[U-Boot] [RFC PATCH] env: add default env size for CONFIG_ENV_IS_NOWHERE

[U-Boot] [RFC PATCH] env: add default env size for CONFIG_ENV_IS_NOWHERE

[Bo Shen]

when CONFIG_ENV_IS_NOWHERE is enabled, it is still need to define
CONFIG_ENV_SIZE. So, add a default size (1024 Bytes) to avoid
compile error if not define CONFIG_ENV_SIZE

Signed-off-by: Bo Shen <voice.shen@gmail.com>

---
The default value for CONFIG_ENV_SIZE (1024 Bytes) maybe not the
better choice, consider runtime decided, however failed.

This patch is only compile testing with CONFIG_ENV_IS_NOWHERE enable
---

 include/environment.h |    6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/include/environment.h b/include/environment.h
index 46a3554..52a7769 100644
--- a/include/environment.h
+++ b/include/environment.h
@@ -146,6 +146,12 @@ extern unsigned long nand_env_oob_offset;
 extern char *env_name_spec;
 #endif
 
+#ifdef CONFIG_ENV_IS_NOWHERE
+# ifndef CONFIG_ENV_SIZE
+# define CONFIG_ENV_SIZE 0x400
+# endif
+#endif
+
 #define ENV_SIZE (CONFIG_ENV_SIZE - ENV_HEADER_SIZE)
 
 typedef struct environment_s {
-- 
1.7.10.4

[U-Boot] [RFC PATCH] env: add default env size for CONFIG_ENV_IS_NOWHERE

[Wolfgang Denk]

Dear Bo Shen,

In message <1376230503-25331-1-git-send-email-voice.shen@gmail.com> you wrote:
> when CONFIG_ENV_IS_NOWHERE is enabled, it is still need to define
> CONFIG_ENV_SIZE. So, add a default size (1024 Bytes) to avoid
> compile error if not define CONFIG_ENV_SIZE

I don;t understand the rationale for this patch.  In which way is the
environment seize for the CONFIG_ENV_IS_NOWHERE case different from
any other cases?  For these, we do not define a default either, so why
should we handle this case differently?

In any cse, the needed environment seize if a pretty board specific
thing, and I think it makes sense to let the user define it.

Best regards,

Wolfgang Denk

-- 
DENX Software Engineering GmbH,     MD: Wolfgang Denk & Detlev Zundel
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd at denx.de
Anyone who isn't confused here doesn't really know what's going on.

[U-Boot] [RFC PATCH] env: add default env size for CONFIG_ENV_IS_NOWHERE

[Bo Shen]

Hi Wolfgang Denk,

On 8/11/2013 10:50 PM, Wolfgang Denk wrote:
> Dear Bo Shen,
>
> In message <1376230503-25331-1-git-send-email-voice.shen@gmail.com> you wrote:
>> when CONFIG_ENV_IS_NOWHERE is enabled, it is still need to define
>> CONFIG_ENV_SIZE. So, add a default size (1024 Bytes) to avoid
>> compile error if not define CONFIG_ENV_SIZE
>
> I don;t understand the rationale for this patch.  In which way is the
> environment seize for the CONFIG_ENV_IS_NOWHERE case different from
> any other cases?  For these, we do not define a default either, so why
> should we handle this case differently?

In my opinion, there is a little different. The CONFIG_ENV_IS_NOWHERE 
case only store environment in volatile memory (e.g. DDR SDRAM) while 
not store in non-volatile device.

At first glance of CONFIG_ENV_IS_NOWHERE, I think no need to define the 
CONFIG_ENV_SIZE, actually, it needs to define the CONFIG_ENV_SIZE. So, I 
think add a default value will be better (Maybe another choice to add a 
description in README file to specify how to use CONFIG_ENV_IS_NOWHERE).

> In any cse, the needed environment seize if a pretty board specific
> thing, and I think it makes sense to let the user define it.

Yes, the environment size is a pretty board specific thing. So, in this 
patch, there is an option for user to define it.

> Best regards,
>
> Wolfgang Denk
>

Best Regards,
Bo Shen

[U-Boot] [RFC PATCH] env: add default env size for CONFIG_ENV_IS_NOWHERE

[Wolfgang Denk]

Dear Bo Shen,

In message <5208DE04.1000405@gmail.com> you wrote:
> 
> At first glance of CONFIG_ENV_IS_NOWHERE, I think no need to define the 
> CONFIG_ENV_SIZE, actually, it needs to define the CONFIG_ENV_SIZE. So, I 
> think add a default value will be better (Maybe another choice to add a 
> description in README file to specify how to use CONFIG_ENV_IS_NOWHERE).

I cannot see in which way the required environment size in this case
is different from all other cases.  To me, a default size makes little
sense - it is just a chance to miss setting a suitable value, so it
bites you later (at run time) instead of earlyin development.

> > In any cse, the needed environment seize if a pretty board specific
> > thing, and I think it makes sense to let the user define it.
> 
> Yes, the environment size is a pretty board specific thing. So, in this 
> patch, there is an option for user to define it.

I think the user should always set this to a useful (for him) value.
For example, you think 1 KiB is a useful size, I would think it is too
small. Ask two other people, and you will hear three other different
numbers.

Best regards,

Wolfgang Denk

-- 
DENX Software Engineering GmbH,     MD: Wolfgang Denk & Detlev Zundel
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd at denx.de
Motto of the Electrical Engineer: Working computer hardware is a  lot
like an erect penis: it stays up as long as you don't fuck with it.

[U-Boot] [RFC PATCH] env: add default env size for CONFIG_ENV_IS_NOWHERE

[Tom Rini]

On Sun, Aug 11, 2013 at 02:15:03PM +0000, Bo Shen wrote:

> when CONFIG_ENV_IS_NOWHERE is enabled, it is still need to define
> CONFIG_ENV_SIZE. So, add a default size (1024 Bytes) to avoid
> compile error if not define CONFIG_ENV_SIZE

The problem is that ENV_SIZE is also a limiting factor on how big the
run-time copy of the environment may be, not just how much space we use
when writing to a backing store, so NAK.

-- 
Tom
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