1 // SPDX-License-Identifier: GPL-2.0-only
3 * Memory subsystem initialization for Hexagon
5 * Copyright (c) 2010-2013, The Linux Foundation. All rights reserved.
8 #include <linux/init.h>
10 #include <linux/memblock.h>
11 #include <asm/atomic.h>
12 #include <linux/highmem.h>
14 #include <asm/sections.h>
15 #include <asm/vm_mmu.h>
18 * Define a startpg just past the end of the kernel image and a lastpg
19 * that corresponds to the end of real or simulated platform memory.
21 #define bootmem_startpg (PFN_UP(((unsigned long) _end) - PAGE_OFFSET + PHYS_OFFSET))
23 unsigned long bootmem_lastpg; /* Should be set by platform code */
24 unsigned long __phys_offset; /* physical kernel offset >> 12 */
26 /* Set as variable to limit PMD copies */
27 int max_kernel_seg = 0x303;
29 /* indicate pfn's of high memory */
30 unsigned long highstart_pfn, highend_pfn;
32 /* Default cache attribute for newly created page tables */
33 unsigned long _dflt_cache_att = CACHEDEF;
36 * The current "generation" of kernel map, which should not roll
37 * over until Hell freezes over. Actual bound in years needs to be
38 * calculated to confirm.
40 DEFINE_SPINLOCK(kmap_gen_lock);
42 /* checkpatch says don't init this to 0. */
43 unsigned long long kmap_generation;
46 * mem_init - initializes memory
49 * Fixes up more stuff for HIGHMEM
50 * Calculates and displays memory available/used
52 void __init mem_init(void)
54 /* No idea where this is actually declared. Seems to evade LXR. */
58 * To-Do: someone somewhere should wipe out the bootmem map
63 * This can be moved to some more virtual-memory-specific
64 * initialization hook at some point. Set the init_mm
65 * descriptors "context" value to point to the initial
66 * kernel segment table's physical address.
68 init_mm.context.ptbase = __pa(init_mm.pgd);
71 void sync_icache_dcache(pte_t pte)
77 addr = (unsigned long) page_address(page);
79 __vmcache_idsync(addr, PAGE_SIZE);
83 * In order to set up page allocator "nodes",
84 * somebody has to call free_area_init() for UMA.
86 * In this mode, we only have one pg_data_t
87 * structure: contig_mem_data.
89 void __init paging_init(void)
91 unsigned long max_zone_pfn[MAX_NR_ZONES] = {0, };
94 * This is not particularly well documented anywhere, but
95 * give ZONE_NORMAL all the memory, including the big holes
96 * left by the kernel+bootmem_map which are already left as reserved
97 * in the bootmem_map; free_area_init should see those bits and
101 max_zone_pfn[ZONE_NORMAL] = max_low_pfn;
103 free_area_init(max_zone_pfn); /* sets up the zonelists and mem_map */
106 * Start of high memory area. Will probably need something more
107 * fancy if we... get more fancy.
109 high_memory = (void *)((bootmem_lastpg + 1) << PAGE_SHIFT);
113 #define DMA_RESERVE (4)
116 #define DMA_CHUNKSIZE (1<<22)
117 #define DMA_RESERVED_BYTES (DMA_RESERVE * DMA_CHUNKSIZE)
120 * Pick out the memory size. We look for mem=size,
121 * where size is "size[KkMm]"
123 static int __init early_mem(char *p)
128 size = memparse(p, &endp);
130 bootmem_lastpg = PFN_DOWN(size);
134 early_param("mem", early_mem);
136 size_t hexagon_coherent_pool_size = (size_t) (DMA_RESERVE << 22);
138 void __init setup_arch_memory(void)
140 /* XXX Todo: this probably should be cleaned up */
141 u32 *segtable = (u32 *) &swapper_pg_dir[0];
145 * Set up boot memory allocator
147 * The Gorman book also talks about these functions.
148 * This needs to change for highmem setups.
151 /* Prior to this, bootmem_lastpg is actually mem size */
152 bootmem_lastpg += ARCH_PFN_OFFSET;
154 /* Memory size needs to be a multiple of 16M */
155 bootmem_lastpg = PFN_DOWN((bootmem_lastpg << PAGE_SHIFT) &
156 ~((BIG_KERNEL_PAGE_SIZE) - 1));
158 memblock_add(PHYS_OFFSET,
159 (bootmem_lastpg - ARCH_PFN_OFFSET) << PAGE_SHIFT);
161 /* Reserve kernel text/data/bss */
162 memblock_reserve(PHYS_OFFSET,
163 (bootmem_startpg - ARCH_PFN_OFFSET) << PAGE_SHIFT);
165 * Reserve the top DMA_RESERVE bytes of RAM for DMA (uncached)
168 max_low_pfn = bootmem_lastpg - PFN_DOWN(DMA_RESERVED_BYTES);
169 min_low_pfn = ARCH_PFN_OFFSET;
170 memblock_reserve(PFN_PHYS(max_low_pfn), DMA_RESERVED_BYTES);
172 printk(KERN_INFO "bootmem_startpg: 0x%08lx\n", bootmem_startpg);
173 printk(KERN_INFO "bootmem_lastpg: 0x%08lx\n", bootmem_lastpg);
174 printk(KERN_INFO "min_low_pfn: 0x%08lx\n", min_low_pfn);
175 printk(KERN_INFO "max_low_pfn: 0x%08lx\n", max_low_pfn);
178 * The default VM page tables (will be) populated with
179 * VA=PA+PAGE_OFFSET mapping. We go in and invalidate entries
180 * higher than what we have memory for.
183 /* this is pointer arithmetic; each entry covers 4MB */
184 segtable = segtable + (PAGE_OFFSET >> 22);
186 /* this actually only goes to the end of the first gig */
187 segtable_end = segtable + (1<<(30-22));
190 * Move forward to the start of empty pages; take into account
194 segtable += (bootmem_lastpg-ARCH_PFN_OFFSET)>>(22-PAGE_SHIFT);
198 for (i = 1 ; i <= DMA_RESERVE ; i++)
199 segtable[-i] = ((segtable[-i] & __HVM_PTE_PGMASK_4MB)
200 | __HVM_PTE_R | __HVM_PTE_W | __HVM_PTE_X
201 | __HEXAGON_C_UNC << 6
205 printk(KERN_INFO "clearing segtable from %p to %p\n", segtable,
207 while (segtable < (segtable_end-8))
208 *(segtable++) = __HVM_PDE_S_INVALID;
209 /* stop the pointer at the device I/O 4MB page */
211 printk(KERN_INFO "segtable = %p (should be equal to _K_io_map)\n",
215 /* Other half of the early device table from vm_init_segtable. */
216 printk(KERN_INFO "&_K_init_devicetable = 0x%08x\n",
217 (unsigned long) _K_init_devicetable-PAGE_OFFSET);
218 *segtable = ((u32) (unsigned long) _K_init_devicetable-PAGE_OFFSET) |
220 printk(KERN_INFO "*segtable = 0x%08x\n", *segtable);
224 * The bootmem allocator seemingly just lives to feed memory
225 * to the paging system
227 printk(KERN_INFO "PAGE_SIZE=%lu\n", PAGE_SIZE);
228 paging_init(); /* See Gorman Book, 2.3 */
231 * At this point, the page allocator is kind of initialized, but
232 * apparently no pages are available (just like with the bootmem
233 * allocator), and need to be freed themselves via mem_init(),
234 * which is called by start_kernel() later on in the process