Re: [U-Boot] [PATCH v1 1/1] cmd: adding malloc, math, and strcmp commands to u-boot

21 Nov 2019


      On Wed, Nov 20, 2019 at 02:50:53PM -0800, Vladimir Olovyannikov wrote:
...
Hi Tom,
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-----Original Message-----
From: Tom Rini [mailto:trini@konsulko.com]
Sent: Tuesday, November 19, 2019 12:38 PM
To: Vladimir Olovyannikov vladimir.olovyannikov@broadcom.com
Cc: u-boot@lists.denx.de; Suji Velupiallai
suji.velupillai@broadcom.com;
...
Heinrich Schuchardt xypron.glpk@gmx.de
Subject: Re: [U-Boot] [PATCH v1 1/1] cmd: adding malloc, math, and
strcmp
...
commands to u-boot
On Mon, Nov 18, 2019 at 04:26:30PM -0800, Vladimir Olovyannikov wrote:
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cmd: adding malloc, math, and strcmp u-boot commands.

malloc  supports allocation of heap memory and free allocated memory
        via u-boot command line.

Can you expand on how this is used in a script?  I'm not sure I see that
exactly.
I am upstreaming the new bcm platform. Here is an excerpt from the script
which uses
these:
#define SD_UPDATE \
   "sd_update="\
   "if malloc tmp 2000; then "\
   "else "\
   	"echo [sd_update] malloc 2000 bytes ** FAILED **;"\
   	"exit;"\
   "fi;"\
   "if fatload mmc ${sd_device_number} ${tmp} "\
   "${sd_update_prefix}.sd-update; then "\
   "else "\
   	"echo [sd_update] fatload ${sd_update_prefix}.sd-update "\
   	"** FAILED **;"\
   	"exit;"\
   "fi;"\
   "if source ${tmp}; then "\
   "else "\
   	"echo [sd_update] Executing script ** FAILED **;"\
   	"exit;"\
   "fi;"\
   "if free tmp; then "\
   "else " \
   	"echo [sd_update] free 2000 bytes ** FAILED **;"\
   	"exit;"\
   "fi \0"
;
   "if math add filesize filesize 1FF; then "\
   "else "\
   	"echo [mmc_flash_image_rsa] math add command ** FAILED
**;"\
   	"exit;"\
   "fi;"\
   "if math div fileblocks filesize 200; then "\
   "else "\
   	"echo [mmc_flash_image_rsa] math div command ** FAILED
**;"\
   	"exit;"\
   "fi;"\
Ah, interesting.  So you're malloc'ing the memory location that you load
in to rather than the usual method of using known variables and
locations for the SoC.  I would discourage this as we generally do not
have a large malloc pool available.
...
...
Also:
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+config CMD_MALLOC

bool "malloc"
default y
help
 Supports allocation of heap memory and free allocated memory



commands.
...

 These commands are used by u-boot scripts.




+config CMD_MATH

bool "math"
default y
help
 Provides math commands such as add, sub, mul, div, shift,


 convert decimal to hex functionalities to be available in the



script.
...
First, why do we need this, rather than using setexpr ?
I agree, the platform needs to use setexpr as it contains all math
operations.
...
...



config CMD_SOURCE
   bool "source"
   default y
@@ -1301,6 +1315,13 @@ config CMD_SETEXPR
     Also supports loading the value at a memory location into a
variable.
...
...
 If CONFIG_REGEX is enabled, setexpr also supports a gsub

function.
...
...
+config CMD_STRCMP

bool "strcmp"
default y
help
 Provides string compare command feature to u-boot scripts.



Second, new commands must not default to y, but they should be enabled
on sandbox and new test.py tests added for them.  Thanks!
OK, thank you.
Is there an example/doc on how to enable these on sandbox and to provide
tests?
Unfortunately there is not (but would be greatly appreciated).  There
are a lot of examples under test/py/ however.  Thanks!
-- 
Tom

    