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Date:   Wed, 26 Jan 2022 14:51:05 -0600
From:   Bjorn Helgaas <helgaas@kernel.org>
To:     Christian Gmeiner <christian.gmeiner@gmail.com>
Cc:     linux-kernel@vger.kernel.org,
        Kishon Vijay Abraham I <kishon@ti.com>,
        Tom Joseph <tjoseph@cadence.com>,
        Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>,
        Rob Herring <robh@kernel.org>,
        Krzysztof =?utf-8?Q?Wilczy=C5=84ski?= <kw@linux.com>,
        Bjorn Helgaas <bhelgaas@google.com>,
        linux-omap@vger.kernel.org, linux-pci@vger.kernel.org,
        linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH] Revert "PCI: j721e: Drop redundant struct device *"
Message-ID: <20220126205105.GA47875@bhelgaas>
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In-Reply-To: <20220124122132.435743-1-christian.gmeiner@gmail.com>
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On Mon, Jan 24, 2022 at 01:21:22PM +0100, Christian Gmeiner wrote:
> This reverts commit 19e863828acf6d8ac8475ba1fd93c0fe17fdc4ef.
> 
> Fixes the following oops:
>  Unable to handle kernel NULL pointer dereference at virtual address 0000000000000010

My fault, sorry for breaking this.  Thanks a lot for the report!

19e863828acf ("PCI: j721e: Drop redundant struct device *") failed to
consider the uses of pcie->cdns_pcie->dev before pcie->cdns_pcie is
initialized.  I'll figure out what to do about it.

