DMA memory allocation --how to more than 1 MB

Hi All, I have a doubt about allocating the DMA memory using kmalloc OR __get_dma_pages OR pci_alloc_consistent. I was unable to allocate the memory greater than 1 MB using any one of the above memory functions. Is there any other method which will allocate the DMA memory greater than 1 MB? My system configuration is: Red Hat 7.3 with 2.4.18-3 kernel version on IA32 platform. Thanks and regards, Srinivas G