linux/arch/hexagon/mm/init.c
<<
>>
Prefs
   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
  36unsigned long bootmem_lastpg;   /*  Should be set by platform code  */
  37unsigned long __phys_offset;    /*  physical kernel offset >> 12  */
  38
  39/*  Set as variable to limit PMD copies  */
  40int max_kernel_seg = 0x303;
  41
  42/*  think this should be (page_size-1) the way it's used...*/
  43unsigned long zero_page_mask;
  44
  45/*  indicate pfn's of high memory  */
  46unsigned long highstart_pfn, highend_pfn;
  47
  48DEFINE_PER_CPU(struct mmu_gather, mmu_gathers);
  49
  50/* Default cache attribute for newly created page tables */
  51unsigned 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 */
  58DEFINE_SPINLOCK(kmap_gen_lock);
  59
  60/*  checkpatch says don't init this to 0.  */
  61unsigned 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 */
  70void __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 */
  96void __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 */
 109void free_initrd_mem(unsigned long start, unsigned long end)
 110{
 111}
 112
 113void 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 */
 131void __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 */
 165static 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}
 176early_param("mem", early_mem);
 177
 178size_t hexagon_coherent_pool_size = (size_t) (DMA_RESERVE << 22);
 179
 180void __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}
 284