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/err.h>
  11 #include <linux/module.h>
  12 #include <linux/types.h>
  13 #include <linux/kernel.h>
  14 #include <linux/io.h>
  15 #include <linux/slab.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 #include <linux/of.h>
  23
  24 #include <lantiq_soc.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 const char ltq_map_name[] = "ltq_nor";
  48 static const char * const ltq_probe_types[] = { "cmdlinepart", "ofpart", 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
 112 ltq_mtd_probe(struct platform_device *pdev)
 113 {
 114         struct mtd_part_parser_data ppdata;
 115         struct ltq_mtd *ltq_mtd;
 116         struct cfi_private *cfi;
 117         int err;
 118
 119         if (of_machine_is_compatible("lantiq,falcon") &&
 120                         (ltq_boot_select() != BS_FLASH)) {
 121                 dev_err(&pdev->dev, "invalid bootstrap options\n");
 122                 return -ENODEV;
 123         }
 124
 125         ltq_mtd = devm_kzalloc(&pdev->dev, sizeof(struct ltq_mtd), GFP_KERNEL);
 126         if (!ltq_mtd)
 127                 return -ENOMEM;
 128
 129         platform_set_drvdata(pdev, ltq_mtd);
 130
 131         ltq_mtd->res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 132         if (!ltq_mtd->res) {
 133                 dev_err(&pdev->dev, "failed to get memory resource\n");
 134                 return -ENOENT;
 135         }
 136
 137         ltq_mtd->map = devm_kzalloc(&pdev->dev, sizeof(struct map_info),
 138                                     GFP_KERNEL);
 139         if (!ltq_mtd->map)
 140                 return -ENOMEM;
 141
 142         ltq_mtd->map->phys = ltq_mtd->res->start;
 143         ltq_mtd->map->size = resource_size(ltq_mtd->res);
 144         ltq_mtd->map->virt = devm_ioremap_resource(&pdev->dev, ltq_mtd->res);
 145         if (IS_ERR(ltq_mtd->map->virt))
 146                 return PTR_ERR(ltq_mtd->map->virt);
 147
 148         ltq_mtd->map->name = ltq_map_name;
 149         ltq_mtd->map->bankwidth = 2;
 150         ltq_mtd->map->read = ltq_read16;
 151         ltq_mtd->map->write = ltq_write16;
 152         ltq_mtd->map->copy_from = ltq_copy_from;
 153         ltq_mtd->map->copy_to = ltq_copy_to;
 154
 155         ltq_mtd->map->map_priv_1 = LTQ_NOR_PROBING;
 156         ltq_mtd->mtd = do_map_probe("cfi_probe", ltq_mtd->map);
 157         ltq_mtd->map->map_priv_1 = LTQ_NOR_NORMAL;
 158
 159         if (!ltq_mtd->mtd) {
 160                 dev_err(&pdev->dev, "probing failed\n");
 161                 return -ENXIO;
 162         }
 163
 164         ltq_mtd->mtd->owner = THIS_MODULE;
 165
 166         cfi = ltq_mtd->map->fldrv_priv;
 167         cfi->addr_unlock1 ^= 1;
 168         cfi->addr_unlock2 ^= 1;
 169
 170         ppdata.of_node = pdev->dev.of_node;
 171         err = mtd_device_parse_register(ltq_mtd->mtd, ltq_probe_types,
 172                                         &ppdata, NULL, 0);
 173         if (err) {
 174                 dev_err(&pdev->dev, "failed to add partitions\n");
 175                 goto err_destroy;
 176         }
 177
 178         return 0;
 179
 180 err_destroy:
 181         map_destroy(ltq_mtd->mtd);
 182         return err;
 183 }
 184
 185 static int
 186 ltq_mtd_remove(struct platform_device *pdev)
 187 {
 188         struct ltq_mtd *ltq_mtd = platform_get_drvdata(pdev);
 189
 190         if (ltq_mtd && ltq_mtd->mtd) {
 191                 mtd_device_unregister(ltq_mtd->mtd);
 192                 map_destroy(ltq_mtd->mtd);
 193         }
 194         return 0;
 195 }
 196
 197 static const struct of_device_id ltq_mtd_match[] = {
 198         { .compatible = "lantiq,nor" },
 199         {},
 200 };
 201 MODULE_DEVICE_TABLE(of, ltq_mtd_match);
 202
 203 static struct platform_driver ltq_mtd_driver = {
 204         .probe = ltq_mtd_probe,
 205         .remove = ltq_mtd_remove,
 206         .driver = {
 207                 .name = "ltq-nor",
 208                 .of_match_table = ltq_mtd_match,
 209         },
 210 };
 211
 212 module_platform_driver(ltq_mtd_driver);
 213
 214 MODULE_LICENSE("GPL");
 215 MODULE_AUTHOR("John Crispin <blogic@openwrt.org>");
 216 MODULE_DESCRIPTION("Lantiq SoC NOR");