2 * Memory subsystem initialization for Hexagon
4 * Copyright (c) 2010-2013, The Linux Foundation. All rights reserved.
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.
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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.
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21 #include <linux/init.h>
23 #include <linux/bootmem.h>
24 #include <linux/memblock.h>
25 #include <asm/atomic.h>
26 #include <linux/highmem.h>
28 #include <asm/sections.h>
29 #include <asm/vm_mmu.h>
32 * Define a startpg just past the end of the kernel image and a lastpg
33 * that corresponds to the end of real or simulated platform memory.
35 #define bootmem_startpg (PFN_UP(((unsigned long) _end) - PAGE_OFFSET + PHYS_OFFSET))
37 unsigned long bootmem_lastpg; /* Should be set by platform code */
38 unsigned long __phys_offset; /* physical kernel offset >> 12 */
40 /* Set as variable to limit PMD copies */
41 int max_kernel_seg = 0x303;
43 /* indicate pfn's of high memory */
44 unsigned long highstart_pfn, highend_pfn;
46 DEFINE_PER_CPU(struct mmu_gather, mmu_gathers);
48 /* Default cache attribute for newly created page tables */
49 unsigned long _dflt_cache_att = CACHEDEF;
52 * The current "generation" of kernel map, which should not roll
53 * over until Hell freezes over. Actual bound in years needs to be
54 * calculated to confirm.
56 DEFINE_SPINLOCK(kmap_gen_lock);
58 /* checkpatch says don't init this to 0. */
59 unsigned long long kmap_generation;
62 * mem_init - initializes memory
65 * Fixes up more stuff for HIGHMEM
66 * Calculates and displays memory available/used
68 void __init mem_init(void)
70 /* No idea where this is actually declared. Seems to evade LXR. */
72 mem_init_print_info(NULL);
75 * To-Do: someone somewhere should wipe out the bootmem map
80 * This can be moved to some more virtual-memory-specific
81 * initialization hook at some point. Set the init_mm
82 * descriptors "context" value to point to the initial
83 * kernel segment table's physical address.
85 init_mm.context.ptbase = __pa(init_mm.pgd);
89 * free_initmem - frees memory used by stuff declared with __init
91 * Todo: free pages between __init_begin and __init_end; possibly
92 * some devtree related stuff as well.
94 void __ref free_initmem(void)
99 * free_initrd_mem - frees... initrd memory.
100 * @start - start of init memory
101 * @end - end of init memory
103 * Apparently has to be passed the address of the initrd memory.
105 * Wrapped by #ifdef CONFIG_BLKDEV_INITRD
107 void free_initrd_mem(unsigned long start, unsigned long end)
111 void sync_icache_dcache(pte_t pte)
116 page = pte_page(pte);
117 addr = (unsigned long) page_address(page);
119 __vmcache_idsync(addr, PAGE_SIZE);
123 * In order to set up page allocator "nodes",
124 * somebody has to call free_area_init() for UMA.
126 * In this mode, we only have one pg_data_t
127 * structure: contig_mem_data.
129 void __init paging_init(void)
131 unsigned long zones_sizes[MAX_NR_ZONES] = {0, };
134 * This is not particularly well documented anywhere, but
135 * give ZONE_NORMAL all the memory, including the big holes
136 * left by the kernel+bootmem_map which are already left as reserved
137 * in the bootmem_map; free_area_init should see those bits and
138 * adjust accordingly.
141 zones_sizes[ZONE_NORMAL] = max_low_pfn;
143 free_area_init(zones_sizes); /* sets up the zonelists and mem_map */
146 * Start of high memory area. Will probably need something more
147 * fancy if we... get more fancy.
