Subject: [PATCH net v2 2/3] drivers: net: cpsw: fix error messages when using phy-handle DT property

From: [email-masked] (Grygorii Strashko)
Date: Mon, 25 Apr 2016 22:12:20 +0300

On 04/22/2016 06:45 PM, David Rivshin (Allworx) wrote:
> On Fri, 22 Apr 2016 16:03:34 +0300
> Grygorii Strashko <[email-masked]> wrote:
> 
>> On 04/21/2016 09:26 PM, David Rivshin (Allworx) wrote:
>>> From: David Rivshin <[email-masked]>
>>>
>>> The phy-handle, phy_id, and fixed-link properties are mutually exclusive,
>>> and only one need be specified. However if phy-handle was specified, an
>>> error message would complain about the lack of phy_id or fixed-link.

I think, commit message need to be updated.
You not only fix log messages - you also fix the issue with 
of_get_phy_mode(slave_node); which will not be called if phy-handle is used.

slave_data->phy_if = of_get_phy_mode(slave_node); 
^ see below
>>>
>>> Also, if phy-handle was specified and the subsequent of_phy_connect()
>>> failed, the error message still referenced slaved->data->phy_id, which
>>> would be empty. Instead, use the name of the device_node as a useful
>>> identifier.
>>>
>>> Fixes: 9e42f715264f ("drivers: net: cpsw: add phy-handle parsing")
>>> Signed-off-by: David Rivshin <[email-masked]>
>>> Acked-by: Rob Herring <[email-masked]>
>>> Tested-by: Nicolas Chauvet <[email-masked]>
>>> ---
>>> If would like this for -stable it should apply cleanly as far back
>>> as 4.5. It failes on 4.4 due to some context differences, but can be
>>> applied with 'git am -C2'. Or, I can produce a separate patch against
>>> linux-4.4.y if preferred.
>>>
>>> Changes since v1 [1]:
>>> - Rebased (no conflicts)
>>> - Added Tested-by from Nicolas Chauvet
>>> - Added Acked-by from Rob Herring for the binding change
>>>
>>> [1] https://patchwork.ozlabs.org/patch/560324/
>>>
>>>    Documentation/devicetree/bindings/net/cpsw.txt |  4 ++--
>>>    drivers/net/ethernet/ti/cpsw.c                 | 17 +++++++++++++----
>>>    2 files changed, 15 insertions(+), 6 deletions(-)
>>>
>>> diff --git a/Documentation/devicetree/bindings/net/cpsw.txt b/Documentation/devicetree/bindings/net/cpsw.txt
>>> index 28a4781..3033c0f 100644
>>> --- a/Documentation/devicetree/bindings/net/cpsw.txt
>>> +++ b/Documentation/devicetree/bindings/net/cpsw.txt
>>> @@ -46,16 +46,16 @@ Optional properties:
>>>    - dual_emac_res_vlan	: Specifies VID to be used to segregate the ports
>>>    - mac-address		: See ethernet.txt file in the same directory
>>>    - phy_id		: Specifies slave phy id
>>
>> May be the "phy_id" can be marked as deprecated? (while here)
>> The recommended property now is "phy-handle".
> 
> I can certainly do that. Perhaps something like this?
>   - phy_id		: Specifies slave phy id (deprecated, use phy-handle)
> 
> Rob, would you have any issues with bundling that?
> 
>>
>>>    - phy-handle		: See ethernet.txt file in the same directory
>>>    
>>>    Slave sub-nodes:
>>>    - fixed-link		: See fixed-link.txt file in the same directory
>>> -			  Either the property phy_id, or the sub-node
>>> -			  fixed-link can be specified
>>> +
>>> +Note: Exactly one of phy_id, phy-handle, or fixed-link must be specified.
>>>    
>>>    Note: "ti,hwmods" field is used to fetch the base address and irq
>>>    resources from TI, omap hwmod data base during device registration.
>>>    Future plan is to migrate hwmod data base contents into device tree
>>>    blob so that, all the required data will be used from device tree dts
>>>    file.
>>>    
>>> diff --git a/drivers/net/ethernet/ti/cpsw.c b/drivers/net/ethernet/ti/cpsw.c
>>> index d69cb3f..3c81413 100644
>>> --- a/drivers/net/ethernet/ti/cpsw.c
>>> +++ b/drivers/net/ethernet/ti/cpsw.c
>>> @@ -1150,16 +1150,19 @@ static void cpsw_slave_open(struct cpsw_slave *slave, struct cpsw_priv *priv)
>>>    	if (slave->data->phy_node)
>>>    		slave->phy = of_phy_connect(priv->ndev, slave->data->phy_node,
>>>    				 &cpsw_adjust_link, 0, slave->data->phy_if);
>>>    	else
>>>    		slave->phy = phy_connect(priv->ndev, slave->data->phy_id,
>>>    				 &cpsw_adjust_link, slave->data->phy_if);
>>>    	if (IS_ERR(slave->phy)) {
>>> -		dev_err(priv->dev, "phy %s not found on slave %d\n",
>>> -			slave->data->phy_id, slave->slave_num);
>>> +		dev_err(priv->dev, "phy \"%s\" not found on slave %d\n",
>>> +			slave->data->phy_node ?
>>> +				slave->data->phy_node->full_name :
>>> +				slave->data->phy_id,
>>> +			slave->slave_num);
>>
>> Unfortunately,  there are some inconsistency between legacy and FDT API :(
>> of_phy_connect() will return valid phy_device or NULL, but phy_connect()
>> can return valid phy_device or ERR_PTR().
> 
> Good catch, I hadn't noticed that. It looks like that's actually a more
> serious (pre-existing) bug: if of_phy_connect() returns NULL, we'd end
> up dereferencing it and pagefaulting.
> 
> How about moving the IS_ERR() check into the phy_connect() case like this:
> 	if (slave->data->phy_node) {
> 		slave->phy = of_phy_connect(priv->ndev, slave->data->phy_node,
> 				 &cpsw_adjust_link, 0, slave->data->phy_if);

