Hi David,
David Miller wrote:
> From: Anatolij Gustschin <ag...@denx.de>
> Date: Tue, 9 Feb 2010 15:23:17 +0100
>
>> In my understanding, in the ESP scsi driver the set of defines for
>> the register offsets is common for all chip drivers. The chip driver
>> methods for register access translate the offsets because the
>> registers on some chips are at different intervals (4-byte, 1-byte,
>> 16-byte for mac_esp.c). But the register order is the same for
>> different chips.
>>
>> In our case non only the register order is not the same for 8xx
>> FEC and 5121 FEC, but there are also other differences, different
>> reserved areas between several registers, some registers are
>> available only on 8xx and some only on 5121.
>
> That only means you would need to use a table based register address
> translation scheme, rather than a simple calculation. Something
> like:
>
> static unsigned int chip_xxx_table[] =
> {
> [GENERIC_REG_FOO] = CHIP_XXX_FOO,
> ...
> };
>
> static u32 chip_xxx_read_reg(struct chip *p, unsigned int reg)
> {
> unsigned int reg_off = chip_xxx_table[reg];
>
> return readl(p->regs + reg_off);
> }
>
> And this table can have special tokens in entries for
> registers which do not exist on a chip, so you can trap
> attempted access to them in these read/write handlers.
Yes, that could be done, but to honest, I do not see any improvement in
respect to the previous patch where the register offset were defined via
pointers within a structure.
> Please stop looking for excuses to fork this driver, a
> unified driver I think can be done cleanly.
Other people suggested to fork the driver because it's getting too ugly.
Wolfgang.
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