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From:   Li Yang <leoyang.li@nxp.com>
Date:   Thu, 27 Sep 2018 15:37:44 -0500
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Subject: Re: [PATCH v2 06/22] soc/fsl/qman_portals: defer probe after qman's probe
To:     Laurentiu Tudor <laurentiu.tudor@nxp.com>
Cc:     "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" 
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        David Miller <davem@davemloft.net>,
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On Wed, Sep 26, 2018 at 8:26 AM <laurentiu.tudor@nxp.com> wrote:
>
> From: Laurentiu Tudor <laurentiu.tudor@nxp.com>
>
> Defer probe of qman portals after qman probing. This fixes the crash
> below, seen on NXP LS1043A SoCs:
>
> Unable to handle kernel NULL pointer dereference at virtual address
> 0000000000000004
> Mem abort info:
>   ESR = 0x96000004
>   Exception class = 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
> [0000000000000004] user address but active_mm is swapper
> Internal error: Oops: 96000004 [#1] PREEMPT SMP
> Modules linked in:
> CPU: 0 PID: 1 Comm: swapper/0 Not tainted
> 4.18.0-rc1-next-20180622-00200-g986f5c179185 #9
> Hardware name: LS1043A RDB Board (DT)
> pstate: 80000005 (Nzcv daif -PAN -UAO)
> pc : qman_set_sdest+0x74/0xa0
> lr : qman_portal_probe+0x22c/0x470
> sp : ffff00000803bbc0
> x29: ffff00000803bbc0 x28: 0000000000000000
> x27: ffff0000090c1b88 x26: ffff00000927cb68
> x25: ffff00000927c000 x24: ffff00000927cb60
> x23: 0000000000000000 x22: 0000000000000000
> x21: ffff0000090e9000 x20: ffff800073b5c810
> x19: ffff800027401298 x18: ffffffffffffffff
> x17: 0000000000000001 x16: 0000000000000000
> x15: ffff0000090e96c8 x14: ffff80002740138a
> x13: ffff0000090f2000 x12: 0000000000000030
> x11: ffff000008f25000 x10: 0000000000000000
> x9 : ffff80007bdfd2c0 x8 : 0000000000004000
> x7 : ffff80007393cc18 x6 : 0040000000000001
> x5 : 0000000000000000 x4 : ffffffffffffffff
> x3 : 0000000000000004 x2 : ffff00000927c900
> x1 : 0000000000000000 x0 : 0000000000000004
> Process swapper/0 (pid: 1, stack limit = 0x(____ptrval____))
> Call trace:
>  qman_set_sdest+0x74/0xa0
>  platform_drv_probe+0x50/0xa8
>  driver_probe_device+0x214/0x2f8
>  __driver_attach+0xd8/0xe0
>  bus_for_each_dev+0x68/0xc8
>  driver_attach+0x20/0x28
>  bus_add_driver+0x108/0x228
>  driver_register+0x60/0x110
>  __platform_driver_register+0x40/0x48
>  qman_portal_driver_init+0x20/0x84
>  do_one_initcall+0x58/0x168
>  kernel_init_freeable+0x184/0x22c
>  kernel_init+0x10/0x108
>  ret_from_fork+0x10/0x18
> Code: f9400443 11001000 927e4800 8b000063 (b9400063)
> ---[ end trace 4f6d50489ecfb930 ]---
> Kernel panic - not syncing: Attempted to kill init! exitcode=0x0000000b
>
> Signed-off-by: Laurentiu Tudor <laurentiu.tudor@nxp.com>

As this is part of a bug fix for v4.19, applied on soc/fsl for fix.

> ---
>  drivers/soc/fsl/qbman/qman_portal.c | 8 ++++++++
>  1 file changed, 8 insertions(+)
>
> diff --git a/drivers/soc/fsl/qbman/qman_portal.c b/drivers/soc/fsl/qbman/qman_portal.c
> index 6d9da3b1b5ad..eef93cab84f1 100644
> --- a/drivers/soc/fsl/qbman/qman_portal.c
> +++ b/drivers/soc/fsl/qbman/qman_portal.c
> @@ -229,6 +229,14 @@ static int qman_portal_probe(struct platform_device *pdev)
>         int irq, cpu, err;
>         u32 val;
>
> +       err = qman_is_probed();
> +       if (!err)
> +               return -EPROBE_DEFER;
> +       if (err < 0) {
> +               dev_err(&pdev->dev, "failing probe due to qman probe error\n");
> +               return -ENODEV;
> +       }
> +
>         pcfg = devm_kmalloc(dev, sizeof(*pcfg), GFP_KERNEL);
>         if (!pcfg)
>                 return -ENOMEM;
> --
> 2.17.1
>