Problem during mtd initialization

Hi,

We are working on MPC8640D based processor board with, 
Boot Loader version       : u-boot-2009-06 
Kernel version               : linux-2.6.30 (Downloaded from kernel.org)
RAM size                     : 1 GB
Flash memory size        : 256 MB

When we are booting the linux kernel, during mtd subsystem initialization the following error message is obtained

           # vmap allocation for size 268439552 failed: use vmalloc=<size> to increase size.
           # of-flash f0000000.bootflash: Failed to ioremap() flash region
           # of-flash: probe of f0000000.bootflash failed with error -12

It seems ioremap call during mtd initialization is failing.

The flash partitions are created through the device tree as follows,

           ranges = <0 0 0xf0000000 0x10000000 >;    // 256MB Boot flash
                        
                bootflash@0,0 {
                        compatible = "cfi-flash";
                        reg = <0 0 0x10000000>;
                        bank-width = <4>;
                        device-width = <2>;
                        #address-cells = <1>;
                        #size-cells = <1>;
                        partition@0 {
                                label = "dtb";
                                reg = <0x00000000 0x00100000>;
                                read-only;
                        };
                        partition@300000 {
                                label = "kernel";
                                reg = <0x00100000 0x00400000>;
                                read-only;
                        };
                        partition@400000 {
                                label = "fs";
                                reg = <0x00500000 0x00a00000>;
                        };
                        partition@700000 {
                                label = "firmware";
                                reg = <0x00f00000 0x00100000>;
                                read-only;
                        };
                };
 
Kindly provide us suggestions regarding this issue whether any kernel configuration changes need to be done or if any additional implementations required in flash memory mapping


Regards,
Divya