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[net-next,v4,4/4] net: sfp: add support for multigig RollBall transceivers

Message ID 20210111050044.22002-5-kabel@kernel.org (mailing list archive)
State Superseded
Delegated to: Netdev Maintainers
Headers show
Series Support for RollBall 10G copper SFP modules | expand

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Commit Message

Marek Behún Jan. 11, 2021, 5 a.m. UTC 
This adds support for multigig copper SFP modules from RollBall/Hilink.
These modules have a specific way to access clause 45 registers of the
internal PHY.

We also need to wait at least 22 seconds after deasserting TX disable
before accessing the PHY. The code waits for 25 seconds just to be sure.

Signed-off-by: Marek Behún <kabel@kernel.org>
Reviewed-by: Russell King <rmk+kernel@armlinux.org.uk>
Cc: Andrew Lunn <andrew@lunn.ch>
---
 drivers/net/phy/sfp.c | 36 ++++++++++++++++++++++++++++++------
 1 file changed, 30 insertions(+), 6 deletions(-)

Comments

Pali Rohár Jan. 13, 2021, 10:49 a.m. UTC | #1 
Hello! (See comment below)

On Monday 11 January 2021 06:00:44 Marek Behún wrote:
> This adds support for multigig copper SFP modules from RollBall/Hilink.
> These modules have a specific way to access clause 45 registers of the
> internal PHY.
> 
> We also need to wait at least 22 seconds after deasserting TX disable
> before accessing the PHY. The code waits for 25 seconds just to be sure.
> 
> Signed-off-by: Marek Behún <kabel@kernel.org>
> Reviewed-by: Russell King <rmk+kernel@armlinux.org.uk>
> Cc: Andrew Lunn <andrew@lunn.ch>
> ---
>  drivers/net/phy/sfp.c | 36 ++++++++++++++++++++++++++++++------
>  1 file changed, 30 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/net/phy/sfp.c b/drivers/net/phy/sfp.c
> index 0621d12cf878..21fb96899518 100644
> --- a/drivers/net/phy/sfp.c
> +++ b/drivers/net/phy/sfp.c
> @@ -165,6 +165,7 @@ static const enum gpiod_flags gpio_flags[] = {
>   * on board (for a copper SFP) time to initialise.
>   */
>  #define T_WAIT			msecs_to_jiffies(50)
> +#define T_WAIT_ROLLBALL		msecs_to_jiffies(25000)
>  #define T_START_UP		msecs_to_jiffies(300)
>  #define T_START_UP_BAD_GPON	msecs_to_jiffies(60000)
>  
> @@ -204,8 +205,11 @@ static const enum gpiod_flags gpio_flags[] = {
>  
>  /* SFP modules appear to always have their PHY configured for bus address
>   * 0x56 (which with mdio-i2c, translates to a PHY address of 22).
> + * RollBall SFPs access phy via SFP Enhanced Digital Diagnostic Interface
> + * via address 0x51 (mdio-i2c will use RollBall protocol on this address).
>   */
> -#define SFP_PHY_ADDR	22
> +#define SFP_PHY_ADDR		22
> +#define SFP_PHY_ADDR_ROLLBALL	17
>  
>  struct sff_data {
>  	unsigned int gpios;
> @@ -218,6 +222,7 @@ struct sfp {
>  	struct mii_bus *i2c_mii;
>  	struct sfp_bus *sfp_bus;
>  	enum mdio_i2c_proto mdio_protocol;
> +	int phy_addr;
>  	struct phy_device *mod_phy;
>  	const struct sff_data *type;
>  	size_t i2c_block_size;
> @@ -250,6 +255,7 @@ struct sfp {
>  	struct sfp_eeprom_id id;
>  	unsigned int module_power_mW;
>  	unsigned int module_t_start_up;
> +	unsigned int module_t_wait;
>  
>  #if IS_ENABLED(CONFIG_HWMON)
>  	struct sfp_diag diag;
> @@ -1453,7 +1459,7 @@ static int sfp_sm_probe_phy(struct sfp *sfp, bool is_c45)
>  	struct phy_device *phy;
>  	int err;
>  
> -	phy = get_phy_device(sfp->i2c_mii, SFP_PHY_ADDR, is_c45);
> +	phy = get_phy_device(sfp->i2c_mii, sfp->phy_addr, is_c45);
>  	if (phy == ERR_PTR(-ENODEV))
>  		return PTR_ERR(phy);
>  	if (IS_ERR(phy)) {
> @@ -1835,6 +1841,23 @@ static int sfp_sm_mod_probe(struct sfp *sfp, bool report)
>  
>  	sfp->mdio_protocol = MDIO_I2C_DEFAULT;
>  
> +	sfp->phy_addr = SFP_PHY_ADDR;
> +	sfp->module_t_wait = T_WAIT;
> +
> +	if (((!memcmp(id.base.vendor_name, "OEM             ", 16) ||
> +	      !memcmp(id.base.vendor_name, "Turris          ", 16)) &&
> +	     (!memcmp(id.base.vendor_pn, "SFP-10G-T       ", 16) ||
> +	      !memcmp(id.base.vendor_pn, "RTSFP-10", 8)))) {
> +		sfp->mdio_protocol = MDIO_I2C_ROLLBALL;
> +		sfp->phy_addr = SFP_PHY_ADDR_ROLLBALL;
> +		sfp->module_t_wait = T_WAIT_ROLLBALL;
> +
> +		/* RollBall SFPs may have wrong (zero) extended compliacne code
> +		 * burned in EEPROM. For PHY probing we need the correct one.
> +		 */
> +		id.base.extended_cc = SFF8024_ECC_10GBASE_T_SFI;

