JFFS2: Return early when file read not necessary

[karo-tx-uboot.git] / doc / README.b4860qds

diff --git a/doc/README.b4860qds b/doc/README.b4860qds
index 3da77d9f0f83a000e1676cf00d11c553cc4ed046..6fcc3bd6e8ae4b4c6a99f9c6b5bcf39ad920c131 100644 (file)
--- a/doc/README.b4860qds
+++ b/doc/README.b4860qds
@@ -119,7 +119,7 @@ B4860QDS Default Settings
 Switch Settings
 ----------------
 
 Switch Settings
 ----------------
 

-SW1    OFF [0] OFF [1] OFF [1] OFF [0] OFF [1] OFF [0] OFF [1] OFF [1]
+SW1    OFF [0] OFF [0] OFF [0] OFF [0] OFF [0] OFF [0] OFF [0] OFF [0]

 SW2    ON      ON      ON      ON      ON      ON      OFF     OFF
 SW3    OFF     OFF     OFF     ON      OFF     OFF     ON      OFF
 SW5    OFF     OFF     OFF     OFF     OFF     OFF     ON      ON
 SW2    ON      ON      ON      ON      ON      ON      OFF     OFF
 SW3    OFF     OFF     OFF     ON      OFF     OFF     ON      OFF
 SW5    OFF     OFF     OFF     OFF     OFF     OFF     ON      ON


@@ -328,3 +328,39 @@ The below commands apply to both B4860QDS and B4420QDS.
    On Linux the interfaces are renamed as:
        . eth2 -> fm1-gb2
        . eth3 -> fm1-gb3
    On Linux the interfaces are renamed as:
        . eth2 -> fm1-gb2
        . eth3 -> fm1-gb3

+
+NAND boot with 2 Stage boot loader
+----------------------------------
+PBL initialise the internal SRAM and copy SPL(160KB) in SRAM.
+SPL further initialise DDR using SPD and environment variables and copy
+u-boot(768 KB) from flash to DDR.
+Finally SPL transer control to u-boot for futher booting.
+
+SPL has following features:
+ - Executes within 256K
+ - No relocation required
+
+ Run time view of SPL framework during  boot :-
+ -----------------------------------------------
+ Area        | Address                         |
+-----------------------------------------------
+ Secure boot | 0xFFFC0000 (32KB)               |
+ headers     |                                 |
+ -----------------------------------------------
+ GD, BD      | 0xFFFC8000 (4KB)                |
+ -----------------------------------------------
+ ENV         | 0xFFFC9000 (8KB)                |
+ -----------------------------------------------
+ HEAP        | 0xFFFCB000 (30KB)               |
+ -----------------------------------------------
+ STACK       | 0xFFFD8000 (22KB)               |
+ -----------------------------------------------
+ U-boot SPL  | 0xFFFD8000 (160KB)              |
+ -----------------------------------------------
+
+NAND Flash memory Map on B4860 and B4420QDS
+------------------------------------------
+ Start          End            Definition                      Size
+0x000000       0x0FFFFF        u-boot                          1MB
+0x140000       0x15FFFF        u-boot env                      128KB
+0x1A0000       0x1BFFFF        FMAN Ucode                      128KB