Coldfire 547x, Linux and big memory.

Hi List,
Hi Tsi-Ching Liew,

I'm using u-boot 1.3.2 (trunk) on my application in order to boot the freescale linux kernel for mcf547x cpus. My application has a lot of memory (256MB) and this causes difficulties to start the linux kernel.

The Head.S code of the mcf547x Linux Kernel allows a one-to-one TLB map for the first 16MB of memory (mcf547x can use up to 1M for page). From this observation it is mandatory that U-BOOT should call the kernel allowing all structures (board descr., intrd, env and command line) onto the first 16M of physical RAM.

The solutions can be:

- to use the env variables bootm_low = 0 and bootm_size = 0x1000000 (16M)
- modify the code of do_bootm function in order to limitate mem_size to 16M
- Pray the Freescale to modify the kernel code in order to use a better and more flexible initialization code.

I'm studying for smart modifications for Kernel and U-Boot (that hasn't guilt).

Best regards,

luigi

     ______       Luigi Mantellini
   .'______'.     R&D - Software
  (.'      '.)    Industrie Dial Face S.p.A.
  ( :=----=: )    Via Canzo, 4
  ('.______.')    20068 Peschiera Borromeo (MI), Italy
   '.______.'     Tel.: +39 02 5167 2813
                  Fax:  +39 02 5167 2459
Ind.  Dial Face   Email: luigi.mantellini at idf-hit.com
www.idf-hit.com   GPG fingerprint: 3DD1 7B71 FBDF 6376 1B4A
                                   B003 175F E979 907E 1650

Luigi,

I believe the kernel you retrieve from Freescale side is based on dBug bootloader and is not u-boot compatible; thus, will cause error when trying to bring up kernel from u-boot. An engineer is working on the new update release for 547x_8x soon. Once the kernel is updated, I believe no update is needed to be done in u-boot side.

Regards,
TsiChung

-----Original Message-----
From: Luigi 'Comio' Mantellini [mailto:luigi.mantellini at idf-hit.com]
Sent: Thursday, June 05, 2008 2:53 AM
To: U-Boot-Users
Cc: Liew Tsi Chung
Subject: Coldfire 547x, Linux and big memory.

Hi List,
Hi Tsi-Ching Liew,

I'm using u-boot 1.3.2 (trunk) on my application in order to boot the freescale linux kernel for mcf547x cpus. My application has a lot of memory (256MB) and this causes difficulties to start the linux kernel.

The Head.S code of the mcf547x Linux Kernel allows a one-to-one TLB map for the first 16MB of memory (mcf547x can use up to 1M for page). From this observation it is mandatory that U-BOOT should call the kernel allowing all structures (board descr., intrd, env and command line) onto the first 16M of physical RAM.

The solutions can be:

- to use the env variables bootm_low = 0 and bootm_size = 0x1000000 (16M)
- modify the code of do_bootm function in order to limitate mem_size to 16M
- Pray the Freescale to modify the kernel code in order to use a better and more flexible initialization code.

I'm studying for smart modifications for Kernel and U-Boot (that hasn't guilt).

Best regards,

luigi

     ______       Luigi Mantellini
   .'______'.     R&D - Software
  (.'      '.)    Industrie Dial Face S.p.A.
  ( :=----=: )    Via Canzo, 4
  ('.______.')    20068 Peschiera Borromeo (MI), Italy
   '.______.'     Tel.: +39 02 5167 2813
                  Fax:  +39 02 5167 2459
Ind.  Dial Face   Email: luigi.mantellini at idf-hit.com
www.idf-hit.com   GPG fingerprint: 3DD1 7B71 FBDF 6376 1B4A
                                   B003 175F E979 907E 1650