net: fec: fix rcv is not last issue when do suspend/resume test

commit 61615cd2 upstream.

When do suspend/resume stress test, some log shows "rcv is not +last".
The issue is that enet suspend will disable phy clock, phy link down,
after resume back, enet MAC redo initial and ready to tx/rx packet,
but phy still is not ready which is doing auto-negotiation. When phy
link is not up, don't schdule napi soft irq.

[Peter]
It has fixed kernel panic after long time suspend/resume test
with nfs rootfs.

[ 8864.429458] fec 2188000.ethernet eth0: rcv is not +last
[ 8864.434799] fec 2188000.ethernet eth0: rcv is not +last
[ 8864.440088] fec 2188000.ethernet eth0: rcv is not +last
[ 8864.445424] fec 2188000.ethernet eth0: rcv is not +last
[ 8864.450782] fec 2188000.ethernet eth0: rcv is not +last
[ 8864.456111] Unable to handle kernel NULL pointer dereference at virtual address 00000000
[ 8864.464225] pgd = 80004000
[ 8864.466997] [00000000] *pgd=00000000
[ 8864.470627] Internal error: Oops: 17 [#1] SMP ARM
[ 8864.475353] Modules linked in: evbug
[ 8864.479006] CPU: 0 PID: 3 Comm: ksoftirqd/0 Not tainted 4.0.0-rc1-00044-g7a2a1d2 #234
[ 8864.486854] Hardware name: Freescale i.MX6 SoloX (Device Tree)
[ 8864.492709] task: be069380 ti: be07a000 task.ti: be07a000
[ 8864.498137] PC is at memcpy+0x80/0x330
[ 8864.501919] LR is at gro_pull_from_frag0+0x34/0xa8
[ 8864.506735] pc : [<802bb080>]    lr : [<8057c204>]    psr: 00000113
[ 8864.506735] sp : be07bbd4  ip : 00000010  fp : be07bc0c
[ 8864.518235] r10: 0000000e  r9 : 00000000  r8 : 809c7754
[ 8864.523479] r7 : 809c7754  r6 : bb43c040  r5 : bd280cc0  r4 : 00000012
[ 8864.530025] r3 : 00000804  r2 : fffffff2  r1 : 00000000  r0 : bb43b83c
[ 8864.536575] Flags: nzcv  IRQs on  FIQs on  Mode SVC_32  ISA ARM  Segment kernel
[ 8864.543904] Control: 10c5387d  Table: bd14c04a  DAC: 00000015
[ 8864.549669] Process ksoftirqd/0 (pid: 3, stack limit = 0xbe07a210)
[ 8864.555869] Stack: (0xbe07bbd4 to 0xbe07c000)
[ 8864.560250] bbc0:                                              bd280cc0 bb43c040 809c7754
[ 8864.568455] bbe0: 809c7754 bb43b83c 00000012 8057c204 00000000 bd280cc0 bd8a0718 00000003
[ 8864.576658] bc00: be07bc5c be07bc10 8057ebf0 8057c1dc 00000000 00000000 8057ecc4 bef59760
[ 8864.584863] bc20: 00000002 bd8a0000 be07bc64 809c7754 00000000 bd8a0718 bd280cc0 bd8a0000
[ 8864.593066] bc40: 00000000 0000001c 00000000 bd8a0000 be07bc74 be07bc60 8057f148 8057eb90
[ 8864.601268] bc60: bf0810a0 00000000 be07bcf4 be07bc78 8044e7b4 8057f12c 00000000 8007df6c
[ 8864.609470] bc80: bd8a0718 00000040 00000000 bd280a80 00000002 00000019 bd8a0600 bd8a1214
[ 8864.617672] bca0: bd8a0690 bf0810a0 00000000 00000000 bd8a1000 00000000 00000027 bd280cc0
[ 8864.625874] bcc0: 80062708 800625cc 000943db bd8a0718 00000001 000d1166 00000040 be7c1ec0
[ 8864.634077] bce0: 0000012c be07bd00 be07bd3c be07bcf8 8057fc98 8044e3ac 809c2ec0 3ddff000
[ 8864.642280] bd00: be07bd00 be07bd00 be07bd08 be07bd08 00000000 00000020 809c608c 00000003
