Re: [PATCH] tty: 8250: handle USR for DesignWare 8250 with correct accessors

[Shane McDonald <mcdonald.shane@gmail.com>]

On Thu, Jun 9, 2011 at 9:58 PM, Ralf Baechle <ralf@linux-mips.org> wrote:
> If you look at arch/mips/include/asm/pmc-sierra/msp71xx/msp_regs.h there's
>
> #define MSP_UART0_BASE          (MSP_SLP_BASE + 0x100)
>                                        /* UART0 controller base        */
> #define MSP_BCPY_CTRL_BASE      (MSP_SLP_BASE + 0x120)
>                                        /* Block Copy controller base   */
>
> So there are just 0x20 of address space reserved for that UART.  Me thinks
> that PMC-Sierra clamped the 256 byte address space of the DesignWare APB
> UART to what is standard for 16550 class UARTs, 8 registers which at a
> shift of 4 is 0x20 bytes and the status register being accesses is really
> something else.  I'd guess PMC-Sierra just remapped the register to
> another address.

I have confirmed with a contact at PMC-Sierra that this is the case.

Shane