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/memblock.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 /*  indicate pfn's of high memory  */
  43 unsigned long highstart_pfn, highend_pfn;
  44
  45 DEFINE_PER_CPU(struct mmu_gather, mmu_gathers);
  46
  47 /* Default cache attribute for newly created page tables */
  48 unsigned long _dflt_cache_att = CACHEDEF;
  49
  50 /*
  51  * The current "generation" of kernel map, which should not roll
  52  * over until Hell freezes over.  Actual bound in years needs to be
  53  * calculated to confirm.
  54  */
  55 DEFINE_SPINLOCK(kmap_gen_lock);
  56
  57 /*  checkpatch says don't init this to 0.  */
  58 unsigned long long kmap_generation;
  59
  60 /*
  61  * mem_init - initializes memory
  62  *
  63  * Frees up bootmem
  64  * Fixes up more stuff for HIGHMEM
  65  * Calculates and displays memory available/used
  66  */
  67 void __init mem_init(void)
  68 {
  69         /*  No idea where this is actually declared.  Seems to evade LXR.  */
  70         memblock_free_all();
  71         mem_init_print_info(NULL);
  72
  73         /*
  74          *  To-Do:  someone somewhere should wipe out the bootmem map
  75          *  after we're done?
  76          */
  77
  78         /*
  79          * This can be moved to some more virtual-memory-specific
  80          * initialization hook at some point.  Set the init_mm
  81          * descriptors "context" value to point to the initial
  82          * kernel segment table's physical address.
  83          */
  84         init_mm.context.ptbase = __pa(init_mm.pgd);
  85 }
  86
  87 /*
  88  * free_initrd_mem - frees...  initrd memory.
  89  * @start - start of init memory
  90  * @end - end of init memory
  91  *
  92  * Apparently has to be passed the address of the initrd memory.
  93  *
  94  * Wrapped by #ifdef CONFIG_BLKDEV_INITRD
  95  */
  96 void free_initrd_mem(unsigned long start, unsigned long end)
  97 {
  98 }
  99
 100 void sync_icache_dcache(pte_t pte)
 101 {
 102         unsigned long addr;
 103         struct page *page;
 104
 105         page = pte_page(pte);
 106         addr = (unsigned long) page_address(page);
 107
 108         __vmcache_idsync(addr, PAGE_SIZE);
 109 }
 110
 111 /*
 112  * In order to set up page allocator "nodes",
 113  * somebody has to call free_area_init() for UMA.
 114  *
 115  * In this mode, we only have one pg_data_t
 116  * structure: contig_mem_data.
 117  */
 118 void __init paging_init(void)
 119 {
 120         unsigned long zones_sizes[MAX_NR_ZONES] = {0, };
 121
 122         /*
 123          *  This is not particularly well documented anywhere, but
 124          *  give ZONE_NORMAL all the memory, including the big holes
 125          *  left by the kernel+bootmem_map which are already left as reserved
 126          *  in the bootmem_map; free_area_init should see those bits and
 127          *  adjust accordingly.
 128          */
 129
 130         zones_sizes[ZONE_NORMAL] = max_low_pfn;
 131
 132         free_area_init(zones_sizes);  /*  sets up the zonelists and mem_map  */
 133
 134         /*
 135          * Start of high memory area.  Will probably need something more
 136          * fancy if we...  get more fancy.
 137          */
 138         high_memory = (void *)((bootmem_lastpg + 1) << PAGE_SHIFT);
 139 }
 140
 141 #ifndef DMA_RESERVE
 142 #define DMA_RESERVE             (4)
 143 #endif
 144
 145 #define DMA_CHUNKSIZE           (1<<22)
 146 #define DMA_RESERVED_BYTES      (DMA_RESERVE * DMA_CHUNKSIZE)
 147
 148 /*
 149  * Pick out the memory size.  We look for mem=size,
 150  * where size is "size[KkMm]"
 151  */
 152 static int __init early_mem(char *p)
 153 {
 154         unsigned long size;
 155         char *endp;
 156
 157         size = memparse(p, &endp);
 158
 159         bootmem_lastpg = PFN_DOWN(size);
 160
 161         return 0;
 162 }
 163 early_param("mem", early_mem);
 164
 165 size_t hexagon_coherent_pool_size = (size_t) (DMA_RESERVE << 22);
 166
 167 void __init setup_arch_memory(void)
 168 {
 169         /*  XXX Todo: this probably should be cleaned up  */
 170         u32 *segtable = (u32 *) &swapper_pg_dir[0];
 171         u32 *segtable_end;
 172
 173         /*
 174          * Set up boot memory allocator
 175          *
 176          * The Gorman book also talks about these functions.
