[PATCH] ram: rockchip: px30: add a config-based ddr selection

["Heiko Stübner" <heiko@sntech.de>]

Hi Simon,

Am Freitag, 2. Oktober 2020, 07:58:35 CEST schrieb Heiko St?bner:
> Am Freitag, 2. Oktober 2020, 04:09:56 CEST schrieb Simon Glass:
> > On Thu, 1 Oct 2020 at 12:40, Heiko Stuebner <heiko@sntech.de> wrote:
> > >
> > > From: Heiko Stuebner <heiko.stuebner@theobroma-systems.com>
> > >
> > > The SRAM on the PX30 is not big enough to hold multiple DDR configs
> > > so it needs to be selected during build.
> > >
> > > So far simply the DDR3 config was always selected and getting DDR4
> > > or LPDDR2/3 initialized would require a code modification.
> > >
> > > So add Kconfig options similar to RK3399 to allow selecting the DDR4
> > > and LPDDR2/3 options instead, while DDR3 stays the default as before.
> > >
> > > Signed-off-by: Heiko Stuebner <heiko.stuebner@theobroma-systems.com>
> > > ---
> > >  drivers/ram/rockchip/Kconfig      | 21 +++++++++++++++++++++
> > >  drivers/ram/rockchip/sdram_px30.c |  8 ++++++++
> > >  2 files changed, 29 insertions(+)
> > >
> > > diff --git a/drivers/ram/rockchip/Kconfig b/drivers/ram/rockchip/Kconfig
> > > index 8e97c2f49e..c459bbf5e2 100644
> > > --- a/drivers/ram/rockchip/Kconfig
> > > +++ b/drivers/ram/rockchip/Kconfig
> > > @@ -22,6 +22,27 @@ config RAM_ROCKCHIP_DEBUG
> > >           This is an option for developers to understand the ram drivers
> > >           initialization, configurations and etc.
> > >
> > > +config RAM_PX30_DDR4
> > > +       bool "DDR3 support for Rockchip PX30"
> > > +       depends on RAM_ROCKCHIP && ROCKCHIP_PX30
> > > +       help
> > > +         This enables DDR4 sdram support instead of the default DDR3 support
> > > +         on Rockchip PC30 SoCs.
> > > +
> > > +config RAM_PX30_LPDDR2
> > > +       bool "LPDDR2 support for Rockchip PX30"
> > > +       depends on RAM_ROCKCHIP && ROCKCHIP_PX30
> > > +       help
> > > +         This enables LPDDR2 sdram support instead of the default DDR3 support
> > > +         on Rockchip PC30 SoCs.
> > > +
> > > +config RAM_PX30_LPDDR3
> > > +       bool "LPDDR3 support for Rockchip PX30"
> > > +       depends on RAM_ROCKCHIP && ROCKCHIP_PX30
> > > +       help
> > > +         This enables LPDDR3 sdram support instead of the default DDR3 support
> > > +         on Rockchip PC30 SoCs.
> > > +
> > >  config RAM_RK3399_LPDDR4
> > >         bool "LPDDR4 support for Rockchip RK3399"
> > >         depends on RAM_ROCKCHIP && ROCKCHIP_RK3399
> > > diff --git a/drivers/ram/rockchip/sdram_px30.c b/drivers/ram/rockchip/sdram_px30.c
> > > index fd5763d0a0..2f1f6e9c0c 100644
> > > --- a/drivers/ram/rockchip/sdram_px30.c
> > > +++ b/drivers/ram/rockchip/sdram_px30.c
> > > @@ -125,7 +125,15 @@ u32 addrmap[][8] = {
> > >  struct dram_info dram_info;
> > >
> > >  struct px30_sdram_params sdram_configs[] = {
> > > +#if defined(CONFIG_RAM_PX30_DDR4)
> > > +#include       "sdram-px30-ddr4-detect-333.inc"
> > > +#elif defined(CONFIG_RAM_PX30_LPDDR2)
> > > +#include       "sdram-px30-lpddr2-detect-333.inc"
> > > +#elif defined(CONFIG_RAM_PX30_LPDDR3)
> > > +#include       "sdram-px30-lpddr3-detect-333.inc"
> > > +#else
> > >  #include       "sdram-px30-ddr3-detect-333.inc"
> > > +#endif
> > 
> > How about putting this in the device tree? I think that would be a better place.
> 
> On the PX30 the TPL does the ram initialization and the SRAM it runs in
> is very limited, so the PX30-TPL doesn't even have devicetree support
> available - hence the ram selection needs to selected at compiletime.
> 
> Even right now we're "dancing" very narrowly on the limit ;-)

Just to provide some more detail, in the PX30-TPL there is neither
devicetree nor driver model support and of the 10240bytes of
available sram, the current TPL binary already uses 10184 bytes.

So right now we have a whopping 56 bytes still available, which doesn't
leave wiggleroom at all and I actually need to hope that uboot stays
on its diet ;-) .


Heiko