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Diffstat (limited to 'drivers/staging/dt3155/allocator.c')
| -rw-r--r-- | drivers/staging/dt3155/allocator.c | 295 |
1 files changed, 295 insertions, 0 deletions
diff --git a/drivers/staging/dt3155/allocator.c b/drivers/staging/dt3155/allocator.c new file mode 100644 index 000000000000..c74234c66895 --- /dev/null +++ b/drivers/staging/dt3155/allocator.c @@ -0,0 +1,295 @@ +/* + * allocator.c -- allocate after high_memory, if available + * + * NOTE: this is different from my previous allocator, the one that + * assembles pages, which revealed itself both slow and unreliable. + * + * Copyright (C) 1998 rubini@linux.it (Alessandro Rubini) + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. + * + +-- Changes -- + + Date Programmer Description of changes made + ------------------------------------------------------------------- + 02-Aug-2002 NJC allocator now steps in 1MB increments, rather + than doubling its size each time. + Also, allocator_init(u32 *) now returns + (in the first arg) the size of the free + space. This is no longer consistent with + using the allocator as a module, and some changes + may be necessary for that purpose. This was + designed to work with the DT3155 driver, in + stand alone mode only!!! + 26-Oct-2009 SS Port to 2.6.30 kernel. + */ + + +#ifndef __KERNEL__ +# define __KERNEL__ +#endif +#ifndef MODULE +# define MODULE +#endif + +#include <linux/version.h> + +#include <linux/sched.h> +#include <linux/kernel.h> +#include <linux/fs.h> +#include <linux/proc_fs.h> +#include <linux/errno.h> +#include <linux/types.h> +#include <linux/mm.h> /* PAGE_ALIGN() */ +#include <linux/io.h> + +#include <asm/page.h> + +/*#define ALL_DEBUG*/ +#define ALL_MSG "allocator: " + +#undef PDEBUG /* undef it, just in case */ +#ifdef ALL_DEBUG +# define __static +# define DUMP_LIST() dump_list() +# ifdef __KERNEL__ + /* This one if debugging is on, and kernel space */ +# define PDEBUG(fmt, args...) printk(KERN_DEBUG ALL_MSG fmt, ## args) +# else + /* This one for user space */ +# define PDEBUG(fmt, args...) fprintf(stderr, fmt, ## args) +# endif +#else +# define PDEBUG(fmt, args...) /* not debugging: nothing */ +# define DUMP_LIST() +# define __static static +#endif + +#undef PDEBUGG +#define PDEBUGG(fmt, args...) +/*#define PDEBUGG(fmt, args...) printk( KERN_DEBUG ALL_MSG fmt, ## args)*/ + + +int allocator_himem = 1; /* 0 = probe, pos. = megs, neg. = disable */ +int allocator_step = 1; /* This is the step size in MB */ +int allocator_probe = 1; /* This is a flag -- 1=probe, 0=don't probe */ + +static unsigned long allocator_buffer; /* physical address */ +static unsigned long allocator_buffer_size; /* kilobytes */ + +/* + * The allocator keeps a list of DMA areas, so multiple devices + * can coexist. The list is kept sorted by address + */ + +struct allocator_struct { + unsigned long address; + unsigned long size; + struct allocator_struct *next; +}; + +struct allocator_struct *allocator_list; + + +#ifdef ALL_DEBUG +static int dump_list(void) +{ + struct allocator_struct *ptr; + + PDEBUG("Current list:\n"); + for (ptr = allocator_list; ptr; ptr = ptr->next) + PDEBUG("0x%08lx (size %likB)\n", ptr->address, ptr->size>>10); + return 0; +} +#endif + +/* ======================================================================== + * This function is the actual allocator. + * + * If space is available in high memory (as detected at load time), that + * one is returned. The return value is a physical address (i.e., it can + * be used straight ahead for DMA, but needs remapping for program use). + */ + +unsigned long allocator_allocate_dma(unsigned long kilobytes, int prio) +{ + struct allocator_struct *ptr = allocator_list, *newptr; + unsigned long bytes = kilobytes << 10; + + /* check if high memory is available */ + if (!allocator_buffer) + return 0; + + /* Round it to a multiple of the pagesize */ + bytes = PAGE_ALIGN(bytes); + PDEBUG("request