Hi Rafał, On Thu, 27 Nov 2014, Rafał Miłecki wrote: > On 27 November 2014 at 20:56, Paul Walmsley <paul@xxxxxxxxx> wrote: > > On Tue, 25 Nov 2014, Rafał Miłecki wrote: > >> I understand your arguments against drivers/soc/, but on the other hand > >> I have no idea where else this driver could go. > > > > After looking around the tree to find out where similar code is located, > > it looks like drivers/firmware is the right place. These days, > > drivers/firmware is mainly used for drivers that parse EFI bootloader > > data, DMI data, that sort of thing. Quite similar to the CFE-provided > > data that the bcm47xx-nvram code deals with. So, by functional analogy, > > drivers/firmware appears to be the right place to stash this device > > data-probing code. > > > >> I guess DT is older than CFE, but Broadcom decided to invent own > >> solution called NVRAM anyway. This is a bit messy, because it actually > >> stores hardware details (CPU, RAM, switch) as well as user settings > >> (e.g. LEDs behavior). I can't say why Broadcom decided to implement it > >> this way. > > > > Yep, based on what the other drivers in drivers/firmware are used for, I > > think drivers/firmware is the right place for the CFE parsing code. > > The problem is I can't find MAINTAINER of the drivers/firmware/. Is > there someone responsible for that? Some mailing list maybe? Who could > give us an ACK to move bcm47xx_nvram there? The list of folks who have committed patches that touch drivers/firmware is large. I did this as a first-order approximation: $ git log --format=fuller drivers/firmware/* | grep Commit: | sort -u Commit: Adrian Bunk <bunk@xxxxxxxxxx> Commit: Adrian Bunk <bunk@xxxxxxxxx> Commit: Al Viro <viro@xxxxxxxxxxxxxxxxxx> Commit: Andi Kleen <andi@xxxxxxxxxxxxxxxxx> Commit: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx> Commit: David S. Miller <davem@xxxxxxxxxxxxx> Commit: David Woodhouse <David.Woodhouse@xxxxxxxxx> Commit: Dmitry Torokhov <dmitry.torokhov@xxxxxxxxx> Commit: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> Commit: Greg Kroah-Hartman <gregkh@xxxxxxx> Commit: H. Peter Anvin <hpa@xxxxxxxxxxxxxxx> Commit: H. Peter Anvin <hpa@xxxxxxxxx> Commit: Ingo Molnar <mingo@xxxxxxx> Commit: Ingo Molnar <mingo@xxxxxxxxxx> Commit: James Bottomley <James.Bottomley@xxxxxxx> Commit: James Bottomley <JBottomley@xxxxxxxxxxxxx> Commit: Jean Delvare <khali@xxxxxxxxxxxx> Commit: Jeff Garzik <jeff@xxxxxxxxxx> Commit: Jeff Garzik <jgarzik@xxxxxxxxxx> Commit: Jesse Barnes <jbarnes@xxxxxxxxxxxxxxxx> Commit: Jiri Kosina <jkosina@xxxxxxx> Commit: Konrad Rzeszutek Wilk <konrad@xxxxxxxxxx> Commit: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx> Commit: Len Brown <len.brown@xxxxxxxxx> Commit: Linus Torvalds <torvalds@xxxxxxxxxxx> Commit: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> Commit: Linus Torvalds <torvalds@xxxxxxxxxxxxxxx> Commit: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxxxxxxxx> Commit: Linus Torvalds <torvalds@xxxxxxxxxxxxxx> Commit: Mark Brown <broonie@xxxxxxxxxxxxxxxxxxxxxxxxxxx> Commit: Mark M. Hoffman <mhoffman@xxxxxxxxxxxxx> Commit: Matt Fleming <matt.fleming@xxxxxxxxx> Commit: Matthew Wilcox <willy@xxxxxxxxxxxxxxx> Commit: Paul Gortmaker <paul.gortmaker@xxxxxxxxxxxxx> Commit: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx> Commit: Russell King <rmk+kernel@xxxxxxxxxxxxxxxx> Commit: Tejun Heo <tj@xxxxxxxxxx> Commit: Theodore Ts'o <tytso@xxxxxxx> Commit: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Commit: Tony Luck <tony.luck@xxxxxxxxx> If I were in your shoes, I would suggest either 1. asking Ralf to merge your patches that touch drivers/firmware, since he'll also presumably be merging the parts that touch arch/mips or 2. asking Greg KH to merge those patches And of course it would not hurt to collect some Reviewed-By:s from other folks. (See below...) > >> > It sounds to me like this code is a combination of three > >> > pieces: > >> > > >> > 1. code that autoprobes the size of the "nvram" partition in the Broadcom > >> > platform flash, by reading various locations in the MMIO flash aperture, > >> > configured by some other system entity > >> > >> That's right, on MIPS we simply detect flash type (drivers/ssb & > >> driver/bcma) and using that we init NVRAM passing memory offset where > >> the flash is mapped. > > > > OK. > > > > So (as a side issue), I would suggest that when you move this code out of > > arch/mips, the MIPS-isms in it should be removed, like KSEG1ADDR(), etc., > > and replaced by the standard ioremap()-type approach. After all, Broadcom > > could build CFE for ARM, and then we'd want to use this same code to parse > > the CFE-provided data. > > > > Also I would suggest getting rid of the #ifdefs for the flash type, and > > probing it dynamically instead. The flash setup code under drivers/ssb/ > > and drivers/bcma/ sets up platform_devices for the flash, right? If so > > then it would be best if this code could run after the bus setup code, > > query the Linux device model for the type of platform flash in use, and > > then extract the appropriate address space to probe from that data. > > I'm pretty sure you look at some old version of arch/bcm47xx/nvram.c. > I wouldn't dare to move such a MIPS-focused driver to some common > place ;) > > Please check for the version of nvram.c in Ralf's upstream-sfr tree. I > think you'll like it much more. Hopefully you will even consider it > ready for moving to the drivers/firmware/ or whatever :) OK I will take a look at this, and will either send comments, or will send a Reviewed-By:. Thanks for all of the good discussion on this :-) - Paul
