1/*
  2 * Memory subsystem initialization for Hexagon
  3 *
  4 * Copyright (c) 2010-2011, Code Aurora Forum. 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/bootmem.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))
 35
 36unsigned long bootmem_lastpg;  /*  Should be set by platform code  */
 37
 38/*  Set as variable to limit PMD copies  */
 39int max_kernel_seg = 0x303;
 40
 41/*  think this should be (page_size-1) the way it's used...*/
 42unsigned long zero_page_mask;
 43
 44/*  indicate pfn's of high memory  */
 45unsigned long highstart_pfn, highend_pfn;
 46
 47/* struct mmu_gather defined in asm-generic.h;  */
 48DEFINE_PER_CPU(struct mmu_gather, mmu_gathers);
 49
 50/* Default cache attribute for newly created page tables */
 51unsigned long _dflt_cache_att = CACHEDEF;
 52
 53/*
 54 * The current "generation" of kernel map, which should not roll
 55 * over until Hell freezes over.  Actual bound in years needs to be
 56 * calculated to confirm.
 57 */
 58DEFINE_SPINLOCK(kmap_gen_lock);
 59
 60/*  checkpatch says don't init this to 0.  */
 61unsigned long long kmap_generation;
 62
 63/*
 64 * mem_init - initializes memory
 65 *
 66 * Frees up bootmem
 67 * Fixes up more stuff for HIGHMEM
 68 * Calculates and displays memory available/used
 69 */
 70void __init mem_init(void)
 71{
 72	/*  No idea where this is actually declared.  Seems to evade LXR.  */
 73	totalram_pages += free_all_bootmem();
 74	num_physpages = bootmem_lastpg;	/*  seriously, what?  */
 75
 76	printk(KERN_INFO "totalram_pages = %ld\n", totalram_pages);
 77
 78	/*
 79	 *  To-Do:  someone somewhere should wipe out the bootmem map
 80	 *  after we're done?
 81	 */
 82
 83	/*
 84	 * This can be moved to some more virtual-memory-specific
 85	 * initialization hook at some point.  Set the init_mm
 86	 * descriptors "context" value to point to the initial
 87	 * kernel segment table's physical address.
 88	 */
 89	init_mm.context.ptbase = __pa(init_mm.pgd);
 90}
 91
 92/*
 93 * free_initmem - frees memory used by stuff declared with __init
 94 *
 95 * Todo:  free pages between __init_begin and __init_end; possibly
 96 * some devtree related stuff as well.
 97 */
 98void __init_refok free_initmem(void)
 99{
100}
101
102/*
103 * free_initrd_mem - frees...  initrd memory.
104 * @start - start of init memory
105 * @end - end of init memory
106 *
107 * Apparently has to be passed the address of the initrd memory.
108 *
109 * Wrapped by #ifdef CONFIG_BLKDEV_INITRD
110 */
111void free_initrd_mem(unsigned long start, unsigned long end)
112{
113}
114
115void sync_icache_dcache(pte_t pte)
116{
117	unsigned long addr;
118	struct page *page;
119
120	page = pte_page(pte);
121	addr = (unsigned long) page_address(page);
122
123	__vmcache_idsync(addr, PAGE_SIZE);
124}
125
126/*
127 * In order to set up page allocator "nodes",
128 * somebody has to call free_area_init() for UMA.
129 *
130 * In this mode, we only have one pg_data_t
131 * structure: contig_mem_data.
132 */
133void __init paging_init(void)
134{
135	unsigned long zones_sizes[MAX_NR_ZONES] = {0, };
136
137	/*
138	 *  This is not particularly well documented anywhere, but
139	 *  give ZONE_NORMAL all the memory, including the big holes
140	 *  left by the kernel+bootmem_map which are already left as reserved
141	 *  in the bootmem_map; free_area_init should see those bits and
142	 *  adjust accordingly.
143	 */
144
145	zones_sizes[ZONE_NORMAL] = max_low_pfn;
146
147	free_area_init(zones_sizes);  /*  sets up the zonelists and mem_map  */
148
149	/*
150	 * Start of high memory area.  Will probably need something more
151	 * fancy if we...  get more fancy.
