drivers/mtd/maps/lantiq-flash.c

   1 /*
   2  *  This program is free software; you can redistribute it and/or modify it
   3  *  under the terms of the GNU General Public License version 2 as published
   4  *  by the Free Software Foundation.
   5  *
   6  *  Copyright (C) 2004 Liu Peng Infineon IFAP DC COM CPE
   7  *  Copyright (C) 2010 John Crispin <blogic@openwrt.org>
   8  */
   9
  10 #include <linux/module.h>
  11 #include <linux/types.h>
  12 #include <linux/kernel.h>
  13 #include <linux/io.h>
  14 #include <linux/slab.h>
  15 #include <linux/init.h>
  16 #include <linux/mtd/mtd.h>
  17 #include <linux/mtd/map.h>
  18 #include <linux/mtd/partitions.h>
  19 #include <linux/mtd/cfi.h>
  20 #include <linux/platform_device.h>
  21 #include <linux/mtd/physmap.h>
  22
  23 #include <lantiq_soc.h>
  24 #include <lantiq_platform.h>
  25
  26 /*
  27  * The NOR flash is connected to the same external bus unit (EBU) as PCI.
  28  * To make PCI work we need to enable the endianness swapping for the address
  29  * written to the EBU. This endianness swapping works for PCI correctly but
  30  * fails for attached NOR devices. To workaround this we need to use a complex
  31  * map. The workaround involves swapping all addresses whilst probing the chip.
  32  * Once probing is complete we stop swapping the addresses but swizzle the
  33  * unlock addresses to ensure that access to the NOR device works correctly.
  34  */
  35
  36 enum {
  37         LTQ_NOR_PROBING,
  38         LTQ_NOR_NORMAL
  39 };
  40
  41 struct ltq_mtd {
  42         struct resource *res;
  43         struct mtd_info *mtd;
  44         struct map_info *map;
  45 };
  46
  47 static char ltq_map_name[] = "ltq_nor";
  48
  49 static map_word
  50 ltq_read16(struct map_info *map, unsigned long adr)
  51 {
  52         unsigned long flags;
  53         map_word temp;
  54
  55         if (map->map_priv_1 == LTQ_NOR_PROBING)
  56                 adr ^= 2;
  57         spin_lock_irqsave(&ebu_lock, flags);
  58         temp.x[0] = *(u16 *)(map->virt + adr);
  59         spin_unlock_irqrestore(&ebu_lock, flags);
  60         return temp;
  61 }
  62
  63 static void
  64 ltq_write16(struct map_info *map, map_word d, unsigned long adr)
  65 {
  66         unsigned long flags;
  67
  68         if (map->map_priv_1 == LTQ_NOR_PROBING)
  69                 adr ^= 2;
  70         spin_lock_irqsave(&ebu_lock, flags);
  71         *(u16 *)(map->virt + adr) = d.x[0];
  72         spin_unlock_irqrestore(&ebu_lock, flags);
  73 }
  74
  75 /*
  76  * The following 2 functions copy data between iomem and a cached memory
  77  * section. As memcpy() makes use of pre-fetching we cannot use it here.
  78  * The normal alternative of using memcpy_{to,from}io also makes use of
  79  * memcpy() on MIPS so it is not applicable either. We are therefore stuck
  80  * with having to use our own loop.
  81  */
  82 static void
  83 ltq_copy_from(struct map_info *map, void *to,
  84         unsigned long from, ssize_t len)
  85 {
  86         unsigned char *f = (unsigned char *)map->virt + from;
  87         unsigned char *t = (unsigned char *)to;
  88         unsigned long flags;
  89
  90         spin_lock_irqsave(&ebu_lock, flags);
  91         while (len--)
  92                 *t++ = *f++;
  93         spin_unlock_irqrestore(&ebu_lock, flags);
  94 }
  95
  96 static void
  97 ltq_copy_to(struct map_info *map, unsigned long to,
  98         const void *from, ssize_t len)
  99 {
 100         unsigned char *f = (unsigned char *)from;
 101         unsigned char *t = (unsigned char *)map->virt + to;
 102         unsigned long flags;
 103
 104         spin_lock_irqsave(&ebu_lock, flags);
 105         while (len--)
 106                 *t++ = *f++;
 107         spin_unlock_irqrestore(&ebu_lock, flags);
 108 }
 109
 110 static const char const *part_probe_types[] = { "cmdlinepart", NULL };
 111
 112 static int __init
 113 ltq_mtd_probe(struct platform_device *pdev)
 114 {
 115         struct physmap_flash_data *ltq_mtd_data = dev_get_platdata(&pdev->dev);
 116         struct ltq_mtd *ltq_mtd;
 117         struct mtd_partition *parts;
 118         struct resource *res;
 119         int nr_parts = 0;
 120         struct cfi_private *cfi;
 121         int err;
 122
 123         ltq_mtd = kzalloc(sizeof(struct ltq_mtd), GFP_KERNEL);
 124         platform_set_drvdata(pdev, ltq_mtd);