for %li bytes\n", bytes); + + while (ptr && ptr->next) { + if (ptr->next->address - (ptr->address + ptr->size) >= bytes) + break; /* enough space */ + ptr = ptr->next; + } + if (!ptr->next) { + DUMP_LIST(); + PDEBUG("alloc failed\n"); + return 0; /* end of list */ + } + newptr = kmalloc(sizeof(struct allocator_struct), prio); + if (!newptr) + return 0; + + /* ok, now stick it after ptr */ + newptr->address = ptr->address + ptr->size; + newptr->size = bytes; + newptr->next = ptr->next; + ptr->next = newptr; + + DUMP_LIST(); + PDEBUG("returning 0x%08lx\n", newptr->address); + return newptr->address; +} + +int allocator_free_dma(unsigned long address) +{ + struct allocator_struct *ptr = allocator_list, *prev; + + while (ptr && ptr->next) { + if (ptr->next->address == address) + break; + ptr = ptr->next; + } + /* the one being freed is ptr->next */ + prev = ptr; ptr = ptr->next; + + if (!ptr) { + printk(KERN_ERR ALL_MSG + "free_dma(0x%08lx) but add. not allocated\n", + ptr->address); + return -EINVAL; + } + PDEBUGG("freeing: %08lx (%li) next %08lx\n", ptr->address, ptr->size, + ptr->next->address); + prev->next = ptr->next; + kfree(ptr); + + /* dump_list(); */ + return 0; +} + +/* ======================================================================== + * Init and cleanup + * + * On cleanup everything is released. If the list is not empty, that a + * problem of our clients + */ +int allocator_init(u32 *allocator_max) +{ + /* check how much free memory is there */ + void *remapped; + unsigned long max; + unsigned long trial_size = allocator_himem<<20; + unsigned long last_trial = 0; + unsigned long step = allocator_step<<20; + unsigned long i = 0; + struct allocator_struct *head, *tail; + char test_string[] = "0123456789abcde"; /* 16 bytes */ + + PDEBUGG("himem = %i\n", allocator_himem); + if (allocator_himem < 0) /* don't even try */ + return -EINVAL; + + if (!trial_size) + trial_size = 1<<20; /* not specified: try one meg */ + + while (1) { + remapped = ioremap(__pa(high_memory), trial_size); + if (!remapped) { + PDEBUGG("%li megs failed!\n", trial_size>>20); + break; + } + PDEBUGG("Trying %li megs (at %p, %p)\n", trial_size>>20, + (void *)__pa(high_memory), remapped); + for (i = last_trial; i < trial_size; i += 16) { + strcpy((char *)(remapped)+i, test_string); + if (strcmp((char *)(remapped)+i, test_string)) + break; + } + iounmap((void *)remapped); + schedule(); + last_trial = trial_size; + if (i == trial_size) + trial_size += step; /* increment, if all went well */ + else { + PDEBUGG("%li megs copy test failed!\n", trial_size>>20); + break; + } + if (!allocator_probe) + break; + } + PDEBUG("%li megs (%li k, %li b)\n", i>>20, i>>10, i); + allocator_buffer_size = i>>10; /* kilobytes */ + allocator_buffer = __pa(high_memory); + if (!allocator_buffer_size) { + printk(KERN_WARNING ALL_MSG "no free high memory to use\n"); + return -ENOMEM; + } + + /* + * to simplify things, always have two cells in the list: + * the first and the last. This avoids some conditionals and + * extra code when allocating and deallocating: we only play + * in the middle of the list + */ + head = kmalloc(sizeof(struct allocator_struct), GFP_KERNEL); + if (!head) + return -ENOMEM; + tail = kmalloc(sizeof(struct allocator_struct), GFP_KERNEL); + if (!tail) { + kfree(head); + return -ENOMEM; + } + + max = allocator_buffer_size<<10; + + head->size = tail->size = 0; + head->address = allocator_buffer; + tail->address = allocator_buffer + max; + head->next = tail; + tail->next = NULL; + allocator_list = head; + + /* Back to the user code, in KB */ + *allocator_max = allocator_buffer_size; + + return 0; /* ok, ready */ +} + +void allocator_cleanup(void) +{ + struct allocator_struct *ptr, *next; + + for (ptr = allocator_list; ptr; ptr = next) { + next = ptr->next; + PDEBUG("freeing list: 0x%08lx\n", ptr->address); + kfree(ptr); + } + + allocator_buffer = 0; + allocator_buffer_size = 0; + allocator_list = NULL; +} + + |