target/linux/generic/patches-3.3/401-partial_eraseblock_write.patch

   1 --- a/drivers/mtd/mtdpart.c
   2 +++ b/drivers/mtd/mtdpart.c
   3 @@ -35,6 +35,8 @@
   4
   5  #include "mtdcore.h"
   6
   7 +#define MTD_ERASE_PARTIAL      0x8000 /* partition only covers parts of an erase block */
   8 +
   9  /* Our partition linked list */
  10  static LIST_HEAD(mtd_partitions);
  11  static DEFINE_MUTEX(mtd_partitions_mutex);
  12 @@ -252,13 +254,60 @@ static int part_erase(struct mtd_info *m
  13                 return -EROFS;
  14         if (instr->addr >= mtd->size)
  15                 return -EINVAL;
  16 +
  17 +       instr->partial_start = false;
  18 +       if (mtd->flags & MTD_ERASE_PARTIAL) {
  19 +               size_t readlen = 0;
  20 +               u64 mtd_ofs;
  21 +
  22 +               instr->erase_buf = kmalloc(part->master->erasesize, GFP_ATOMIC);
  23 +               if (!instr->erase_buf)
  24 +                       return -ENOMEM;
  25 +
  26 +               mtd_ofs = part->offset + instr->addr;
  27 +               instr->erase_buf_ofs = do_div(mtd_ofs, part->master->erasesize);
  28 +
  29 +               if (instr->erase_buf_ofs > 0) {
  30 +                       instr->addr -= instr->erase_buf_ofs;
  31 +                       ret = mtd_read(part->master,
  32 +                               instr->addr + part->offset,
  33 +                               part->master->erasesize,
  34 +                               &readlen, instr->erase_buf);
  35 +
  36 +                       instr->partial_start = true;
  37 +               } else {
  38 +                       mtd_ofs = part->offset + part->mtd.size;
  39 +                       instr->erase_buf_ofs = part->master->erasesize -
  40 +                               do_div(mtd_ofs, part->master->erasesize);
  41 +
  42 +                       if (instr->erase_buf_ofs > 0) {
  43 +                               instr->len += instr->erase_buf_ofs;
  44 +                               ret = mtd_read(part->master,
  45 +                                       part->offset + instr->addr +
  46 +                                       instr->len - part->master->erasesize,
  47 +                                       part->master->erasesize, &readlen,
  48 +                                       instr->erase_buf);
  49 +                       } else {
  50 +                               ret = 0;
  51 +                       }
  52 +               }
  53 +               if (ret < 0) {
  54 +                       kfree(instr->erase_buf);
  55 +                       return ret;
  56 +               }
  57 +
  58 +       }
  59 +
  60         instr->addr += part->offset;
  61         ret = mtd_erase(part->master, instr);
  62         if (ret) {
  63                 if (instr->fail_addr != MTD_FAIL_ADDR_UNKNOWN)
  64                         instr->fail_addr -= part->offset;
  65                 instr->addr -= part->offset;
  66 +               if (mtd->flags & MTD_ERASE_PARTIAL)
  67 +                       kfree(instr->erase_buf);
  68         }
  69 +
  70         return ret;
  71  }
  72
  73 @@ -266,7 +315,25 @@ void mtd_erase_callback(struct erase_inf
  74  {
  75         if (instr->mtd->erase == part_erase) {
  76                 struct mtd_part *part = PART(instr->mtd);
  77 +               size_t wrlen = 0;
  78
  79 +               if (instr->mtd->flags & MTD_ERASE_PARTIAL) {
  80 +                       if (instr->partial_start) {
  81 +                               part->master->write(part->master,
  82 +                                       instr->addr, instr->erase_buf_ofs,
  83 +                                       &wrlen, instr->erase_buf);
  84 +                               instr->addr += instr->erase_buf_ofs;
  85 +                       } else {
  86 +                               instr->len -= instr->erase_buf_ofs;
  87 +                               part->master->write(part->master,
  88 +                                       instr->addr + instr->len,
  89 +                                       instr->erase_buf_ofs, &wrlen,
  90 +                                       instr->erase_buf +
  91 +                                       part->master->erasesize -
  92 +                                       instr->erase_buf_ofs);
  93 +                       }
  94 +                       kfree(instr->erase_buf);
  95 +               }
  96                 if (instr->fail_addr != MTD_FAIL_ADDR_UNKNOWN)
  97                         instr->fail_addr -= part->offset;
  98                 instr->addr -= part->offset;
  99 @@ -537,18 +604,24 @@ static struct mtd_part *allocate_partiti
 100         if ((slave->mtd.flags & MTD_WRITEABLE) &&
 101             mtd_mod_by_eb(slave->offset, &slave->mtd)) {
 102                 /* Doesn't start on a boundary of major erase size */
 103 -               /* FIXME: Let it be writable if it is on a boundary of
 104 -                * _minor_ erase size though */
 105 -               slave->mtd.flags &= ~MTD_WRITEABLE;
 106 -               printk(KERN_WARNING"mtd: partition \"%s\" doesn't start on an erase block boundary -- force read-only\n",
 107 -                       part->name);
 108 +               slave->mtd.flags |= MTD_ERASE_PARTIAL;
 109 +               if (((u32) slave->mtd.size) > master->erasesize)
 110 +                       slave->mtd.flags &= ~MTD_WRITEABLE;
 111 +               else
 112 +                       slave->mtd.erasesize = slave->mtd.size;
 113         }
 114         if ((slave->mtd.flags & MTD_WRITEABLE) &&
 115 -           mtd_mod_by_eb(slave->mtd.size, &slave->mtd)) {
 116 -               slave->mtd.flags &= ~MTD_WRITEABLE;
 117 -               printk(KERN_WARNING"mtd: partition \"%s\" doesn't end on an erase block -- force read-only\n",
 118 -                       part->name);
 119 +           mtd_mod_by_eb(slave->offset + slave->mtd.size, &slave->mtd)) {
 120 +               slave->mtd.flags |= MTD_ERASE_PARTIAL;
 121 +
 122 +               if ((u32) slave->mtd.size > master->erasesize)
 123 +                       slave->mtd.flags &= ~MTD_WRITEABLE;
 124 +               else
 125 +                       slave->mtd.erasesize = slave->mtd.size;
 126         }
 127 +       if ((slave->mtd.flags & (MTD_ERASE_PARTIAL|MTD_WRITEABLE)) == MTD_ERASE_PARTIAL)
 128 +               printk(KERN_WARNING"mtd: partition \"%s\" must either start or end on erase block boundary or be smaller than an erase block -- forcing read-only\n",
 129 +                               part->name);
 130
 131         slave->mtd.ecclayout = master->ecclayout;
 132         if (master->block_isbad) {
 133 --- a/include/linux/mtd/mtd.h
 134 +++ b/include/linux/mtd/mtd.h
 135 @@ -58,6 +58,10 @@ struct erase_info {
 136         u_long priv;
 137         u_char state;
 138         struct erase_info *next;
 139 +
 140 +       u8 *erase_buf;
 141 +       u32 erase_buf_ofs;
 142 +       bool partial_start;
 143  };
 144
 145  struct mtd_erase_region_info {