[U-Boot] "Reset" values for clksel_con registers in clk_rk3399.c:rkclk_init()
Kever,
I came across an odd question in clk_rk3399.c while implementing the reparenting (for assigned-clock-parents) that I today discussed with David Wu… looks like the following code is supposed to restore the reset values to 3 registers, but both the NDA-version of the TRM and the public version of the TRM list different (consistent between the two TRM versions) values.
The code in question is: /* * some cru registers changed by bootrom, we'd better reset them to * reset/default values described in TRM to avoid confusion in kernel. * Please consider these three lines as a fix of bootrom bug. */ rk_clrsetreg(&cru->clksel_con[12], 0xffff, 0x4101); rk_clrsetreg(&cru->clksel_con[19], 0xffff, 0x033f); rk_clrsetreg(&cru->clksel_con[56], 0x0003, 0x0003);
However, my manual states that the default values are: CLKSEL_CON12 0x100 CLKSEL_CON19 0x100 CLKSEL_CON56 0x320
This came in with commit 9f636a24 ("rockchip: rk3399: init CPU clock when rkclk_init()”).
This popped up on my radar, as I was wondering why GbE had been working so far for us, even though we never had any reparenting code for the RK3399.
Do you know why our init code is setting these values and why this doesn’t match the comment? I also tried to see if the register-numbers were wrong and the writes went to the wrong registers, but I couldn’t find any register in the CLKSEL_CON block that had 0x4101 or 0x33f as a default/reset value.
Thanks, Philipp.
Philipp,
On 01/05/2018 04:23 AM, Dr. Philipp Tomsich wrote:
Kever,
I came across an odd question in clk_rk3399.c while implementing the reparenting (for assigned-clock-parents) that I today discussed with David Wu… looks like the following code is supposed to restore the reset values to 3 registers, but both the NDA-version of the TRM and the public version of the TRM list different (consistent between the two TRM versions) values.
The code in question is: /* * some cru registers changed by bootrom, we'd better reset them to * reset/default values described in TRM to avoid confusion in kernel. * Please consider these three lines as a fix of bootrom bug. */ rk_clrsetreg(&cru->clksel_con[12], 0xffff, 0x4101); rk_clrsetreg(&cru->clksel_con[19], 0xffff, 0x033f); rk_clrsetreg(&cru->clksel_con[56], 0x0003, 0x0003);
However, my manual states that the default values are: CLKSEL_CON12 0x100 CLKSEL_CON19 0x100 CLKSEL_CON56 0x320
This came in with commit 9f636a24 ("rockchip: rk3399: init CPU clock when rkclk_init()”).
The code comes from the first version clock driver and enabled in the commit you mentioned, I port it from coreboot clock driver, however, after I sync internally, I didn't find why we still need this, I think we can remove it if no impact find in system.
Thanks, - Kever
This popped up on my radar, as I was wondering why GbE had been working so far for us, even though we never had any reparenting code for the RK3399.
Do you know why our init code is setting these values and why this doesn’t match the comment? I also tried to see if the register-numbers were wrong and the writes went to the wrong registers, but I couldn’t find any register in the CLKSEL_CON block that had 0x4101 or 0x33f as a default/reset value.
Thanks, Philipp.
participants (2)
-
Dr. Philipp Tomsich -
Kever Yang