[ 8864.650481] bd20: 809c6080 40000001 809c6088 00200100 be07bd84 be07bd40 8002e690 8057fac8
[ 8864.658684] bd40: be07bd64 be07bd50 00000001 04208040 000d1165 0000000a be07bd84 809c0d7c
[ 8864.666885] bd60: 00000000 809c6af8 00000000 00000001 be008000 00000000 be07bd9c be07bd88
[ 8864.675087] bd80: 8002eb64 8002e564 00000125 809c0d7c be07bdc4 be07bda0 8006f100 8002eaac
[ 8864.683291] bda0: c080e10c be07bde8 809c6c6c c080e100 00000002 00000000 be07bde4 be07bdc8
[ 8864.691492] bdc0: 800087a0 8006f098 806f2934 20000013 ffffffff be07be1c be07be44 be07bde8
[ 8864.699695] bde0: 800133a4 80008784 00000001 00000001 00000000 00000000 be7c1680 00000000
[ 8864.707896] be00: be0cfe00 bd93eb40 00000002 00000000 00000000 be07be44 be07be00 be07be30
[ 8864.716098] be20: 8006278c 806f2934 20000013 ffffffff be069380 be7c1680 be07be7c be07be48
[ 8864.724300] be40: 80049cfc 806f2910 00000001 00000000 80049cb4 00000000 be07be7c be7c1680
[ 8864.732502] be60: be3289c0 be069380 bd23b600 be0cfe00 be07bebc be07be80 806ed614 80049c68
[ 8864.740706] be80: be07a000 0000020a 809c608c 00000003 00000001 8002e858 be07a000 be035740
[ 8864.748907] bea0: 00000000 00000001 809d4598 00000000 be07bed4 be07bec0 806edd0c 806ed440
[ 8864.757110] bec0: be07a000 be07a000 be07bee4 be07bed8 806edd68 806edcf0 be07bef4 be07bee8
[ 8864.765311] bee0: 8002e860 806edd34 be07bf24 be07bef8 800494b0 8002e828 be069380 00000000
[ 8864.773512] bf00: be035780 be035740 8004938c 00000000 00000000 00000000 be07bfac be07bf28
[ 8864.781715] bf20: 80045928 80049398 be07bf44 00000001 00000000 be035740 00000000 00030003
[ 8864.789917] bf40: dead4ead ffffffff ffffffff 80a2716c 80b59b00 00000000 8088c954 be07bf5c
[ 8864.798120] bf60: be07bf5c 00000000 00000000 dead4ead ffffffff ffffffff 80a2716c 00000000
[ 8864.806320] bf80: 00000000 8088c954 be07bf88 be07bf88 be035780 8004584c 00000000 00000000
[ 8864.814523] bfa0: 00000000 be07bfb0 8000ed10 80045858 00000000 00000000 00000000 00000000
[ 8864.822723] bfc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
[ 8864.830925] bfe0: 00000000 00000000 00000000 00000000 00000013 00000000 5ffbb5f7 f9fcf5e7
[ 8864.839115] Backtrace:
[ 8864.841631] [<8057c1d0>] (gro_pull_from_frag0) from [<8057ebf0>] (dev_gro_receive+0x6c/0x3f8)
[ 8864.850173]  r6:00000003 r5:bd8a0718 r4:bd280cc0 r3:00000000
[ 8864.855958] [<8057eb84>] (dev_gro_receive) from [<8057f148>] (napi_gro_receive+0x28/0xac)
[ 8864.864152]  r10:bd8a0000 r9:00000000 r8:0000001c r7:00000000 r6:bd8a0000 r5:bd280cc0
[ 8864.872115]  r4:bd8a0718
[ 8864.874713] [<8057f120>] (napi_gro_receive) from [<8044e7b4>] (fec_enet_rx_napi+0x414/0xc74)
[ 8864.883167]  r5:00000000 r4:bf0810a0
[ 8864.886823] [<8044e3a0>] (fec_enet_rx_napi) from [<8057fc98>] (net_rx_action+0x1dc/0x2ec)
[ 8864.895016]  r10:be07bd00 r9:0000012c r8:be7c1ec0 r7:00000040 r6:000d1166 r5:00000001
[ 8864.902982]  r4:bd8a0718
[ 8864.905570] [<8057fabc>] (net_rx_action) from [<8002e690>] (__do_softirq+0x138/0x2c4)
[ 8864.913417]  r10:00200100 r9:809c6088 r8:40000001 r7:809c6080 r6:00000003 r5:809c608c
