[U-Boot] [PATCH v3 09/15] env: Support multiple environments

[York Sun]

On 01/30/2018 12:16 PM, York Sun wrote:
> On 01/30/2018 11:40 AM, York Sun wrote:
>> On 01/30/2018 12:19 AM, Simon Goldschmidt wrote:
>>> On 23.01.2018 21:16, Maxime Ripard wrote:
>>>> Now that we have everything in place to support multiple environment, let's
>>>> make sure the current code can use it.
>>>>
>>>> The priority used between the various environment is the same one that was
>>>> used in the code previously.
>>>>
>>>> At read / init times, the highest priority environment is going to be
>>>> detected,
>>>
>>> Does priority handling really work here? Most env drivers seem to ignore 
>>> the return value of env_import and may thus return success although 
>>> importing the environment failed (only reading the data from the device 
>>> succeeded).
>>>
>>> This is from reading the code, I haven't had a chance to test this, yet.
>>
>> It is broken on my LS1043ARDB with simply NOR flash. I am trying to
>> determine what went wrong.
>>
> 
> I found the problem. The variable "env_load_location" is static. It is
> probably not write-able during booting from flash. It is expected to be
> set during ENVOP_INIT. But if I print this variable, it has
> ENVL_UNKNOWN. I can make it work by moving env_load_location to global
> data structure.
> 
> That being said, this addition of multiple environments really slows
> down the booting process for me. I see every time env_get_char() is
> called, env_driver_lookup() runs. A simple call of env_get_f() gets
> slowed down dramatically. I didn't find out where the most time is spent
> yet.
> 
> Does anyone else experience this unbearable slowness?
> 

I found the problem. In patch #3 in this series, the default get_char()
was dropped so there is no driver for a plain NOR flash. A quick (and
maybe dirty) fix is this


diff --git a/env/env.c b/env/env.c
index edfb575..210bae2 100644
--- a/env/env.c
+++ b/env/env.c
@@ -159,7 +159,7 @@ int env_get_char(int index)
                int ret;

                if (!drv->get_char)
-                       continue;
+                       return *(uchar *)(gd->env_addr + index);

                if (!env_has_inited(drv->location))
                        continue;

With this temporary fix, my flash chip works again and I can boot all
the way up in a timely manner. I still don't like to call
env_driver_lookup() thousands of times to get a simple env variable.

Can Maxime post a quick post soon?

York