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Linux/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/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 static const char * const ltq_probe_types[] = { "cmdlinepart", "ofpart", NULL };
 49 
 50 static map_word
 51 ltq_read16(struct map_info *map, unsigned long adr)
 52 {
 53         unsigned long flags;
 54         map_word temp;
 55 
 56         if (map->map_priv_1 == LTQ_NOR_PROBING)
 57                 adr ^= 2;
 58         spin_lock_irqsave(&ebu_lock, flags);
 59         temp.x[0] = *(u16 *)(map->virt + adr);
 60         spin_unlock_irqrestore(&ebu_lock, flags);
 61         return temp;
 62 }
 63 
 64 static void
 65 ltq_write16(struct map_info *map, map_word d, unsigned long adr)
 66 {
 67         unsigned long flags;
 68 
 69         if (map->map_priv_1 == LTQ_NOR_PROBING)
 70                 adr ^= 2;
 71         spin_lock_irqsave(&ebu_lock, flags);
 72         *(u16 *)(map->virt + adr) = d.x[0];
 73         spin_unlock_irqrestore(&ebu_lock, flags);
 74 }
 75 
 76 /*
 77  * The following 2 functions copy data between iomem and a cached memory
 78  * section. As memcpy() makes use of pre-fetching we cannot use it here.
 79  * The normal alternative of using memcpy_{to,from}io also makes use of
 80  * memcpy() on MIPS so it is not applicable either. We are therefore stuck
 81  * with having to use our own loop.
 82  */
 83 static void
 84 ltq_copy_from(struct map_info *map, void *to,
 85         unsigned long from, ssize_t len)
 86 {
 87         unsigned char *f = (unsigned char *)map->virt + from;
 88         unsigned char *t = (unsigned char *)to;
 89         unsigned long flags;
 90 
 91         spin_lock_irqsave(&ebu_lock, flags);
 92         while (len--)
 93                 *t++ = *f++;
 94         spin_unlock_irqrestore(&ebu_lock, flags);
 95 }
 96 
 97 static void
 98 ltq_copy_to(struct map_info *map, unsigned long to,
 99         const void *from, ssize_t len)
100 {
101         unsigned char *f = (unsigned char *)from;
102         unsigned char *t = (unsigned char *)map->virt + to;
103         unsigned long flags;
104 
105         spin_lock_irqsave(&ebu_lock, flags);
106         while (len--)
107                 *t++ = *f++;
108         spin_unlock_irqrestore(&ebu_lock, flags);
109 }
110 
111 static int
112 ltq_mtd_probe(struct platform_device *pdev)
113 {
114         struct mtd_part_parser_data ppdata;
115         struct ltq_mtd *ltq_mtd;
116         struct cfi_private *cfi;
117         int err;
118 
119         if (of_machine_is_compatible("lantiq,falcon") &&
120                         (ltq_boot_select() != BS_FLASH)) {
121                 dev_err(&pdev->dev, "invalid bootstrap options\n");
122                 return -ENODEV;
123         }
124 
125         ltq_mtd = devm_kzalloc(&pdev->dev, sizeof(struct ltq_mtd), GFP_KERNEL);
126         if (!ltq_mtd)
127                 return -ENOMEM;
128 
129         platform_set_drvdata(pdev, ltq_mtd);
130 
131         ltq_mtd->res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
132         if (!ltq_mtd->res) {
133                 dev_err(&pdev->dev, "failed to get memory resource\n");
134                 return -ENOENT;
135         }
136 
137         ltq_mtd->map = devm_kzalloc(&pdev->dev, sizeof(struct map_info),
138                                     GFP_KERNEL);
139         if (!ltq_mtd->map)
140                 return -ENOMEM;
141 
142         ltq_mtd->map->phys = ltq_mtd->res->start;
143         ltq_mtd->map->size = resource_size(ltq_mtd->res);
144         ltq_mtd->map->virt = devm_ioremap_resource(&pdev->dev, ltq_mtd->res);
145         if (IS_ERR(ltq_mtd->map->virt))
146                 return PTR_ERR(ltq_mtd->map->virt);
147 
148         ltq_mtd->map->name = ltq_map_name;
149         ltq_mtd->map->bankwidth = 2;
150         ltq_mtd->map->read = ltq_read16;
151         ltq_mtd->map->write = ltq_write16;
152         ltq_mtd->map->copy_from = ltq_copy_from;
153         ltq_mtd->map->copy_to = ltq_copy_to;
154 
155         ltq_mtd->map->map_priv_1 = LTQ_NOR_PROBING;
156         ltq_mtd->mtd = do_map_probe("cfi_probe", ltq_mtd->map);
157         ltq_mtd->map->map_priv_1 = LTQ_NOR_NORMAL;
158 
159         if (!ltq_mtd->mtd) {
160                 dev_err(&pdev->dev, "probing failed\n");
161                 return -ENXIO;
162         }
163 
164         ltq_mtd->mtd->owner = THIS_MODULE;
165 
166         cfi = ltq_mtd->map->fldrv_priv;
167         cfi->addr_unlock1 ^= 1;
168         cfi->addr_unlock2 ^= 1;
169 
170         ppdata.of_node = pdev->dev.of_node;
171         err = mtd_device_parse_register(ltq_mtd->mtd, ltq_probe_types,
172                                         &ppdata, NULL, 0);
173         if (err) {
174                 dev_err(&pdev->dev, "failed to add partitions\n");
175                 goto err_destroy;
176         }
177 
178         return 0;
179 
180 err_destroy:
181         map_destroy(ltq_mtd->mtd);
182         return err;
183 }
184 
185 static int
186 ltq_mtd_remove(struct platform_device *pdev)
187 {
188         struct ltq_mtd *ltq_mtd = platform_get_drvdata(pdev);
189 
190         if (ltq_mtd && ltq_mtd->mtd) {
191                 mtd_device_unregister(ltq_mtd->mtd);
192                 map_destroy(ltq_mtd->mtd);
193         }
194         return 0;
195 }
196 
197 static const struct of_device_id ltq_mtd_match[] = {
198         { .compatible = "lantiq,nor" },
199         {},
200 };
201 MODULE_DEVICE_TABLE(of, ltq_mtd_match);
202 
203 static struct platform_driver ltq_mtd_driver = {
204         .probe = ltq_mtd_probe,
205         .remove = ltq_mtd_remove,
206         .driver = {
207                 .name = "ltq-nor",
208                 .owner = THIS_MODULE,
209                 .of_match_table = ltq_mtd_match,
210         },
211 };
212 
213 module_platform_driver(ltq_mtd_driver);
214 
215 MODULE_LICENSE("GPL");
216 MODULE_AUTHOR("John Crispin <blogic@openwrt.org>");
217 MODULE_DESCRIPTION("Lantiq SoC NOR");
218 

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