Hi Heiko, On Thu, 25 Apr 2019 at 03:00, Heiko Stuebner <he...@sntech.de> wrote: > > Hi Simon, > > Am Donnerstag, 25. April 2019, 00:26:28 CEST schrieb Simon Glass: > > On Thu, 18 Apr 2019 at 10:47, Heiko Stübner <he...@sntech.de> wrote: > > > > > > Am Donnerstag, 18. April 2019, 08:35:49 CEST schrieb Philipp Tomsich: > > > > Simon, > > > > > > > > > On 18.04.2019, at 06:32, Simon Glass <s...@chromium.org> wrote: > > > > > > > > > > Hi Kever, > > > > > > > > > > On Mon, 1 Apr 2019 at 02:21, Kever Yang <kever.y...@rock-chips.com> > > > > > wrote: > > > > >> > > > > >> Rockchip platform suppose to use TPL(run in SRAM) as dram init and > > > > >> SPL(run in DDR SDRAM) as pre-loader, so that the SPL would not be > > > > >> limited by SRAM size. > > > > >> This patch add rk3399-board-tpl.c and its common configs. > > > > > > > > > > So this means that TPL inits SDRAM? That seems strange to me...why > > > > > have SPL at all, then? What is SPL supported to do on RK3399 > > > > > platforms? > > > > > > > > For TPL->SPL implementation on Rockchip, we generally rely on the > > > > BootROM > > > > to load the TPL stage (to SRAM) and the SPL stage (to the start of > > > > DRAM). The > > > > BootROM usually limits the size of the SPL stage, so we can’t use a > > > > full U-Boot > > > > already. > > > > > > > > Even more constricting are the TPL size constraints (as this seems to > > > > have originally > > > > only been intended to be size-optimized DRAM init code) on some devices. > > > > > > and maybe for a broader functionality description, something needs to > > > load things like ATF via a FIT image from a mmc for example. > > > (which needs FIT code and also real mmc drivers). > > > > > > And as we experienced on rk3288 as well recently, SRAM may be very well > > > too small to accomplish that, so TPL needs to init the sdram separately > > > to make room for the code needed to get ATF up and running, which must > > > be done before jumping into proper uboot. > > > > I have to ask what the boot ROM is buying us? U-Boot TPL/SPL can load > > programs itself without the boot ROM and its size limit. Why not just > > stop using the boot ROM on these devices? > > The problem is more that the sram is to small to hold mmc + fit + everything > else. So we need at least on some socs > bootrom -> tpl (in sram) -> sdram init -> bootrom -> spl (in ddr) > (1) -> load fit with u-boot and atf binaries -> jump to ATF -> jump > to uboot > or in falcon mode for vyasa for example > (2) -> load linux directly -> jump to Linux
But my understanding is that RK3399 has 192KB of SRAM. How much do you need? That should be plenty for SPL? Regards, Simon _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de https://lists.denx.de/listinfo/u-boot
