lantiq-flash.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  *
   4  *  Copyright (C) 2004 Liu Peng Infineon IFAP DC COM CPE
   5  *  Copyright (C) 2010 John Crispin <john@phrozen.org>
   6  */
   7
   8 #include <linux/err.h>
   9 #include <linux/module.h>
  10 #include <linux/types.h>
  11 #include <linux/kernel.h>
  12 #include <linux/io.h>
  13 #include <linux/slab.h>
  14 #include <linux/mtd/mtd.h>
  15 #include <linux/mtd/map.h>
  16 #include <linux/mtd/partitions.h>
  17 #include <linux/mtd/cfi.h>
  18 #include <linux/platform_device.h>
  19 #include <linux/mtd/physmap.h>
  20 #include <linux/of.h>
  21
  22 #include <lantiq_soc.h>
  23
  24 /*
  25  * The NOR flash is connected to the same external bus unit (EBU) as PCI.
  26  * To make PCI work we need to enable the endianness swapping for the address
  27  * written to the EBU. This endianness swapping works for PCI correctly but
  28  * fails for attached NOR devices. To workaround this we need to use a complex
  29  * map. The workaround involves swapping all addresses whilst probing the chip.
  30  * Once probing is complete we stop swapping the addresses but swizzle the
  31  * unlock addresses to ensure that access to the NOR device works correctly.
  32  */
  33
  34 enum {
  35         LTQ_NOR_PROBING,
  36         LTQ_NOR_NORMAL
  37 };
  38
  39 struct ltq_mtd {
  40         struct resource *res;
  41         struct mtd_info *mtd;
  42         struct map_info *map;
  43 };
  44
  45 static const char ltq_map_name[] = "ltq_nor";
  46
  47 static map_word
  48 ltq_read16(struct map_info *map, unsigned long adr)
  49 {
  50         unsigned long flags;
  51         map_word temp;
  52
  53         if (map->map_priv_1 == LTQ_NOR_PROBING)
  54                 adr ^= 2;
  55         spin_lock_irqsave(&ebu_lock, flags);
  56         temp.x[0] = *(u16 *)(map->virt + adr);
  57         spin_unlock_irqrestore(&ebu_lock, flags);
  58         return temp;
  59 }
  60
  61 static void
  62 ltq_write16(struct map_info *map, map_word d, unsigned long adr)
  63 {
  64         unsigned long flags;
  65
  66         if (map->map_priv_1 == LTQ_NOR_PROBING)
  67                 adr ^= 2;
  68         spin_lock_irqsave(&ebu_lock, flags);
  69         *(u16 *)(map->virt + adr) = d.x[0];
  70         spin_unlock_irqrestore(&ebu_lock, flags);
  71 }
  72
  73 /*
  74  * The following 2 functions copy data between iomem and a cached memory
  75  * section. As memcpy() makes use of pre-fetching we cannot use it here.
  76  * The normal alternative of using memcpy_{to,from}io also makes use of
  77  * memcpy() on MIPS so it is not applicable either. We are therefore stuck
  78  * with having to use our own loop.
