A question about the 8250/16550 Driver

A question about the 8250/16550 Driver

[旭 罗]

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Hello:
    I have founded that the serial can't be initialized as the bootting process. My platform is MPC8313 and my kernel version is linux-2.6.23.9. I look though the source code and find that the MPC8313 driver is compatible with 8250/16550. The driver is in the \drivers\serial\8250.c

In the function serial8250_isa_init_ports we should use the structer old_serial_port  but i can't find the definition for this struct. I can only find the following senrense in the head of this file 

#ifndef SERIAL_PORT_DFNS
#define SERIAL_PORT_DFNS
#endif

static const struct old_serial_port old_serial_port[] = {
    SERIAL_PORT_DFNS /* defined in asm/serial.h */
};

i think this is a bug for this driver. Could any one can told me how to define the SERIAL_PORT_DFNS  for the MPC8313 system? Hi Scott, Have you ever find this problem and how do you solve it.


Thanks
Best Wishs



       
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RE: A question about the 8250/16550 Driver

[Li Yang]

> -----Original Message-----
> From: linuxppc-dev-bounces+leoli=3Dfreescale.com@ozlabs.org=20
> [mailto:linuxppc-dev-bounces+leoli=3Dfreescale.com@ozlabs.org]=20
> On Behalf Of =D0=F1 =C2=DE
> Sent: Thursday, April 17, 2008 3:32 PM
> To: Linu PPC Mail list
> Cc: Wood Scott
> Subject: A question about the 8250/16550 Driver
>=20
> Hello:
>     I have founded that the serial can't be initialized as=20
> the bootting process. My platform is MPC8313 and my kernel=20
> version is linux-2.6.23.9. I look though the source code and=20
> find that the MPC8313 driver is compatible with 8250/16550.=20
> The driver is in the \drivers\serial\8250.c
>=20
> In the function serial8250_isa_init_ports we should use the=20
> structer old_serial_port  but i can't find the definition for=20
> this struct. I can only find the following senrense in the=20
> head of this file=20

If you look into the function carefully enough, you can find that =
old_serial_port is optional and can be empty.  It seems to be some =
leftover to provide backward compatibility when the port structure =
changed.

- Leo

回复： RE: A question about the 8250/16550 Driver

[旭 罗]

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Hello Leo:
    Follow your advises, i look the source code and find that you are right. In the source code, There are 2 functions can do some work for the serial port initralization. The code is followed.
1. static int __devinit serial8250_probe(struct platform_device *dev)
2. static void __init serial8250_isa_init_ports(void)

In my system i use the function 2 and this function should use the structer old_serial_port. 
In fact the function 1 can initralize the serial port too. But i don't known how to call this function. 

For the more, i have find some source code in of_serial.c which is in the \drivers\serial directory. In this file, the function 
static int __devinit of_platform_serial_probe(struct of_device *ofdev,
                        const struct of_device_id *id)
call the serial8250_register_port function to initralized the serial port.

This issues makes me puzzlled, Could you help me to analyzed it? and what kind of the function i should used to initralize my serial port.



thanks 
best wishs

Li Yang <LeoLi@freescale.com> 写道： > -----Original Message-----
> From: linuxppc-dev-bounces+leoli=freescale.com@ozlabs.org 
> [mailto:linuxppc-dev-bounces+leoli=freescale.com@ozlabs.org] 
> On Behalf Of 旭 罗
> Sent: Thursday, April 17, 2008 3:32 PM
> To: Linu PPC Mail list
> Cc: Wood Scott
> Subject: A question about the 8250/16550 Driver
> 
> Hello:
>     I have founded that the serial can't be initialized as 
> the bootting process. My platform is MPC8313 and my kernel 
> version is linux-2.6.23.9. I look though the source code and 
> find that the MPC8313 driver is compatible with 8250/16550. 
> The driver is in the \drivers\serial\8250.c
> 
> In the function serial8250_isa_init_ports we should use the 
> structer old_serial_port  but i can't find the definition for 
> this struct. I can only find the following senrense in the 
> head of this file 

If you look into the function carefully enough, you can find that old_serial_port is optional and can be empty.  It seems to be some leftover to provide backward compatibility when the port structure changed.

- Leo


       
---------------------------------
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