1/*
2 * arch/m68k/atari/stram.c: Functions for ST-RAM allocations
3 *
4 * Copyright 1994-97 Roman Hodek <Roman.Hodek@informatik.uni-erlangen.de>
5 *
6 * This file is subject to the terms and conditions of the GNU General Public
7 * License.  See the file COPYING in the main directory of this archive
8 * for more details.
9 */
10
11#include <linux/types.h>
12#include <linux/kernel.h>
13#include <linux/mm.h>
14#include <linux/kdev_t.h>
15#include <linux/major.h>
16#include <linux/init.h>
17#include <linux/slab.h>
18#include <linux/vmalloc.h>
19#include <linux/pagemap.h>
20#include <linux/bootmem.h>
21#include <linux/mount.h>
22#include <linux/blkdev.h>
23
24#include <asm/setup.h>
25#include <asm/machdep.h>
26#include <asm/page.h>
27#include <asm/pgtable.h>
28#include <asm/atarihw.h>
29#include <asm/atari_stram.h>
30#include <asm/io.h>
31#include <asm/semaphore.h>
32
33#undef DEBUG
34
35#ifdef DEBUG
36#define	DPRINTK(fmt,args...) printk( fmt, ##args )
37#else
38#define DPRINTK(fmt,args...)
39#endif
40
41#if defined(CONFIG_PROC_FS) && defined(CONFIG_STRAM_PROC)
42/* abbrev for the && above... */
43#define DO_PROC
44#include <linux/proc_fs.h>
45#endif
46
47/*
48 * ++roman:
49 *
50 * New version of ST-Ram buffer allocation. Instead of using the
51 * 1 MB - 4 KB that remain when the ST-Ram chunk starts at $1000
52 * (1 MB granularity!), such buffers are reserved like this:
53 *
54 *  - If the kernel resides in ST-Ram anyway, we can take the buffer
55 *    from behind the current kernel data space the normal way
56 *    (incrementing start_mem).
57 *
58 *  - If the kernel is in TT-Ram, stram_init() initializes start and
59 *    end of the available region. Buffers are allocated from there
60 *    and mem_init() later marks the such used pages as reserved.
61 *    Since each TT-Ram chunk is at least 4 MB in size, I hope there
62 *    won't be an overrun of the ST-Ram region by normal kernel data
63 *    space.
64 *
65 * For that, ST-Ram may only be allocated while kernel initialization
66 * is going on, or exactly: before mem_init() is called. There is also
67 * no provision now for freeing ST-Ram buffers. It seems that isn't
68 * really needed.
69 *
70 */
71
72/* Start and end (virtual) of ST-RAM */
73static void *stram_start, *stram_end;
74
75/* set after memory_init() executed and allocations via start_mem aren't
76 * possible anymore */
77static int mem_init_done;
78
79/* set if kernel is in ST-RAM */
80static int kernel_in_stram;
81
82typedef struct stram_block {
83	struct stram_block *next;
84	void *start;
85	unsigned long size;
86	unsigned flags;
87	const char *owner;
88} BLOCK;
89
90/* values for flags field */
91#define BLOCK_FREE	0x01	/* free structure in the BLOCKs pool */
92#define BLOCK_KMALLOCED	0x02	/* structure allocated by kmalloc() */
93#define BLOCK_GFP	0x08	/* block allocated with __get_dma_pages() */
94
95/* list of allocated blocks */
96static BLOCK *alloc_list;
97
98/* We can't always use kmalloc() to allocate BLOCK structures, since
99 * stram_alloc() can be called rather early. So we need some pool of
100 * statically allocated structures. 20 of them is more than enough, so in most
101 * cases we never should need to call kmalloc(). */
102#define N_STATIC_BLOCKS	20
103static BLOCK static_blocks[N_STATIC_BLOCKS];
104
105/***************************** Prototypes *****************************/
106
107static BLOCK *add_region( void *addr, unsigned long size );
