Subject: Re: [PATCH RESEND] net: sfp: add debugfs support

From: Russell King - ARM Linux admin <[email-masked]>
Date: Sun, 10 Jan 2021 10:59:06 +0000

Hi,

This should've had net-next in the subject line! I'll re-send.

On Sun, Jan 10, 2021 at 10:57:23AM +0000, Russell King wrote:
> Add debugfs support to SFP so that the internal state of the SFP state
> machines and hardware signal state can be viewed from userspace, rather
> than having to compile a debug kernel to view state state transitions
> in the kernel log.  The 'state' output looks like:
> 
> Module state: empty
> Module probe attempts: 0 0
> Device state: up
> Main state: down
> Fault recovery remaining retries: 5
> PHY probe remaining retries: 12
> moddef0: 0
> rx_los: 1
> tx_fault: 1
> tx_disable: 1
> 
> Reviewed-by: Andrew Lunn <[email-masked]>
> Signed-off-by: Russell King <[email-masked]>
> ---
>  drivers/net/phy/sfp.c | 55 +++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 55 insertions(+)
> 
> diff --git a/drivers/net/phy/sfp.c b/drivers/net/phy/sfp.c
> index 91d74c1a920a..374351de2063 100644
> --- a/drivers/net/phy/sfp.c
> +++ b/drivers/net/phy/sfp.c
> @@ -1,6 +1,7 @@
>  // SPDX-License-Identifier: GPL-2.0
>  #include <linux/acpi.h>
>  #include <linux/ctype.h>
> +#include <linux/debugfs.h>
>  #include <linux/delay.h>
>  #include <linux/gpio/consumer.h>
>  #include <linux/hwmon.h>
> @@ -258,6 +259,9 @@ struct sfp {
>  	char *hwmon_name;
>  #endif
>  
> +#if IS_ENABLED(CONFIG_DEBUG_FS)
> +	struct dentry *debugfs_dir;
> +#endif
>  };
>  
>  static bool sff_module_supported(const struct sfp_eeprom_id *id)
> @@ -1390,6 +1394,54 @@ static void sfp_module_tx_enable(struct sfp *sfp)
>  	sfp_set_state(sfp, sfp->state);
>  }
>  
> +#if IS_ENABLED(CONFIG_DEBUG_FS)
> +static int sfp_debug_state_show(struct seq_file *s, void *data)
> +{
> +	struct sfp *sfp = s->private;
> +
> +	seq_printf(s, "Module state: %s\n",
> +		   mod_state_to_str(sfp->sm_mod_state));
> +	seq_printf(s, "Module probe attempts: %d %d\n",
> +		   R_PROBE_RETRY_INIT - sfp->sm_mod_tries_init,
> +		   R_PROBE_RETRY_SLOW - sfp->sm_mod_tries);
> +	seq_printf(s, "Device state: %s\n",
> +		   dev_state_to_str(sfp->sm_dev_state));
> +	seq_printf(s, "Main state: %s\n",
> +		   sm_state_to_str(sfp->sm_state));
> +	seq_printf(s, "Fault recovery remaining retries: %d\n",
> +		   sfp->sm_fault_retries);
> +	seq_printf(s, "PHY probe remaining retries: %d\n",
> +		   sfp->sm_phy_retries);
> +	seq_printf(s, "moddef0: %d\n", !!(sfp->state & SFP_F_PRESENT));
> +	seq_printf(s, "rx_los: %d\n", !!(sfp->state & SFP_F_LOS));
> +	seq_printf(s, "tx_fault: %d\n", !!(sfp->state & SFP_F_TX_FAULT));
> +	seq_printf(s, "tx_disable: %d\n", !!(sfp->state & SFP_F_TX_DISABLE));
> +	return 0;
> +}
> +DEFINE_SHOW_ATTRIBUTE(sfp_debug_state);
> +
> +static void sfp_debugfs_init(struct sfp *sfp)
> +{
> +	sfp->debugfs_dir = debugfs_create_dir(dev_name(sfp->dev), NULL);
> +
> +	debugfs_create_file("state", 0600, sfp->debugfs_dir, sfp,
> +			    &sfp_debug_state_fops);
> +}
> +
> +static void sfp_debugfs_exit(struct sfp *sfp)
> +{
> +	debugfs_remove_recursive(sfp->debugfs_dir);
> +}
> +#else
> +static void sfp_debugfs_init(struct sfp *sfp)
> +{
> +}
> +
> +static void sfp_debugfs_exit(struct sfp *sfp)
> +{
> +}
> +#endif
> +
>  static void sfp_module_tx_fault_reset(struct sfp *sfp)
>  {
>  	unsigned int state = sfp->state;
> @@ -2483,6 +2535,8 @@ static int sfp_probe(struct platform_device *pdev)
>  	if (!sfp->sfp_bus)
>  		return -ENOMEM;
>  
> +	sfp_debugfs_init(sfp);
> +
>  	return 0;
>  }
>  
> @@ -2490,6 +2544,7 @@ static int sfp_remove(struct platform_device *pdev)
>  {
>  	struct sfp *sfp = platform_get_drvdata(pdev);
>  
> +	sfp_debugfs_exit(sfp);
>  	sfp_unregister_socket(sfp->sfp_bus);
>  
>  	rtnl_lock();
> -- 
> 2.20.1
> 
> 

-- 
RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
FTTP is here! 40Mbps down 10Mbps up. Decent connectivity at last!