netdev - Re: [PATCH net-next v3 2/2] net/8390: apne.c - add 100 Mbit support to apne.c driver

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Date:   Fri, 18 Jun 2021 07:33:31 +1200
From:   Michael Schmitz <schmitzmic@...il.com>
To:     Finn Thain <fthain@...ux-m68k.org>
Cc:     linux-m68k@...r.kernel.org, geert@...ux-m68k.org, alex@...ik.de,
        netdev@...r.kernel.org
Subject: Re: [PATCH net-next v3 2/2] net/8390: apne.c - add 100 Mbit support
 to apne.c driver

Hi Finn,

thanks for your review!

On 17/06/21 6:51 pm, Finn Thain wrote:
> On Thu, 17 Jun 2021, Michael Schmitz wrote:
>
>> Add Kconfig option, module parameter and PCMCIA reset code
>> required to support 100 Mbit PCMCIA ethernet cards on Amiga.
>>
>> 10 Mbit and 100 Mbit mode are supported by the same module.
>> A module parameter switches Amiga ISA IO accessors to word
>> access by changing isa_type at runtime. Additional code to
>> reset the PCMCIA hardware is also added to the driver probe.
>>
>> Patch modified after patch "[PATCH RFC net-next] Amiga PCMCIA
>> 100 MBit card support" submitted to netdev 2018/09/16 by Alex
>> Kazik <alex@...ik.de>.
>>
>> CC: netdev@...r.kernel.org
>> Tested-by: Alex Kazik <alex@...ik.de>
>> Signed-off-by: Michael Schmitz <schmitzmic@...il.com>
>>
>> --
>> Changes from v1:
>>
>> - fix module parameter name in Kconfig help text
>>
>> Alex Kazik:
>> - change module parameter type to bool, fix module parameter
>>    permission
>>
>> Changes from RFC:
>>
>> Geert Uytterhoeven:
>> - change APNE_100MBIT to depend on APNE
>> - change '---help---' to 'help' (former no longer supported)
>> - fix whitespace errors
>> - fix module_param_named() arg count
>> - protect all added code by #ifdef CONFIG_APNE_100MBIT
>> ---
>>   drivers/net/ethernet/8390/Kconfig | 12 ++++++++++++
>>   drivers/net/ethernet/8390/apne.c  | 21 +++++++++++++++++++++
>>   2 files changed, 33 insertions(+)
>>
>> diff --git a/drivers/net/ethernet/8390/Kconfig b/drivers/net/ethernet/8390/Kconfig
>> index 9f4b302..6e4db63 100644
>> --- a/drivers/net/ethernet/8390/Kconfig
>> +++ b/drivers/net/ethernet/8390/Kconfig
>> @@ -143,6 +143,18 @@ config APNE
>>   	  To compile this driver as a module, choose M here: the module
>>   	  will be called apne.
>>   
>> +config APNE100MBIT
>> +	bool "PCMCIA NE2000 100MBit support"
>> +	depends on APNE
>> +	default n
>> +	help
>> +	  This changes the driver to support 10/100Mbit cards (e.g. Netgear
>> +	  FA411, CNet Singlepoint). 10 MBit cards and 100 MBit cards are
>> +	  supported by the same driver.
>> +
>> +	  To activate 100 Mbit support at runtime or from the kernel
>> +	  command line, use the apne.100mbit module parameter.
>> +
>>   config PCMCIA_PCNET
>>   	tristate "NE2000 compatible PCMCIA support"
>>   	depends on PCMCIA
>> diff --git a/drivers/net/ethernet/8390/apne.c b/drivers/net/ethernet/8390/apne.c
>> index fe6c834..59e41ad 100644
>> --- a/drivers/net/ethernet/8390/apne.c
>> +++ b/drivers/net/ethernet/8390/apne.c
>> @@ -120,6 +120,12 @@ static u32 apne_msg_enable;
>>   module_param_named(msg_enable, apne_msg_enable, uint, 0444);
>>   MODULE_PARM_DESC(msg_enable, "Debug message level (see linux/netdevice.h for bitmap)");
>>   
>> +#ifdef CONFIG_APNE100MBIT
>> +static bool apne_100_mbit;
>> +module_param_named(apne_100_mbit_msg, apne_100_mbit, bool, 0444);
>> +MODULE_PARM_DESC(apne_100_mbit_msg, "Enable 100 Mbit support");
>> +#endif
>> +
>>   struct net_device * __init apne_probe(int unit)
>>   {
>>   	struct net_device *dev;
>> @@ -139,6 +145,11 @@ struct net_device * __init apne_probe(int unit)
>>   	if ( !(AMIGAHW_PRESENT(PCMCIA)) )
>>   		return ERR_PTR(-ENODEV);
>>   
>> +#ifdef CONFIG_APNE100MBIT
>> +	if (apne_100_mbit)
>> +		isa_type = ISA_TYPE_AG16;
>> +#endif
>> +
> I think isa_type has to be assigned unconditionally otherwise it can't be
> reset for 10 mbit cards. Therefore, the AMIGAHW_PRESENT(PCMCIA) logic in
> arch/m68k/kernel/setup_mm.c probably should move here.

Good catch! I am uncertain though as to whether replacing a 100 Mbit 
card by a 10 Mbit one at run time is a common use case (or even 
possible, given constraints of the Amiga PCMCIA interface?), but it 
ought to work even if rarely used.

The comment there says isa_type must be set as early as possible, so I'd 
rather leave that alone, and add an 'else' clause here.

This of course raise the question whether we ought to move the entire 
isa_type handling into arch code instead - make it a generic 
amiga_pcmcia_16bit option settable via sysfs. There may be other 16 bit 
cards that require the same treatment, and duplicating PCMCIA mode 
switching all over the place could be avoided. Opinions?

>
>>   	pr_info("Looking for PCMCIA ethernet card : ");
>>   
>>   	/* check if a card is inserted */
>> @@ -590,6 +601,16 @@ static int init_pcmcia(void)
>>   #endif
>>   	u_long offset;
>>   
>> +#ifdef CONFIG_APNE100MBIT
>> +	/* reset card (idea taken from CardReset by Artur Pogoda) */
>> +	{
>> +		u_char  tmp = gayle.intreq;
>> +
>> +		gayle.intreq = 0xff;    mdelay(1);
>> +		gayle.intreq = tmp;     mdelay(300);
>> +	}
>> +#endif
>> +
> The indentation/alignment here doesn't conform to the kernel coding style.

Good one. Checkpatch missed that for some reason...

I'll respin ...

Cheers,

     Michael