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