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 static const char *ltq_probe_types[] __devinitconst = { "cmdlinepart", NULL };
  49
  50 static map_word
  51 ltq_read16(struct map_info *map, unsigned long adr)
  52 {
  53         unsigned long flags;
  54         map_word temp;
  55
  56         if (map->map_priv_1 == LTQ_NOR_PROBING)
  57                 adr ^= 2;
  58         spin_lock_irqsave(&ebu_lock, flags);
  59         temp.x[0] = *(u16 *)(map->virt + adr);
  60         spin_unlock_irqrestore(&ebu_lock, flags);
  61         return temp;
  62 }
  63
  64 static void
  65 ltq_write16(struct map_info *map, map_word d, unsigned long adr)
  66 {
  67         unsigned long flags;
  68
  69         if (map->map_priv_1 == LTQ_NOR_PROBING)
  70                 adr ^= 2;
  71         spin_lock_irqsave(&ebu_lock, flags);
  72         *(u16 *)(map->virt + adr) = d.x[0];
  73         spin_unlock_irqrestore(&ebu_lock, flags);
  74 }
  75
  76 /*
  77  * The following 2 functions copy data between iomem and a cached memory
  78  * section. As memcpy() makes use of pre-fetching we cannot use it here.
  79  * The normal alternative of using memcpy_{to,from}io also makes use of
  80  * memcpy() on MIPS so it is not applicable either. We are therefore stuck
  81  * with having to use our own loop.
  82  */
  83 static void
  84 ltq_copy_from(struct map_info *map, void *to,
  85         unsigned long from, ssize_t len)
  86 {
  87         unsigned char *f = (unsigned char *)map->virt + from;
  88         unsigned char *t = (unsigned char *)to;
  89         unsigned long flags;
  90
  91         spin_lock_irqsave(&ebu_lock, flags);
  92         while (len--)
  93                 *t++ = *f++;
  94         spin_unlock_irqrestore(&ebu_lock, flags);
  95 }
  96
  97 static void
  98 ltq_copy_to(struct map_info *map, unsigned long to,
  99         const void *from, ssize_t len)
 100 {
 101         unsigned char *f = (unsigned char *)from;
 102         unsigned char *t = (unsigned char *)map->virt + to;
 103         unsigned long flags;
 104
 105         spin_lock_irqsave(&ebu_lock, flags);
 106         while (len--)
 107                 *t++ = *f++;
 108         spin_unlock_irqrestore(&ebu_lock, flags);
 109 }
 110
 111 static int __init
 112 ltq_mtd_probe(struct platform_device *pdev)
 113 {
 114         struct physmap_flash_data *ltq_mtd_data = dev_get_platdata(&pdev->dev);
 115         struct ltq_mtd *ltq_mtd;
 116         struct resource *res;
 117         struct cfi_private *cfi;
 118         int err;
 119
 120         ltq_mtd = kzalloc(sizeof(struct ltq_mtd), GFP_KERNEL);
 121         platform_set_drvdata(pdev, ltq_mtd);
 122
 123         ltq_mtd->res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 124         if (!ltq_mtd->res) {
 125                 dev_err(&pdev->dev, "failed to get memory resource");
 126                 err = -ENOENT;
 127                 goto err_out;
 128         }
 129
 130         res = devm_request_mem_region(&pdev->dev, ltq_mtd->res->start,
 131                 resource_size(ltq_mtd->res), dev_name(&pdev->dev));
 132         if (!ltq_mtd->res) {
 133                 dev_err(&pdev->dev, "failed to request mem resource");
 134                 err = -EBUSY;
 135                 goto err_out;
 136         }
 137
 138         ltq_mtd->map = kzalloc(sizeof(struct map_info), GFP_KERNEL);
 139         ltq_mtd->map->phys = res->start;
 140         ltq_mtd->map->size = resource_size(res);
 141         ltq_mtd->map->virt = devm_ioremap_nocache(&pdev->dev,
 142                                 ltq_mtd->map->phys, ltq_mtd->map->size);
 143         if (!ltq_mtd->map->virt) {
 144                 dev_err(&pdev->dev, "failed to ioremap!\n");
 145                 err = -ENOMEM;
 146                 goto err_free;
 147         }
 148
 149         ltq_mtd->map->name = ltq_map_name;
 150         ltq_mtd->map->bankwidth = 2;
 151         ltq_mtd->map->read = ltq_read16;
 152         ltq_mtd->map->write = ltq_write16;
 153         ltq_mtd->map->copy_from = ltq_copy_from;
 154         ltq_mtd->map->copy_to = ltq_copy_to;
 155
 156         ltq_mtd->map->map_priv_1 = LTQ_NOR_PROBING;
 157         ltq_mtd->mtd = do_map_probe("cfi_probe", ltq_mtd->map);
 158         ltq_mtd->map->map_priv_1 = LTQ_NOR_NORMAL;
 159
 160         if (!ltq_mtd->mtd) {
 161                 dev_err(&pdev->dev, "probing failed\n");
 162                 err = -ENXIO;
 163                 goto err_free;
 164         }
 165
 166         ltq_mtd->mtd->owner = THIS_MODULE;
 167
 168         cfi = ltq_mtd->map->fldrv_priv;
 169         cfi->addr_unlock1 ^= 1;
 170         cfi->addr_unlock2 ^= 1;
 171
 172         err = mtd_device_parse_register(ltq_mtd->mtd, ltq_probe_types, 0,
 173                         ltq_mtd_data->parts, ltq_mtd_data->nr_parts);
 174         if (err) {
 175                 dev_err(&pdev->dev, "failed to add partitions\n");
 176                 goto err_destroy;
 177         }
 178
 179         return 0;
 180
 181 err_destroy:
 182         map_destroy(ltq_mtd->mtd);
 183 err_free:
 184         kfree(ltq_mtd->map);
 185 err_out:
 186         kfree(ltq_mtd);
 187         return err;
 188 }
 189
 190 static int __devexit
 191 ltq_mtd_remove(struct platform_device *pdev)
 192 {
 193         struct ltq_mtd *ltq_mtd = platform_get_drvdata(pdev);
 194
 195         if (ltq_mtd) {
 196                 if (ltq_mtd->mtd) {
 197                         mtd_device_unregister(ltq_mtd->mtd);
 198                         map_destroy(ltq_mtd->mtd);
 199                 }
 200                 kfree(ltq_mtd->map);
 201                 kfree(ltq_mtd);
 202         }
 203         return 0;
 204 }
 205
 206 static struct platform_driver ltq_mtd_driver = {
 207         .remove = __devexit_p(ltq_mtd_remove),
 208         .driver = {
 209                 .name = "ltq_nor",
 210                 .owner = THIS_MODULE,
 211         },
 212 };
 213
 214 static int __init
 215 init_ltq_mtd(void)
 216 {
 217         int ret = platform_driver_probe(&ltq_mtd_driver, ltq_mtd_probe);
 218
 219         if (ret)
 220                 pr_err("ltq_nor: error registering platform driver");
 221         return ret;
 222 }
 223
 224 static void __exit
 225 exit_ltq_mtd(void)
 226 {
 227         platform_driver_unregister(&ltq_mtd_driver);
 228 }
 229
 230 module_init(init_ltq_mtd);
 231 module_exit(exit_ltq_mtd);
 232
 233 MODULE_LICENSE("GPL");
 234 MODULE_AUTHOR("John Crispin <blogic@openwrt.org>");
 235 MODULE_DESCRIPTION("Lantiq SoC NOR");