Hello,
On my platform, one HW block pulls the interrupt line high
as long as it remains idle, and low when it is busy.
The device tree node is:
test@22222 {
compatible = "vendor,testme";
interrupts = <23 IRQ_TYPE_LEVEL_HIGH>;
};
I wrote a minimal driver which registers the irq.
And in the interrupt handler, I disable said irq.
Since the irq is IRQ_TYPE_LEVEL_HIGH, it will fire as soon as
it is registered (because the block is idle).
Here is the code I've been running, request_irq doesn't return.
#include <linux/module.h>
#include <linux/of_irq.h>
#include <linux/interrupt.h>
#include <linux/platform_device.h>
static irqreturn_t test_isr(int irq, void *dev)
{
printk("irq=%d dev=%p\n", irq, dev);
disable_irq_nosync(irq);
printk("IRQ %d NOW DISABLED\n", irq);
return IRQ_HANDLED;
}
static int test_probe(struct platform_device *pdev)
{
unsigned res, virq;
printk("ENTER %s\n", __func__);
virq = irq_of_parse_and_map(pdev->dev.of_node, 0);
printk("virq = %u\n", virq);
res = request_irq(virq, test_isr, 0, "testme", (void *)0x42);
printk("request_irq = %d\n", res);
return 0;
}
static const struct of_device_id test_ids[] = {
{ .compatible = "vendor,testme" },
{ /* sentinel */ }
};
static struct platform_driver test_driver = {
.probe = test_probe,
.driver = {
.name = "test",
.of_match_table = test_ids,
},
};
module_platform_driver(test_driver);
MODULE_LICENSE("GPL");
And here's what I get when I try to load the module:
(I'm using the default CONFIG_RCU_CPU_STALL_TIMEOUT=21)
$ insmod test.ko
[ 91.571065] ENTER test_probe
[ 91.574208] virq = 21
[ 91.576902] irq=21 dev=00000042
[ 91.580061] IRQ 21 NOW DISABLED
[ 102.038544] nfs: server 172.27.64.1 not responding, still trying
[ 112.571855] INFO: rcu_preempt self-detected stall on CPU
[ 112.577201] 0-...: (6298 ticks this GP) idle=c45/140000000000002/0
softirq=1295/1295 fqs=2045
[ 112.585942] (t=6300 jiffies g=208 c=207 q=20)
[ 112.590497] Task dump for CPU 0:
[ 112.593735] insmod R running 0 951 929 0x00000002
[ 112.600124] Backtrace:
[ 112.602601] [<c010b9a4>] (dump_backtrace) from [<c010bba0>]
(show_stack+0x18/0x1c)
[ 112.610207] r7:c0702434[ 112.612571] r6:c07024c8
r5:000003a1[ 112.616163] r4:df570dc0
[ 112.618701]
[ 112.620202] [<c010bb88>] (show_stack) from [<c0143a28>]
(sched_show_task+0xbc/0x110)
[ 112.627989] [<c014396c>] (sched_show_task) from [<c0145ef0>]
(dump_cpu_task+0x40/0x48)
[ 112.635943] r5:00000000[ 112.638307] r4:00000000
[ 112.640845]
[ 112.642347] [<c0145eb0>] (dump_cpu_task) from [<c01a8130>]
(rcu_dump_cpu_stacks+0xb0/0xcc)
[ 112.650651] r5:00000000[ 112.653014] r4:c070a840
[ 112.655553]
[ 112.657055] [<c01a8080>] (rcu_dump_cpu_stacks) from [<c01743ec>]
(rcu_check_callbacks+0x8f8/0x9b0)
[ 112.666058] r10:c07024c0[ 112.668509] r9:c0702518
r8:1f5a3000[ 112.672100] r7:c070a840
r6:c0702100[ 112.675691] r5:c0637f40
[ 112.678230] r4:dfbdaf40[ 112.680592] r3:ffff2458
[ 112.683130]
[ 112.684629] [<c0173af4>] (rcu_check_callbacks) from [<c0177b70>]
(update_process_times+0x3c/0x64)
[ 112.693545] r10:c0188c54[ 112.695995] r9:00000001
r8:dfbd870c[ 112.699588] r7:0000001a
r6:00000000[ 112.703178] r5:df570dc0
[ 112.705717] r4:ffffe000[ 112.708080]
[ 112.709581] [<c0177b34>] (update_process_times) from [<c0188c50>]
(tick_sched_handle+0x50/0x54)
