/* * arch/m68k/atari/stram.c: Functions for ST-RAM allocations * * Copyright 1994-97 Roman Hodek * * This file is subject to the terms and conditions of the GNU General Public * License. See the file COPYING in the main directory of this archive * for more details. */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #undef DEBUG #ifdef DEBUG #define DPRINTK(fmt,args...) printk( fmt, ##args ) #else #define DPRINTK(fmt,args...) #endif #if defined(CONFIG_PROC_FS) && defined(CONFIG_STRAM_PROC) /* abbrev for the && above... */ #define DO_PROC #include #include #endif /* * ++roman: * * New version of ST-Ram buffer allocation. Instead of using the * 1 MB - 4 KB that remain when the ST-Ram chunk starts at $1000 * (1 MB granularity!), such buffers are reserved like this: * * - If the kernel resides in ST-Ram anyway, we can take the buffer * from behind the current kernel data space the normal way * (incrementing start_mem). * * - If the kernel is in TT-Ram, stram_init() initializes start and * end of the available region. Buffers are allocated from there * and mem_init() later marks the such used pages as reserved. * Since each TT-Ram chunk is at least 4 MB in size, I hope there * won't be an overrun of the ST-Ram region by normal kernel data * space. * * For that, ST-Ram may only be allocated while kernel initialization * is going on, or exactly: before mem_init() is called. There is also * no provision now for freeing ST-Ram buffers. It seems that isn't * really needed. * */ /* Start and end (virtual) of ST-RAM */ static void *stram_start, *stram_end; /* set after memory_init() executed and allocations via start_mem aren't * possible anymore */ static int mem_init_done; /* set if kernel is in ST-RAM */ static int kernel_in_stram; typedef struct stram_block { struct stram_block *next; void *start; unsigned long size; unsigned flags; const char *owner; } BLOCK; /* values for flags field */ #define BLOCK_FREE 0x01 /* free structure in the BLOCKs pool */ #define BLOCK_KMALLOCED 0x02 /* structure allocated by kmalloc() */ #define BLOCK_GFP 0x08 /* block allocated with __get_dma_pages() */ /* list of allocated blocks */ static BLOCK *alloc_list; /* We can't always use kmalloc() to allocate BLOCK structures, since * stram_alloc() can be called rather early. So we need some pool of * statically allocated structures. 20 of them is more than enough, so in most * cases we never should need to call kmalloc(). */ #define N_STATIC_BLOCKS 20 static BLOCK static_blocks[N_STATIC_BLOCKS]; /***************************** Prototypes *****************************/ static BLOCK *add_region( void *addr, unsigned long size ); static BLOCK *find_region( void *addr ); static int remove_region( BLOCK *block ); /************************* End of Prototypes **************************/ /* ------------------------------------------------------------------------ */ /* Public Interface */ /* ------------------------------------------------------------------------ */ /* * This init function is called very early by atari/config.c * It initializes some internal variables needed for stram_alloc() */ void __init atari_stram_init(void) { int i; /* initialize static blocks */ for( i = 0; i < N_STATIC_BLOCKS; ++i ) static_blocks[i].flags = BLOCK_FREE; /* determine whether kernel code resides in ST-RAM (then ST-RAM is the * first memory block at virtual 0x0) */ stram_start = phys_to_virt(0); kernel_in_stram = (stram_start == 0); for( i = 0; i < m68k_num_memory; ++i ) { if (m68k_memory[i].addr == 0) { /* skip first 2kB or page (supervisor-only!) */ stram_end = stram_start + m68k_memory[i].size; return; } } /* Should never come here! (There is always ST-Ram!) */ panic( "atari_stram_init: no ST-RAM found!" ); } /* * This function is called from setup_arch() to reserve the pages needed for * ST-RAM management. */ void __init atari_stram_reserve_pages(void *start_mem) { /* always reserve first page of ST-RAM, the first 2 kB are * supervisor-only! */ if (!kernel_in_stram) reserve_bootmem(0, PAGE_SIZE, BOOTMEM_DEFAULT); } void atari_stram_mem_init_hook (void) { mem_init_done = 1; } /* * This is main public interface: somehow allocate a ST-RAM block * * - If we're before mem_init(), we have to make a static allocation. The * region is taken in the kernel data area (if the kernel is in ST-RAM) or * from the start of ST-RAM (if the kernel is in TT-RAM) and added to the * rsvd_stram_* region. The ST-RAM is