 228         /*
 229          * Move forward to the start of empty pages; take into account
 230          * phys_offset shift.
 231          */
 232
 233         segtable += (bootmem_lastpg-ARCH_PFN_OFFSET)>>(22-PAGE_SHIFT);
 234         {
 235                 int i;
 236
 237                 for (i = 1 ; i <= DMA_RESERVE ; i++)
 238                         segtable[-i] = ((segtable[-i] & __HVM_PTE_PGMASK_4MB)
 239                                 | __HVM_PTE_R | __HVM_PTE_W | __HVM_PTE_X
 240                                 | __HEXAGON_C_UNC << 6
 241                                 | __HVM_PDE_S_4MB);
 242         }
 243
 244         printk(KERN_INFO "clearing segtable from %p to %p\n", segtable,
 245                 segtable_end);
 246         while (segtable < (segtable_end-8))
 247                 *(segtable++) = __HVM_PDE_S_INVALID;
 248         /* stop the pointer at the device I/O 4MB page  */
 249
 250         printk(KERN_INFO "segtable = %p (should be equal to _K_io_map)\n",
 251                 segtable);
 252
 253 #if 0
 254         /*  Other half of the early device table from vm_init_segtable. */
 255         printk(KERN_INFO "&_K_init_devicetable = 0x%08x\n",
 256                 (unsigned long) _K_init_devicetable-PAGE_OFFSET);
 257         *segtable = ((u32) (unsigned long) _K_init_devicetable-PAGE_OFFSET) |
 258                 __HVM_PDE_S_4KB;
 259         printk(KERN_INFO "*segtable = 0x%08x\n", *segtable);
 260 #endif
 261
 262         /*
 263          * Free all the memory that wasn't taken up by the bootmap, the DMA
 264          * reserve, or kernel itself.
 265          */
 266         free_bootmem(PFN_PHYS(bootmem_startpg) + bootmap_size,
 267                      PFN_PHYS(bootmem_lastpg - bootmem_startpg) - bootmap_size -
 268                      DMA_RESERVED_BYTES);
 269
 270         /*
 271          *  The bootmem allocator seemingly just lives to feed memory
 272          *  to the paging system
 273          */
 274         printk(KERN_INFO "PAGE_SIZE=%lu\n", PAGE_SIZE);
 275         paging_init();  /*  See Gorman Book, 2.3  */
 276
 277         /*
 278          *  At this point, the page allocator is kind of initialized, but
 279          *  apparently no pages are available (just like with the bootmem
 280          *  allocator), and need to be freed themselves via mem_init(),
 281          *  which is called by start_kernel() later on in the process
 282          */
 283 }