152	 */
153	high_memory = (void *)((bootmem_lastpg + 1) << PAGE_SHIFT);
154}
155
156#ifndef DMA_RESERVE
157#define DMA_RESERVE		(4)
158#endif
159
160#define DMA_CHUNKSIZE		(1<<22)
161#define DMA_RESERVED_BYTES	(DMA_RESERVE * DMA_CHUNKSIZE)
162
163/*
164 * Pick out the memory size.  We look for mem=size,
165 * where size is "size[KkMm]"
166 */
167static int __init early_mem(char *p)
168{
169	unsigned long size;
170	char *endp;
171
172	size = memparse(p, &endp);
173
174	bootmem_lastpg = PFN_DOWN(size);
175
176	return 0;
177}
178early_param("mem", early_mem);
179
180size_t hexagon_coherent_pool_size = (size_t) (DMA_RESERVE << 22);
181
182void __init setup_arch_memory(void)
183{
184	int bootmap_size;
185	/*  XXX Todo: this probably should be cleaned up  */
186	u32 *segtable = (u32 *) &swapper_pg_dir[0];
187	u32 *segtable_end;
188
189	/*
190	 * Set up boot memory allocator
191	 *
192	 * The Gorman book also talks about these functions.
193	 * This needs to change for highmem setups.
194	 */
195
196	/* Memory size needs to be a multiple of 16M */
197	bootmem_lastpg = PFN_DOWN((bootmem_lastpg << PAGE_SHIFT) &
198		~((BIG_KERNEL_PAGE_SIZE) - 1));
199
200	/*
201	 * Reserve the top DMA_RESERVE bytes of RAM for DMA (uncached)
202	 * memory allocation
203	 */
204	bootmap_size = init_bootmem(bootmem_startpg, bootmem_lastpg -
205				    PFN_DOWN(DMA_RESERVED_BYTES));
206
207	printk(KERN_INFO "bootmem_startpg:  0x%08lx\n", bootmem_startpg);
208	printk(KERN_INFO "bootmem_lastpg:  0x%08lx\n", bootmem_lastpg);
209	printk(KERN_INFO "bootmap_size:  %d\n", bootmap_size);
210	printk(KERN_INFO "max_low_pfn:  0x%08lx\n", max_low_pfn);
211
212	/*
213	 * The default VM page tables (will be) populated with
214	 * VA=PA+PAGE_OFFSET mapping.  We go in and invalidate entries
215	 * higher than what we have memory for.
216	 */
217
218	/*  this is pointer arithmetic; each entry covers 4MB  */
219	segtable = segtable + (PAGE_OFFSET >> 22);
220
221	/*  this actually only goes to the end of the first gig  */
222	segtable_end = segtable + (1<<(30-22));
223
224	/*  Move forward to the start of empty pages  */
225	segtable += bootmem_lastpg >> (22-PAGE_SHIFT);
226
227	{
228	    int i;
229
230	    for (i = 1 ; i <= DMA_RESERVE ; i++)
231		segtable[-i] = ((segtable[-i] & __HVM_PTE_PGMASK_4MB)
232				| __HVM_PTE_R | __HVM_PTE_W | __HVM_PTE_X
233				| __HEXAGON_C_UNC << 6
234				| __HVM_PDE_S_4MB);
235	}
236
237	printk(KERN_INFO "clearing segtable from %p to %p\n", segtable,
238		segtable_end);
239	while (segtable < (segtable_end-8))
240		*(segtable++) = __HVM_PDE_S_INVALID;
241	/* stop the pointer at the device I/O 4MB page  */
242
243	printk(KERN_INFO "segtable = %p (should be equal to _K_io_map)\n",
244		segtable);
245
246#if 0
247	/*  Other half of the early device table from vm_init_segtable. */
248	printk(KERN_INFO "&_K_init_devicetable = 0x%08x\n",
249		(unsigned long) _K_init_devicetable-PAGE_OFFSET);
250	*segtable = ((u32) (unsigned long) _K_init_devicetable-PAGE_OFFSET) |
251		__HVM_PDE_S_4KB;
252	printk(KERN_INFO "*segtable = 0x%08x\n", *segtable);
253#endif
254
255	/*
256	 * Free all the memory that wasn't taken up by the bootmap, the DMA
257	 * reserve, or kernel itself.
258	 */
259	free_bootmem(PFN_PHYS(bootmem_startpg)+bootmap_size,
260		     PFN_PHYS(bootmem_lastpg - bootmem_startpg) - bootmap_size -
261		     DMA_RESERVED_BYTES);
262
263	/*
264	 *  The bootmem allocator seemingly just lives to feed memory
265	 *  to the paging system
266	 */
267	printk(KERN_INFO "PAGE_SIZE=%lu\n", PAGE_SIZE);
268	paging_init();  /*  See Gorman Book, 2.3  */
269
270	/*
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
275	 */
276}