[U-Boot-Users] FAT mbr on MMC or SD cards

[Joey Oravec <joravec@drewtech.com>]

"Wolfgang Denk" <wd@denx.de> wrote in message 
news:20070613184133.A9478352681 at atlas.denx.de...
>> 1. This code assumes that sector 0 contains a VBR. Instead I think it 
>> should
>> decide if 0 is an MBR or VBR, or even better utilize the dev:part command
>> line. Can I make this determination that from the first three bytes, or 
>> is
>> there a better way?
>
> We have a patch in the queue to fix this, but it  did  not  pass  our
> internal  review  and unfortunately the engineer is on vacation right
> now so he cannot clean it up. Please be patiend for a week or two.

I wanted to share that with the list in case anybody else gets stuck.

Since my original email, I noticed code in fat_register_device() which 
determines a part_offset for 1.1.5 and 1.1.6. For now I've hacked this code 
to check the first three bytes EB:xx:90 or E9:xx:xx to make the mbr/pbr 
decision instead of the ascii string. Also I have it reading the valid 
partition offset instead of assuming 32. And finally I added a packed 
attribute to all structs.

>> 2. The decision of fat12, fat16, and fat32 is made upon fat_length and an
>> ascii field. The Microsoft document claims that the determination shall 
>> be
>> made only by the count of clusters. Any disputes on that fix?
>
> I have no idea...

I was reading a document "FAT: General Overfiew of On-Disk Format" v1.02 May 
5, 1999 by Microsoft Corporation. The correct way is to calculate 
CountofClusters. Less than 4085 is FAT12, less than 65525 is FAT16, anything 
else is FAT32. I'll watch, and after he gets back from vacation we can do 
something about it.

-joey 






From "abiyani at unix dot telasic dot com" at unix.telasic.com  Wed Jun 13 23:01:29 2007
From: "abiyani at unix dot telasic dot com" at unix.telasic.com (Arun Biyani)
Date: Wed, 13 Jun 2007 14:01:29 -0700
Subject: [U-Boot-Users] U-Boot 1.2 - Cannot run hello_world - Coldfire
Message-ID: <200706132101.OAA10296@unix.telasic.com>

I have a target board with a Coldfire CPU. I am unable to run the 
example program
hello_world which comes with the distribution. Transcript of session is 
below. What
am I missing? The cross compile tools were run on Linux (FC 7), 
downloaded from
snapgear.org uClinux directory. I tried this with v1.1.6 also. I'll be 
glad to provide
any additional data. I have just started with U-Boot so please be 
explicit. On the host,
I was running Tera Term and used "send file" from the "File" menu to 
send the srec file.
I ran the program with parameters as well with the same result.

U-Boot 1.2.0 (Jun 13 2007 - 07:36:11)

CPU:   Freescale MCF5272 (Mask:1)
Board: Telasic RLB 2.0
DRAM:  16 MB
FLASH: 32 MB
In:    serial
Out:   serial
Err:   serial
Hit any key to stop autoboot:  0
->
-> ds
Unknown command 'ds' - try 'help'
-> loads
## Ready for S-Record download ...

## First Load Addr = 0x00020000
## Last  Load Addr = 0x000222F7
## Total Size      = 0x000022F8 = 8952 Bytes
## Start Addr      = 0x00020000
-> go 0x00020004
## Starting application at 0x00020004 ...


*** Unexpected exception ***
Vector Number: 4  Format: 04  Fault Status: 0

PC: 00ff94fc    SR: 00002004    SP: 00f6db0c
D0: 00000000    D1: 0000048c    D2: 00000000    D3: 00ff8fac
D4: 000000f3    D5: 00000000    D6: 00000000    D7: 00f7df90
A0: 00fed912    A1: 00ff94fc    A2: 00020004    A3: 00f6ded8
A4: 00000002    A5: 00ff7300    A6: 00f6db8c

*** Please Reset Board! ***