Commit e117be74 authored by Russell King's avatar Russell King Committed by David S. Miller
Browse files

net: sfp: allow sfp to probe slow to initialise GPON modules 



Some GPON modules (e.g. Huawei MA5671A) take a significant amount of
time to start responding on the I2C bus, contary to the SFF
specifications.

Work around this by implementing a two-level timeout strategy, where
we initially quickly retry for the module, and then use a slower retry
after we exceed a maximum number of quick attempts.

Signed-off-by: default avatarRussell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 73f5e847

drivers/net/phy/sfp.c

+28 −10
Original line number Diff line number Diff line
@@ -169,7 +169,10 @@ static const enum gpiod_flags gpio_flags[] = { 
 */

#define T_SERIAL		msecs_to_jiffies(300)

#define T_HPOWER_LEVEL		msecs_to_jiffies(300)

#define T_PROBE_RETRY	msecs_to_jiffies(100)

#define T_PROBE_RETRY_INIT	msecs_to_jiffies(100)

#define R_PROBE_RETRY_INIT	10

#define T_PROBE_RETRY_SLOW	msecs_to_jiffies(5000)

#define R_PROBE_RETRY_SLOW	12



/* SFP modules appear to always have their PHY configured for bus address

 * 0x56 (which with mdio-i2c, translates to a PHY address of 22).
@@ -204,6 +207,8 @@ struct sfp { 
	struct delayed_work timeout;

	struct mutex sm_mutex;			/* Protects state machine */

	unsigned char sm_mod_state;

	unsigned char sm_mod_tries_init;

	unsigned char sm_mod_tries;

	unsigned char sm_dev_state;

	unsigned short sm_state;

	unsigned int sm_retries;
@@ -1457,7 +1462,7 @@ static int sfp_sm_mod_hpower(struct sfp *sfp, bool enable) 
	return 0;

}



static int sfp_sm_mod_probe(struct sfp *sfp)

static int sfp_sm_mod_probe(struct sfp *sfp, bool report)

{

	/* SFP module inserted - read I2C data */

	struct sfp_eeprom_id id;
@@ -1467,6 +1472,7 @@ static int sfp_sm_mod_probe(struct sfp *sfp) 


	ret = sfp_read(sfp, false, 0, &id, sizeof(id));

	if (ret < 0) {

		if (report)

			dev_err(sfp->dev, "failed to read EEPROM: %d\n", ret);

		return -EAGAIN;

	}
@@ -1614,8 +1620,11 @@ static void sfp_sm_module(struct sfp *sfp, unsigned int event) 


	switch (sfp->sm_mod_state) {

	default:

		if (event == SFP_E_INSERT)

		if (event == SFP_E_INSERT) {

			sfp_sm_mod_next(sfp, SFP_MOD_PROBE, T_SERIAL);

			sfp->sm_mod_tries_init = R_PROBE_RETRY_INIT;

			sfp->sm_mod_tries = R_PROBE_RETRY_SLOW;

		}

		break;



	case SFP_MOD_PROBE:
@@ -1623,11 +1632,20 @@ static void sfp_sm_module(struct sfp *sfp, unsigned int event) 
		if (event != SFP_E_TIMEOUT)

			break;



		err = sfp_sm_mod_probe(sfp);

		err = sfp_sm_mod_probe(sfp, sfp->sm_mod_tries == 1);

		if (err == -EAGAIN) {

			sfp_sm_set_timer(sfp, T_PROBE_RETRY);

			if (sfp->sm_mod_tries_init &&

			   --sfp->sm_mod_tries_init) {

				sfp_sm_set_timer(sfp, T_PROBE_RETRY_INIT);

				break;

			} else if (sfp->sm_mod_tries && --sfp->sm_mod_tries) {

				if (sfp->sm_mod_tries == R_PROBE_RETRY_SLOW - 1)

					dev_warn(sfp->dev,

						 "please wait, module slow to respond\n");

				sfp_sm_set_timer(sfp, T_PROBE_RETRY_SLOW);

				break;

			}

		}

		if (err < 0) {

			sfp_sm_mod_next(sfp, SFP_MOD_ERROR, 0);

			break;
@@ -1661,7 +1679,7 @@ static void sfp_sm_module(struct sfp *sfp, unsigned int event) 
				sfp_module_remove(sfp->sfp_bus);

				sfp_sm_mod_next(sfp, SFP_MOD_ERROR, 0);

			} else {

				sfp_sm_set_timer(sfp, T_PROBE_RETRY);

				sfp_sm_set_timer(sfp, T_PROBE_RETRY_INIT);

			}

			break;

		}

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