linux-kernel - Re: [PATCH net-next v2 1/9] octeon_ep: defer probe if firmware not ready

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Date:   Wed, 30 Nov 2022 11:24:43 +0200
From:   Leon Romanovsky <leon@...nel.org>
To:     Veerasenareddy Burru <vburru@...vell.com>
Cc:     netdev@...r.kernel.org, linux-kernel@...r.kernel.org,
        lironh@...vell.com, aayarekar@...vell.com, sedara@...vell.com,
        sburla@...vell.com, linux-doc@...r.kernel.org,
        "David S. Miller" <davem@...emloft.net>,
        Eric Dumazet <edumazet@...gle.com>,
        Jakub Kicinski <kuba@...nel.org>,
        Paolo Abeni <pabeni@...hat.com>
Subject: Re: [PATCH net-next v2 1/9] octeon_ep: defer probe if firmware not
 ready

On Tue, Nov 29, 2022 at 05:09:24AM -0800, Veerasenareddy Burru wrote:
> Defer probe if firmware is not ready for device usage.
> 
> Signed-off-by: Veerasenareddy Burru <vburru@...vell.com>
> Signed-off-by: Abhijit Ayarekar <aayarekar@...vell.com>
> Signed-off-by: Satananda Burla <sburla@...vell.com>
> ---
> v1 -> v2:
>  * was scheduling workqueue task to wait for firmware ready,
>    to probe/initialize the device.
>  * now, removed the workqueue task; the probe returns EPROBE_DEFER,
>    if firmware is not ready.
>  * removed device status oct->status, as it is not required with the
>    modified implementation.
> 
>  .../ethernet/marvell/octeon_ep/octep_main.c   | 26 +++++++++++++++++++
>  1 file changed, 26 insertions(+)
> 
> diff --git a/drivers/net/ethernet/marvell/octeon_ep/octep_main.c b/drivers/net/ethernet/marvell/octeon_ep/octep_main.c
> index 5a898fb88e37..aa7d0ced9807 100644
> --- a/drivers/net/ethernet/marvell/octeon_ep/octep_main.c
> +++ b/drivers/net/ethernet/marvell/octeon_ep/octep_main.c
> @@ -1017,6 +1017,25 @@ static void octep_device_cleanup(struct octep_device *oct)
>  	oct->conf = NULL;
>  }
>  
> +static u8 get_fw_ready_status(struct pci_dev *pdev)

Please change this function to return bool, you are not interested in
status.

> +{
> +	u32 pos = 0;
> +	u16 vsec_id;
> +	u8 status;
> +
> +	while ((pos = pci_find_next_ext_capability(pdev, pos,
> +						   PCI_EXT_CAP_ID_VNDR))) {
> +		pci_read_config_word(pdev, pos + 4, &vsec_id);
> +#define FW_STATUS_VSEC_ID  0xA3
> +		if (vsec_id == FW_STATUS_VSEC_ID) {

Success oriented flow, plase
if (vsec_id != FW_STATUS_VSEC_ID)
 cotitnue;

....

> +			pci_read_config_byte(pdev, (pos + 8), &status);
> +			dev_info(&pdev->dev, "Firmware ready %u\n", status);
> +			return status;
> +		}
> +	}
> +	return 0;
> +}
> +
>  /**
>   * octep_probe() - Octeon PCI device probe handler.
>   *
> @@ -1053,6 +1072,13 @@ static int octep_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
>  	pci_enable_pcie_error_reporting(pdev);
>  	pci_set_master(pdev);
>  
> +#define FW_STATUS_READY    1
> +	if (get_fw_ready_status(pdev) != FW_STATUS_READY) {

No need to this new define if you change get_fw_ready_status() to return
true/false.

And I think that you can put this check earlier in octep_probe().

Thanks

> +		dev_notice(&pdev->dev, "Firmware not ready; defer probe.\n");
> +		err = -EPROBE_DEFER;
> +		goto err_alloc_netdev;
> +	}
> +
>  	netdev = alloc_etherdev_mq(sizeof(struct octep_device),
>  				   OCTEP_MAX_QUEUES);
>  	if (!netdev) {
> -- 
> 2.36.0
>