MAC address, hardware type, calibration values and etc are stored in efuse,
so we read them at probe stage and use them as capabilities to register
hardware.

There are two physical efuse -- one is the main efuse for digital hardware
part, and the other is for analog part. Because they are very similar, we
only describe the main efuse below.

The main efuse is split into two regions -- one is for logic map, and the
other is for physical map. For both regions, we use the same method to read
data, but need additional parser to get logic map. To allow reading
operation, we need to convert power state to active, and turn to idle state
after reading.

For WiFi 7 chips, we introduce efuse blocks to define feature group easier,
and these blocks are discontinue. For example, RF block is from 0x1_0000 ~
0x1_0240, and the next block PCIE_SDIO is starting from 0x2_0000.
Comparing to old one used by WiFi 6 chips, there is only single one logic
map, it would be a little hard to add an new field to a group if we don't
reserve a room in advance.

The relationship between efuse, region and block is shown as below:

                                           (logical map)
 +------------+    +---------------+    +-----------------+
 | main efuse |    |   region 1    |    | block 0x1_0000~ |
 | (digital)  |    |(to logcal map)|    +-----------------+
 |            |    |               | => +-----------------+
 |            | => |               |    | block 0x2_0000~ |
 |            |    |               |    +-----------------+
 |            |    |---------------|             :
 |            |    |    region 2   |
 +------------+    +---------------+

 +------------+                         +-----------------+
 | 2nd efuse  | ======================> | block 0x7_0000~ |
 | (analog)   |                         +-----------------+
 +------------+

The parser converting from raw data to logic map is to decode block page,
block page offset, and word_en bits. Each word_en bit indicates two
following bytes as data of logic map, so total four word_en bits can
represent eight bytes. Thus, block page offset is 8-byte alignment.
The layout of a tuple is shown as below

  +--------+--------+--------+--------+--------+--------+
  | fixed 3 byte header      |        |        |        |
  |                          |        |        |        |
  | [19:17] block_page       |        |        |  ...   |
  | [16:4]  block_page_offset|        |        |        |
  | [3:0]   word_en          |   ^    |    ^   |        |
  +----|---+--------+--------+---|----+----|---+--------+
       |                         |         |
       +-------------------------+---------+
         a word_en bit indicates two bytes as data

For example,
  block_page = 0x3
  block_page_offset = 0x80 (must 8-byte alignment)
  word_en = 0x6 (b'0110; 0 means data is presented)
  following 4 bytes = 34 56 78 90
  Then,
    0x3_0080 = 34 56
    0x3_0086 = 78 90

A special block page is RTW89_EFUSE_BLOCK_ADIE (7) that uses different
but similar format, because its real efuse size is smaller than main efuse.
Signed-off-by: Ping-Ke Shih <pkshih@realtek.com>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://lore.kernel.org/r/20231117024029.113845-4-pkshih@realtek.com