Messages in this thread | | | Date | Mon, 18 Jul 2022 20:40:14 +0200 | From | Christian Marangi <> | Subject | Re: [net-next RFC PATCH 1/4] net: dsa: qca8k: drop qca8k_read/write/rmw for regmap variant |
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On Mon, Jul 18, 2022 at 09:40:17PM +0300, Vladimir Oltean wrote: > On Mon, Jul 18, 2022 at 07:55:26PM +0200, Christian Marangi wrote: > > Sure. > > When the regmap conversion was done at times, to limit patch delta it > > was suggested to keep these function. This was to not get crazy with > > eventual backports and fixes. > > > > The logic here is: > > As we are moving these function AND the function will use regmap api > > anyway, we can finally drop them and user the regmap api directly > > instead of these additional function. > > > > When the regmap conversion was done, I pointed out that in the future > > the driver had to be split in specific and common code and it was said > > that only at that times there was a good reason to make all these > > changes and drop these special functions. > > > > Now these function are used by both setup function for qca8k and by > > common function that will be moved to a different file. > > > > > > If we really want I can skip the dropping of these function and move > > them to qca8k common code. > > I don't really have a preference, I just want to understand why you want > to call regmap_read(priv->regmap) directly every time as opposed to > qca8k_read(priv) which is shorter to type and allows more stuff to fit > on one line.
The main reason is that it's one less function. qca8k_read calls directly the regmap ops so it seems a good time to drop it.
> > I think if you run "make drivers/net/dsa/qca/qca8k.lst" and you look at > the generated code listing before and after, you'll find it is identical > (note, I haven't actually done that). > > > An alternative is to keep them for qca8k specific code and migrate the > > common function to regmap api. > > No, that's silly and I can't even find a reason to do that. > It's not like you're trying to create a policy to not call qca8k-common.c > functions from qca8k-8xxx.c, right? That should work just fine (in this > case, qca8k_read etc).
The idea of qca8k-common is to keep them as generilized as possible. Considering ipq4019 will have a different way to write/read regs we can't lock common function to specific implementation.
> > In fact, while typing this I realized that in your code structure, > you'll have one struct dsa_switch_ops in qca8k-8xxx.c and another one in > qca8k-ipq4019.c. But the vast majority of dsa_switch_ops are common, > with the exception of .setup() which is switch-specific, correct?
Phylink ops will also be different as ipq4019 will have qsgmii and will require some calibration logic.
> > Wouldn't you consider, as an alternative, to move the dsa_switch_ops > structure to the common C file as well, and have a switch-specific > (*setup) operation in the match_data structure? Or even much better, > make the switch-specific ops as fine-grained as possible, rather than > reimplementing the entire qca8k_setup() (note, I don't know how similar > they are, but there should be as little duplication of logic as possible, > the common code should dictate what there is to do, and the switch > specific code just how to do it). >
qca8k_setup will require major investigation and I think it would be better to do do a qca8k_setup generalization when ipq4019 will be proposed.
On the other hand I like the idea of putting the qca8k ops in common.c and make the driver adds the relevant specific options. Think I will also move that to common.c. That would permit to keep function static aka even less delta and less bloat in the header file.
(is it a problem if it won't be const?)
> > So it's really a choice of drop these additional function or keep using > > them for the sake of not modifying too much source. > > > > Hope it's clear now the reason of this change. > > If I were to summarize your reason, it would be "because I prefer it > that way and because now is a good time", right? That's fine with me, > but I honestly didn't understand that while reading the commit message.
I have to be honest... Yes you are right... This is really my opinion and I don't have a particular strong reason on why dropping them.
It's really that I don't like keeping function that are just leftover of an old implementation. But my target here is not argue and find a solution so it's OK for me if I should keep these compat function and migrate them to common.c.
-- Ansuel
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