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Linux/drivers/mtd/maps/ixp4xx.c

  1 /*
  2  * drivers/mtd/maps/ixp4xx.c
  3  *
  4  * MTD Map file for IXP4XX based systems. Please do not make per-board
  5  * changes in here. If your board needs special setup, do it in your
  6  * platform level code in arch/arm/mach-ixp4xx/board-setup.c
  7  *
  8  * Original Author: Intel Corporation
  9  * Maintainer: Deepak Saxena <dsaxena@mvista.com>
 10  *
 11  * Copyright (C) 2002 Intel Corporation
 12  * Copyright (C) 2003-2004 MontaVista Software, Inc.
 13  *
 14  */
 15 
 16 #include <linux/err.h>
 17 #include <linux/module.h>
 18 #include <linux/types.h>
 19 #include <linux/kernel.h>
 20 #include <linux/string.h>
 21 #include <linux/slab.h>
 22 #include <linux/ioport.h>
 23 #include <linux/device.h>
 24 #include <linux/platform_device.h>
 25 
 26 #include <linux/mtd/mtd.h>
 27 #include <linux/mtd/map.h>
 28 #include <linux/mtd/partitions.h>
 29 
 30 #include <asm/io.h>
 31 #include <asm/mach/flash.h>
 32 
 33 #include <linux/reboot.h>
 34 
 35 /*
 36  * Read/write a 16 bit word from flash address 'addr'.
 37  *
 38  * When the cpu is in little-endian mode it swizzles the address lines
 39  * ('address coherency') so we need to undo the swizzling to ensure commands
 40  * and the like end up on the correct flash address.
 41  *
 42  * To further complicate matters, due to the way the expansion bus controller
 43  * handles 32 bit reads, the byte stream ABCD is stored on the flash as:
 44  *     D15    D0
 45  *     +---+---+
 46  *     | A | B | 0
 47  *     +---+---+
 48  *     | C | D | 2
 49  *     +---+---+
 50  * This means that on LE systems each 16 bit word must be swapped. Note that
 51  * this requires CONFIG_MTD_CFI_BE_BYTE_SWAP to be enabled to 'unswap' the CFI
 52  * data and other flash commands which are always in D7-D0.
 53  */
 54 #ifndef __ARMEB__
 55 #ifndef CONFIG_MTD_CFI_BE_BYTE_SWAP
 56 #  error CONFIG_MTD_CFI_BE_BYTE_SWAP required
 57 #endif
 58 
 59 static inline u16 flash_read16(void __iomem *addr)
 60 {
 61         return be16_to_cpu(__raw_readw((void __iomem *)((unsigned long)addr ^ 0x2)));
 62 }
 63 
 64 static inline void flash_write16(u16 d, void __iomem *addr)
 65 {
 66         __raw_writew(cpu_to_be16(d), (void __iomem *)((unsigned long)addr ^ 0x2));
 67 }
 68 
 69 #define BYTE0(h)        ((h) & 0xFF)
 70 #define BYTE1(h)        (((h) >> 8) & 0xFF)
 71 
 72 #else
 73 
 74 static inline u16 flash_read16(const void __iomem *addr)
 75 {
 76         return __raw_readw(addr);
 77 }
 78 
 79 static inline void flash_write16(u16 d, void __iomem *addr)
 80 {
 81         __raw_writew(d, addr);
 82 }
 83 
 84 #define BYTE0(h)        (((h) >> 8) & 0xFF)
 85 #define BYTE1(h)        ((h) & 0xFF)
 86 #endif
 87 
 88 static map_word ixp4xx_read16(struct map_info *map, unsigned long ofs)
 89 {
 90         map_word val;
 91         val.x[0] = flash_read16(map->virt + ofs);
 92         return val;
 93 }
 94 
 95 /*
 96  * The IXP4xx expansion bus only allows 16-bit wide acceses
 97  * when attached to a 16-bit wide device (such as the 28F128J3A),
 98  * so we can't just memcpy_fromio().
 99  */
100 static void ixp4xx_copy_from(struct map_info *map, void *to,
101                              unsigned long from, ssize_t len)
102 {
103         u8 *dest = (u8 *) to;
104         void __iomem *src = map->virt + from;
105 
106         if (len <= 0)
107                 return;
108 
109         if (from & 1) {
110                 *dest++ = BYTE1(flash_read16(src-1));
111                 src++;
112                 --len;
113         }
114 
115         while (len >= 2) {
116                 u16 data = flash_read16(src);
117                 *dest++ = BYTE0(data);
118                 *dest++ = BYTE1(data);
119                 src += 2;
120                 len -= 2;
121         }
122 
123         if (len > 0)
124                 *dest++ = BYTE0(flash_read16(src));
125 }
126 
127 /*
128  * Unaligned writes are ignored, causing the 8-bit
129  * probe to fail and proceed to the 16-bit probe (which succeeds).
