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 = devm_kzalloc(&pdev->dev, sizeof(struct ltq_mtd), GFP_KERNEL);
 127         if (!ltq_mtd)
 128                 return -ENOMEM;
 129
 130         platform_set_drvdata(pdev, ltq_mtd);
 131
 132         ltq_mtd->res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 133         if (!ltq_mtd->res) {
 134                 dev_err(&pdev->dev, "failed to get memory resource\n");
 135                 return -ENOENT;
 136         }
 137
 138         ltq_mtd->map = devm_kzalloc(&pdev->dev, sizeof(struct map_info),
 139                                     GFP_KERNEL);
 140         if (!ltq_mtd->map)
 141                 return -ENOMEM;
 142
 143         ltq_mtd->map->phys = ltq_mtd->res->start;
 144         ltq_mtd->map->size = resource_size(ltq_mtd->res);
 145         ltq_mtd->map->virt = devm_ioremap_resource(&pdev->dev, ltq_mtd->res);
 146         if (IS_ERR(ltq_mtd->map->virt))
 147                 return PTR_ERR(ltq_mtd->map->virt);
 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                 return -ENXIO;
 163         }
 164
 165         ltq_mtd->mtd->owner = THIS_MODULE;
 166
 167         cfi = ltq_mtd->map->fldrv_priv;
 168         cfi->addr_unlock1 ^= 1;
 169         cfi->addr_unlock2 ^= 1;
 170
 171         ppdata.of_node = pdev->dev.of_node;
 172         err = mtd_device_parse_register(ltq_mtd->mtd, ltq_probe_types,
 173                                         &ppdata, NULL, 0);
 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         return err;
 184 }
 185
 186 static int
 187 ltq_mtd_remove(struct platform_device *pdev)
 188 {
 189         struct ltq_mtd *ltq_mtd = platform_get_drvdata(pdev);
 190
 191         if (ltq_mtd && ltq_mtd->mtd) {
 192                 mtd_device_unregister(ltq_mtd->mtd);
 193                 map_destroy(ltq_mtd->mtd);
 194         }
 195         return 0;
 196 }
 197
 198 static const struct of_device_id ltq_mtd_match[] = {
 199         { .compatible = "lantiq,nor" },
 200         {},
 201 };
 202 MODULE_DEVICE_TABLE(of, ltq_mtd_match);
 203
 204 static struct platform_driver ltq_mtd_driver = {
 205         .probe = ltq_mtd_probe,
 206         .remove = ltq_mtd_remove,
 207         .driver = {
 208                 .name = "ltq-nor",
 209                 .owner = THIS_MODULE,
 210                 .of_match_table = ltq_mtd_match,
 211         },
 212 };
 213
 214 module_platform_driver(ltq_mtd_driver);
 215
 216 MODULE_LICENSE("GPL");
 217 MODULE_AUTHOR("John Crispin <blogic@openwrt.org>");
 218 MODULE_DESCRIPTION("Lantiq SoC NOR");