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 DEFINE_PER_CPU(struct mmu_gather, mmu_gathers);
34 /* Default cache attribute for newly created page tables */
35 unsigned long _dflt_cache_att = CACHEDEF;
38 * The current "generation" of kernel map, which should not roll
39 * over until Hell freezes over. Actual bound in years needs to be
40 * calculated to confirm.
42 DEFINE_SPINLOCK(kmap_gen_lock);
44 /* checkpatch says don't init this to 0. */
45 unsigned long long kmap_generation;
48 * mem_init - initializes memory
51 * Fixes up more stuff for HIGHMEM
52 * Calculates and displays memory available/used
54 void __init mem_init(void)
56 /* No idea where this is actually declared. Seems to evade LXR. */
58 mem_init_print_info(NULL);
61 * To-Do: someone somewhere should wipe out the bootmem map
66 * This can be moved to some more virtual-memory-specific
67 * initialization hook at some point. Set the init_mm
68 * descriptors "context" value to point to the initial
69 * kernel segment table's physical address.
71 init_mm.context.ptbase = __pa(init_mm.pgd);
75 * free_initrd_mem - frees... initrd memory.
76 * @start - start of init memory
77 * @end - end of init memory
79 * Apparently has to be passed the address of the initrd memory.
81 * Wrapped by #ifdef CONFIG_BLKDEV_INITRD
83 void free_initrd_mem(unsigned long start, unsigned long end)
87 void sync_icache_dcache(pte_t pte)
93 addr = (unsigned long) page_address(page);
95 __vmcache_idsync(addr, PAGE_SIZE);
99 * In order to set up page allocator "nodes",
100 * somebody has to call free_area_init() for UMA.
102 * In this mode, we only have one pg_data_t
103 * structure: contig_mem_data.
105 void __init paging_init(void)
107 unsigned long zones_sizes[MAX_NR_ZONES] = {0, };
110 * This is not particularly well documented anywhere, but
111 * give ZONE_NORMAL all the memory, including the big holes
112 * left by the kernel+bootmem_map which are already left as reserved
113 * in the bootmem_map; free_area_init should see those bits and
114 * adjust accordingly.
117 zones_sizes[ZONE_NORMAL] = max_low_pfn;
119 free_area_init(zones_sizes); /* sets up the zonelists and mem_map */
122 * Start of high memory area. Will probably need something more
123 * fancy if we... get more fancy.
125 high_memory = (void *)((bootmem_lastpg + 1) << PAGE_SHIFT);
129 #define DMA_RESERVE (4)
132 #define DMA_CHUNKSIZE (1<<22)
133 #define DMA_RESERVED_BYTES (DMA_RESERVE * DMA_CHUNKSIZE)
136 * Pick out the memory size. We look for mem=size,
137 * where size is "size[KkMm]"
139 static int __init early_mem(char *p)
144 size = memparse(p, &endp);
146 bootmem_lastpg = PFN_DOWN(size);
150 early_param("mem", early_mem);
152 size_t hexagon_coherent_pool_size = (size_t) (DMA_RESERVE << 22);
154 void __init setup_arch_memory(void)
156 /* XXX Todo: this probably should be cleaned up */
157 u32 *segtable = (u32 *) &swapper_pg_dir[0];
161 * Set up boot memory allocator
163 * The Gorman book also talks about these functions.
164 * This needs to change for highmem setups.
167 /* Prior to this, bootmem_lastpg is actually mem size */
168 bootmem_lastpg += ARCH_PFN_OFFSET;
170 /* Memory size needs to be a multiple of 16M */
171 bootmem_lastpg = PFN_DOWN((bootmem_lastpg << PAGE_SHIFT) &
172 ~((BIG_KERNEL_PAGE_SIZE) - 1));
174 memblock_add(PHYS_OFFSET,
175 (bootmem_lastpg - ARCH_PFN_OFFSET) << PAGE_SHIFT);
177 /* Reserve kernel text/data/bss */
178 memblock_reserve(PHYS_OFFSET,
179 (bootmem_startpg - ARCH_PFN_OFFSET) << PAGE_SHIFT);
181 * Reserve the top DMA_RESERVE bytes of RAM for DMA (uncached)
184 max_low_pfn = bootmem_lastpg - PFN_DOWN(DMA_RESERVED_BYTES);
185 min_low_pfn = ARCH_PFN_OFFSET;
186 memblock_reserve(PFN_PHYS(max_low_pfn), DMA_RESERVED_BYTES);
188 printk(KERN_INFO "bootmem_startpg: 0x%08lx\n", bootmem_startpg);
189 printk(KERN_INFO "bootmem_lastpg: 0x%08lx\n", bootmem_lastpg);
190 printk(KERN_INFO "min_low_pfn: 0x%08lx\n", min_low_pfn);
191 printk(KERN_INFO "max_low_pfn: 0x%08lx\n", max_low_pfn);
194 * The default VM page tables (will be) populated with
195 * VA=PA+PAGE_OFFSET mapping. We go in and invalidate entries
196 * higher than what we have memory for.
199 /* this is pointer arithmetic; each entry covers 4MB */
200 segtable = segtable + (PAGE_OFFSET >> 22);
202 /* this actually only goes to the end of the first gig */
203 segtable_end = segtable + (1<<(30-22));
206 * Move forward to the start of empty pages; take into account
210 segtable += (bootmem_lastpg-ARCH_PFN_OFFSET)>>(22-PAGE_SHIFT);
214 for (i = 1 ; i <= DMA_RESERVE ; i++)
215 segtable[-i] = ((segtable[-i] & __HVM_PTE_PGMASK_4MB)
216 | __HVM_PTE_R | __HVM_PTE_W | __HVM_PTE_X
217 | __HEXAGON_C_UNC << 6
221 printk(KERN_INFO "clearing segtable from %p to %p\n", segtable,
223 while (segtable < (segtable_end-8))
224 *(segtable++) = __HVM_PDE_S_INVALID;
225 /* stop the pointer at the device I/O 4MB page */
227 printk(KERN_INFO "segtable = %p (should be equal to _K_io_map)\n",
231 /* Other half of the early device table from vm_init_segtable. */
232 printk(KERN_INFO "&_K_init_devicetable = 0x%08x\n",
233 (unsigned long) _K_init_devicetable-PAGE_OFFSET);
234 *segtable = ((u32) (unsigned long) _K_init_devicetable-PAGE_OFFSET) |
236 printk(KERN_INFO "*segtable = 0x%08x\n", *segtable);
240 * The bootmem allocator seemingly just lives to feed memory
241 * to the paging system
243 printk(KERN_INFO "PAGE_SIZE=%lu\n", PAGE_SIZE);
244 paging_init(); /* See Gorman Book, 2.3 */
247 * At this point, the page allocator is kind of initialized, but
248 * apparently no pages are available (just like with the bootmem
249 * allocator), and need to be freed themselves via mem_init(),
250 * which is called by start_kernel() later on in the process