Hi Fabio,
On Friday, December 20, 2013 9:46:37 PM, Fabio Estevam wrote:
From: Fabio Estevam fabio.estevam@freescale.com
When using the fuse API in U-boot user must calculate the 'bank' and 'word' values.
Provide a real example on how to calculate such values for the mx6q.
Signed-off-by: Fabio Estevam fabio.estevam@freescale.com
Changes since v1:
- Move the example into doc/README.imx6
doc/README.imx6 | 57 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 57 insertions(+)
diff --git a/doc/README.imx6 b/doc/README.imx6 index 513a06e..728b32c 100644 --- a/doc/README.imx6 +++ b/doc/README.imx6 @@ -8,3 +8,60 @@ SoC.
1.1 MAC Address: It is stored in fuse bank 4, with the 32 lsbs in word 2 and the 16 msbs in word 3.
+Example:
+For reading the MAC address fuses on a MX6Q:
+- The MAC address are stored in two fuse addresses (the fuse addresses are
^ ^ 'is' or 'fuses are'
+described in the Fusemap Descriptions table from the mx6q Reference Manual):
+0x620[31:0] - MAC_ADDR[31:0] +0x630[15:0] - MAC_ADDR[47:32]
+In order to use the fuse API, we need to pass the bank and word values, which +are calculated as below:
+Fuse address for the lower MAC address: 0x620 +Base address for the fuses: 0x400
+(0x620 - 0x400)/0x10 = 0x22 = 34 decimal
+As the fuses are arranged in banks of 8 words:
+34 / 8 = 4 and the remainder is 2, so in this case:
+bank = 4 +word = 2
+And the U-boot command would be:
+=> fuse read 4 2 +Reading bank 4:
+Word 0x00000002: 9f027772
+Doing the same for the upper MAC address:
+Fuse address for the upper MAC address: 0x630 +Base address for the fuses: 0x400
+(0x630 - 0x400)/0x10 = 0x23 = 35 decimal
+As the fuses are arranged in banks of 8 words:
+35 / 8 = 4 and the remainder is 3, so in this case:
+bank = 4 +word = 3
+And the U-boot command would be:
+=> fuse read 4 3 +Reading bank 4:
+Word 0x00000003: 00000004
+,which matches the ethaddr value: +=> echo ${ethaddr} +00:04:9f:02:77:72
Good. As we said earlier, you could also add: - 'fuse read 4 2 2' as an example to read the whole MAC address at once, - a reference to '46.5 OCOTP Memory Map/Register Definition' in the RM also giving these bank/word pairs.
--
Best regards, Benoît