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/init.h>
  17 #include <linux/mtd/mtd.h>
  18 #include <linux/mtd/map.h>
  19 #include <linux/mtd/partitions.h>
  20 #include <linux/mtd/cfi.h>
  21 #include <linux/platform_device.h>
  22 #include <linux/mtd/physmap.h>
  23 #include <linux/of.h>
  24
  25 #include <lantiq_soc.h>
  26
  27 /*
  28  * The NOR flash is connected to the same external bus unit (EBU) as PCI.
  29  * To make PCI work we need to enable the endianness swapping for the address
  30  * written to the EBU. This endianness swapping works for PCI correctly but
  31  * fails for attached NOR devices. To workaround this we need to use a complex
  32  * map. The workaround involves swapping all addresses whilst probing the chip.
  33  * Once probing is complete we stop swapping the addresses but swizzle the
  34  * unlock addresses to ensure that access to the NOR device works correctly.
  35  */
  36
  37 enum {
  38         LTQ_NOR_PROBING,
  39         LTQ_NOR_NORMAL
  40 };
  41
  42 struct ltq_mtd {
  43         struct resource *res;
  44         struct mtd_info *mtd;
  45         struct map_info *map;
  46 };
  47
  48 static const char ltq_map_name[] = "ltq_nor";
  49 static const char *ltq_probe_types[] = {
  50                                         "cmdlinepart", "ofpart", NULL };
  51
  52 static map_word
  53 ltq_read16(struct map_info *map, unsigned long adr)
  54 {
  55         unsigned long flags;
  56         map_word temp;
  57
  58         if (map->map_priv_1 == LTQ_NOR_PROBING)
  59                 adr ^= 2;
  60         spin_lock_irqsave(&ebu_lock, flags);
  61         temp.x[0] = *(u16 *)(map->virt + adr);
  62         spin_unlock_irqrestore(&ebu_lock, flags);
  63         return temp;
  64 }
  65
  66 static void
  67 ltq_write16(struct map_info *map, map_word d, unsigned long adr)
  68 {
  69         unsigned long flags;
  70
  71         if (map->map_priv_1 == LTQ_NOR_PROBING)
  72                 adr ^= 2;
  73         spin_lock_irqsave(&ebu_lock, flags);
  74         *(u16 *)(map->virt + adr) = d.x[0];
  75         spin_unlock_irqrestore(&ebu_lock, flags);
  76 }
  77
  78 /*
  79  * The following 2 functions copy data between iomem and a cached memory
  80  * section. As memcpy() makes use of pre-fetching we cannot use it here.
  81  * The normal alternative of using memcpy_{to,from}io also makes use of
  82  * memcpy() on MIPS so it is not applicable either. We are therefore stuck
  83  * with having to use our own loop.
  84  */
  85 static void
  86 ltq_copy_from(struct map_info *map, void *to,
  87         unsigned long from, ssize_t len)
  88 {
  89         unsigned char *f = (unsigned char *)map->virt + from;
  90         unsigned char *t = (unsigned char *)to;
  91         unsigned long flags;
  92
  93         spin_lock_irqsave(&ebu_lock, flags);
  94         while (len--)
  95                 *t++ = *f++;
  96         spin_unlock_irqrestore(&ebu_lock, flags);
  97 }
  98
  99 static void
 100 ltq_copy_to(struct map_info *map, unsigned long to,
 101         const void *from, ssize_t len)
 102 {
 103         unsigned char *f = (unsigned char *)from;
 104         unsigned char *t = (unsigned char *)map->virt + to;
 105         unsigned long flags;
 106
 107         spin_lock_irqsave(&ebu_lock, flags);
 108         while (len--)
 109                 *t++ = *f++;
 110         spin_unlock_irqrestore(&ebu_lock, flags);
 111 }
 112
 113 static int
 114 ltq_mtd_probe(struct platform_device *pdev)
 115 {
 116         struct mtd_part_parser_data ppdata;
 117         struct ltq_mtd *ltq_mtd;
 118         struct cfi_private *cfi;
 119         int err;
