Hi Weijie, On Mon, 19 Nov 2018 at 23:36, Weijie Gao <weijie....@mediatek.com> wrote: > > Hi Simon, > > On Mon, 2018-11-19 at 10:14 -0700, Simon Glass wrote: > > Hi Weijie, > > > > On Mon, 19 Nov 2018 at 00:16, Weijie Gao <weijie....@mediatek.com> wrote: > > > > > > On Fri, 2018-11-16 at 11:26 -0700, Simon Glass wrote: > > > > Hi Weijie, > > > > > > > > On 15 November 2018 at 23:08, Weijie Gao <weijie....@mediatek.com> > > > > wrote: > > > > > On Thu, 2018-11-15 at 11:21 -0800, Simon Glass wrote: > > > > >> Hi, > > > > >> > > > > >> On 14 November 2018 at 18:07, Ryder Lee <ryder....@mediatek.com> > > > > wrote: > > > > >> > From: Weijie Gao <weijie....@mediatek.com> > > > > >> > > > > > >> > This adds a general board file based on MT7623 SoCs from > > > > MediaTek. > > > > >> > > > > > >> > As this u-boot is loaded by MTK proprietary preloader, there is > > > > no > > > > >> > low level initializtion codes. > > > > >> > > > > > >> > Signed-off-by: Weijie Gao <weijie....@mediatek.com> > > > > >> > Signed-off-by: Ryder Lee <ryder....@mediatek.com> > > > > >> > Tested-by: Matthias Brugger <matthias....@gmail.com> > > > > >> > --- > > > > >> > Changes since v5: None > > > > >> > Changes since v4: > > > > >> > -Add gd->bd->bi_boot_params for legacy method - ATAGs. > > > > >> > --- > > > > >> > arch/arm/mach-mediatek/Kconfig | 13 ++++ > > > > >> > arch/arm/mach-mediatek/Makefile | 1 + > > > > >> > arch/arm/mach-mediatek/mt7623/Makefile | 4 ++ > > > > >> > arch/arm/mach-mediatek/mt7623/init.c | 54 > > > > +++++++++++++++ > > > > >> > arch/arm/mach-mediatek/mt7623/lowlevel_init.S | 22 ++++++ > > > > >> > arch/arm/mach-mediatek/mt7623/preloader.h | 99 > > > > +++++++++++++++++++++++++++ > > > > >> > board/mediatek/mt7623/Kconfig | 13 ++++ > > > > >> > board/mediatek/mt7623/MAINTAINERS | 7 ++ > > > > >> > board/mediatek/mt7623/Makefile | 3 + > > > > >> > board/mediatek/mt7623/mt7623_rfb.c | 16 +++++ > > > > >> > configs/mt7623n_bpir2_defconfig | 54 > > > > +++++++++++++++ > > > > >> > include/configs/mt7623.h | 56 > > > > +++++++++++++++ > > > > >> > 12 files changed, 342 insertions(+) > > > > >> > create mode 100644 arch/arm/mach-mediatek/mt7623/Makefile > > > > >> > create mode 100644 arch/arm/mach-mediatek/mt7623/init.c > > > > >> > create mode 100644 arch/arm/mach-mediatek/mt7623/lowlevel_init.S > > > > >> > create mode 100644 arch/arm/mach-mediatek/mt7623/preloader.h > > > > >> > create mode 100644 board/mediatek/mt7623/Kconfig > > > > >> > create mode 100644 board/mediatek/mt7623/MAINTAINERS > > > > >> > create mode 100644 board/mediatek/mt7623/Makefile > > > > >> > create mode 100644 board/mediatek/mt7623/mt7623_rfb.c > > > > >> > create mode 100644 configs/mt7623n_bpir2_defconfig > > > > >> > create mode 100644 include/configs/mt7623.h > > > > >> > > > > >> Can this use the bloblist feature which should land soon? > > > > >> > > > > >> For now, see dm/spl-working. > > > > >> > > > > >> Regards, > > > > >> Simon > > > > > > > > > > Hi Simon, > > > > > > > > > > I've read the code for spl handoff. It's a good way though but > > > > > unfortunately it cannot be applied to the MT7623 boards. > > > > > > > > > > The reason is that MT7623 uses a MediaTek proprietary preloader > > > > which > > > > > has the same function as the U-Boot SPL. But the preloader is > > > > > close-sourced (by company policy) and only available in binary > > > > release. > > > > > This means we can't use a real U-Boot SPL to replace the preloader. > > > > > > > > Can you work to get U-Boot SPL running on the chip? > > > > > > > > What is the reason for the proprietary SPL? > > > > > > > > > > > > > > At present this chip has already been used in many products. We > > > > can't > > > > > either release a different preloader which introduces compatibility > > > > > issues. > > > > > > > > What sort of compatibility issues? I cannot see any advantage with a > > > > proprietary SPL. > > > > > > > > > > > > > > So the conclusion is that we cannot use the bloblist feature for > > > > this > > > > > SoC. > > > > > > > > Regards, > > > > Simon > > > > > > > Hi Simon, > > > > > > > > > Sorry for that I didn't describe the function of the preloader clearly. > > > > > > The MT7623 is like a smart phone SoC which has the ability to upgrade > > > bootloader/firmware via a USB cable. This function