[PATCH 1/1] net: phy: dp83867: Disable IRQs on suspend

[Alexander Stein <alexander.stein@ew.tq-group.com>]

Before putting the PHY into IEEE power down mode, disable IRQs to
prevent accessing the PHY once MDIO has already been shutdown.

Signed-off-by: Alexander Stein <alexander.stein@ew.tq-group.com>
---
I get this backtrace when trying to put the system into 'mem' powersaving
state.

[   31.355468] ------------[ cut here ]------------
[   31.360089] WARNING: CPU: 1 PID: 77 at drivers/net/phy/phy.c:1183 phy_error+0x10/0x54
[   31.367932] Modules linked in: bluetooth 8021q garp stp mrp llc snd_soc_tlv320aic32x4_spi hantro_vpu snd_soc_fsl_
asoc_card snd_soc_fsl_sai snd_soc_imx_audmux snd_soc_fsl_utils snd_soc_tlv320aic32x4_i2c snd_soc_simple_card_utils i
mx_pcm_dma snd_soc_tlv320aic32x4 snd_soc_core v4l2_vp9 snd_pcm_dmaengine v4l2_h264 videobuf2_dma_contig v4l2_mem2mem
 videobuf2_memops videobuf2_v4l2 videobuf2_common snd_pcm crct10dif_ce governor_userspace snd_timer imx_bus snd cfg8
0211 soundcore pwm_imx27 imx_sdma virt_dma qoriq_thermal pwm_beeper fuse ipv6
[   31.372014] PM: suspend devices took 0.184 seconds
[   31.415246] CPU: 1 PID: 77 Comm: irq/39-0-0025 Not tainted 6.2.0-next-20230228+ #1425 2e0329a68388c493d090f81d406
77fb8aeac52cf
[   31.415257] Hardware name: TQ-Systems GmbH i.MX8MQ TQMa8MQ on MBa8Mx (DT)
[   31.415261] pstate: 60000005 (nZCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--)
[   31.445168] pc : phy_error+0x10/0x54
[   31.448749] lr : dp83867_handle_interrupt+0x78/0x88
[   31.453633] sp : ffff80000a353cb0
[   31.456947] x29: ffff80000a353cb0 x28: 0000000000000000 x27: 0000000000000000
[   31.464091] x26: 0000000000000000 x25: ffff800008dbb408 x24: ffff800009885568
[   31.471235] x23: ffff0000c0e4b860 x22: ffff0000c0e4b8dc x21: ffff0000c0a46d18
[   31.478380] x20: ffff8000098d18a8 x19: ffff0000c0a46800 x18: 0000000000000007
[   31.485525] x17: 6f63657320313030 x16: 2e30206465737061 x15: 6c65282064657465
[   31.492669] x14: 6c706d6f6320736b x13: 2973646e6f636573 x12: 0000000000000000
[   31.499815] x11: ffff800009362180 x10: 0000000000000a80 x9 : ffff80000a3537a0
[   31.506959] x8 : 0000000000000000 x7 : 0000000000000930 x6 : ffff0000c1494700
[   31.514104] x5 : 0000000000000000 x4 : 0000000000000000 x3 : ffff0000c0a3d480
[   31.521248] x2 : 0000000000000000 x1 : ffff0000c0f3d700 x0 : ffff0000c0a46800
[   31.528393] Call trace:
[   31.530840]  phy_error+0x10/0x54
[   31.534071]  dp83867_handle_interrupt+0x78/0x88
[   31.538605]  phy_interrupt+0x98/0xd8
[   31.542183]  handle_nested_irq+0xcc/0x148
[   31.546199]  pca953x_irq_handler+0xc8/0x154
[   31.550389]  irq_thread_fn+0x28/0xa0
[   31.553966]  irq_thread+0xcc/0x180
[   31.557371]  kthread+0xf4/0xf8
[   31.560429]  ret_from_fork+0x10/0x20
[   31.564009] ---[ end trace 0000000000000000 ]---

$ ./scripts/faddr2line build_arm64/vmlinux dp83867_handle_interrupt+0x78/0x88
dp83867_handle_interrupt+0x78/0x88:
dp83867_handle_interrupt at drivers/net/phy/dp83867.c:332

 drivers/net/phy/dp83867.c | 30 ++++++++++++++++++++++++++++--
 1 file changed, 28 insertions(+), 2 deletions(-)

diff --git a/drivers/net/phy/dp83867.c b/drivers/net/phy/dp83867.c
index 89cd821f1f46..ed7e3df7dfd1 100644
--- a/drivers/net/phy/dp83867.c
+++ b/drivers/net/phy/dp83867.c
@@ -693,6 +693,32 @@ static int dp83867_of_init(struct phy_device *phydev)
 }
 #endif /* CONFIG_OF_MDIO */
 
+static int dp83867_suspend(struct phy_device *phydev)
+{
+	/* Disable PHY Interrupts */
+	if (phy_interrupt_is_valid(phydev)) {
+		phydev->interrupts = PHY_INTERRUPT_DISABLED;
+		if (phydev->drv->config_intr)
+			phydev->drv->config_intr(phydev);
+	}
+
+	return genphy_suspend(phydev);
+}
+
+static int dp83867_resume(struct phy_device *phydev)
+{
+	genphy_resume(phydev);
+
+	/* Enable PHY Interrupts */
+	if (phy_interrupt_is_valid(phydev)) {
+		phydev->interrupts = PHY_INTERRUPT_ENABLED;
+		if (phydev->drv->config_intr)
+			phydev->drv->config_intr(phydev);
+	}
+
+	return 0;
+}
+
 static int dp83867_probe(struct phy_device *phydev)
 {
 	struct dp83867_private *dp83867;
@@ -968,8 +994,8 @@ static struct phy_driver dp83867_driver[] = {
 		.config_intr	= dp83867_config_intr,
 		.handle_interrupt = dp83867_handle_interrupt,
 
-		.suspend	= genphy_suspend,
-		.resume		= genphy_resume,
+		.suspend	= dp83867_suspend,
+		.resume		= dp83867_resume,
 
 		.link_change_notify = dp83867_link_change_notify,
 		.set_loopback	= dp83867_loopback,
-- 
2.34.1