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References: <20221220121231.20120-1-kvalo@kernel.org>
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From:   Robert Marko <robert.marko@sartura.hr>
Date:   Mon, 2 Jan 2023 16:42:55 +0100
Message-ID: <CA+HBbNGBKemtF9ZsFBFCe7_1eqMJ80QhEPCsinOJY2LQ4+tiFg@mail.gmail.com>
Subject: Re: [PATCH] ath11k: debugfs: fix to work with multiple PCI devices
To:     Kalle Valo <kvalo@kernel.org>
Cc:     ath11k@lists.infradead.org, linux-wireless@vger.kernel.org
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On Tue, Dec 20, 2022 at 1:16 PM Kalle Valo <kvalo@kernel.org> wrote:
>
> From: Kalle Valo <quic_kvalo@quicinc.com>
>
> ath11k fails to load if there are multiple ath11k PCI devices with same name:
>
>  ath11k_pci 0000:01:00.0: Hardware name qcn9074 hw1.0
>  debugfs: Directory 'ath11k' with parent '/' already present!
>  ath11k_pci 0000:01:00.0: failed to create ath11k debugfs
>  ath11k_pci 0000:01:00.0: failed to create soc core: -17
>  ath11k_pci 0000:01:00.0: failed to init core: -17
>  ath11k_pci: probe of 0000:01:00.0 failed with error -17
>
> Fix this by creating a directory for each ath11k device using schema
> <bus>-<devname>, for example "pci-0000:06:00.0". This directory created under
> the top-level ath11k directory, for example /sys/kernel/debug/ath11k.
>
> The reference to the toplevel ath11k directory is not stored anymore within ath11k, instead
> it's retrieved using debugfs_lookup(). If the directory does not exist it will
> be created. After the last directory from the ath11k directory is removed, for
> example when doing rmmod ath11k, the empty ath11k directory is left in place,
> it's a minor cosmetic issue anyway.
>
> Here's an example hierarchy with one WCN6855:
>
> ath11k
> `-- pci-0000:06:00.0
>     |-- mac0
>     |   |-- dfs_block_radar_events
>     |   |-- dfs_simulate_radar
>     |   |-- ext_rx_stats
>     |   |-- ext_tx_stats
>     |   |-- fw_dbglog_config
>     |   |-- fw_stats
>     |   |   |-- beacon_stats
>     |   |   |-- pdev_stats
>     |   |   `-- vdev_stats
>     |   |-- htt_stats
>     |   |-- htt_stats_reset
>     |   |-- htt_stats_type
>     |   `-- pktlog_filter
>     |-- simulate_fw_crash
>     `-- soc_dp_stats
>
> I didn't have a test setup where I could connect multiple ath11k devices to the
> same the host, so I have only tested this with one device.
>
> Tested-on: WCN6855 hw2.0 PCI WLAN.HSP.1.1-03125-QCAHSPSWPL_V1_V2_SILICONZ_LITE-3.6510.9


I can confirm that this works on a combination of IPQ8074 with an
external QCN9074 radio which
would previously clash and error out, so:

Tested-on: IPQ8074 hw2.0 AHB WLAN.HK.2.5.0.1-01208-QCAHKSWPL_SILICONZ-1
Tested-on: QCN9074 hw1.0 PCI WLAN.HK.2.5.0.1-01208-QCAHKSWPL_SILICONZ-1
Tested-by: Robert Marko <robert.marko@sartura.hr>