108static BLOCK *find_region( void *addr );
109static int remove_region( BLOCK *block );
110
111/************************* End of Prototypes **************************/
112
113
114/* ------------------------------------------------------------------------ */
115/*							   Public Interface								*/
116/* ------------------------------------------------------------------------ */
117
118/*
119 * This init function is called very early by atari/config.c
120 * It initializes some internal variables needed for stram_alloc()
121 */
122void __init atari_stram_init(void)
123{
124	int i;
125
126	/* initialize static blocks */
127	for( i = 0; i < N_STATIC_BLOCKS; ++i )
128		static_blocks[i].flags = BLOCK_FREE;
129
130	/* determine whether kernel code resides in ST-RAM (then ST-RAM is the
131	 * first memory block at virtual 0x0) */
132	stram_start = phys_to_virt(0);
133	kernel_in_stram = (stram_start == 0);
134
135	for( i = 0; i < m68k_num_memory; ++i ) {
136		if (m68k_memory[i].addr == 0) {
137			/* skip first 2kB or page (supervisor-only!) */
138			stram_end = stram_start + m68k_memory[i].size;
139			return;
140		}
141	}
142	/* Should never come here! (There is always ST-Ram!) */
143	panic( "atari_stram_init: no ST-RAM found!" );
144}
145
146
147/*
148 * This function is called from setup_arch() to reserve the pages needed for
149 * ST-RAM management.
150 */
151void __init atari_stram_reserve_pages(void *start_mem)
152{
153	/* always reserve first page of ST-RAM, the first 2 kB are
154	 * supervisor-only! */
155	if (!kernel_in_stram)
156		reserve_bootmem (0, PAGE_SIZE);
157
158}
159
160void atari_stram_mem_init_hook (void)
161{
162	mem_init_done = 1;
163}
164
165
166/*
167 * This is main public interface: somehow allocate a ST-RAM block
168 *
169 *  - If we're before mem_init(), we have to make a static allocation. The
170 *    region is taken in the kernel data area (if the kernel is in ST-RAM) or
171 *    from the start of ST-RAM (if the kernel is in TT-RAM) and added to the
172 *    rsvd_stram_* region. The ST-RAM is somewhere in the middle of kernel
173 *    address space in the latter case.
174 *
175 *  - If mem_init() already has been called, try with __get_dma_pages().
176 *    This has the disadvantage that it's very hard to get more than 1 page,
177 *    and it is likely to fail :-(
178 *
179 */
180void *atari_stram_alloc(long size, const char *owner)
181{
182	void *addr = NULL;
183	BLOCK *block;
184	int flags;
185
186	DPRINTK("atari_stram_alloc(size=%08lx,owner=%s)\n", size, owner);
187
188	if (!mem_init_done)
189		return alloc_bootmem_low(size);
190	else {
191		/* After mem_init(): can only resort to __get_dma_pages() */
192		addr = (void *)__get_dma_pages(GFP_KERNEL, get_order(size));
193		flags = BLOCK_GFP;
194		DPRINTK( "atari_stram_alloc: after mem_init, "
195				 "get_pages=%p\n", addr );
196	}
197
198	if (addr) {
199		if (!(block = add_region( addr, size ))) {
200			/* out of memory for BLOCK structure :-( */
201			DPRINTK( "atari_stram_alloc: out of mem for BLOCK -- "
202					 "freeing again\n" );
203			free_pages((unsigned long)addr, get_order(size));
204			return( NULL );
205		}
206		block->owner = owner;
207		block->flags |= flags;
208	}
209	return( addr );
210}
211
212void atari_stram_free( void *addr )
213
214{
215	BLOCK *block;
216
217	DPRINTK( "atari_stram_free(addr=%p)\n", addr );
218
219	if (!(block = find_region( addr ))) {
220		printk( KERN_ERR "Attempt to free non-allocated ST-RAM block at %p "
