[PATCH RFC 02/18] clk: rockchip: rk3568: Fix probe with OF_PLATDATA enabled

[Jonas Karlman]

Hi Pavel,

On 5/24/2026 9:39 PM, Pavel Golikov wrote:
> Hi Jonas,
> 
> On Sun, May 24, 2026 at 08:42:33PM +0200, Jonas Karlman wrote:
>> Hi Pavel,
>>
>> On 5/17/2026 9:24 PM, Pavel Golikov wrote:
>>> Properly initialize cru address space reference when CONFIG_OF_PLATDATA
>>> is enabled.
>>
>> Do we have to use OF_PLATDATA for TPL to fit into SRAM?
> 
> DRAM driver is heavily based on one for rv1126. rv1126 utilizes OF_PLATDATA,
> even though it is 32 bit (with the same amount of SRAM), and 32 bit TPL should
> be even smaller.

None of the existing Rockchip TPL implementation is very optimized and
likely not a good candidate on how optimized DRAM init can be handled :-)

>> Also, why do we need CLK driver in TPL? Based on small glance at the
>> code it looks like the DPLL was handled by the RAM driver itself.
> 
> I'm getting
> 
> aarch64-linux-gnu-ld: arch/arm/mach-rockchip/rk3568/clk_rk3568.o: in function `rockchip_get_clk':
> <...>/build-tpl/../arch/arm/mach-rockchip/rk3568/clk_rk3568.c:14: undefined reference to `_u_boot_list_2_driver_2_rockchip_rk3568_cru'
> aarch64-linux-gnu-ld: <...>/build-tpl/../arch/arm/mach-rockchip/rk3568/clk_rk3568.c:14: undefined reference to `_u_boot_list_2_driver_2_rockchip_rk3568_cru'
> 
> when trying to build TPL without CLK (both with OF_PLATDATA and OF_REAL).
> rockchip_get_clk is needed by sysreset_rockchip, which, in turn, is always
> built for ARCH_ROCKCHIP (sorry).

Correct, as I mentioned, there are dependency issues that needs to be
resolved, the question remains, does the DRAM init code need to
initialize any clocks that is currently handled in the clock driver?

Or could macros from cru_rk3568.h be used directly in DRAM init code
to save on size?

Anyway, I have some work-in-progress code [1] that cleanup some of these
dependency issues and should allow for a very light TPL.

  make generic-rk3568_defconfig rockchip-tpl-lpddr4.config

With that I get a ~2 KiB TPL that could be used as a starting ground
for a size optimized DRAM init.

Implement board_debug_uart_init(), sdram_init() and the missing RK3568
specific TPL Kconfig options, i.e. TPL_TEXT_BASE etc. and hopefully that
should be enough for a size optimized DRAM init.

[1] https://source.denx.de/u-boot/contributors/kwiboo/u-boot/-/commits/ci

I will rework some of those patches and send to list later this week.

Regards,
Jonas

> 
> We could actually delegate DPLL to CLK, but there is no API to configure spread
> spectrum (although it is disabled by default in loader_params). I also have no
> idea of how MSCH clock tree looks like.
> 
> Regards,
> Pavel