Should not we rather in sfp_sm_probe_for_phy() function in "default"
section try to probe also for clause 45 PHY when clause 22 fails?

> +	}
> +
>  	return 0;
>  }
>  
> @@ -2030,9 +2053,10 @@ static void sfp_sm_main(struct sfp *sfp, unsigned int event)
>  
>  		/* We need to check the TX_FAULT state, which is not defined
>  		 * while TX_DISABLE is asserted. The earliest we want to do
> -		 * anything (such as probe for a PHY) is 50ms.
> +		 * anything (such as probe for a PHY) is 50ms. (or more on
> +		 * specific modules).
>  		 */
> -		sfp_sm_next(sfp, SFP_S_WAIT, T_WAIT);
> +		sfp_sm_next(sfp, SFP_S_WAIT, sfp->module_t_wait);
>  		break;
>  
>  	case SFP_S_WAIT:
> @@ -2046,8 +2070,8 @@ static void sfp_sm_main(struct sfp *sfp, unsigned int event)
>  			 * deasserting.
>  			 */
>  			timeout = sfp->module_t_start_up;
> -			if (timeout > T_WAIT)
> -				timeout -= T_WAIT;
> +			if (timeout > sfp->module_t_wait)
> +				timeout -= sfp->module_t_wait;
>  			else
>  				timeout = 1;
>  
> -- 
> 2.26.2
>
Russell King (Oracle) Jan. 13, 2021, 11:08 a.m. UTC | #2 
On Wed, Jan 13, 2021 at 11:49:36AM +0100, Pali Rohár wrote:
> On Monday 11 January 2021 06:00:44 Marek Behún wrote:
> > @@ -1453,7 +1459,7 @@ static int sfp_sm_probe_phy(struct sfp *sfp, bool is_c45)
> >  	struct phy_device *phy;
> >  	int err;
> >  
> > -	phy = get_phy_device(sfp->i2c_mii, SFP_PHY_ADDR, is_c45);
> > +	phy = get_phy_device(sfp->i2c_mii, sfp->phy_addr, is_c45);
> >  	if (phy == ERR_PTR(-ENODEV))
> >  		return PTR_ERR(phy);
> >  	if (IS_ERR(phy)) {
> > @@ -1835,6 +1841,23 @@ static int sfp_sm_mod_probe(struct sfp *sfp, bool report)
> >  
> >  	sfp->mdio_protocol = MDIO_I2C_DEFAULT;
> >  
> > +	sfp->phy_addr = SFP_PHY_ADDR;
> > +	sfp->module_t_wait = T_WAIT;
> > +
> > +	if (((!memcmp(id.base.vendor_name, "OEM             ", 16) ||
> > +	      !memcmp(id.base.vendor_name, "Turris          ", 16)) &&
> > +	     (!memcmp(id.base.vendor_pn, "SFP-10G-T       ", 16) ||
> > +	      !memcmp(id.base.vendor_pn, "RTSFP-10", 8)))) {
> > +		sfp->mdio_protocol = MDIO_I2C_ROLLBALL;
> > +		sfp->phy_addr = SFP_PHY_ADDR_ROLLBALL;
> > +		sfp->module_t_wait = T_WAIT_ROLLBALL;
> > +
> > +		/* RollBall SFPs may have wrong (zero) extended compliacne code

Spelling error - "compliance"

> > +		 * burned in EEPROM. For PHY probing we need the correct one.
> > +		 */
> > +		id.base.extended_cc = SFF8024_ECC_10GBASE_T_SFI;
> 
> Should not we rather in sfp_sm_probe_for_phy() function in "default"
> section try to probe also for clause 45 PHY when clause 22 fails?