130  */
131 static void ixp4xx_probe_write16(struct map_info *map, map_word d, unsigned long adr)
132 {
133         if (!(adr & 1))
134                 flash_write16(d.x[0], map->virt + adr);
135 }
136 
137 /*
138  * Fast write16 function without the probing check above
139  */
140 static void ixp4xx_write16(struct map_info *map, map_word d, unsigned long adr)
141 {
142         flash_write16(d.x[0], map->virt + adr);
143 }
144 
145 struct ixp4xx_flash_info {
146         struct mtd_info *mtd;
147         struct map_info map;
148         struct resource *res;
149 };
150 
151 static const char * const probes[] = { "RedBoot", "cmdlinepart", NULL };
152 
153 static int ixp4xx_flash_remove(struct platform_device *dev)
154 {
155         struct flash_platform_data *plat = dev_get_platdata(&dev->dev);
156         struct ixp4xx_flash_info *info = platform_get_drvdata(dev);
157 
158         if(!info)
159                 return 0;
160 
161         if (info->mtd) {
162                 mtd_device_unregister(info->mtd);
163                 map_destroy(info->mtd);
164         }
165 
166         if (plat->exit)
167                 plat->exit();
168 
169         return 0;
170 }
171 
172 static int ixp4xx_flash_probe(struct platform_device *dev)
173 {
174         struct flash_platform_data *plat = dev_get_platdata(&dev->dev);
175         struct ixp4xx_flash_info *info;
176         struct mtd_part_parser_data ppdata = {
177                 .origin = dev->resource->start,
178         };
179         int err = -1;
180 
181         if (!plat)
182                 return -ENODEV;
183 
184         if (plat->init) {
185                 err = plat->init();
186                 if (err)
187                         return err;
188         }
189 
190         info = devm_kzalloc(&dev->dev, sizeof(struct ixp4xx_flash_info),
191                             GFP_KERNEL);
192         if(!info) {
193                 err = -ENOMEM;
194                 goto Error;
195         }
196 
197         platform_set_drvdata(dev, info);
198 
199         /*
200          * Tell the MTD layer we're not 1:1 mapped so that it does
201          * not attempt to do a direct access on us.
202          */
203         info->map.phys = NO_XIP;
204         info->map.size = resource_size(dev->resource);
205 
206         /*
207          * We only support 16-bit accesses for now. If and when
208          * any board use 8-bit access, we'll fixup the driver to
209          * handle that.
210          */
211         info->map.bankwidth = 2;
212         info->map.name = dev_name(&dev->dev);
213         info->map.read = ixp4xx_read16;
214         info->map.write = ixp4xx_probe_write16;
215         info->map.copy_from = ixp4xx_copy_from;
216 
217         info->map.virt = devm_ioremap_resource(&dev->dev, dev->resource);
218         if (IS_ERR(info->map.virt)) {
219                 err = PTR_ERR(info->map.virt);
220                 goto Error;
221         }
222 
223         info->mtd = do_map_probe(plat->map_name, &info->map);
224         if (!info->mtd) {
225                 printk(KERN_ERR "IXP4XXFlash: map_probe failed\n");
226                 err = -ENXIO;
227                 goto Error;
228         }
229         info->mtd->owner = THIS_MODULE;
230 
231         /* Use the fast version */
232         info->map.write = ixp4xx_write16;
233 
234         err = mtd_device_parse_register(info->mtd, probes, &ppdata,
235                         plat->parts, plat->nr_parts);
236         if (err) {
237                 printk(KERN_ERR "Could not parse partitions\n");
238                 goto Error;
239         }
240 
241         return 0;
242 
243 Error:
244         ixp4xx_flash_remove(dev);
245         return err;
246 }
247 
248 static struct platform_driver ixp4xx_flash_driver = {
249         .probe          = ixp4xx_flash_probe,
250         .remove         = ixp4xx_flash_remove,
251         .driver         = {
252                 .name   = "IXP4XX-Flash",
253                 .owner  = THIS_MODULE,
254         },
255 };
256 
257 module_platform_driver(ixp4xx_flash_driver);
258 
259 MODULE_LICENSE("GPL");
260 MODULE_DESCRIPTION("MTD map driver for Intel IXP4xx systems");
261 MODULE_AUTHOR("Deepak Saxena");
262 MODULE_ALIAS("platform:IXP4XX-Flash");
263 

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