  79  */
  80 static void
  81 ltq_copy_from(struct map_info *map, void *to,
  82         unsigned long from, ssize_t len)
  83 {
  84         unsigned char *f = (unsigned char *)map->virt + from;
  85         unsigned char *t = (unsigned char *)to;
  86         unsigned long flags;
  87
  88         spin_lock_irqsave(&ebu_lock, flags);
  89         while (len--)
  90                 *t++ = *f++;
  91         spin_unlock_irqrestore(&ebu_lock, flags);
  92 }
  93
  94 static void
  95 ltq_copy_to(struct map_info *map, unsigned long to,
  96         const void *from, ssize_t len)
  97 {
  98         unsigned char *f = (unsigned char *)from;
  99         unsigned char *t = (unsigned char *)map->virt + to;
 100         unsigned long flags;
 101
 102         spin_lock_irqsave(&ebu_lock, flags);
 103         while (len--)
 104                 *t++ = *f++;
 105         spin_unlock_irqrestore(&ebu_lock, flags);
 106 }
 107
 108 static int
 109 ltq_mtd_probe(struct platform_device *pdev)
 110 {
 111         struct ltq_mtd *ltq_mtd;
 112         struct cfi_private *cfi;
 113         int err;
 114
 115         ltq_mtd = devm_kzalloc(&pdev->dev, sizeof(struct ltq_mtd), GFP_KERNEL);
 116         if (!ltq_mtd)
 117                 return -ENOMEM;
 118
 119         platform_set_drvdata(pdev, ltq_mtd);
 120
 121         ltq_mtd->map->virt = devm_platform_get_and_ioremap_resource(pdev, 0, &ltq_mtd->res);
 122         if (IS_ERR(ltq_mtd->map->virt))
 123                 return PTR_ERR(ltq_mtd->map->virt);
 124
 125         ltq_mtd->map = devm_kzalloc(&pdev->dev, sizeof(struct map_info),
 126                                     GFP_KERNEL);
 127         if (!ltq_mtd->map)
 128                 return -ENOMEM;
 129
 130         ltq_mtd->map->phys = ltq_mtd->res->start;
 131         ltq_mtd->map->size = resource_size(ltq_mtd->res);
 132
 133         ltq_mtd->map->name = ltq_map_name;
 134         ltq_mtd->map->bankwidth = 2;
 135         ltq_mtd->map->read = ltq_read16;
 136         ltq_mtd->map->write = ltq_write16;
 137         ltq_mtd->map->copy_from = ltq_copy_from;
 138         ltq_mtd->map->copy_to = ltq_copy_to;
 139
 140         ltq_mtd->map->map_priv_1 = LTQ_NOR_PROBING;
 141         ltq_mtd->mtd = do_map_probe("cfi_probe", ltq_mtd->map);
 142         ltq_mtd->map->map_priv_1 = LTQ_NOR_NORMAL;
 143
 144         if (!ltq_mtd->mtd) {
 145                 dev_err(&pdev->dev, "probing failed\n");
 146                 return -ENXIO;
 147         }
 148
 149         ltq_mtd->mtd->dev.parent = &pdev->dev;
 150         mtd_set_of_node(ltq_mtd->mtd, pdev->dev.of_node);
 151
 152         cfi = ltq_mtd->map->fldrv_priv;
 153         cfi->addr_unlock1 ^= 1;
 154         cfi->addr_unlock2 ^= 1;
 155
 156         err = mtd_device_register(ltq_mtd->mtd, NULL, 0);
 157         if (err) {
 158                 dev_err(&pdev->dev, "failed to add partitions\n");
 159                 goto err_destroy;
 160         }
 161
 162         return 0;
 163
 164 err_destroy:
 165         map_destroy(ltq_mtd->mtd);
 166         return err;
 167 }
 168
 169 static void ltq_mtd_remove(struct platform_device *pdev)
 170 {
 171         struct ltq_mtd *ltq_mtd = platform_get_drvdata(pdev);
 172
 173         if (ltq_mtd && ltq_mtd->mtd) {
 174                 mtd_device_unregister(ltq_mtd->mtd);
 175                 map_destroy(ltq_mtd->mtd);
 176         }
 177 }
 178
 179 static const struct of_device_id ltq_mtd_match[] = {
 180         { .compatible = "lantiq,nor" },
 181         {},
 182 };
 183 MODULE_DEVICE_TABLE(of, ltq_mtd_match);
 184
 185 static struct platform_driver ltq_mtd_driver = {
 186         .probe = ltq_mtd_probe,
 187         .remove_new = ltq_mtd_remove,
 188         .driver = {
 189                 .name = "ltq-nor",
 190                 .of_match_table = ltq_mtd_match,
 191         },
 192 };
 193
 194 module_platform_driver(ltq_mtd_driver);
 195
 196 MODULE_LICENSE("GPL");
 197 MODULE_AUTHOR("John Crispin <john@phrozen.org>");
 198 MODULE_DESCRIPTION("Lantiq SoC NOR");