Why? That's opening the possibilities for more problems - remember,
the access method is vendor defined, and we already have the situation
where I2C address 0x56 is used in two different styles that are
indistinguishable:

- Clause 22 write:
	Write register address, value high, value low.
- Clause 22 read:
	Write register address.
	Read value high, low.
- Clause 45 write:
	Write devad, register address high, register address low,
		value high, value low.
- Clause 45 read:
	Write devad, register address high, register address low.
	Read value high, low.

Look closely at the similarities of Clause 22 write and Clause 45
read, you'll see that if you issue a clause 45 read to a SFP module
that implements Clause 22, you actually end up issuing a write to it.

Sending random MDIO cycles to a SFP is a really bad idea.
Pali Rohár Jan. 13, 2021, 11:26 a.m. UTC | #3 
On Wednesday 13 January 2021 11:08:52 Russell King - ARM Linux admin wrote:
> On Wed, Jan 13, 2021 at 11:49:36AM +0100, Pali Rohár wrote:
> > On Monday 11 January 2021 06:00:44 Marek Behún wrote:
> > > @@ -1453,7 +1459,7 @@ static int sfp_sm_probe_phy(struct sfp *sfp, bool is_c45)
> > >  	struct phy_device *phy;
> > >  	int err;
> > >  
> > > -	phy = get_phy_device(sfp->i2c_mii, SFP_PHY_ADDR, is_c45);
> > > +	phy = get_phy_device(sfp->i2c_mii, sfp->phy_addr, is_c45);
> > >  	if (phy == ERR_PTR(-ENODEV))
> > >  		return PTR_ERR(phy);
> > >  	if (IS_ERR(phy)) {
> > > @@ -1835,6 +1841,23 @@ static int sfp_sm_mod_probe(struct sfp *sfp, bool report)
> > >  
> > >  	sfp->mdio_protocol = MDIO_I2C_DEFAULT;
> > >  
> > > +	sfp->phy_addr = SFP_PHY_ADDR;
> > > +	sfp->module_t_wait = T_WAIT;
> > > +
> > > +	if (((!memcmp(id.base.vendor_name, "OEM             ", 16) ||
> > > +	      !memcmp(id.base.vendor_name, "Turris          ", 16)) &&
> > > +	     (!memcmp(id.base.vendor_pn, "SFP-10G-T       ", 16) ||
> > > +	      !memcmp(id.base.vendor_pn, "RTSFP-10", 8)))) {
> > > +		sfp->mdio_protocol = MDIO_I2C_ROLLBALL;
> > > +		sfp->phy_addr = SFP_PHY_ADDR_ROLLBALL;
> > > +		sfp->module_t_wait = T_WAIT_ROLLBALL;
> > > +
> > > +		/* RollBall SFPs may have wrong (zero) extended compliacne code
> 
> Spelling error - "compliance"
> 
> > > +		 * burned in EEPROM. For PHY probing we need the correct one.
> > > +		 */
> > > +		id.base.extended_cc = SFF8024_ECC_10GBASE_T_SFI;
> > 
> > Should not we rather in sfp_sm_probe_for_phy() function in "default"
> > section try to probe also for clause 45 PHY when clause 22 fails?
> 
> Why? That's opening the possibilities for more problems - remember,
> the access method is vendor defined, and we already have the situation
> where I2C address 0x56 is used in two different styles that are
> indistinguishable:
> 
> - Clause 22 write:
> 	Write register address, value high, value low.
> - Clause 22 read:
> 	Write register address.
> 	Read value high, low.
> - Clause 45 write:
> 	Write devad, register address high, register address low,
> 		value high, value low.
> - Clause 45 read:
> 	Write devad, register address high, register address low.
> 	Read value high, low.
> 
> Look closely at the similarities of Clause 22 write and Clause 45
> read, you'll see that if you issue a clause 45 read to a SFP module
> that implements Clause 22, you actually end up issuing a write to it.
> 
> Sending random MDIO cycles to a SFP is a really bad idea.

