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Re: Is it any serial8250 platform driver available?

To: "Ardelean, Andrei" <>
Subject: Re: Is it any serial8250 platform driver available?
From: David Daney <>
Date: Mon, 25 Oct 2010 09:43:53 -0700
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On 10/25/2010 08:37 AM, Ardelean, Andrei wrote:
Hi David,

I studied this driver and few other examples and I have one question
regarding the driver configuration:
Which field must be initialized in the plat_serial8250_port structure:
        unsigned long   iobase;         /* io base address */
        void __iomem    *membase;       /* ioremap cookie or NULL */
        resource_size_t mapbase;        /* resource base */
Some drivers init only one of them, other two fields.

My UART is located at 0x1bf01000, can I put this value in all those

As with many things in life, it depends.

In this case it depends on the flags you pass as well as any serial_in() and serial_out() functions you may have. It is fortunate you have the source code available, you can use it to see how the different options affect things.

David Daney


-----Original Message-----
From: David Daney []
Sent: Friday, October 22, 2010 3:31 PM
To: Ardelean, Andrei
Subject: Re: Is it any serial8250 platform driver available?

On 10/22/2010 12:23 PM, Ardelean, Andrei wrote:

I am porting MIPS Linux from MALTA to a new board. I ported early
console code from malta_console.c and I am looking now to use a
interrupt driven driver for TTY. My UART is compatible with 8250 (1
port only) but the UART registers are directly mapped in CPU memory
There is no PCI bus. My problem is that the driver implemented in
is very complex and it seems to be hardcode for ISA bus, is it any
simple platform UART driver available to be directly mapped in the CPU
space? Can you give me some advice what would be a good approach for

Many chips have 8250 compatible ports and use 8250.c.

See arch/mips/cavium-octeon/serial.c

David Daeny

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