On Fri, 2018-11-23 at 18:07 +0100, Matthias Brugger wrote: > > On 12/11/2018 02:28, Ryder Lee wrote: > > The crash http://termbin.com/zitb is caused by the timer register > > into system in early pahse during kernel boot, but the clock > > sources didn't get ready at that time. > > > > A better way is to switch to use CLK_OF_DECLARE() in driver for things > > that need them early, but this node is actually useless in MT7622. > > So we drop it. > > I suppose the root cause is, that the driver doesn't check the error > timer_of_init returned. > > Would you mind to test the following patch to see if this fixes the problem? > > --->8 > From be91e56ed527261137335af340845eb3dd3dd33a Mon Sep 17 00:00:00 2001 > From: Matthias Brugger <matthias.bgg@xxxxxxxxx> > Date: Fri, 23 Nov 2018 17:04:08 +0100 > Subject: [PATCH] clocksource/drivers/timer-mediatek: error out on probe defer > > If the clocks are not yet present, because they are loaded after > the timer is initialized, we are unable to boot. > Check if the return value of timer_of_init and return on EPROBE_DEFER. > > Error seen is: > [ 0.008337] Failed to get clock for /timer@10004000 > [ 0.013435] WARNING: CPU: 0 PID: 0 at ../drivers/clk/clk.c:3615 > __clk_put+0xf0/0x120 > [ 0.021453] Modules linked in: > [ 0.024614] CPU: 0 PID: 0 Comm: swapper/0 Not tainted > 4.20.0-rc1-00063-g2859d9abd7e8 #2 > [ 0.032902] Hardware name: MediaTek MT7622 RFB1 board (DT) > [ 0.038580] pstate: 20000085 (nzCv daIf -PAN -UAO) > [ 0.043538] pc : __clk_put+0xf0/0x120 > [ 0.047328] lr : clk_put+0xc/0x18 > [ 0.050753] sp : ffff000009163ed0 > [ 0.054178] x29: ffff000009163ed0 x28: 0000000041010018 > [ 0.059676] x27: 0000000000000000 x26: 0000000000000000 > [ 0.065174] x25: ffff0000090cb008 x24: ffff80001dfd7800 > [ 0.070672] x23: ffff000008f934b8 x22: ffff80001dfdeae0 > [ 0.076169] x21: ffff80001dfdeae0 x20: fffffffffffffdfb > [ 0.081668] x19: ffff00000929ac40 x18: ffffffffffffffff > [ 0.087166] x17: 0000000000000000 x16: 0000000000000000 > [ 0.092664] x15: ffff0000091696c8 x14: ffff0000892cd70f > [ 0.098162] x13: ffff0000092cd71d x12: ffff000009181348 > [ 0.103661] x11: ffff000009181000 x10: 0000000005f5e0ff > [ 0.109159] x9 : 0000000000000040 x8 : ffff000009181400 > [ 0.114657] x7 : ffff80001c800270 x6 : 0000000000000000 > [ 0.120155] x5 : ffff80001c800248 x4 : 0000000000000000 > [ 0.125653] x3 : 0000000000000000 x2 : 0000000000000000 > [ 0.131151] x1 : 0000000000000000 x0 : fffffffffffffdfb > [ 0.136649] Call trace: > [ 0.139175] __clk_put+0xf0/0x120 > [ 0.142605] timer_of_cleanup+0x60/0x7c > [ 0.146572] mtk_gpt_init+0x18c/0x1a0 > [ 0.150359] timer_probe+0x74/0x10c > [ 0.153969] time_init+0x14/0x44 > [ 0.157307] start_kernel+0x29c/0x414 > [ 0.161098] ---[ end trace c3137b005300b618 ]--- > > Fixes: a0858f937960 ("clocksource/drivers/timer-mediatek: Convert the driver to > timer-of") > Fixes: e3af677607d9 ("clocksource/drivers/timer-mediatek: Add support for system > timer") > Signed-off-by: Matthias Brugger <matthias.bgg@xxxxxxxxx> > --- > drivers/clocksource/timer-mediatek.c | 12 ++++++++++-- > 1 file changed, 10 insertions(+), 2 deletions(-) > > diff --git a/drivers/clocksource/timer-mediatek.c > b/drivers/clocksource/timer-mediatek.c > index eb10321f8517..d40c77a65b08 100644 > --- a/drivers/clocksource/timer-mediatek.c > +++ b/drivers/clocksource/timer-mediatek.c > @@ -276,8 +276,12 @@ static int __init mtk_syst_init(struct device_node *node) > to.of_irq.handler = mtk_syst_handler; > > ret = timer_of_init(node, &to); > - if (ret) > + if (ret) { > + if (ret == -EPROBE_DEFER) > + return ret; > + > goto err; > + } > > clockevents_config_and_register(&to.clkevt, timer_of_rate(&to), > TIMER_SYNC_TICKS, 0xffffffff); > @@ -301,8 +305,12 @@ static int __init mtk_gpt_init(struct device_node *node) > to.of_irq.handler = mtk_gpt_interrupt; > > ret = timer_of_init(node, &to); > - if (ret) > + if (ret) { > + if (ret == -EPROBE_DEFER) > + return ret; > + > goto err; > + } > > /* Configure clock source */ > mtk_gpt_setup(&to, TIMER_CLK_SRC, GPT_CTRL_OP_FREERUN); I tried this patch, but it didn't work. I think *_OF_DECLARE() is not compatible with EPROBE_DEFER. I also found the similar discussion about this issue: https://patchwork.kernel.org/patch/10580345/ Ryder