149 high_memory = (void *)((bootmem_lastpg + 1) << PAGE_SHIFT);
153 #define DMA_RESERVE (4)
156 #define DMA_CHUNKSIZE (1<<22)
157 #define DMA_RESERVED_BYTES (DMA_RESERVE * DMA_CHUNKSIZE)
160 * Pick out the memory size. We look for mem=size,
161 * where size is "size[KkMm]"
163 static int __init early_mem(char *p)
168 size = memparse(p, &endp);
170 bootmem_lastpg = PFN_DOWN(size);
174 early_param("mem", early_mem);
176 size_t hexagon_coherent_pool_size = (size_t) (DMA_RESERVE << 22);
178 void __init setup_arch_memory(void)
180 /* XXX Todo: this probably should be cleaned up */
181 u32 *segtable = (u32 *) &swapper_pg_dir[0];
185 * Set up boot memory allocator
187 * The Gorman book also talks about these functions.
188 * This needs to change for highmem setups.
191 /* Prior to this, bootmem_lastpg is actually mem size */
192 bootmem_lastpg += ARCH_PFN_OFFSET;
194 /* Memory size needs to be a multiple of 16M */
195 bootmem_lastpg = PFN_DOWN((bootmem_lastpg << PAGE_SHIFT) &
196 ~((BIG_KERNEL_PAGE_SIZE) - 1));
198 memblock_add(PHYS_OFFSET,
199 (bootmem_lastpg - ARCH_PFN_OFFSET) << PAGE_SHIFT);
201 /* Reserve kernel text/data/bss */
202 memblock_reserve(PHYS_OFFSET,
203 (bootmem_startpg - ARCH_PFN_OFFSET) << PAGE_SHIFT);
205 * Reserve the top DMA_RESERVE bytes of RAM for DMA (uncached)
208 max_low_pfn = bootmem_lastpg - PFN_DOWN(DMA_RESERVED_BYTES);
209 min_low_pfn = ARCH_PFN_OFFSET;
210 memblock_reserve(PFN_PHYS(max_low_pfn), DMA_RESERVED_BYTES);
212 printk(KERN_INFO "bootmem_startpg: 0x%08lx\n", bootmem_startpg);
213 printk(KERN_INFO "bootmem_lastpg: 0x%08lx\n", bootmem_lastpg);
214 printk(KERN_INFO "min_low_pfn: 0x%08lx\n", min_low_pfn);
215 printk(KERN_INFO "max_low_pfn: 0x%08lx\n", max_low_pfn);
218 * The default VM page tables (will be) populated with
219 * VA=PA+PAGE_OFFSET mapping. We go in and invalidate entries
220 * higher than what we have memory for.
223 /* this is pointer arithmetic; each entry covers 4MB */
224 segtable = segtable + (PAGE_OFFSET >> 22);
226 /* this actually only goes to the end of the first gig */
227 segtable_end = segtable + (1<<(30-22));
230 * Move forward to the start of empty pages; take into account
234 segtable += (bootmem_lastpg-ARCH_PFN_OFFSET)>>(22-PAGE_SHIFT);
238 for (i = 1 ; i <= DMA_RESERVE ; i++)
239 segtable[-i] = ((segtable[-i] & __HVM_PTE_PGMASK_4MB)
240 | __HVM_PTE_R | __HVM_PTE_W | __HVM_PTE_X
241 | __HEXAGON_C_UNC << 6
245 printk(KERN_INFO "clearing segtable from %p to %p\n", segtable,
247 while (segtable < (segtable_end-8))
248 *(segtable++) = __HVM_PDE_S_INVALID;
249 /* stop the pointer at the device I/O 4MB page */
251 printk(KERN_INFO "segtable = %p (should be equal to _K_io_map)\n",
255 /* Other half of the early device table from vm_init_segtable. */
256 printk(KERN_INFO "&_K_init_devicetable = 0x%08x\n",
257 (unsigned long) _K_init_devicetable-PAGE_OFFSET);
258 *segtable = ((u32) (unsigned long) _K_init_devicetable-PAGE_OFFSET) |
260 printk(KERN_INFO "*segtable = 0x%08x\n", *segtable);
264 * The bootmem allocator seemingly just lives to feed memory
265 * to the paging system
267 printk(KERN_INFO "PAGE_SIZE=%lu\n", PAGE_SIZE);
268 paging_init(); /* See Gorman Book, 2.3 */
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