arch/m68k/atari/stram.c

   1 /*
   2  * 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 #include <linux/module.h>
  24
  25 #include <asm/setup.h>
  26 #include <asm/machdep.h>
  27 #include <asm/page.h>
  28 #include <asm/pgtable.h>
  29 #include <asm/atarihw.h>
  30 #include <asm/atari_stram.h>
  31 #include <asm/io.h>
  32
  33
  34 /*
  35  * The ST-RAM allocator allocates memory from a pool of reserved ST-RAM of
  36  * configurable size, set aside on ST-RAM init.
  37  * As long as this pool is not exhausted, allocation of real ST-RAM can be
  38  * guaranteed.
  39  */
  40
  41 /* set if kernel is in ST-RAM */
  42 static int kernel_in_stram;
  43
  44 static struct resource stram_pool = {
  45         .name = "ST-RAM Pool"
  46 };
  47
  48 static unsigned long pool_size = 1024*1024;
  49
  50 static unsigned long stram_virt_offset;
  51
  52 static int __init atari_stram_setup(char *arg)
  53 {
  54         if (!MACH_IS_ATARI)
  55                 return 0;
  56
  57         pool_size = memparse(arg, NULL);
  58         return 0;
  59 }
  60
  61 early_param("stram_pool", atari_stram_setup);
  62
  63
  64 /*
  65  * This init function is called very early by atari/config.c
  66  * It initializes some internal variables needed for stram_alloc()
  67  */
  68 void __init atari_stram_init(void)
  69 {
  70         int i;
  71
  72         /*
  73          * determine whether kernel code resides in ST-RAM
  74          * (then ST-RAM is the first memory block at virtual 0x0)
  75          */
  76         kernel_in_stram = (m68k_memory[0].addr == 0);
  77
  78         for (i = 0; i < m68k_num_memory; ++i) {
  79                 if (m68k_memory[i].addr == 0) {
  80                         return;
  81                 }
  82         }
  83
  84         /* Should never come here! (There is always ST-Ram!) */
  85         panic("atari_stram_init: no ST-RAM found!");
  86 }
  87
  88
  89 /*
  90  * This function is called from setup_arch() to reserve the pages needed for
  91  * ST-RAM management, if the kernel resides in ST-RAM.
  92  */
  93 void __init atari_stram_reserve_pages(void *start_mem)
  94 {
  95         if (kernel_in_stram) {
  96                 pr_debug("atari_stram pool: kernel in ST-RAM, using alloc_bootmem!\n");
  97                 stram_pool.start = (resource_size_t)alloc_bootmem_low_pages(pool_size);
  98                 stram_pool.end = stram_pool.start + pool_size - 1;
  99                 request_resource(&iomem_resource, &stram_pool);
 100                 stram_virt_offset = 0;
 101                 pr_debug("atari_stram pool: size = %lu bytes, resource = %pR\n",
 102                         pool_size, &stram_pool);
 103                 pr_debug("atari_stram pool: stram_virt_offset = %lx\n",
 104                         stram_virt_offset);
 105         }
 106 }
 107
 108
 109 /*
 110  * This function is called as arch initcall to reserve the pages needed for
 111  * ST-RAM management, if the kernel does not reside in ST-RAM.
 112  */
 113 int __init atari_stram_map_pages(void)
 114 {
 115         if (!kernel_in_stram) {
 116                 /*
 117                  * Skip page 0, as the fhe first 2 KiB are supervisor-only!
 118                  */
 119                 pr_debug("atari_stram pool: kernel not in ST-RAM, using ioremap!\n");
 120                 stram_pool.start = PAGE_SIZE;
 121                 stram_pool.end = stram_pool.start + pool_size - 1;
 122                 request_resource(&iomem_resource, &stram_pool);
 123                 stram_virt_offset = (unsigned long) ioremap(stram_pool.start,
 124                                 resource_size(&stram_pool)) - stram_pool.start;
 125                 pr_debug("atari_stram pool: size = %lu bytes, resource = %pR\n",
 126                         pool_size, &stram_pool);
 127                 pr_debug("atari_stram pool: stram_virt_offset = %lx\n",
 128                         stram_virt_offset);
 129         }
 130         return 0;
 131 }
 132 arch_initcall(atari_stram_map_pages);
 133
 134
 135 void *atari_stram_to_virt(unsigned long phys)
 136 {
 137         return (void *)(phys + stram_virt_offset);
 138 }
 139 EXPORT_SYMBOL(atari_stram_to_virt);
 140
 141
 142 unsigned long atari_stram_to_phys(void *virt)
 143 {
 144         return (unsigned long)(virt - stram_virt_offset);
 145 }
 146 EXPORT_SYMBOL(atari_stram_to_phys);
 147
 148
 149 void *atari_stram_alloc(unsigned long size, const char *owner)
 150 {
 151         struct resource *res;
 152         int error;
 153
 154         pr_debug("atari_stram_alloc: allocate %lu bytes\n", size);
 155
 156         /* round up */
 157         size = PAGE_ALIGN(size);
 158
 159         res = kzalloc(sizeof(struct resource), GFP_KERNEL);
 160         if (!res)
 161                 return NULL;
 162
 163         res->name = owner;
 164         error = allocate_resource(&stram_pool, res, size, 0, UINT_MAX,
 165                                   PAGE_SIZE, NULL, NULL);
 166         if (error < 0) {
 167                 pr_err("atari_stram_alloc: allocate_resource() failed %d!\n",
 168                        error);
 169                 kfree(res);
 170                 return NULL;
 171         }
 172
 173         pr_debug("atari_stram_alloc: returning %pR\n", res);
 174         return atari_stram_to_virt(res->start);
 175 }
 176 EXPORT_SYMBOL(atari_stram_alloc);
 177
 178
 179 void atari_stram_free(void *addr)
 180 {
 181         unsigned long start = atari_stram_to_phys(addr);
 182         struct resource *res;
 183         unsigned long size;
 184
 185         res = lookup_resource(&stram_pool, start);
 186         if (!res) {
 187                 pr_err("atari_stram_free: trying to free nonexistent region "
 188                        "at %p\n", addr);
 189                 return;
 190         }
 191
 192         size = resource_size(res);
 193         pr_debug("atari_stram_free: free %lu bytes at %p\n", size, addr);
 194         release_resource(res);
 195         kfree(res);
 196 }
 197 EXPORT_SYMBOL(atari_stram_free);