 125
 126         ltq_mtd->res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 127         if (!ltq_mtd->res) {
 128                 dev_err(&pdev->dev, "failed to get memory resource");
 129                 err = -ENOENT;
 130                 goto err_out;
 131         }
 132
 133         res = devm_request_mem_region(&pdev->dev, ltq_mtd->res->start,
 134                 resource_size(ltq_mtd->res), dev_name(&pdev->dev));
 135         if (!ltq_mtd->res) {
 136                 dev_err(&pdev->dev, "failed to request mem resource");
 137                 err = -EBUSY;
 138                 goto err_out;
 139         }
 140
 141         ltq_mtd->map = kzalloc(sizeof(struct map_info), GFP_KERNEL);
 142         ltq_mtd->map->phys = res->start;
 143         ltq_mtd->map->size = resource_size(res);
 144         ltq_mtd->map->virt = devm_ioremap_nocache(&pdev->dev,
 145                                 ltq_mtd->map->phys, ltq_mtd->map->size);
 146         if (!ltq_mtd->map->virt) {
 147                 dev_err(&pdev->dev, "failed to ioremap!\n");
 148                 err = -ENOMEM;
 149                 goto err_free;
 150         }
 151
 152         ltq_mtd->map->name = ltq_map_name;
 153         ltq_mtd->map->bankwidth = 2;
 154         ltq_mtd->map->read = ltq_read16;
 155         ltq_mtd->map->write = ltq_write16;
 156         ltq_mtd->map->copy_from = ltq_copy_from;
 157         ltq_mtd->map->copy_to = ltq_copy_to;
 158
 159         ltq_mtd->map->map_priv_1 = LTQ_NOR_PROBING;
 160         ltq_mtd->mtd = do_map_probe("cfi_probe", ltq_mtd->map);
 161         ltq_mtd->map->map_priv_1 = LTQ_NOR_NORMAL;
 162
 163         if (!ltq_mtd->mtd) {
 164                 dev_err(&pdev->dev, "probing failed\n");
 165                 err = -ENXIO;
 166                 goto err_unmap;
 167         }
 168
 169         ltq_mtd->mtd->owner = THIS_MODULE;
 170
 171         cfi = ltq_mtd->map->fldrv_priv;
 172         cfi->addr_unlock1 ^= 1;
 173         cfi->addr_unlock2 ^= 1;
 174
 175         nr_parts = parse_mtd_partitions(ltq_mtd->mtd,
 176                                 part_probe_types, &parts, 0);
 177         if (nr_parts > 0) {
 178                 dev_info(&pdev->dev,
 179                         "using %d partitions from cmdline", nr_parts);
 180         } else {
 181                 nr_parts = ltq_mtd_data->nr_parts;
 182                 parts = ltq_mtd_data->parts;
 183         }
 184
 185         err = mtd_device_register(ltq_mtd->mtd, parts, nr_parts);
 186         if (err) {
 187                 dev_err(&pdev->dev, "failed to add partitions\n");
 188                 goto err_destroy;
 189         }
 190
 191         return 0;
 192
 193 err_destroy:
 194         map_destroy(ltq_mtd->mtd);
 195 err_unmap:
 196         iounmap(ltq_mtd->map->virt);
 197 err_free:
 198         kfree(ltq_mtd->map);
 199 err_out:
 200         kfree(ltq_mtd);
 201         return err;
 202 }
 203
 204 static int __devexit
 205 ltq_mtd_remove(struct platform_device *pdev)
 206 {
 207         struct ltq_mtd *ltq_mtd = platform_get_drvdata(pdev);
 208
 209         if (ltq_mtd) {
 210                 if (ltq_mtd->mtd) {
 211                         mtd_device_unregister(ltq_mtd->mtd);
 212                         map_destroy(ltq_mtd->mtd);
 213                 }
 214                 if (ltq_mtd->map->virt)
 215                         iounmap(ltq_mtd->map->virt);
 216                 kfree(ltq_mtd->map);
 217                 kfree(ltq_mtd);
 218         }
 219         return 0;
 220 }
 221
 222 static struct platform_driver ltq_mtd_driver = {
 223         .remove = __devexit_p(ltq_mtd_remove),
 224         .driver = {
 225                 .name = "ltq_nor",
 226                 .owner = THIS_MODULE,
 227         },
 228 };
 229
 230 static int __init
 231 init_ltq_mtd(void)
 232 {
 233         int ret = platform_driver_probe(&ltq_mtd_driver, ltq_mtd_probe);
 234
 235         if (ret)
 236                 pr_err("ltq_nor: error registering platform driver");
 237         return ret;
 238 }
 239
 240 static void __exit
 241 exit_ltq_mtd(void)
 242 {
 243         platform_driver_unregister(&ltq_mtd_driver);
 244 }
 245
 246 module_init(init_ltq_mtd);
 247 module_exit(exit_ltq_mtd);
 248
 249 MODULE_LICENSE("GPL");
 250 MODULE_AUTHOR("John Crispin <blogic@openwrt.org>");
 251 MODULE_DESCRIPTION("Lantiq SoC NOR");