>
> Signed-off-by: Kalle Valo <quic_kvalo@quicinc.com>
> ---
>  drivers/net/wireless/ath/ath11k/core.h    |  1 -
>  drivers/net/wireless/ath/ath11k/debugfs.c | 48 +++++++++++++++++++----
>  2 files changed, 40 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/net/wireless/ath/ath11k/core.h b/drivers/net/wireless/ath/ath11k/core.h
> index a8acb8b7b8d5..beb552108ac3 100644
> --- a/drivers/net/wireless/ath/ath11k/core.h
> +++ b/drivers/net/wireless/ath/ath11k/core.h
> @@ -921,7 +921,6 @@ struct ath11k_base {
>         enum ath11k_dfs_region dfs_region;
>  #ifdef CONFIG_ATH11K_DEBUGFS
>         struct dentry *debugfs_soc;
> -       struct dentry *debugfs_ath11k;
>  #endif
>         struct ath11k_soc_dp_stats soc_stats;
>
> diff --git a/drivers/net/wireless/ath/ath11k/debugfs.c b/drivers/net/wireless/ath/ath11k/debugfs.c
> index ccdf3d5ba1ab..5bb6fd17fdf6 100644
> --- a/drivers/net/wireless/ath/ath11k/debugfs.c
> +++ b/drivers/net/wireless/ath/ath11k/debugfs.c
> @@ -976,10 +976,6 @@ int ath11k_debugfs_pdev_create(struct ath11k_base *ab)
>         if (test_bit(ATH11K_FLAG_REGISTERED, &ab->dev_flags))
>                 return 0;
>
> -       ab->debugfs_soc = debugfs_create_dir(ab->hw_params.name, ab->debugfs_ath11k);
> -       if (IS_ERR(ab->debugfs_soc))
> -               return PTR_ERR(ab->debugfs_soc);
> -
>         debugfs_create_file("simulate_fw_crash", 0600, ab->debugfs_soc, ab,
>                             &fops_simulate_fw_crash);
>
> @@ -1001,15 +997,51 @@ void ath11k_debugfs_pdev_destroy(struct ath11k_base *ab)
>
>  int ath11k_debugfs_soc_create(struct ath11k_base *ab)
>  {
> -       ab->debugfs_ath11k = debugfs_create_dir("ath11k", NULL);
> +       struct dentry *root;
> +       bool dput_needed;
> +       char name[64];
> +       int ret;
> +
> +       root = debugfs_lookup("ath11k", NULL);
> +       if (!root) {
> +               root = debugfs_create_dir("ath11k", NULL);
> +               if (IS_ERR_OR_NULL(root))
> +                       return PTR_ERR(root);
> +
> +               dput_needed = false;
> +       } else {
> +               /* a dentry from lookup() needs dput() after we don't use it */
> +               dput_needed = true;
> +       }
> +
> +       scnprintf(name, sizeof(name), "%s-%s", ath11k_bus_str(ab->hif.bus),
> +                 dev_name(ab->dev));
> +
> +       ab->debugfs_soc = debugfs_create_dir(name, root);
> +       if (IS_ERR_OR_NULL(ab->debugfs_soc)) {
> +               ret = PTR_ERR(ab->debugfs_soc);
> +               goto out;
> +       }
> +
> +       ret = 0;
>
> -       return PTR_ERR_OR_ZERO(ab->debugfs_ath11k);
> +out:
> +       if (dput_needed)
> +               dput(root);
> +
> +       return ret;
>  }
>
>  void ath11k_debugfs_soc_destroy(struct ath11k_base *ab)
>  {
> -       debugfs_remove_recursive(ab->debugfs_ath11k);
> -       ab->debugfs_ath11k = NULL;
> +       debugfs_remove_recursive(ab->debugfs_soc);
> +       ab->debugfs_soc = NULL;
> +
> +       /* We are not removing ath11k directory on purpose, even if it
> +        * would be empty. This simplifies the directory handling and it's
> +        * a minor cosmetic issue to leave an empty ath11k directory to
> +        * debugfs.
> +        */
>  }
>  EXPORT_SYMBOL(ath11k_debugfs_soc_destroy);
>
>
> base-commit: 922932ca02191a390f7f52fb6e21c44b50e14025
> --
> 2.30.2
>
>
> --
> ath11k mailing list
> ath11k@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/ath11k


-- 
Robert Marko
Staff Embedded Linux Engineer
Sartura Ltd.
Lendavska ulica 16a
10000 Zagreb, Croatia
Email: robert.marko@sartura.hr
Web: www.sartura.hr