Re: [PATCH net-next v3 2/2] net: phy: aquantia: allow forcing order of MDI pairs

[Jon Hunter <jonathanh@nvidia.com>]

On 11/10/2024 18:37, Jon Hunter wrote:
> Hi Daniel,
> 
> On 04/10/2024 17:18, Daniel Golle wrote:
>> Despite supporting Auto MDI-X, it looks like Aquantia only supports
>> swapping pair (1,2) with pair (3,6) like it used to be for MDI-X on
>> 100MBit/s networks.
>>
>> When all 4 pairs are in use (for 1000MBit/s or faster) the link does not
>> come up with pair order is not configured correctly, either using
>> MDI_CFG pin or using the "PMA Receive Reserved Vendor Provisioning 1"
>> register.
>>
>> Normally, the order of MDI pairs being either ABCD or DCBA is configured
>> by pulling the MDI_CFG pin.
>>
>> However, some hardware designs require overriding the value configured
>> by that bootstrap pin. The PHY allows doing that by setting a bit in
>> "PMA Receive Reserved Vendor Provisioning 1" register which allows
>> ignoring the state of the MDI_CFG pin and another bit configuring
>> whether the order of MDI pairs should be normal (ABCD) or reverse
>> (DCBA). Pair polarity is not affected and remains identical in both
>> settings.
>>
>> Introduce property "marvell,mdi-cfg-order" which allows forcing either
>> normal or reverse order of the MDI pairs from DT.
>>
>> If the property isn't present, the behavior is unchanged and MDI pair
>> order configuration is untouched (ie. either the result of MDI_CFG pin
>> pull-up/pull-down, or pair order override already configured by the
>> bootloader before Linux is started).
>>
>> Forcing normal pair order is required on the Adtran SDG-8733A Wi-Fi 7
>> residential gateway.
>>
>> Signed-off-by: Daniel Golle <daniel@makrotopia.org>
>> ---
>> v3: use u32 'marvell,mdi-cfg-order' instead of two mutually exclusive
>>      properties as suggested
>> v2: add missing 'static' keyword, improve commit description
>>
>>   drivers/net/phy/aquantia/aquantia_main.c | 33 ++++++++++++++++++++++++
>>   1 file changed, 33 insertions(+)
>>
>> diff --git a/drivers/net/phy/aquantia/aquantia_main.c 
>> b/drivers/net/phy/aquantia/aquantia_main.c
>> index 4d156d406bab..dcad3fa1ddc3 100644
>> --- a/drivers/net/phy/aquantia/aquantia_main.c
>> +++ b/drivers/net/phy/aquantia/aquantia_main.c
>> @@ -11,6 +11,7 @@
>>   #include <linux/module.h>
>>   #include <linux/delay.h>
>>   #include <linux/bitfield.h>
>> +#include <linux/of.h>
>>   #include <linux/phy.h>
>>   #include "aquantia.h"
>> @@ -71,6 +72,11 @@
>>   #define MDIO_AN_TX_VEND_INT_MASK2        0xd401
>>   #define MDIO_AN_TX_VEND_INT_MASK2_LINK        BIT(0)
>> +#define PMAPMD_RSVD_VEND_PROV            0xe400
>> +#define PMAPMD_RSVD_VEND_PROV_MDI_CONF        GENMASK(1, 0)
>> +#define PMAPMD_RSVD_VEND_PROV_MDI_REVERSE    BIT(0)
>> +#define PMAPMD_RSVD_VEND_PROV_MDI_FORCE        BIT(1)
>> +
>>   #define MDIO_AN_RX_LP_STAT1            0xe820
>>   #define MDIO_AN_RX_LP_STAT1_1000BASET_FULL    BIT(15)
>>   #define MDIO_AN_RX_LP_STAT1_1000BASET_HALF    BIT(14)
>> @@ -485,6 +491,29 @@ static void aqr107_chip_info(struct phy_device 
>> *phydev)
>>              fw_major, fw_minor, build_id, prov_id);
>>   }
>> +static int aqr107_config_mdi(struct phy_device *phydev)
>> +{
>> +    struct device_node *np = phydev->mdio.dev.of_node;
>> +    u32 mdi_conf;
>> +    int ret;
>> +
>> +    ret = of_property_read_u32(np, "marvell,mdi-cfg-order", &mdi_conf);
>> +
>> +    /* Do nothing in case property "marvell,mdi-cfg-order" is not 
>> present */
>> +    if (ret == -ENOENT)
>> +        return 0;
> 
> 
> This change is breaking networking for one of our Tegra boards and on 
> boot I am seeing ...
> 
>   tegra-mgbe 6800000.ethernet eth0: Register MEM_TYPE_PAGE_POOL RxQ-0
>   tegra-mgbe 6800000.ethernet eth0: __stmmac_open: Cannot attach to PHY
>   (error: -22)
> 
> The issue is that of_property_read_u32() does not return -ENOENT if the 
> property is missing, it actually returns -EINVAL. See the description of 
> of_property_read_variable_u32_array() which is called by 
> of_property_read_u32().
> 
> Andrew, can we drop this change from -next until this is fixed?

Sorry, I believe Jakub applied and not Andrew.

Jon

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