[1]

> 	} else {
> 		slave->phy = phy_connect(priv->ndev, slave->data->phy_id,
> 				 &cpsw_adjust_link, slave->data->phy_if);
> 		if (IS_ERR(slave->phy))
> 			slave->phy = NULL;
[2]
> 	}
> 	if (!slave->phy) {
> 		dev_err(priv->dev, "phy \"%s\" not found on slave %d\n",
> 			slave->data->phy_node ?
> 				slave->data->phy_node->full_name :
> 				slave->data->phy_id,
> 			slave->slave_num);
> 	} else {
> 
> Since you say the phy_id case is deprecated anyways, I'm not too concerned
> about not printing the error code returned by phy_connect() in that case
> (especially since it never did so in the past). That lets us still avoid
> duplicating the dev_err() itself.

I'm not worry too much about duplicating dev_err() - it's always good to know
the reason of failure.

So, may be for of_phy_connect() [1]:
 dev_err(priv->dev, "phy \"%s\" not found on slave %d\n",
	slave->data->phy_node->full_name,
 	slave->slave_num);

and for phy_connect() [2]:
  dev_err(priv->dev, "phy %s not found on slave %d, err %d\n",
  	slave->data->phy_id, slave->slave_num, PTR_ERR(slave->phy));

Mugunthan, any comments?

> 
> 
>>
>>
>>
>>>    		slave->phy = NULL;
>>>    	} else {
>>>    		phy_attached_info(slave->phy);
>>>    
>>>    		phy_start(slave->phy);
>>>    
>>>    		/* Configure GMII_SEL register */
>>> @@ -2030,15 +2033,19 @@ static int cpsw_probe_dt(struct cpsw_platform_data *data,
>>>    		/* This is no slave child node, continue */
>>>    		if (strcmp(slave_node->name, "slave"))
>>>    			continue;
>>>    
>>>    		slave_data->phy_node = of_parse_phandle(slave_node,
>>>    							"phy-handle", 0);
>>>    		parp = of_get_property(slave_node, "phy_id", &lenp);
>>> -		if (of_phy_is_fixed_link(slave_node)) {
>>> +		if (slave_data->phy_node) {
>>> +			dev_dbg(&pdev->dev,
>>> +				"slave[%d] using phy-handle=\"%s\"\n",
>>> +				i, slave_data->phy_node->full_name);
>>> +		} else if (of_phy_is_fixed_link(slave_node)) {
>>>    			struct device_node *phy_node;
>>>    			struct phy_device *phy_dev;
>>>    
>>>    			/* In the case of a fixed PHY, the DT node associated
>>>    			 * to the PHY is the Ethernet MAC DT node.
>>>    			 */
>>>    			ret = of_phy_register_fixed_link(slave_node);
>>> @@ -2067,15 +2074,17 @@ static int cpsw_probe_dt(struct cpsw_platform_data *data,
>>>    			if (!mdio) {
>>>    				dev_err(&pdev->dev, "Missing mdio platform device\n");
>>>    				return -EINVAL;
>>>    			}
>>>    			snprintf(slave_data->phy_id, sizeof(slave_data->phy_id),
>>>    				 PHY_ID_FMT, mdio->name, phyid);
>>>    		} else {
>>> -			dev_err(&pdev->dev, "No slave[%d] phy_id or fixed-link property\n", i);
>>> +			dev_err(&pdev->dev,
>>> +				"No slave[%d] phy_id, phy-handle, or fixed-link property\n",
>>> +				i);
>>>    			goto no_phy_slave;
>>>    		}
>>>    		slave_data->phy_if = of_get_phy_mode(slave_node);

Your change will allow the code to reach this point in case of phy-handle.

>>>    		if (slave_data->phy_if < 0) {
>>>    			dev_err(&pdev->dev, "Missing or malformed slave[%d] phy-mode property\n",
>>>    				i);
>>>    			return slave_data->phy_if;
>>>    
>>
>>

-- 
regards,
-grygorii