is always available > > > even if there is no valid preloader/bootloader. > > > > > > This is done by cooperation of the BootROM and preloader. This is a > > > simple description of the flow: > > > 1. Connect the MT7623 board to the PC using USB cable. Do not power up. > > > 2. Run MediaTek's FlashTool and start downloading. > > > 3. Power up the board. > > > 4. The BootROM will initialize the USB device immediately for few > > > seconds and waiting for commands from PC. > > > 5. The PC will start transmit commands to the board as soon as it > > > detects the board device. > > > 6. Thee BootROM will then download the preloader into SRAM, and run it. > > > Several informations will be passed to the preloader, to let it > > > continue to communicate with the FlashTool. > > > 7. The preloader will initialize the DRAM, download data via USB and > > > write it to flash. > > > > > > So the preloader is not only a simple SPL. It initializes DRAM and many > > > other components which will only be initialized once or used by > > > preloader. It also performs USB downloading and other things. > > > > > > The preloader is also used by other MediaTek's smart phone SoCs. The > > > DRAM initialization code is the mainly part that are not allowed to be > > > open-sourced. > > > > > > The preloader has so many functions which are not easy to port to the > > > U-Boot SPL. > > > Assume all the codes are allowed to be open sourced.If all the functions > > > are ported to SPL, the DM must be used in SPL, which will make the SPL > > > binary too large to fit in the SRAM.If only the necessary parts are > > > ported (e.g. DRAM initialization), the SPL will be incompatible with the > > > BootROM and the FlashTool and the users will be in trouble recovering a > > > board. > > > > > > At present the preloader can be downloaded from the Internet. Users can > > > concentrate on the development without managing the low level parts. > > > > > > BTW, there are also chips use U-Boot as a second/third bootloader while > > > using their proprietary binary as the first stage bootloader. For > > > example the bcm7xxx. > > > > Thank you for your detailed explanation. I am not so concerned about > > the short-term solution or older chips. > > > > A few questions: > > > > 1. Why can you not open-source the DRAM init code? > > 2. You don't need to enable DM in SPL if that makes the size too big. > > > > This actually doesn't sound so different from the Rockchip situation, > > and there it has been possible to have an open-source SPL. In fact it > > does use DM although on some boards it uses of-platdata to remove > > device-tree size. From the high quality of your patches it doesn't > > seem like your team would need any help to do this, but I am happy to > > help if that is useful. > > > > Anyway, we can go ahead with what you have and hopefully resolve this > > in the future. > > > > Reviewed-by: Simon Glass <s...@chromium.org> > > > > Regards, > > Simon > > > For the first question, it's not only about the dram init codes. MT7623 > used many components from a smart phone chip, which contains many > security mechanisms like anti-debug and anti-clone which is protected > by the company. The preloader will initialize them thus make it unable > to be open-sourced.
I do feel this is confusing obscurity with security. If the system is secure then it can be open-source. In fact it is probably better that way (more eyes). > > For the rest questions, yes we always have ways to implement an > source-source SPL to replace the preloader if at least essential source > codes can be opened. The MT7623 actually uses technologies from old > chips (e.g. the USB download). Current design can let the users upgrade > their old u-boot seamlessly. For our newly designed chips, such as the > MT7629 in this patch series, the SPL has already been used to replace > the preloader. We removed USB download and other unnecessary parts and > used full u-boot from the beginning. There is no compatibility issue for > this chip. I think you can start with a basic U-Boot SPL and add features over time. > > And again we thank for your kind help. You are welcome. I encourage you to upstream more MediaTek platforms. Regards, Simon _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de https://lists.denx.de/listinfo/u-boot