I see, thank you for explanation. Incorrect data in SFP EEPROM may cause
lot of other issues :-(
diff mbox series

Patch

diff --git a/drivers/net/phy/sfp.c b/drivers/net/phy/sfp.c
index 0621d12cf878..21fb96899518 100644
--- a/drivers/net/phy/sfp.c
+++ b/drivers/net/phy/sfp.c
@@ -165,6 +165,7 @@  static const enum gpiod_flags gpio_flags[] = {
  * on board (for a copper SFP) time to initialise.
  */
 #define T_WAIT			msecs_to_jiffies(50)
+#define T_WAIT_ROLLBALL		msecs_to_jiffies(25000)
 #define T_START_UP		msecs_to_jiffies(300)
 #define T_START_UP_BAD_GPON	msecs_to_jiffies(60000)
 
@@ -204,8 +205,11 @@  static const enum gpiod_flags gpio_flags[] = {
 
 /* SFP modules appear to always have their PHY configured for bus address
  * 0x56 (which with mdio-i2c, translates to a PHY address of 22).
+ * RollBall SFPs access phy via SFP Enhanced Digital Diagnostic Interface
+ * via address 0x51 (mdio-i2c will use RollBall protocol on this address).
  */
-#define SFP_PHY_ADDR	22
+#define SFP_PHY_ADDR		22
+#define SFP_PHY_ADDR_ROLLBALL	17
 
 struct sff_data {
 	unsigned int gpios;
@@ -218,6 +222,7 @@  struct sfp {
 	struct mii_bus *i2c_mii;
 	struct sfp_bus *sfp_bus;
 	enum mdio_i2c_proto mdio_protocol;
+	int phy_addr;
 	struct phy_device *mod_phy;
 	const struct sff_data *type;
 	size_t i2c_block_size;
@@ -250,6 +255,7 @@  struct sfp {
 	struct sfp_eeprom_id id;
 	unsigned int module_power_mW;
 	unsigned int module_t_start_up;
+	unsigned int module_t_wait;
 
 #if IS_ENABLED(CONFIG_HWMON)
 	struct sfp_diag diag;
@@ -1453,7 +1459,7 @@  static int sfp_sm_probe_phy(struct sfp *sfp, bool is_c45)
 	struct phy_device *phy;
 	int err;
 
-	phy = get_phy_device(sfp->i2c_mii, SFP_PHY_ADDR, is_c45);
+	phy = get_phy_device(sfp->i2c_mii, sfp->phy_addr, is_c45);
 	if (phy == ERR_PTR(-ENODEV))
 		return PTR_ERR(phy);
 	if (IS_ERR(phy)) {
@@ -1835,6 +1841,23 @@  static int sfp_sm_mod_probe(struct sfp *sfp, bool report)
 
 	sfp->mdio_protocol = MDIO_I2C_DEFAULT;
 
+	sfp->phy_addr = SFP_PHY_ADDR;
+	sfp->module_t_wait = T_WAIT;
+
+	if (((!memcmp(id.base.vendor_name, "OEM             ", 16) ||
+	      !memcmp(id.base.vendor_name, "Turris          ", 16)) &&
+	     (!memcmp(id.base.vendor_pn, "SFP-10G-T       ", 16) ||
+	      !memcmp(id.base.vendor_pn, "RTSFP-10", 8)))) {
+		sfp->mdio_protocol = MDIO_I2C_ROLLBALL;
+		sfp->phy_addr = SFP_PHY_ADDR_ROLLBALL;
+		sfp->module_t_wait = T_WAIT_ROLLBALL;
+
+		/* RollBall SFPs may have wrong (zero) extended compliacne code
+		 * burned in EEPROM. For PHY probing we need the correct one.
+		 */
+		id.base.extended_cc = SFF8024_ECC_10GBASE_T_SFI;
+	}
+
 	return 0;
 }
 
@@ -2030,9 +2053,10 @@  static void sfp_sm_main(struct sfp *sfp, unsigned int event)
 
 		/* We need to check the TX_FAULT state, which is not defined
 		 * while TX_DISABLE is asserted. The earliest we want to do
-		 * anything (such as probe for a PHY) is 50ms.
+		 * anything (such as probe for a PHY) is 50ms. (or more on
+		 * specific modules).
 		 */
-		sfp_sm_next(sfp, SFP_S_WAIT, T_WAIT);
+		sfp_sm_next(sfp, SFP_S_WAIT, sfp->module_t_wait);
 		break;
 
 	case SFP_S_WAIT:
@@ -2046,8 +2070,8 @@  static void sfp_sm_main(struct sfp *sfp, unsigned int event)
 			 * deasserting.
 			 */
 			timeout = sfp->module_t_start_up;
-			if (timeout > T_WAIT)
-				timeout -= T_WAIT;
+			if (timeout > sfp->module_t_wait)
+				timeout -= sfp->module_t_wait;
 			else
 				timeout = 1;