[ 112.718322] r7:0000001a[ 112.720684] r6:35192494
r5:def2dab8[ 112.724274] r4:dfbd88f8
[ 112.726812]
[ 112.728309] [<c0188c00>] (tick_sched_handle) from [<c0188cb0>]
(tick_sched_timer+0x5c/0xa0)
[ 112.736705] [<c0188c54>] (tick_sched_timer) from [<c0178bf4>]
(__hrtimer_run_queues+0x11c/0x1ac)
[ 112.745533] r7:00000000[ 112.747896] r6:dfbd8700
r5:dfbd88f8[ 112.751486] r4:dfbd86c0
[ 112.754025]
[ 112.755519] [<c0178ad8>] (__hrtimer_run_queues) from [<c0178e88>]
(hrtimer_interrupt+0xbc/0x20c)
[ 112.764347] r10:dfbd8738[ 112.766798] r9:dfbd8778
r8:dfbd8758[ 112.770389] r7:dfbd86d4
r6:ffffffff[ 112.773979] r5:00000003
[ 112.776518] r4:dfbd86c0[ 112.778881]
[ 112.780378] [<c0178dcc>] (hrtimer_interrupt) from [<c010ed0c>]
(twd_handler+0x38/0x48)
[ 112.788332] r10:def2dab8[ 112.790782] r9:df402400
r8:00000001[ 112.794373] r7:df408700
r6:00000013[ 112.797964] r5:c0702744
[ 112.800504] r4:00000001[ 112.802866]
[ 112.804362] [<c010ecd4>] (twd_handler) from [<c016a134>]
(handle_percpu_devid_irq+0x94/0x14c)
[ 112.812928] r5:c0702744[ 112.815291] r4:df405300
[ 112.817829]
[ 112.819327] [<c016a0a0>] (handle_percpu_devid_irq) from [<c0165134>]
(generic_handle_irq+0x2c/0x3c)
[ 112.828417] r7:def2dbd0[ 112.830780] r6:00000013
r5:00000000[ 112.834370] r4:c0635ec4
[ 112.836909]
[ 112.838404] [<c0165108>] (generic_handle_irq) from [<c01656dc>]
(__handle_domain_irq+0x84/0xf4)
[ 112.847150] [<c0165658>] (__handle_domain_irq) from [<c01014ac>]
(gic_handle_irq+0x50/0x94)
[ 112.855541] r10:def2dbd0[ 112.857992] r9:e0803100
r8:e0802100[ 112.861583] r7:def2dab8
r6:e080210c[ 112.865173] r5:c0702744
[ 112.867712] r4:c070ff50[ 112.870076] r3:def2dab8
[ 112.872614]
[ 112.874107] [<c010145c>] (gic_handle_irq) from [<c010c70c>]
(__irq_svc+0x6c/0xa8)
[ 112.881626] Exception stack(0xdef2dab8 to 0xdef2db00)
[ 112.886699] daa0:
00000000 c057c9b4
[ 112.894919] dac0: c07216c0 00000000 00000202 ffffe000 00000013 00000000
00000001 df402400
[ 112.903140] dae0: def2dbd0 def2db64 def2daf8 def2db08 c030db68 c0121068
20000113 ffffffff
[ 112.911356] r9:def2c000[ 112.913719] r8:00000001
r7:def2daec[ 112.917310] r6:ffffffff
r5:20000113[ 112.920901] r4:c0121068
[ 112.923448] [<c0120fc0>] (__do_softirq) from [<c0121520>]
(irq_exit+0xd4/0x110)
[ 112.930792] r10:def2dbd0[ 112.933242] r9:df402400
r8:00000001[ 112.936833] r7:00000000
r6:00000013[ 112.940423] r5:00000000
[ 112.942962] r4:c0635ec4[ 112.945324]
[ 112.946819] [<c012144c>] (irq_exit) from [<c01656e0>]
(__handle_domain_irq+0x88/0xf4)
[ 112.954690] [<c0165658>] (__handle_domain_irq) from [<c01014ac>]
(gic_handle_irq+0x50/0x94)
[ 112.963080] r10:00000000[ 112.965531] r9:e0803100
r8:e0802100[ 112.969122] r7:def2dbd0
r6:e080210c[ 112.972714] r5:c0702744
[ 112.975253] r4:c070ff50[ 112.977617] r3:def2dbd0
[ 112.980154]
[ 112.981648] [<c010145c>] (gic_handle_irq) from [<c010c70c>]
(__irq_svc+0x6c/0xa8)
[ 112.989166] Exception stack(0xdef2dbd0 to 0xdef2dc18)
[ 112.994240] dbc0: df506260 60000013
00000000 00000005
[ 113.002460] dbe0: dedbd680 df506200 00000015 df506260 60000013 df506238
00000000 def2dc2c
[ 113.010679] dc00: def2dc30 def2dc20 c0167f90 c04d68d0 60000013 ffffffff
[ 113.017324] r9:def2c000[ 113.019687] r8:60000013
r7:def2dc04[ 113.023277] r6:ffffffff
r5:60000013[ 113.026868] r4:c04d68d0
