[U-Boot] [PATCH] arm: socfpga: move gen5 SDR driver to DM

Simon Goldschmidt simon.k.r.goldschmidt at gmail.com
Fri Feb 8 20:36:48 UTC 2019

Am Fr., 8. Feb. 2019, 21:28 hat Dalon L Westergreen <
dalon.westergreen at linux.intel.com> geschrieben:

> On Thu, 2019-02-07 at 22:23 +0100, Simon Goldschmidt wrote:
> > To clean up reset handling for socfpga gen5, let's move the code snippet
> > taking the DDR controller out of reset from SPL to the DDR driver.
> >
> > While at it, port the ddr driver to UCLASS_RAM and use dts.
> >
> > Signed-off-by: Simon Goldschmidt <simon.k.r.goldschmidt at gmail.com>
> > ---
> >
> > This is an RFC to show what the SDRAM driver moved to DM (UCLASS_RAM)
> would
> > look like. It's RFC both because Dinh did not seem too fond of changing
> the
> > register address of the SDR in devicetree to include what the
> undocumented
> > registers 'sequencer.c' uses as well as because of my observed code
> growth.
> >
> > Basically, I want to move this to UCLASS_RAM and I want to read the reset
> > property for SDR from devicetree. What remains RFC is: do we want/need to
> > read the base address from devicetree, or can we live with it being hard-
> > coded (and maybe sanity-checked during probe)?
> >
> My 2 cents, i love the idea of moving all of the socfgpa sdram code to DM.
> Looking at the code, i would suggest that we should handle the case where
> there is no HPS sdram controller, and instead an FPGA based controller is
> used.  Although not common, it is a use case i have seen repeatedly.

While I haven't used it like that (I did use an FPGA RAM controller, but
that was with a NIOS and not Linux, not HPS), I guess it should work with
my changed. Just disable the 'sdr' node in the devicetree. You'll need a
driver for the FPGA based RAM controller though.

Or, in the setup you mentioned, would the existing driver be the same? I.e.
just use a different base address? Or is it a different IP?


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