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