[ 113.029418] [<c04d68a8>] (_raw_spin_unlock_irqrestore) from [<c0167f90>]
(__setup_irq+0x440/0x5f0)
[ 113.038426] [<c0167b50>] (__setup_irq) from [<c0168300>]
(request_threaded_irq+0xf0/0x188)
[ 113.046730] r10:00000000[ 113.049179] r9:00000015
r8:df506210[ 113.052770] r7:00000000
r6:df506200[ 113.056362] r5:00000000
[ 113.058901] r4:dedbd680[ 113.061263]
[ 113.062767] [<c0168210>] (request_threaded_irq) from [<bf0040b8>]
(test_probe+0x74/0x90 [zozo])
[ 113.071508] r10:00000000[ 113.073959] r9:21242a5c
r8:00000001[ 113.077550] r7:fffffdfb
r6:bf004320[ 113.081142] r5:df516810
[ 113.083681] r4:00000015[ 113.086044] r3:00000000
[ 113.088582]
[ 113.090085] [<bf004044>] (test_probe [zozo]) from [<c03595e8>]
(platform_drv_probe+0x54/0xb8)
[ 113.098652] r4:c0752d30[ 113.101014]
[ 113.102510] [<c0359594>] (platform_drv_probe) from [<c0357b88>]
(driver_probe_device+0x228/0x2b8)
[ 113.111425] r7:bf004320[ 113.113789] r6:df516844
r5:df516810[ 113.117379] r4:c0752d30
[ 113.119917]
[ 113.121412] [<c0357960>] (driver_probe_device) from [<c0357cd8>]
(__driver_attach+0xc0/0xc4)
[ 113.129891] r9:21242a5c[ 113.132255] r8:00000001
r7:00000000[ 113.135845] r6:df516844
r5:bf004320[ 113.139436] r4:df516810
[ 113.141980] [<c0357c18>] (__driver_attach) from [<c0355d00>]
(bus_for_each_dev+0x70/0xa4)
[ 113.150196] r7:00000000[ 113.152560] r6:c0357c18
r5:bf004320[ 113.156150] r4:00000000
[ 113.158689]
[ 113.160183] [<c0355c90>] (bus_for_each_dev) from [<c03573d4>]
(driver_attach+0x24/0x28)
[ 113.168224] r6:c0714090[ 113.170587] r5:df7efc80
r4:bf004320[ 113.174178]
[ 113.175673] [<c03573b0>] (driver_attach) from [<c0356fa0>]
(bus_add_driver+0x1a8/0x220)
[ 113.183719] [<c0356df8>] (bus_add_driver) from [<c0358498>]
(driver_register+0x80/0x100)
[ 113.191848] r7:bf004380[ 113.194211] r6:dedbdc80
r5:bf006000[ 113.197801] r4:bf004320
[ 113.200339]
[ 113.201834] [<c0358418>] (driver_register) from [<c0359548>]
(__platform_driver_register+0x48/0x50)
[ 113.210924] r5:bf006000[ 113.213287] r4:c0714090
[ 113.215826]
[ 113.217323] [<c0359500>] (__platform_driver_register) from [<bf006020>]
(test_driver_init+0x20/0x24 [zozo])
[ 113.227113] r5:bf006000[ 113.229475] r4:ffffe000
[ 113.232014]
[ 113.233511] [<bf006000>] (test_driver_init [zozo]) from [<c01017f4>]
(do_one_initcall+0x4c/0x17c)
[ 113.242432] [<c01017a8>] (do_one_initcall) from [<c01a81b4>]
(do_init_module+0x68/0x3a4)
[ 113.250561] r10:dedbd5c8[ 113.253011] r9:21242a5c
r8:00000001[ 113.256602] r7:bf004380
r6:dedbdc80[ 113.260193] r5:00000001
[ 113.262732] r4:bf004380[ 113.265094]
[ 113.266591] [<c01a814c>] (do_init_module) from [<c01925f0>]
(load_module+0x1dc0/0x2180)
[ 113.274633] r6:dedbd5c0[ 113.276997] r5:00000001
r4:def2df34[ 113.280587]
[ 113.282082] [<c0190830>] (load_module) from [<c0192b08>]
(SyS_init_module+0x158/0x170)
[ 113.290037] r10:00000051[ 113.292487] r9:def2c000
r8:01bbf008[ 113.296078] r7:e08682cc
r6:00000000[ 113.299667] r5:01bc02e4
[ 113.302207] r4:000012cc[ 113.304569]
[ 113.306065] [<c01929b0>] (SyS_init_module) from [<c0107ba0>]
(ret_fast_syscall+0x0/0x3c)
[ 113.314194] r10:00000000[ 113.316645] r9:def2c000
r8:c0107d64[ 113.320236] r7:00000080
r6:be98bb54[ 113.323828] r5:be98bc6d
[ 113.326368] r4:000012cc[ 113.328729]
Are we not supposed to disable the irq in the handler?
Regards.
