drivers/firmware/sigma.c

   1 /*
   2  * Load Analog Devices SigmaStudio firmware files
   3  *
   4  * Copyright 2009-2011 Analog Devices Inc.
   5  *
   6  * Licensed under the GPL-2 or later.
   7  */
   8
   9 #include <linux/crc32.h>
  10 #include <linux/delay.h>
  11 #include <linux/firmware.h>
  12 #include <linux/kernel.h>
  13 #include <linux/i2c.h>
  14 #include <linux/module.h>
  15 #include <linux/sigma.h>
  16
  17 static size_t sigma_action_size(struct sigma_action *sa)
  18 {
  19         size_t payload = 0;
  20
  21         switch (sa->instr) {
  22         case SIGMA_ACTION_WRITEXBYTES:
  23         case SIGMA_ACTION_WRITESINGLE:
  24         case SIGMA_ACTION_WRITESAFELOAD:
  25                 payload = sigma_action_len(sa);
  26                 break;
  27         default:
  28                 break;
  29         }
  30
  31         payload = ALIGN(payload, 2);
  32
  33         return payload + sizeof(struct sigma_action);
  34 }
  35
  36 /*
  37  * Returns a negative error value in case of an error, 0 if processing of
  38  * the firmware should be stopped after this action, 1 otherwise.
  39  */
  40 static int
  41 process_sigma_action(struct i2c_client *client, struct sigma_action *sa)
  42 {
  43         size_t len = sigma_action_len(sa);
  44         int ret;
  45
  46         pr_debug("%s: instr:%i addr:%#x len:%zu\n", __func__,
  47                 sa->instr, sa->addr, len);
  48
  49         switch (sa->instr) {
  50         case SIGMA_ACTION_WRITEXBYTES:
  51         case SIGMA_ACTION_WRITESINGLE:
  52         case SIGMA_ACTION_WRITESAFELOAD:
  53                 ret = i2c_master_send(client, (void *)&sa->addr, len);
  54                 if (ret < 0)
  55                         return -EINVAL;
  56                 break;
  57         case SIGMA_ACTION_DELAY:
  58                 udelay(len);
  59                 len = 0;
  60                 break;
  61         case SIGMA_ACTION_END:
  62                 return 0;
  63         default:
  64                 return -EINVAL;
  65         }
  66
  67         return 1;
  68 }
  69
  70 static int
  71 process_sigma_actions(struct i2c_client *client, struct sigma_firmware *ssfw)
  72 {
  73         struct sigma_action *sa;
  74         size_t size;
  75         int ret;
  76
  77         while (ssfw->pos + sizeof(*sa) <= ssfw->fw->size) {
  78                 sa = (struct sigma_action *)(ssfw->fw->data + ssfw->pos);
  79
  80                 size = sigma_action_size(sa);
  81                 ssfw->pos += size;
  82                 if (ssfw->pos > ssfw->fw->size || size == 0)
  83                         break;
  84
  85                 ret = process_sigma_action(client, sa);
  86
  87                 pr_debug("%s: action returned %i\n", __func__, ret);
  88
  89                 if (ret <= 0)
  90                         return ret;
  91         }
  92
  93         if (ssfw->pos != ssfw->fw->size)
  94                 return -EINVAL;
  95
  96         return 0;
  97 }
  98
  99 int process_sigma_firmware(struct i2c_client *client, const char *name)
 100 {
 101         int ret;
 102         struct sigma_firmware_header *ssfw_head;
 103         struct sigma_firmware ssfw;
 104         const struct firmware *fw;
 105         u32 crc;
 106
 107         pr_debug("%s: loading firmware %s\n", __func__, name);
 108
 109         /* first load the blob */
 110         ret = request_firmware(&fw, name, &client->dev);
 111         if (ret) {
 112                 pr_debug("%s: request_firmware() failed with %i\n", __func__, ret);
 113                 return ret;
 114         }
 115         ssfw.fw = fw;
 116
 117         /* then verify the header */
 118         ret = -EINVAL;
 119
 120         /*
 121          * Reject too small or unreasonable large files. The upper limit has been
 122          * chosen a bit arbitrarily, but it should be enough for all practical
 123          * purposes and having the limit makes it easier to avoid integer
 124          * overflows later in the loading process.
 125          */
 126         if (fw->size < sizeof(*ssfw_head) || fw->size >= 0x4000000)
 127                 goto done;
 128
 129         ssfw_head = (void *)fw->data;
 130         if (memcmp(ssfw_head->magic, SIGMA_MAGIC, ARRAY_SIZE(ssfw_head->magic)))
 131                 goto done;
 132
 133         crc = crc32(0, fw->data + sizeof(*ssfw_head),
 134                         fw->size - sizeof(*ssfw_head));
 135         pr_debug("%s: crc=%x\n", __func__, crc);
 136         if (crc != le32_to_cpu(ssfw_head->crc))
 137                 goto done;
 138
 139         ssfw.pos = sizeof(*ssfw_head);
 140
 141         /* finally process all of the actions */
 142         ret = process_sigma_actions(client, &ssfw);
 143
 144  done:
 145         release_firmware(fw);
 146
 147         pr_debug("%s: loaded %s\n", __func__, name);
 148
 149         return ret;
 150 }
 151 EXPORT_SYMBOL(process_sigma_firmware);
 152
 153 MODULE_LICENSE("GPL");