>  Internal error: Oops: 96000004 [#1] PREEMPT SMP
>  Modules linked in:
>  CPU: 1 PID: 7 Comm: kworker/u4:0 Not tainted 5.17.0-rc1-00086-ge38b27816fea-dirty #71
>  Hardware name: CPE0108 (DT)
>  Workqueue: events_unbound deferred_probe_work_func
>  pstate: 20000005 (nzCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--)
>  pc : j721e_pcie_probe+0x184/0x600
>  lr : j721e_pcie_probe+0x170/0x600
>  sp : ffff80000957bae0
>  x29: ffff80000957bae0 x28: ffff800009357000 x27: ffff00000000c078
>  x26: ffff00003fe047a8 x25: 0000000000000000 x24: ffff0000000f5280
>  x23: ffff800008c98f78 x22: ffff800008f90ff0 x21: ffff000000231410
>  x20: ffff000002ef2780 x19: 0000000000000021 x18: 0000000000000001
>  x17: 0000000000000000 x16: 0000000000058c00 x15: ffffffffffffffff
>  x14: ffffffffffffffff x13: 0000000000000010 x12: 0101010101010101
>  x11: 0000000000000040 x10: ffff8000093e06c8 x9 : ffff8000093e06c0
>  x8 : ffff000000400270 x7 : 0000000000000000 x6 : ffff000000231590
>  x5 : ffff80000957b9e0 x4 : 0000000000000000 x3 : ffff0000002314f4
>  x2 : 0000000000000000 x1 : ffff0000000f5280 x0 : 0000000000000000
>  Call trace:
>   j721e_pcie_probe+0x184/0x600
>   platform_probe+0x68/0xe0
>   really_probe+0x144/0x320
>   __driver_probe_device+0xc4/0xe0
>   driver_probe_device+0x7c/0x110
>   __device_attach_driver+0x90/0xe0
>   bus_for_each_drv+0x78/0xd0
>   __device_attach+0xf0/0x150
>   device_initial_probe+0x14/0x20
>   bus_probe_device+0x9c/0xb0
>   deferred_probe_work_func+0x88/0xc0
>   process_one_work+0x1bc/0x340
>   worker_thread+0x1f8/0x420
>   kthread+0x110/0x120
>   ret_from_fork+0x10/0x20
>  Code: f9400280 a90573fb d0005396 913fc2d6 (f9400800)
> 
> Fixes: 19e863828acf ("PCI: j721e: Drop redundant struct device *")
> Signed-off-by: Christian Gmeiner <christian.gmeiner@gmail.com>
> ---
>  drivers/pci/controller/cadence/pci-j721e.c | 14 ++++++++------
>  1 file changed, 8 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/pci/controller/cadence/pci-j721e.c b/drivers/pci/controller/cadence/pci-j721e.c
> index 489586a4cdc7..cd43d1898482 100644
> --- a/drivers/pci/controller/cadence/pci-j721e.c
> +++ b/drivers/pci/controller/cadence/pci-j721e.c
> @@ -51,10 +51,11 @@ enum link_status {
>  #define MAX_LANES			2
>  
>  struct j721e_pcie {
> -	struct cdns_pcie	*cdns_pcie;
> +	struct device		*dev;
>  	struct clk		*refclk;
>  	u32			mode;
>  	u32			num_lanes;
> +	struct cdns_pcie	*cdns_pcie;
>  	void __iomem		*user_cfg_base;
>  	void __iomem		*intd_cfg_base;
>  	u32			linkdown_irq_regfield;
> @@ -98,7 +99,7 @@ static inline void j721e_pcie_intd_writel(struct j721e_pcie *pcie, u32 offset,
>  static irqreturn_t j721e_pcie_link_irq_handler(int irq, void *priv)
>  {
>  	struct j721e_pcie *pcie = priv;
> -	struct device *dev = pcie->cdns_pcie->dev;
> +	struct device *dev = pcie->dev;
>  	u32 reg;
>  
>  	reg = j721e_pcie_intd_readl(pcie, STATUS_REG_SYS_2);
> @@ -164,7 +165,7 @@ static const struct cdns_pcie_ops j721e_pcie_ops = {
>  static int j721e_pcie_set_mode(struct j721e_pcie *pcie, struct regmap *syscon,
>  			       unsigned int offset)
>  {
> -	struct device *dev = pcie->cdns_pcie->dev;
> +	struct device *dev = pcie->dev;
>  	u32 mask = J721E_MODE_RC;
>  	u32 mode = pcie->mode;
>  	u32 val = 0;
> @@ -183,7 +184,7 @@ static int j721e_pcie_set_mode(struct j721e_pcie *pcie, struct regmap *syscon,
>  static int j721e_pcie_set_link_speed(struct j721e_pcie *pcie,
>  				     struct regmap *syscon, unsigned int offset)
>  {
> -	struct device *dev = pcie->cdns_pcie->dev;
> +	struct device *dev = pcie->dev;
>  	struct device_node *np = dev->of_node;
>  	int link_speed;
>  	u32 val = 0;
> @@ -204,7 +205,7 @@ static int j721e_pcie_set_link_speed(struct j721e_pcie *pcie,
>  static int j721e_pcie_set_lane_count(struct j721e_pcie *pcie,
>  				     struct regmap *syscon, unsigned int offset)
>  {
> -	struct device *dev = pcie->cdns_pcie->dev;
> +	struct device *dev = pcie->dev;
>  	u32 lanes = pcie->num_lanes;
>  	u32 val = 0;
>  	int ret;
> @@ -219,7 +220,7 @@ static int j721e_pcie_set_lane_count(struct j721e_pcie *pcie,
>  
>  static int j721e_pcie_ctrl_init(struct j721e_pcie *pcie)
>  {
> -	struct device *dev = pcie->cdns_pcie->dev;
> +	struct device *dev = pcie->dev;
>  	struct device_node *node = dev->of_node;
>  	struct of_phandle_args args;
>  	unsigned int offset = 0;
> @@ -376,6 +377,7 @@ static int j721e_pcie_probe(struct platform_device *pdev)
>  	if (!pcie)
>  		return -ENOMEM;
>  
> +	pcie->dev = dev;
>  	pcie->mode = mode;
>  	pcie->linkdown_irq_regfield = data->linkdown_irq_regfield;
>  
> -- 
> 2.34.1
> 
> 
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