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/memblock.h>
  21 #include <linux/mount.h>
  22 #include <linux/blkdev.h>
  23 #include <linux/module.h>
  24 #include <linux/ioport.h>
  25
  26 #include <asm/setup.h>
  27 #include <asm/machdep.h>
  28 #include <asm/page.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)memblock_alloc_low(pool_size,
  98                                                                        PAGE_SIZE);
  99                 if (!stram_pool.start)
 100                         panic("%s: Failed to allocate %lu bytes align=%lx\n",
 101                               __func__, pool_size, PAGE_SIZE);
 102
 103                 stram_pool.end = stram_pool.start + pool_size - 1;
 104                 request_resource(&iomem_resource, &stram_pool);
 105                 stram_virt_offset = 0;
 106                 pr_debug("atari_stram pool: size = %lu bytes, resource = %pR\n",
 107                         pool_size, &stram_pool);
 108                 pr_debug("atari_stram pool: stram_virt_offset = %lx\n",
 109                         stram_virt_offset);
 110         }
 111 }
 112
 113
 114 /*
 115  * This function is called as arch initcall to reserve the pages needed for
 116  * ST-RAM management, if the kernel does not reside in ST-RAM.
 117  */
 118 int __init atari_stram_map_pages(void)
 119 {
 120         if (!kernel_in_stram) {
 121                 /*
 122                  * Skip page 0, as the fhe first 2 KiB are supervisor-only!
 123                  */
 124                 pr_debug("atari_stram pool: kernel not in ST-RAM, using ioremap!\n");
 125                 stram_pool.start = PAGE_SIZE;
 126                 stram_pool.end = stram_pool.start + pool_size - 1;
 127                 request_resource(&iomem_resource, &stram_pool);
 128                 stram_virt_offset = (unsigned long) ioremap(stram_pool.start,
 129                                 resource_size(&stram_pool)) - stram_pool.start;
 130                 pr_debug("atari_stram pool: size = %lu bytes, resource = %pR\n",
 131                         pool_size, &stram_pool);
 132                 pr_debug("atari_stram pool: stram_virt_offset = %lx\n",
 133                         stram_virt_offset);
 134         }
 135         return 0;
 136 }
 137 arch_initcall(atari_stram_map_pages);
 138
 139
 140 void *atari_stram_to_virt(unsigned long phys)
 141 {
 142         return (void *)(phys + stram_virt_offset);
 143 }
 144 EXPORT_SYMBOL(atari_stram_to_virt);
 145
 146
 147 unsigned long atari_stram_to_phys(void *virt)
 148 {
 149         return (unsigned long)(virt - stram_virt_offset);
 150 }
 151 EXPORT_SYMBOL(atari_stram_to_phys);
 152
 153
 154 void *atari_stram_alloc(unsigned long size, const char *owner)
 155 {
 156         struct resource *res;
 157         int error;
 158
 159         pr_debug("atari_stram_alloc: allocate %lu bytes\n", size);
 160
 161         /* round up */
 162         size = PAGE_ALIGN(size);
 163
 164         res = kzalloc(sizeof(struct resource), GFP_KERNEL);
 165         if (!res)
 166                 return NULL;
 167
 168         res->name = owner;
 169         error = allocate_resource(&stram_pool, res, size, 0, UINT_MAX,
 170                                   PAGE_SIZE, NULL, NULL);
 171         if (error < 0) {
 172                 pr_err("atari_stram_alloc: allocate_resource() failed %d!\n",
 173                        error);
 174                 kfree(res);
 175                 return NULL;
 176         }
 177
 178         pr_debug("atari_stram_alloc: returning %pR\n", res);
 179         return atari_stram_to_virt(res->start);
 180 }
 181 EXPORT_SYMBOL(atari_stram_alloc);
 182
 183
 184 void atari_stram_free(void *addr)
 185 {
 186         unsigned long start = atari_stram_to_phys(addr);
 187         struct resource *res;
 188         unsigned long size;
 189
 190         res = lookup_resource(&stram_pool, start);
 191         if (!res) {
 192                 pr_err("atari_stram_free: trying to free nonexistent region "
 193                        "at %p\n", addr);
 194                 return;
 195         }
 196
 197         size = resource_size(res);
 198         pr_debug("atari_stram_free: free %lu bytes at %p\n", size, addr);
 199         release_resource(res);
 200         kfree(res);
 201 }
 202 EXPORT_SYMBOL(atari_stram_free);