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Message-ID: <7f7fb71a-6d15-46f1-b63c-b569a2e230b7@baylibre.com>
Date: Thu, 18 Apr 2024 16:03:15 +0200
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Subject: Re: [PATCH net-next v9 0/3] Add minimal XDP support to TI AM65 CPSW
 Ethernet driver
To: Siddharth Vadapalli <s-vadapalli@ti.com>
Cc: "David S. Miller" <davem@davemloft.net>,
 Eric Dumazet <edumazet@google.com>, Jakub Kicinski <kuba@kernel.org>,
 Paolo Abeni <pabeni@redhat.com>, Russell King <linux@armlinux.org.uk>,
 Alexei Starovoitov <ast@kernel.org>, Daniel Borkmann <daniel@iogearbox.net>,
 Jesper Dangaard Brouer <hawk@kernel.org>,
 John Fastabend <john.fastabend@gmail.com>,
 Sumit Semwal <sumit.semwal@linaro.org>,
 =?UTF-8?Q?Christian_K=C3=B6nig?= <christian.koenig@amd.com>,
 Simon Horman <horms@kernel.org>, Andrew Lunn <andrew@lunn.ch>,
 Ratheesh Kannoth <rkannoth@marvell.com>,
 Naveen Mamindlapalli <naveenm@marvell.com>,
 Jacob Keller <jacob.e.keller@intel.com>, danishanwar@ti.com,
 yuehaibing@huawei.com, rogerq@kernel.org, netdev@vger.kernel.org,
 linux-kernel@vger.kernel.org, bpf@vger.kernel.org,
 linux-media@vger.kernel.org, dri-devel@lists.freedesktop.org,
 linaro-mm-sig@lists.linaro.org
References: <20240223-am65-cpsw-xdp-basic-v9-0-2c194217e325@baylibre.com>
 <260d258f-87a1-4aac-8883-aab4746b32d8@ti.com>
 <08319f88-36a9-445a-9920-ad1fba666b6a@baylibre.com>
 <1da48c7e-ba87-4f7a-b6d1-d35961005ab0@ti.com>
Content-Language: en-US
From: Julien Panis <jpanis@baylibre.com>
In-Reply-To: <1da48c7e-ba87-4f7a-b6d1-d35961005ab0@ti.com>
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On 4/18/24 13:25, Siddharth Vadapalli wrote:
> On Thu, Apr 18, 2024 at 01:17:47PM +0200, Julien Panis wrote:
>> On 4/18/24 13:00, Siddharth Vadapalli wrote:
>>> On 12-04-2024 21:08, Julien Panis wrote:
>>>> This patch adds XDP support to TI AM65 CPSW Ethernet driver.
>>>>
>>>> The following features are implemented: NETDEV_XDP_ACT_BASIC,
>>>> NETDEV_XDP_ACT_REDIRECT, and NETDEV_XDP_ACT_NDO_XMIT.
>>>>
>>>> Zero-copy and non-linear XDP buffer supports are NOT implemented.
>>>>
>>>> Besides, the page pool memory model is used to get better performance.
>>>>
>>>> Signed-off-by: Julien Panis <jpanis@baylibre.com>
>>> Hello Julien,
>>>
>>> This series crashes Linux on AM62ax SoC which also uses the
>>> AM65-CPSW-NUSS driver:
>>> https://gist.github.com/Siddharth-Vadapalli-at-TI/5ed0e436606001c247a7da664f75edee
>>>
>>> Regards,
>>> Siddharth.
>> Hello Siddharth.
>>
>> Thanks for the log. I can read:
>> [    1.966094] Missing net_device from driver
>>
>> Did you check that nodes exist in the device tree for the net devices ?
> Yes it exists. The device-tree used was also built with linux-next
> tagged next-20240417. The node corresponding to eth0 is cpsw_port1 which
> is present and enabled in the device-tree:
> https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/tree/arch/arm64/boot/dts/ti/k3-am62a7-sk.dts?h=next-20240417#n644
>
> Regards,
> Siddharth.

I could reproduce the bug by disabling 'cpsw_port2' in my device tree,
which is 'k3-am625-sk.dts' for the board I use.

A condition is missing in am65_cpsw_create_xdp_rxqs() and
am65_cpsw_destroy_xdp_rxqs() functions.

For these 2 functions, the code which is in the for loop should be
run only when port ethX is enabled. That's why it crashes with
your device tree (cpsw_port2 is disabled, which is not the case by
default for the board I developed with).

I'll send a patch to fix the issue. Thanks for reporting it.

Julien