Hi Michal,
(adding Kever & Philipp to Cc)
On 04.10.22 13:49, Michal Simek wrote:
Hi Stefan,
On 9/30/22 15:45, Stefan Roese wrote:
Hi Michal,
On 30.09.22 14:02, Michal Simek wrote:
Hi Simon and Stefan,
On 9/28/22 03:54, Simon Glass wrote:
Hi Simon, Hi Michal,
On 25.09.22 16:15, Simon Glass wrote:
Hi Stefan,
On Wed, 21 Sept 2022 at 08:06, Stefan Roese sr@denx.de wrote: > > Currently this timer driver provides timer_get_boot_us() to > support the > BOOTSTAGE functionality. This patch adds the timer_early > functions so > that the "normal" timer functions can be used, when > CONFIG_TIMER_EARLY > is enabled. > > timer_get_boot_us() will get removed in a follow-up patch, once the > BOOTSTAGE interface is migrated to timer_get_us(). > > Signed-off-by: Stefan Roese sr@denx.de > Cc: Michal Simek michal.simek@xilinx.com > --- > drivers/timer/cadence-ttc.c | 25 +++++++++++++++++++++++++ > 1 file changed, 25 insertions(+) > > diff --git a/drivers/timer/cadence-ttc.c > b/drivers/timer/cadence-ttc.c > index 2eff45060ad6..e26c7923a140 100644 > --- a/drivers/timer/cadence-ttc.c > +++ b/drivers/timer/cadence-ttc.c > @@ -58,6 +58,31 @@ ulong timer_get_boot_us(void) > } > #endif > > +unsigned long notrace timer_early_get_rate(void) > +{ > + return 1; > +} > + > +u64 notrace timer_early_get_count(void) > +{ > + u64 ticks = 0; > + u32 rate = 1; > + u64 us; > + int ret; > + > + ret = dm_timer_init();
I don't think you can call this if you want to support bootstage, since driver model may not be inited.
Yes, thanks for noticing. Still, this code is copied from the original timer_get_boot_us() function in this driver. Which also has problems with early timer access AFAICT.
Yes, good point.
Reviewed-by: Simon Glass sjg@chromium.org
I looked at it and kind of interesting code. For getting this working with this whole series if ttc gets u-boot,dm-pre-reloc everthing is working fine.
Yes, makes sense that this is needed.
diff --git a/arch/arm/dts/zynqmp-r5.dts b/arch/arm/dts/zynqmp-r5.dts index a72172ef2ea4..8059931f2162 100644 --- a/arch/arm/dts/zynqmp-r5.dts +++ b/arch/arm/dts/zynqmp-r5.dts @@ -56,6 +56,7 @@
ttc0: timer@ff110000 { compatible = "cdns,ttc"; + u-boot,dm-pre-reloc; status = "okay"; reg = <0xff110000 0x1000>; timer-width = <32>;
What I see based on behavior. Every bootstage call is asking for timer_early_get_count() and because dm_timer_init() is failing 0 is returned.
Inside initf_dm() dm_init_and_scan() is called and initialized timer uclass also with timer instance. With u-boot,dm-pre-reloc also cadence timer driver. On the next dm_timer_init() gd->timer is initialized and value is returned and initf_dm() passes.
This "early" implementation of the counter is broken, as you have noticed above. Resulting in timer functions only returning valid values after dm_timer_init(). This timer driver needs re-written early_timer functions, that will return proper timer values even in the early boot phase. Please take a look at e.g. rockchip_timer.c, perhaps something similar works for the cadence timer driver as well?
I looked at it and there is a code when OF_REAL is enabled. If not then 0 is returned. That's why I can't see any difference between rockchip and cadence when OF_REAL is not enabled.
And not sure how this is working in rockchip case. Who is starting timer in their case?
I have no idea. My best guess is that its already enabled when U-Boot starts.
I see start when probe happens but after it dm_timer_init() should return 0 and value can be obtained.
Kever / Philipp, could you perhaps shed some light in the current rockchip early timer implementation timer_get_boot_us(). How does it work?
Here is the log and output from bootstage.
U-Boot 2022.10-rc5-00130-g1be5bed207c9 (Sep 30 2022 - 14:00:08 +0200)
Model: Xilinx ZynqMP R5 DRAM: 512 MiB Core: 7 devices, 7 uclasses, devicetree: embed MMC: Loading Environment from nowhere... OK In: serial@ff010000 Out: serial@ff010000 Err: serial@ff010000 Net: No ethernet found. ZynqMP r5> dm tree Class Index Probed Driver Name
root 0 [ + ] root_driver root_driver clk 0 [ + ] fixed_clock |-- clk100 simple_bus 0 [ + ] simple_bus |-- amba timer 0 [ + ] cadence_ttc | |-- timer@ff110000 serial 0 [ + ] serial_zynq | `-- serial@ff010000 bootstd 0 [ ] bootstd_drv `-- bootstd bootmeth 0 [ ] bootmeth_distro `-- distro ZynqMP r5> bootstage report Timer summary in microseconds (8 records): Mark Elapsed Stage 0 0 reset 0 0 board_init_f 0 0 dm_f 0 0 dm_r 16,319 16,319 eth_common_init 18,061 1,742 main_loop 18,281 220 cli_loop 29,249 10,968 board_init_r
Accumulated time:
Take a look at sandbox - here you will get proper early timing values as well:
I expect early functions are called before DM is ready that's why to get it work that early we would have to start timer on the first call of early function. It is definitely doable but is it worth to do it?
Depends on your needs of course.
Is there any other use case where early timer counts are needed other then bootstage?
Definitely. I can think of early code that needs timer functionality, like udelay() etc. I'm pretty sure there are many occurrences for such timing usages before DM is initialized on some platforms.
Thanks, Stefan