 120
 121         if (of_machine_is_compatible("lantiq,falcon") &&
 122                         (ltq_boot_select() != BS_FLASH)) {
 123                 dev_err(&pdev->dev, "invalid bootstrap options\n");
 124                 return -ENODEV;
 125         }
 126
 127         ltq_mtd = kzalloc(sizeof(struct ltq_mtd), GFP_KERNEL);
 128         platform_set_drvdata(pdev, ltq_mtd);
 129
 130         ltq_mtd->res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 131         if (!ltq_mtd->res) {
 132                 dev_err(&pdev->dev, "failed to get memory resource\n");
 133                 err = -ENOENT;
 134                 goto err_out;
 135         }
 136
 137         ltq_mtd->map = kzalloc(sizeof(struct map_info), GFP_KERNEL);
 138         ltq_mtd->map->phys = ltq_mtd->res->start;
 139         ltq_mtd->map->size = resource_size(ltq_mtd->res);
 140         ltq_mtd->map->virt = devm_ioremap_resource(&pdev->dev, ltq_mtd->res);
 141         if (IS_ERR(ltq_mtd->map->virt)) {
 142                 err = PTR_ERR(ltq_mtd->map->virt);
 143                 goto err_out;
 144         }
 145
 146         ltq_mtd->map->name = ltq_map_name;
 147         ltq_mtd->map->bankwidth = 2;
 148         ltq_mtd->map->read = ltq_read16;
 149         ltq_mtd->map->write = ltq_write16;
 150         ltq_mtd->map->copy_from = ltq_copy_from;
 151         ltq_mtd->map->copy_to = ltq_copy_to;
 152
 153         ltq_mtd->map->map_priv_1 = LTQ_NOR_PROBING;
 154         ltq_mtd->mtd = do_map_probe("cfi_probe", ltq_mtd->map);
 155         ltq_mtd->map->map_priv_1 = LTQ_NOR_NORMAL;
 156
 157         if (!ltq_mtd->mtd) {
 158                 dev_err(&pdev->dev, "probing failed\n");
 159                 err = -ENXIO;
 160                 goto err_free;
 161         }
 162
 163         ltq_mtd->mtd->owner = THIS_MODULE;
 164
 165         cfi = ltq_mtd->map->fldrv_priv;
 166         cfi->addr_unlock1 ^= 1;
 167         cfi->addr_unlock2 ^= 1;
 168
 169         ppdata.of_node = pdev->dev.of_node;
 170         err = mtd_device_parse_register(ltq_mtd->mtd, ltq_probe_types,
 171                                         &ppdata, NULL, 0);
 172         if (err) {
 173                 dev_err(&pdev->dev, "failed to add partitions\n");
 174                 goto err_destroy;
 175         }
 176
 177         return 0;
 178
 179 err_destroy:
 180         map_destroy(ltq_mtd->mtd);
 181 err_free:
 182         kfree(ltq_mtd->map);
 183 err_out:
 184         kfree(ltq_mtd);
 185         return err;
 186 }
 187
 188 static int
 189 ltq_mtd_remove(struct platform_device *pdev)
 190 {
 191         struct ltq_mtd *ltq_mtd = platform_get_drvdata(pdev);
 192
 193         if (ltq_mtd) {
 194                 if (ltq_mtd->mtd) {
 195                         mtd_device_unregister(ltq_mtd->mtd);
 196                         map_destroy(ltq_mtd->mtd);
 197                 }
 198                 kfree(ltq_mtd->map);
 199                 kfree(ltq_mtd);
 200         }
 201         return 0;
 202 }
 203
 204 static const struct of_device_id ltq_mtd_match[] = {
 205         { .compatible = "lantiq,nor" },
 206         {},
 207 };
 208 MODULE_DEVICE_TABLE(of, ltq_mtd_match);
 209
 210 static struct platform_driver ltq_mtd_driver = {
 211         .probe = ltq_mtd_probe,
 212         .remove = ltq_mtd_remove,
 213         .driver = {
 214                 .name = "ltq-nor",
 215                 .owner = THIS_MODULE,
 216                 .of_match_table = ltq_mtd_match,
 217         },
 218 };
 219
 220 module_platform_driver(ltq_mtd_driver);
 221
 222 MODULE_LICENSE("GPL");
 223 MODULE_AUTHOR("John Crispin <blogic@openwrt.org>");
 224 MODULE_DESCRIPTION("Lantiq SoC NOR");