Sergei, Shmulik, Thanks a lot for your suggestions. I was using UPIO_MEM since I was not aware of the difference between UPIO_MEM and UPIO_MEM32. I just tried UPIO_MEM32 without adding a offset of 3. But the result is bad - after the kernel initializes the serial console, the console print out messes up. The early printk is fine because the u-boot initialises the serial port fine. How I tried UPIO_MEM32 is in platform.c changing the iotype to UPIO_MEM32 in the uart_port structure and passing the structure to early_serial_setup. What I did is the same as in arch/mips/ar7/platform.c. In 8250.c I removed the offset I added to mem_serial_out and mem_serial_in. Did I miss anything? Thanks again for your help. On Wed, 28 Oct 2009 14:04 +0300, "Sergei Shtylyov" <sshtylyov@xxxxxxxxxxxxx> wrote: > Hello. > > Shmulik Ladkani wrote: > > >> Thanks, Florian. I found the cause of the problem. My board is 32 bit > >> based, so each serial port register is 32bit even only 8 bit is used. So > >> when the board is switched endianess, I need to change the address > >> offset to access the same registers. > >> For example, original RHR register address is 0x8001000 with little > >> endian mode. With big endian, I need to access it as 0x8001003. > >> > > > > I assume your uart_port's iotype is defined as UPIO_MEM32. > > > > He wouldn't have to add 3 to the register addresses then. > > > UPIO_MEM32 makes 8250 access serial registers using readl/writel (which might > > be a problem for big-endian), while UPIO_MEM makes 8250 access the registers > > using readb/writeb. > > > > Both may be a problem for big endian. > > > Maybe you should try UPIO_MEM (assuming hardware allows byte access). > > Contrarywise, I think he now has UPIO_MEM and needs to try UPIO_MEM32. > > WBR, Sergei > >