somewhere in the middle of kernel * address space in the latter case. * * - If mem_init() already has been called, try with __get_dma_pages(). * This has the disadvantage that it's very hard to get more than 1 page, * and it is likely to fail :-( * */ void *atari_stram_alloc(long size, const char *owner) { void *addr = NULL; BLOCK *block; int flags; DPRINTK("atari_stram_alloc(size=%08lx,owner=%s)\n", size, owner); if (!mem_init_done) return alloc_bootmem_low(size); else { /* After mem_init(): can only resort to __get_dma_pages() */ addr = (void *)__get_dma_pages(GFP_KERNEL, get_order(size)); flags = BLOCK_GFP; DPRINTK( "atari_stram_alloc: after mem_init, " "get_pages=%p\n", addr ); } if (addr) { if (!(block = add_region( addr, size ))) { /* out of memory for BLOCK structure :-( */ DPRINTK( "atari_stram_alloc: out of mem for BLOCK -- " "freeing again\n" ); free_pages((unsigned long)addr, get_order(size)); return( NULL ); } block->owner = owner; block->flags |= flags; } return( addr ); } EXPORT_SYMBOL(atari_stram_alloc); void atari_stram_free( void *addr ) { BLOCK *block; DPRINTK( "atari_stram_free(addr=%p)\n", addr ); if (!(block = find_region( addr ))) { printk( KERN_ERR "Attempt to free non-allocated ST-RAM block at %p " "from %p\n", addr, __builtin_return_address(0) ); return; } DPRINTK( "atari_stram_free: found block (%p): size=%08lx, owner=%s, " "flags=%02x\n", block, block->size, block->owner, block->flags ); if (!(block->flags & BLOCK_GFP)) goto fail; DPRINTK("atari_stram_free: is kmalloced, order_size=%d\n", get_order(block->size)); free_pages((unsigned long)addr, get_order(block->size)); remove_region( block ); return; fail: printk( KERN_ERR "atari_stram_free: cannot free block at %p " "(called from %p)\n", addr, __builtin_return_address(0) ); } EXPORT_SYMBOL(atari_stram_free); /* ------------------------------------------------------------------------ */ /* Region Management */ /* ------------------------------------------------------------------------ */ /* insert a region into the alloced list (sorted) */ static BLOCK *add_region( void *addr, unsigned long size ) { BLOCK **p, *n = NULL; int i; for( i = 0; i < N_STATIC_BLOCKS; ++i ) { if (static_blocks[i].flags & BLOCK_FREE) { n = &static_blocks[i]; n->flags = 0; break; } } if (!n && mem_init_done) { /* if statics block pool exhausted and we can call kmalloc() already * (after mem_init()), try that */ n = kmalloc( sizeof(BLOCK), GFP_KERNEL ); if (n) n->flags = BLOCK_KMALLOCED; } if (!n) { printk( KERN_ERR "Out of memory for ST-RAM descriptor blocks\n" ); return( NULL ); } n->start = addr; n->size = size; for( p = &alloc_list; *p; p = &((*p)->next) ) if ((*p)->start > addr) break; n->next = *p; *p = n; return( n ); } /* find a region (by start addr) in the alloced list */ static BLOCK *find_region( void *addr ) { BLOCK *p; for( p = alloc_list; p; p = p->next ) { if (p->start == addr) return( p ); if (p->start > addr) break; } return( NULL ); } /* remove a block from the alloced list */ static int remove_region( BLOCK *block ) { BLOCK **p; for( p = &alloc_list; *p; p = &((*p)->next) ) if (*p == block) break; if (!*p) return( 0 ); *p = block->next; if (block->flags & BLOCK_KMALLOCED) kfree( block ); else block->flags |= BLOCK_FREE; return( 1 ); } /* ------------------------------------------------------------------------ */ /* /proc statistics file stuff */ /* ------------------------------------------------------------------------ */ #ifdef DO_PROC #define PRINT_PROC(fmt,args...) seq_printf( m, fmt, ##args ) static int stram_proc_show(struct seq_file *m, void *v) { BLOCK *p; PRINT_PROC("Total ST-RAM: %8u kB\n", (stram_end - stram_start) >> 10); PRINT_PROC( "Allocated regions:\n" ); for( p = alloc_list; p; p = p->next ) { PRINT_PROC("0x%08lx-0x%08lx: %s (", virt_to_phys(p->start), virt_to_phys(p->start+p->size-1), p->owner); if (p->flags & BLOCK_GFP) PRINT_PROC( "page-alloced)\n" ); else PRINT_PROC( "??)\n" ); } return 0; } static int stram_proc_open(struct inode *inode, struct file *file) { return single_open(file, stram_proc_show, NULL); } static const struct file_operations stram_proc_fops = { .open = stram_proc_open, .read = seq_read, .llseek = seq_lseek, .release = single_release, }; static int __init proc_stram_init(void) { proc_create("stram", 0, NULL, &stram_proc_fops); return 0; } module_init(proc_stram_init); #endif /* * Local variables: * c-indent-level: 4 * tab-width: 4 * End: */