[U-Boot] [PATCH 1/2] doc: README.fuse: Add an example on how to use the fuse API on mx6q
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 --- doc/README.fuse | 57 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 57 insertions(+)
diff --git a/doc/README.fuse b/doc/README.fuse index 1bc91c4..aca1e5e 100644 --- a/doc/README.fuse +++ b/doc/README.fuse @@ -65,3 +65,60 @@ Configuration:
CONFIG_CMD_FUSE Define this to enable the fuse commands. + +Example: + +For reading the MAC address fuses on a MX6Q: + +- The MAC address are stored in two fuse addresses (the fuse addresses 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
From: Fabio Estevam fabio.estevam@freescale.com
Add CONFIG_CMD_FUSE option, so that the fuse API can be used.
Signed-off-by: Fabio Estevam fabio.estevam@freescale.com --- include/configs/mx6sabre_common.h | 5 +++++ 1 file changed, 5 insertions(+)
diff --git a/include/configs/mx6sabre_common.h b/include/configs/mx6sabre_common.h index d52c9a8..63405aa 100644 --- a/include/configs/mx6sabre_common.h +++ b/include/configs/mx6sabre_common.h @@ -34,6 +34,11 @@
#define CONFIG_MXC_UART
+#define CONFIG_CMD_FUSE +#ifdef CONFIG_CMD_FUSE +#define CONFIG_MXC_OCOTP +#endif + /* MMC Configs */ #define CONFIG_FSL_ESDHC #define CONFIG_FSL_USDHC
Hi Fabio,
On Tuesday, December 17, 2013 9:03:41 PM, Fabio Estevam wrote:
From: Fabio Estevam fabio.estevam@freescale.com
Add CONFIG_CMD_FUSE option, so that the fuse API can be used.
Signed-off-by: Fabio Estevam fabio.estevam@freescale.com
include/configs/mx6sabre_common.h | 5 +++++ 1 file changed, 5 insertions(+)
diff --git a/include/configs/mx6sabre_common.h b/include/configs/mx6sabre_common.h index d52c9a8..63405aa 100644 --- a/include/configs/mx6sabre_common.h +++ b/include/configs/mx6sabre_common.h @@ -34,6 +34,11 @@
#define CONFIG_MXC_UART
+#define CONFIG_CMD_FUSE +#ifdef CONFIG_CMD_FUSE +#define CONFIG_MXC_OCOTP +#endif
/* MMC Configs */ #define CONFIG_FSL_ESDHC
#define CONFIG_FSL_USDHC
1.8.1.2
Reviewed-by: Benoît Thébaudeau benoit.thebaudeau@advansee.com
Best regards, Benoît
Hi Fabio,
On Tuesday, December 17, 2013 9:03:40 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
doc/README.fuse | 57 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 57 insertions(+)
diff --git a/doc/README.fuse b/doc/README.fuse index 1bc91c4..aca1e5e 100644 --- a/doc/README.fuse +++ b/doc/README.fuse @@ -65,3 +65,60 @@ Configuration:
CONFIG_CMD_FUSE Define this to enable the fuse commands.
+Example:
+For reading the MAC address fuses on a MX6Q:
+- The MAC address are stored in two fuse addresses (the fuse addresses 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
1.8.1.2
Note that the documentation in this file is also completed for i.MX6 by doc/README.mxc_ocotp and doc/README.imx6, as explained in each README. The information that you add here regarding the location of the MAC fuses for i.MX6Q is already present in doc/README.imx6.
Regarding the 'calculation' part, it is actually not needed since the values obtained with these calculations are already given by the reference manual in '46.5 OCOTP Memory Map/Register Definition'.
Examples could still be interesting though. What do you think? - Should the calculation part be removed and replaced with a reference to the RM §46.5 be added? - Should this example be moved to doc/README.imx6, or kept in doc/README.fuse as a generic example for the fuse API? - Should an example be added to show how to read the whole MAC address with a single fuse command (i.e. 'fuse read 4 2 2')?
Best regards, Benoît
Hi Benoît, hi Fabio,
On 17/12/2013 22:18, Benoît Thébaudeau wrote:
Hi Fabio,
On Tuesday, December 17, 2013 9:03:40 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
doc/README.fuse | 57 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 57 insertions(+)
diff --git a/doc/README.fuse b/doc/README.fuse index 1bc91c4..aca1e5e 100644 --- a/doc/README.fuse +++ b/doc/README.fuse @@ -65,3 +65,60 @@ Configuration:
CONFIG_CMD_FUSE Define this to enable the fuse commands.
+Example:
+For reading the MAC address fuses on a MX6Q:
+- The MAC address are stored in two fuse addresses (the fuse addresses 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
1.8.1.2
Note that the documentation in this file is also completed for i.MX6 by doc/README.mxc_ocotp and doc/README.imx6, as explained in each README. The information that you add here regarding the location of the MAC fuses for i.MX6Q is already present in doc/README.imx6.
This is true, but the current documentation is poor. I like that Fabio adds a real example, providing a better understanding.
IMHO we should avoid to add a new file, if (as it is), this patch is only for i.MX6. Putting it in README.imx6 seems the best solution.
Regarding the 'calculation' part, it is actually not needed since the values obtained with these calculations are already given by the reference manual in '46.5 OCOTP Memory Map/Register Definition'.
A reference is not bad, but of course documentation is changing. I was working with manual 04/2013, and there is not an example - only "empty example". Anyway, most people is searching exactly how to store in SOC the MAC address - not how to write another fuse. I think it is a good idea to add the MAC's example, because it is what most people are looking for.
Examples could still be interesting though. What do you think?
- Should the calculation part be removed and replaced with a reference to the RM §46.5 be added?
I will add only a refererence, but I will let the example.
- Should this example be moved to doc/README.imx6,
+1, as the example is only for i.MX6.
Best regards, Stefano Babic
On Thu, Dec 19, 2013 at 7:49 AM, Stefano Babic sbabic@denx.de wrote:
- Should this example be moved to doc/README.imx6,
+1, as the example is only for i.MX6.
Sounds good. Just sent v2 as suggested.
Regards,
Fabio Estevam
participants (3)
-
Benoît Thébaudeau -
Fabio Estevam -
Stefano Babic