[PATCH] soc: fsl: dpio: register dpio irq handlers after dpio create

[Laurentiu Tudor]

From: Grigore Popescu <grigore.popescu@xxxxxxx>

The dpio irqs must be registered when you can actually
receive interrupts, ie when the dpios are created.
Kernel goes through NULL pointer dereference errors
followed by kernel panic [1] because the dpio irqs are
enabled before the dpio is created.

[1]
Unable to handle kernel NULL pointer dereference at virtual address 0040
fsl_mc_dpio dpio.14: probed
fsl_mc_dpio dpio.13: Adding to iommu group 11
  ISV = 0, ISS = 0x00000004
Unable to handle kernel NULL pointer dereference at virtual address 0040
Mem abort info:
  ESR = 0x96000004
  EC = 0x25: DABT (current EL), IL = 32 bits
  SET = 0, FnV = 0
  EA = 0, S1PTW = 0
Data abort info:
  ISV = 0, ISS = 0x00000004
  CM = 0, WnR = 0
[0000000000000040] user address but active_mm is swapper
Internal error: Oops: 96000004 [#1] PREEMPT SMP
Modules linked in:
CPU: 2 PID: 151 Comm: kworker/2:1 Not tainted 5.6.0-rc4-next-20200304 #1
Hardware name: NXP Layerscape LX2160ARDB (DT)
Workqueue: events deferred_probe_work_func
pstate: 00000085 (nzcv daIf -PAN -UAO)
pc : dpaa2_io_irq+0x18/0xe0
lr : dpio_irq_handler+0x1c/0x28
sp : ffff800010013e20
x29: ffff800010013e20 x28: ffff0026d9b4c140
x27: ffffa1d38a142018 x26: ffff0026d2953400
x25: ffffa1d38a142018 x24: ffffa1d38a7ba1d8
x23: ffff800010013f24 x22: 0000000000000000
x21: 0000000000000072 x20: ffff0026d2953400
x19: ffff0026d2a68b80 x18: 0000000000000001
x17: 000000002fb37f3d x16: 0000000035eafadd
x15: ffff0026d9b4c5b8 x14: ffffffffffffffff
x13: ff00000000000000 x12: 0000000000000038
x11: 0101010101010101 x10: 0000000000000040
x9 : ffffa1d388db11e4 x8 : ffffa1d38a7e40f0
x7 : ffff0026da414f38 x6 : 0000000000000000
x5 : ffff0026da414d80 x4 : ffff5e5353d0c000
x3 : ffff800010013f60 x2 : ffffa1d388db11c8
x1 : ffff0026d2a67c00 x0 : 0000000000000000
Call trace:
 dpaa2_io_irq+0x18/0xe0
 dpio_irq_handler+0x1c/0x28
 __handle_irq_event_percpu+0x78/0x2c0
 handle_irq_event_percpu+0x38/0x90
 handle_irq_event+0x4c/0xd0
 handle_fasteoi_irq+0xbc/0x168
 generic_handle_irq+0x2c/0x40
 __handle_domain_irq+0x68/0xc0
 gic_handle_irq+0x64/0x150
 el1_irq+0xb8/0x180
 _raw_spin_unlock_irqrestore+0x14/0x48
 irq_set_affinity_hint+0x6c/0xa0
 dpaa2_dpio_probe+0x2a4/0x518
 fsl_mc_driver_probe+0x28/0x70
 really_probe+0xdc/0x320
 driver_probe_device+0x5c/0xf0
 __device_attach_driver+0x88/0xc0
 bus_for_each_drv+0x7c/0xc8
 __device_attach+0xe4/0x140
 device_initial_probe+0x18/0x20
 bus_probe_device+0x98/0xa0
 device_add+0x41c/0x758
 fsl_mc_device_add+0x184/0x530
 dprc_scan_objects+0x280/0x370
 dprc_probe+0x124/0x3b0
 fsl_mc_driver_probe+0x28/0x70
 really_probe+0xdc/0x320
 driver_probe_device+0x5c/0xf0
 __device_attach_driver+0x88/0xc0
 bus_for_each_drv+0x7c/0xc8
 __device_attach+0xe4/0x140
 device_initial_probe+0x18/0x20
 bus_probe_device+0x98/0xa0
 deferred_probe_work_func+0x74/0xa8
 process_one_work+0x1c8/0x470
 worker_thread+0x1f8/0x428
 kthread+0x124/0x128
 ret_from_fork+0x10/0x18
Code: a9bc7bfd 910003fd a9025bf5 a90363f7 (f9402015)
---[ end trace 38298e1a29e7a570 ]---
Kernel panic - not syncing: Fatal exception in interrupt
SMP: stopping secondary CPUs
Mem abort info:
  ESR = 0x96000004
  CM = 0, WnR = 0
  EC = 0x25: DABT (current EL), IL = 32 bits
[0000000000000040] user address but active_mm is swapper
  SET = 0, FnV = 0
  EA = 0, S1PTW = 0
Data abort info:
  ISV = 0, ISS = 0x00000004
  CM = 0, WnR = 0
[0000000000000040] user address but active_mm is swapper
SMP: failed to stop secondary CPUs 0-2
Kernel Offset: 0x21d378600000 from 0xffff800010000000
PHYS_OFFSET: 0xffffe92180000000
CPU features: 0x10002,21806008
Memory Limit: none
---[ end Kernel panic - not syncing: Fatal exception in interrupt ]---

Signed-off-by: Laurentiu Tudor <laurentiu.tudor@xxxxxxx>
Signed-off-by: Grigore Popescu <grigore.popescu@xxxxxxx>
---
 drivers/soc/fsl/dpio/dpio-driver.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/soc/fsl/dpio/dpio-driver.c b/drivers/soc/fsl/dpio/dpio-driver.c
index 70014ecce2a7..7b642c330977 100644
--- a/drivers/soc/fsl/dpio/dpio-driver.c
+++ b/drivers/soc/fsl/dpio/dpio-driver.c
@@ -233,10 +233,6 @@ static int dpaa2_dpio_probe(struct fsl_mc_device *dpio_dev)
 		goto err_allocate_irqs;
 	}
 
-	err = register_dpio_irq_handlers(dpio_dev, desc.cpu);
-	if (err)
-		goto err_register_dpio_irq;
-
 	priv->io = dpaa2_io_create(&desc, dev);
 	if (!priv->io) {
 		dev_err(dev, "dpaa2_io_create failed\n");
@@ -244,6 +240,10 @@ static int dpaa2_dpio_probe(struct fsl_mc_device *dpio_dev)
 		goto err_dpaa2_io_create;
 	}
 
+	err = register_dpio_irq_handlers(dpio_dev, desc.cpu);
+	if (err)
+		goto err_register_dpio_irq;
+
 	dev_info(dev, "probed\n");
 	dev_dbg(dev, "   receives_notifications = %d\n",
 		desc.receives_notifications);
-- 
2.17.1