[U-Boot] [PATCH 4/8] ARM: socfpga: arria10: Add generic handoff devicetree include

[Dalon L Westergreen]

On Sun, 2019-10-06 at 20:05 +0200, Simon Goldschmidt wrote:
> Am 06.10.2019 um 19:44 schrieb Dalon L Westergreen:
> > On Sun, 2019-10-06 at 15:44 +0200, Marek Vasut wrote:
> > > On 10/6/19 1:19 AM, Dalon L Westergreen wrote:
> > > > On Sat, 2019-10-05 at 01:51 +0200, Marek Vasut wrote:
> > > > > On 10/5/19 12:30 AM, Dalon Westergreen wrote:
> > > > > > From: Dalon Westergreen <dalon.westergreen at intel.com
> > > > > >  <mailto:dalon.westergreen at intel.com>
> > > > > > Generic handoff devicetree include uses a header generated bythe
> > > > > > qts-filter-a10.sh script in mach-socfpga.  The scriptcreates the
> > > > > > header based on designspecific implementationsfor clock and pinmux
> > > > > > configurations.
> > > > > 
> > > > > [...]
> > > > > > diff --git a/arch/arm/dts/socfpga_arria10_handoff_u-
> > > > > > boot.dtsib/arch/arm/dts/socfpga_arria10_handoff_u-boot.dtsi
> > > > > 
> > > > > [...]
> > > > > > -	clock_manager at 0xffd04000 {+	clkmgr at 0xffd04000 {+		comp
> > > > > > atible ="altr,socfpga-a10-clk-init";+		reg =
> > > > > > <0xffd04000 0x00000200>;+		reg-names =
> > > > > > "soc_clock_manager_OCP_SLV"; 		u-boot,dm-pre-reloc;  	
> > > > > > 	mainpll {+			vco0-psrc =<MAINPLLGRP_VCO0_PSRC>;+	
> > > > > > 		vco1-denom =<MAINPLLGRP_VCO1_DENOM>;+			
> > > > > > vco1-numer =<MAINPLLGRP_VCO1_NUMER>;
> > > > > 
> > > > > But these bits are board-specific , they shouldn't be in common DT.
> > > > 
> > > > This common dtsi requires that the top level u-boot.dtsi include the
> > > > boardspecific header.  The formatand #define names are in fact common.
> > > 
> > > OK, I now see what you're doing here. Can you explain that in a bit
> > > moredetail in the commit message ?
> > > Basically socfpga_board.h is included socfpga_board.dts , and then
> > > thepreprocessor correctly expands the values from socfpga_board.h in
> > > thesocfpga_board.dts , so this works for multiple boards too ?
> > 
> > Exactly. Will add more detail in the commit message, and slim down the
> > included clocks inthe u-boot.dtsi
> 
> I'm (still) working on a series to bring gen5 completely to devicetree, so
> that the 'qts' directories can be removed. I chose a different approach
> however, in that I generated everything into a '-handoff.dtsi' file (*). I'd
> be happy if we could find a common mechanism for all socfpga sub-archs. How
> does S10/Agilex handle this?
> (*): Gen5 has the downside that we're low on memory in SPL (regarding DM), and
> as we require large binary arrays there, I chose to encode the binary blob
> arrays in host byte order so that they could be used in-place instead of
> copying them from BE (dtb) to LE (stack/heap). Maybe that doesn't fit
> A10/S10/Agilex anyway?

S10/Agilex are entirely different.  The onchip ram is loaded with any
configuration data bythe secure device manager.  There is no need to modify the
dts for any io/pll/bridgeconfiguration. 
A10 is better than cv/av in that is requires far less configuration data, and no
dataregarding the dram is needed.  Also, there is no binary parsing required for
extractingthe required data, hence the simple qts-filter-a10.sh.  
I think a -handoff.dtsi is a good approach, but why not do the same thing i do
here anduse a header file for the config data.  that way the -handoff.dtsi can
be common and theheader only needs to be included in the toplevel -u-boot.dtsi?
--dalon
> Regards,Simon