221				"from %p\n", addr, __builtin_return_address(0) );
222		return;
223	}
224	DPRINTK( "atari_stram_free: found block (%p): size=%08lx, owner=%s, "
225			 "flags=%02x\n", block, block->size, block->owner, block->flags );
226
227	if (!(block->flags & BLOCK_GFP))
228		goto fail;
229
230	DPRINTK("atari_stram_free: is kmalloced, order_size=%d\n",
231		get_order(block->size));
232	free_pages((unsigned long)addr, get_order(block->size));
233	remove_region( block );
234	return;
235
236  fail:
237	printk( KERN_ERR "atari_stram_free: cannot free block at %p "
238			"(called from %p)\n", addr, __builtin_return_address(0) );
239}
240
241
242/* ------------------------------------------------------------------------ */
243/*							  Region Management								*/
244/* ------------------------------------------------------------------------ */
245
246
247/* insert a region into the alloced list (sorted) */
248static BLOCK *add_region( void *addr, unsigned long size )
249{
250	BLOCK **p, *n = NULL;
251	int i;
252
253	for( i = 0; i < N_STATIC_BLOCKS; ++i ) {
254		if (static_blocks[i].flags & BLOCK_FREE) {
255			n = &static_blocks[i];
256			n->flags = 0;
257			break;
258		}
259	}
260	if (!n && mem_init_done) {
261		/* if statics block pool exhausted and we can call kmalloc() already
262		 * (after mem_init()), try that */
263		n = kmalloc( sizeof(BLOCK), GFP_KERNEL );
264		if (n)
265			n->flags = BLOCK_KMALLOCED;
266	}
267	if (!n) {
268		printk( KERN_ERR "Out of memory for ST-RAM descriptor blocks\n" );
269		return( NULL );
270	}
271	n->start = addr;
272	n->size  = size;
273
274	for( p = &alloc_list; *p; p = &((*p)->next) )
275		if ((*p)->start > addr) break;
276	n->next = *p;
277	*p = n;
278
279	return( n );
280}
281
282
283/* find a region (by start addr) in the alloced list */
284static BLOCK *find_region( void *addr )
285{
286	BLOCK *p;
287
288	for( p = alloc_list; p; p = p->next ) {
289		if (p->start == addr)
290			return( p );
291		if (p->start > addr)
292			break;
293	}
294	return( NULL );
295}
296
297
298/* remove a block from the alloced list */
299static int remove_region( BLOCK *block )
300{
301	BLOCK **p;
302
303	for( p = &alloc_list; *p; p = &((*p)->next) )
304		if (*p == block) break;
305	if (!*p)
306		return( 0 );
307
308	*p = block->next;
309	if (block->flags & BLOCK_KMALLOCED)
310		kfree( block );
311	else
312		block->flags |= BLOCK_FREE;
313	return( 1 );
314}
315
316
317
318/* ------------------------------------------------------------------------ */
319/*						 /proc statistics file stuff						*/
320/* ------------------------------------------------------------------------ */
321
322#ifdef DO_PROC
323
324#define	PRINT_PROC(fmt,args...) len += sprintf( buf+len, fmt, ##args )
325
326int get_stram_list( char *buf )
327{
328	int len = 0;
329	BLOCK *p;
330
331	PRINT_PROC("Total ST-RAM:      %8u kB\n",
332			   (stram_end - stram_start) >> 10);
333	PRINT_PROC( "Allocated regions:\n" );
334	for( p = alloc_list; p; p = p->next ) {
335		if (len + 50 >= PAGE_SIZE)
336			break;
337		PRINT_PROC("0x%08lx-0x%08lx: %s (",
338			   virt_to_phys(p->start),
339			   virt_to_phys(p->start+p->size-1),
340			   p->owner);
341		if (p->flags & BLOCK_GFP)
342			PRINT_PROC( "page-alloced)\n" );
343		else
344			PRINT_PROC( "??)\n" );
345	}
346
347	return( len );
348}
349
350#endif
351
352
353/*
354 * Local variables:
355 *  c-indent-level: 4
356 *  tab-width: 4
357 * End:
358 */
359