[U-Boot] [PATCH] armv8/ls1043a: Add MTD partition scheme

[Wenbin Song]

Hi: York

Please see my inline comments.

Best Regards
Wenbin Song

> -----Original Message-----
> From: York Sun [mailto:york.sun at nxp.com]
> Sent: Thursday, April 07, 2016 1:18 AM
> To: Wenbin Song <wenbin.song at nxp.com>; Mingkai Hu
> <mingkai.hu at nxp.com>; u-boot at lists.denx.de
> Cc: Qianyu Gong <qianyu.gong at nxp.com>; Shaohui Xie
> <shaohui.xie at nxp.com>; Zhiqiang Hou <zhiqiang.hou at nxp.com>
> Subject: Re: [PATCH] armv8/ls1043a: Add MTD partition scheme
> 
> On 04/06/2016 12:11 AM, Wenbin Song wrote:
> > Hi: York
> >
> > I set bootargs  as the following steps:
> >
> > => env default mtdparts
> > => printenv mtdparts
> >
> mtdparts=mtdparts=60000000.nor:1m(nor_bank0_rcw),1m(nor_bank0_uboot)
> ,1
> >
> m(nor_bank0_uboot_env),1m(nor_bank0_fman_uconde),40m(nor_bank0_fit
> ),1m
> >
> (nor_bank4_rcw),1m(nor_bank4_uboot),1m(nor_bank4_uboot_env),1m(nor_
> ban
> >
> k4_fman_ucode),40m(nor_bank4_fit);7e800000.flash:1m(nand_uboot),1m(na
> n
> > d_uboot_env),20m(nand_fit);spi0.0:1m(uboot),5m(kernel),1m(dtb),9m(file
> > _system)
> > => env default bootargs
> > => printenv bootargs
> > bootargs=console=ttyS0,115200 root=/dev/ram0
> > earlycon=uart8250,mmio,0x21c0500 ${mtdparts}
> >
> >
> > The macro  CONFIG_BOOTARGS  only be extern as an char-string, and it will
> be spliced into default_environment array .
> >
> >  const uchar default_environment[] = { #ifdef  CONFIG_BOOTARGS
> >           "bootargs="     CONFIG_BOOTARGS                 "\0"
> >  #endif
> >
> > The variable we use to have $consoledev, $othbootargs  was used in the
> following cases:
> >
> > 858  #define CONFIG_BOOTCOMMAND \
> > 859         "setenv bootargs root=/dev/ram rw "             \
> > 860         "console=$consoledev,$baudrate $othbootargs;"   \
> > 861         "setenv ramdiskaddr 0x02000000;"                \
> > 862         "setenv fdtaddr 0x00c00000;"                    \
> > 863         "setenv loadaddr 0x1000000;"                    \
> > 864         "bootm $loadaddr $ramdiskaddr $fdtaddr"
> >
> > Because the "setenv"  will be executed  , So the variable could be extended.
> 
> I see what you mean. I am trying to reduce the environmental variables.
> Do you need the variable "mtdparts"?

[wenbin] 

I export this variable in order to make easier  to modify the bootargs under uboot command-line.

For example:
=>setenv bootargs  "console=ttyS0,115200  root=/dev/ram0  $mtdparts"
=>setenv bootargs  "console=ttyLP0,115200  root=/dev/ram0  $mtdparts"

Use the $mtdparts to instead of a long string.


> Would it be a better idea to set bootargs using the bootcmd?
[wenbin]

 yes, It is a good idea.
 But we need all kinds of  ways to boot kernel  with this  "bootargs".  The bootcmd only can specify one boot-way.
IOW,  only the way specified by this "bootcmd"  can  execute " setenv  bootargs".
So I want to supply the default bootargs  by the CONFIG_BOOTARGS .


> 
> While you are on it, I suggest you take a look at other variables.
> "console=ttyAMA0,38400n8" is wrong here.
> 
> We don't have to copy kernel image from NOR flash to DDR if the ramdisk load
> address is set properly in its file. So you can remove the copying from bootcmd.
> 
[wenbin]

Ok, thanks for your advices,  I will modify them on the later patch. 

> York