 177          * This needs to change for highmem setups.
 178          */
 179
 180         /*  Prior to this, bootmem_lastpg is actually mem size  */
 181         bootmem_lastpg += ARCH_PFN_OFFSET;
 182
 183         /* Memory size needs to be a multiple of 16M */
 184         bootmem_lastpg = PFN_DOWN((bootmem_lastpg << PAGE_SHIFT) &
 185                 ~((BIG_KERNEL_PAGE_SIZE) - 1));
 186
 187         memblock_add(PHYS_OFFSET,
 188                      (bootmem_lastpg - ARCH_PFN_OFFSET) << PAGE_SHIFT);
 189
 190         /* Reserve kernel text/data/bss */
 191         memblock_reserve(PHYS_OFFSET,
 192                          (bootmem_startpg - ARCH_PFN_OFFSET) << PAGE_SHIFT);
 193         /*
 194          * Reserve the top DMA_RESERVE bytes of RAM for DMA (uncached)
 195          * memory allocation
 196          */
 197         max_low_pfn = bootmem_lastpg - PFN_DOWN(DMA_RESERVED_BYTES);
 198         min_low_pfn = ARCH_PFN_OFFSET;
 199         memblock_reserve(PFN_PHYS(max_low_pfn), DMA_RESERVED_BYTES);
 200
 201         printk(KERN_INFO "bootmem_startpg:  0x%08lx\n", bootmem_startpg);
 202         printk(KERN_INFO "bootmem_lastpg:  0x%08lx\n", bootmem_lastpg);
 203         printk(KERN_INFO "min_low_pfn:  0x%08lx\n", min_low_pfn);
 204         printk(KERN_INFO "max_low_pfn:  0x%08lx\n", max_low_pfn);
 205
 206         /*
 207          * The default VM page tables (will be) populated with
 208          * VA=PA+PAGE_OFFSET mapping.  We go in and invalidate entries
 209          * higher than what we have memory for.
 210          */
 211
 212         /*  this is pointer arithmetic; each entry covers 4MB  */
 213         segtable = segtable + (PAGE_OFFSET >> 22);
 214
 215         /*  this actually only goes to the end of the first gig  */
 216         segtable_end = segtable + (1<<(30-22));
 217
 218         /*
 219          * Move forward to the start of empty pages; take into account
 220          * phys_offset shift.
 221          */
 222
 223         segtable += (bootmem_lastpg-ARCH_PFN_OFFSET)>>(22-PAGE_SHIFT);
 224         {
 225                 int i;
 226
 227                 for (i = 1 ; i <= DMA_RESERVE ; i++)
 228                         segtable[-i] = ((segtable[-i] & __HVM_PTE_PGMASK_4MB)
 229                                 | __HVM_PTE_R | __HVM_PTE_W | __HVM_PTE_X
 230                                 | __HEXAGON_C_UNC << 6
 231                                 | __HVM_PDE_S_4MB);
 232         }
 233
 234         printk(KERN_INFO "clearing segtable from %p to %p\n", segtable,
 235                 segtable_end);
 236         while (segtable < (segtable_end-8))
 237                 *(segtable++) = __HVM_PDE_S_INVALID;
 238         /* stop the pointer at the device I/O 4MB page  */
 239
 240         printk(KERN_INFO "segtable = %p (should be equal to _K_io_map)\n",
 241                 segtable);
 242
 243 #if 0
 244         /*  Other half of the early device table from vm_init_segtable. */
 245         printk(KERN_INFO "&_K_init_devicetable = 0x%08x\n",
 246                 (unsigned long) _K_init_devicetable-PAGE_OFFSET);
 247         *segtable = ((u32) (unsigned long) _K_init_devicetable-PAGE_OFFSET) |
 248                 __HVM_PDE_S_4KB;
 249         printk(KERN_INFO "*segtable = 0x%08x\n", *segtable);
 250 #endif
 251
 252         /*
 253          *  The bootmem allocator seemingly just lives to feed memory
 254          *  to the paging system
 255          */
 256         printk(KERN_INFO "PAGE_SIZE=%lu\n", PAGE_SIZE);
 257         paging_init();  /*  See Gorman Book, 2.3  */
 258
 259         /*
 260          *  At this point, the page allocator is kind of initialized, but
 261          *  apparently no pages are available (just like with the bootmem
 262          *  allocator), and need to be freed themselves via mem_init(),
 263          *  which is called by start_kernel() later on in the process
 264          */
 265 }