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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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/memblock.h>
24 #include <asm/atomic.h>
25 #include <linux/highmem.h>
27 #include <asm/sections.h>
28 #include <asm/vm_mmu.h>
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.
34 #define bootmem_startpg (PFN_UP(((unsigned long) _end) - PAGE_OFFSET + PHYS_OFFSET))
36 unsigned long bootmem_lastpg; /* Should be set by platform code */
37 unsigned long __phys_offset; /* physical kernel offset >> 12 */
39 /* Set as variable to limit PMD copies */
40 int max_kernel_seg = 0x303;
42 /* indicate pfn's of high memory */
43 unsigned long highstart_pfn, highend_pfn;
45 DEFINE_PER_CPU(struct mmu_gather, mmu_gathers);
47 /* Default cache attribute for newly created page tables */
48 unsigned long _dflt_cache_att = CACHEDEF;
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.
55 DEFINE_SPINLOCK(kmap_gen_lock);
57 /* checkpatch says don't init this to 0. */
58 unsigned long long kmap_generation;
61 * mem_init - initializes memory
64 * Fixes up more stuff for HIGHMEM
65 * Calculates and displays memory available/used
67 void __init mem_init(void)
69 /* No idea where this is actually declared. Seems to evade LXR. */
71 mem_init_print_info(NULL);
74 * To-Do: someone somewhere should wipe out the bootmem map
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.
84 init_mm.context.ptbase = __pa(init_mm.pgd);
88 * free_initmem - frees memory used by stuff declared with __init
90 * Todo: free pages between __init_begin and __init_end; possibly
91 * some devtree related stuff as well.
93 void __ref free_initmem(void)
98 * free_initrd_mem - frees... initrd memory.
99 * @start - start of init memory
100 * @end - end of init memory
102 * Apparently has to be passed the address of the initrd memory.
104 * Wrapped by #ifdef CONFIG_BLKDEV_INITRD
106 void free_initrd_mem(unsigned long start, unsigned long end)
110 void sync_icache_dcache(pte_t pte)
115 page = pte_page(pte);
116 addr = (unsigned long) page_address(page);
118 __vmcache_idsync(addr, PAGE_SIZE);
122 * In order to set up page allocator "nodes",
123 * somebody has to call free_area_init() for UMA.
125 * In this mode, we only have one pg_data_t
126 * structure: contig_mem_data.
128 void __init paging_init(void)
130 unsigned long zones_sizes[MAX_NR_ZONES] = {0, };
133 * This is not particularly well documented anywhere, but
134 * give ZONE_NORMAL all the memory, including the big holes
135 * left by the kernel+bootmem_map which are already left as reserved
136 * in the bootmem_map; free_area_init should see those bits and
137 * adjust accordingly.
140 zones_sizes[ZONE_NORMAL] = max_low_pfn;
142 free_area_init(zones_sizes); /* sets up the zonelists and mem_map */
145 * Start of high memory area. Will probably need something more
146 * fancy if we... get more fancy.
148 high_memory = (void *)((bootmem_lastpg + 1) << PAGE_SHIFT);
152 #define DMA_RESERVE (4)
155 #define DMA_CHUNKSIZE (1<<22)
156 #define DMA_RESERVED_BYTES (DMA_RESERVE * DMA_CHUNKSIZE)
159 * Pick out the memory size. We look for mem=size,
160 * where size is "size[KkMm]"
162 static int __init early_mem(char *p)
167 size = memparse(p, &endp);
169 bootmem_lastpg = PFN_DOWN(size);
173 early_param("mem", early_mem);
175 size_t hexagon_coherent_pool_size = (size_t) (DMA_RESERVE << 22);
177 void __init setup_arch_memory(void)
179 /* XXX Todo: this probably should be cleaned up */
180 u32 *segtable = (u32 *) &swapper_pg_dir[0];
184 * Set up boot memory allocator
186 * The Gorman book also talks about these functions.
187 * This needs to change for highmem setups.
190 /* Prior to this, bootmem_lastpg is actually mem size */
191 bootmem_lastpg += ARCH_PFN_OFFSET;
193 /* Memory size needs to be a multiple of 16M */
194 bootmem_lastpg = PFN_DOWN((bootmem_lastpg << PAGE_SHIFT) &
195 ~((BIG_KERNEL_PAGE_SIZE) - 1));
197 memblock_add(PHYS_OFFSET,
198 (bootmem_lastpg - ARCH_PFN_OFFSET) << PAGE_SHIFT);
200 /* Reserve kernel text/data/bss */
201 memblock_reserve(PHYS_OFFSET,
202 (bootmem_startpg - ARCH_PFN_OFFSET) << PAGE_SHIFT);
204 * Reserve the top DMA_RESERVE bytes of RAM for DMA (uncached)
207 max_low_pfn = bootmem_lastpg - PFN_DOWN(DMA_RESERVED_BYTES);
208 min_low_pfn = ARCH_PFN_OFFSET;
209 memblock_reserve(PFN_PHYS(max_low_pfn), DMA_RESERVED_BYTES);
211 printk(KERN_INFO "bootmem_startpg: 0x%08lx\n", bootmem_startpg);
212 printk(KERN_INFO "bootmem_lastpg: 0x%08lx\n", bootmem_lastpg);
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);
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.
222 /* this is pointer arithmetic; each entry covers 4MB */
223 segtable = segtable + (PAGE_OFFSET >> 22);
225 /* this actually only goes to the end of the first gig */
226 segtable_end = segtable + (1<<(30-22));
229 * Move forward to the start of empty pages; take into account
233 segtable += (bootmem_lastpg-ARCH_PFN_OFFSET)>>(22-PAGE_SHIFT);
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
244 printk(KERN_INFO "clearing segtable from %p to %p\n", segtable,
246 while (segtable < (segtable_end-8))
247 *(segtable++) = __HVM_PDE_S_INVALID;
248 /* stop the pointer at the device I/O 4MB page */
250 printk(KERN_INFO "segtable = %p (should be equal to _K_io_map)\n",
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) |
259 printk(KERN_INFO "*segtable = 0x%08x\n", *segtable);
263 * The bootmem allocator seemingly just lives to feed memory
264 * to the paging system
266 printk(KERN_INFO "PAGE_SIZE=%lu\n", PAGE_SIZE);
267 paging_init(); /* See Gorman Book, 2.3 */
270 * At this point, the page allocator is kind of initialized, but
271 * apparently no pages are available (just like with the bootmem
272 * allocator), and need to be freed themselves via mem_init(),
273 * which is called by start_kernel() later on in the process