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