Date: Tue, 26 Feb 2008 23:00:17 +0530 From: "s.balamurugan" s.balamurugan@gdatech.co.in Subject: [U-Boot-Users] Regarding Dcache Flush in MPC85xx To: u-boot-users@lists.sourceforge.net Message-ID: 47C44CA9.6010906@gdatech.co.in Content-Type: text/plain; charset=ISO-8859-1; format=flowed

Hi, We are using MPC8555 processor and uboot 1.1.4 both the uboot and linux was up. Now we plan to port QNX, we are facing following issues.

1. Qnx is not jumping to the startup location. After giving

go command control is still in the uboot only.

2. When searching in the mailling list we came to know qnx

required to flush the Data Cache before disabling it in the uboot level (common/cmd_bootelf.c line no:59)

3. I checked other powerpc architecture like 7xx/74xx, 86xx and 4xx.

These architecture has seperate cache.S file ( cpu/mpc86xx/cache.S). That file contains flush_data_cache function to flush the cache before disabling it. But in the MPC85xx flushing the data cache was missing.

4. This is a bug in the 85xx uboot code. Is there any work

arround for this?

Thanks and Regards S.Balamurugan

Hi S.Balamurugan,

I've worked around U-Boot's data cache issue when booting to QNX in a couple of ways:

1. Configure the cache commands into U-Boot and run the "dcache off" command before jumping to QNX, or 2. Add code to the QNX startup module that turns off & unlocks the data cache.

Contact me directly if you want help with #2.

Regards,

Doug