On Sat, 2006-05-27 at 17:13 +0530, Muneeswaran P - TLS, Chennai wrote: > Hi, > > Pls help me. > > I am writing device driver (kernel 2.6 ) for PCI-X card. > > Pls clarify the following doubts: > 1. DPRAM is memory mapped to PCI-X card. BAR-0 is mapped to DPRAM. > 2. I have to transfer data from main memory to DPRAM using bus > master concept. > > 3. I have allocated main memory using kmalloc() call. How to make > this main memory area as non-cacheable one ? why would it have to be uncachable? > > 4. Whether DMA mapping (pci_map_single() call ) should be done for > both DPRAM and main memory ? for main memory only; you would need ioremap for the BAR memory *IF* you want the cpu to access it > > 4.a) I will get the physical address of DPRAM memory (memory > mapped to PCI-X card) from BAR-0 register. Can i use this physical addres > directly for data transer using bus master (without pci_map_single() call.) that is device memory and up to your device; more than likely the bus master function of your device just starts at offset 0 of the dpram and doesn't care at all about the bar address -- Kernelnewbies: Help each other learn about the Linux kernel. Archive: http://mail.nl.linux.org/kernelnewbies/ FAQ: http://kernelnewbies.org/faq/