[ 8864.921382]  r4:00000020
[ 8864.923966] [<8002e558>] (__do_softirq) from [<8002eb64>] (irq_exit+0xc4/0x138)
[ 8864.931289]  r10:00000000 r9:be008000 r8:00000001 r7:00000000 r6:809c6af8 r5:00000000
[ 8864.939252]  r4:809c0d7c
[ 8864.941841] [<8002eaa0>] (irq_exit) from [<8006f100>] (__handle_domain_irq+0x74/0xe8)
[ 8864.949688]  r4:809c0d7c r3:00000125
[ 8864.953342] [<8006f08c>] (__handle_domain_irq) from [<800087a0>] (gic_handle_irq+0x28/0x68)
[ 8864.961707]  r9:00000000 r8:00000002 r7:c080e100 r6:809c6c6c r5:be07bde8 r4:c080e10c
[ 8864.969597] [<80008778>] (gic_handle_irq) from [<800133a4>] (__irq_svc+0x44/0x5c)
[ 8864.977097] Exception stack(0xbe07bde8 to 0xbe07be30)
[ 8864.982173] bde0:                   00000001 00000001 00000000 00000000 be7c1680 00000000
[ 8864.990377] be00: be0cfe00 bd93eb40 00000002 00000000 00000000 be07be44 be07be00 be07be30
[ 8864.998573] be20: 8006278c 806f2934 20000013 ffffffff
[ 8865.003638]  r7:be07be1c r6:ffffffff r5:20000013 r4:806f2934
[ 8865.009447] [<806f2904>] (_raw_spin_unlock_irq) from [<80049cfc>] (finish_task_switch+0xa0/0x160)
[ 8865.018334]  r4:be7c1680 r3:be069380
[ 8865.021993] [<80049c5c>] (finish_task_switch) from [<806ed614>] (__schedule+0x1e0/0x5dc)
[ 8865.030098]  r8:be0cfe00 r7:bd23b600 r6:be069380 r5:be3289c0 r4:be7c1680
[ 8865.036942] [<806ed434>] (__schedule) from [<806edd0c>] (preempt_schedule_common+0x28/0x44)
[ 8865.045307]  r9:00000000 r8:809d4598 r7:00000001 r6:00000000 r5:be035740 r4:be07a000
[ 8865.053197] [<806edce4>] (preempt_schedule_common) from [<806edd68>] (_cond_resched+0x40/0x48)
[ 8865.061822]  r4:be07a000 r3:be07a000
[ 8865.065472] [<806edd28>] (_cond_resched) from [<8002e860>] (run_ksoftirqd+0x44/0x64)
[ 8865.073252] [<8002e81c>] (run_ksoftirqd) from [<800494b0>] (smpboot_thread_fn+0x124/0x190)
[ 8865.081550] [<8004938c>] (smpboot_thread_fn) from [<80045928>] (kthread+0xdc/0xf8)
[ 8865.089133]  r10:00000000 r9:00000000 r8:00000000 r7:8004938c r6:be035740 r5:be035780
[ 8865.097097]  r4:00000000 r3:be069380
[ 8865.100752] [<8004584c>] (kthread) from [<8000ed10>] (ret_from_fork+0x14/0x24)
[ 8865.107990]  r7:00000000 r6:00000000 r5:8004584c r4:be035780
[ 8865.113767] Code: e320f000 e4913004 e4914004 e4915004 (e4916004)
[ 8865.120006] ---[ end trace b0a4c6bd499288ca ]---
[ 8865.124697] Kernel panic - not syncing: Fatal exception in interrupt
[ 8865.131084] ---[ end Kernel panic - not syncing: Fatal exception in interrupt
Tested-by: Peter Chen <peter.chen@freescale.com>
Signed-off-by: Peter Chen <peter.chen@freescale.com>
Signed-off-by: Fugang Duan <B38611@freescale.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/net/ethernet/freescale/fec_main.c

@@ -1565,7 +1565,7 @@ fec_enet_interrupt(int irq, void *dev_id)
 	writel(int_events, fep->hwp + FEC_IEVENT);
 	fec_enet_collect_events(fep, int_events);
 
-	if (fep->work_tx || fep->work_rx) {
+	if ((fep->work_tx || fep->work_rx) && fep->link) {
 		ret = IRQ_HANDLED;
 
 		if (napi_schedule_prep(&fep->napi)) {