[PATCH net 1/2] net: dsa: mv88e6xxx: Add support for model-specific pre- and post-reset handlers

From: Matthias Schiffer
Date: Thu Apr 18 2024 - 08:16:49 EST


Instead of calling mv88e6xxx_g2_eeprom_wait() directly from
mv88e6xxx_hardware_reset(), add configurable pre- and post-reset hard
reset handlers. Initially, the handlers are set to
mv88e6xxx_g2_eeprom_wait() for all families that have get/set_eeprom()
to match the existing behavior. No functional change intended (except
for additional error messages on failure).

Fixes: 6ccf50d4d474 ("net: dsa: mv88e6xxx: Avoid EEPROM timeout when EEPROM is absent")
Signed-off-by: Matthias Schiffer <matthias.schiffer@xxxxxxxxxxxxxxx>
---

One other thing I noticed about the patch referenced in the Fixes tag:
It completely removed the wait for switches without a get_eeprom() op.
Are there any switches that do load their configuration from an EEPROM,
but don't provide read/write access, and thus don't have
get/set_eeprom() ops, but that still need their config load to be
completed before/after reset?

I've left that behavior unchanged in this series, as I currently don't
have access to other switch manuals and no way to test their behavior.


drivers/net/dsa/mv88e6xxx/chip.c | 53 ++++++++++++++++++++++++++------
drivers/net/dsa/mv88e6xxx/chip.h | 13 ++++++++
2 files changed, 56 insertions(+), 10 deletions(-)

diff --git a/drivers/net/dsa/mv88e6xxx/chip.c b/drivers/net/dsa/mv88e6xxx/chip.c
index c95787cb90867..8650d8646120a 100644
--- a/drivers/net/dsa/mv88e6xxx/chip.c
+++ b/drivers/net/dsa/mv88e6xxx/chip.c
@@ -3075,25 +3075,26 @@ static int mv88e6xxx_software_reset(struct mv88e6xxx_chip *chip)
static void mv88e6xxx_hardware_reset(struct mv88e6xxx_chip *chip)
{
struct gpio_desc *gpiod = chip->reset;
+ int err;

/* If there is a GPIO connected to the reset pin, toggle it */
if (gpiod) {
- /* If the switch has just been reset and not yet completed
- * loading EEPROM, the reset may interrupt the I2C transaction
- * mid-byte, causing the first EEPROM read after the reset
- * from the wrong location resulting in the switch booting
- * to wrong mode and inoperable.
- */
- if (chip->info->ops->get_eeprom)
- mv88e6xxx_g2_eeprom_wait(chip);
+ if (chip->info->ops->hardware_reset_pre) {
+ err = chip->info->ops->hardware_reset_pre(chip);
+ if (err)
+ dev_err(chip->dev, "pre-reset error: %d\n", err);
+ }

gpiod_set_value_cansleep(gpiod, 1);
usleep_range(10000, 20000);
gpiod_set_value_cansleep(gpiod, 0);
usleep_range(10000, 20000);

- if (chip->info->ops->get_eeprom)
- mv88e6xxx_g2_eeprom_wait(chip);
+ if (chip->info->ops->hardware_reset_post) {
+ err = chip->info->ops->hardware_reset_post(chip);
+ if (err)
+ dev_err(chip->dev, "post-reset error: %d\n", err);
+ }
}
}

@@ -4323,6 +4324,8 @@ static const struct mv88e6xxx_ops mv88e6141_ops = {
.watchdog_ops = &mv88e6390_watchdog_ops,
.mgmt_rsvd2cpu = mv88e6390_g1_mgmt_rsvd2cpu,
.pot_clear = mv88e6xxx_g2_pot_clear,
+ .hardware_reset_pre = mv88e6xxx_g2_eeprom_wait,
+ .hardware_reset_post = mv88e6xxx_g2_eeprom_wait,
.reset = mv88e6352_g1_reset,
.rmu_disable = mv88e6390_g1_rmu_disable,
.atu_get_hash = mv88e6165_g1_atu_get_hash,
@@ -4513,6 +4516,8 @@ static const struct mv88e6xxx_ops mv88e6172_ops = {
.watchdog_ops = &mv88e6097_watchdog_ops,
.mgmt_rsvd2cpu = mv88e6352_g2_mgmt_rsvd2cpu,
.pot_clear = mv88e6xxx_g2_pot_clear,
+ .hardware_reset_pre = mv88e6xxx_g2_eeprom_wait,
+ .hardware_reset_post = mv88e6xxx_g2_eeprom_wait,
.reset = mv88e6352_g1_reset,
.rmu_disable = mv88e6352_g1_rmu_disable,
.atu_get_hash = mv88e6165_g1_atu_get_hash,
@@ -4613,6 +4618,8 @@ static const struct mv88e6xxx_ops mv88e6176_ops = {
.watchdog_ops = &mv88e6097_watchdog_ops,
.mgmt_rsvd2cpu = mv88e6352_g2_mgmt_rsvd2cpu,
.pot_clear = mv88e6xxx_g2_pot_clear,
+ .hardware_reset_pre = mv88e6xxx_g2_eeprom_wait,
+ .hardware_reset_post = mv88e6xxx_g2_eeprom_wait,
.reset = mv88e6352_g1_reset,
.rmu_disable = mv88e6352_g1_rmu_disable,
.atu_get_hash = mv88e6165_g1_atu_get_hash,
@@ -4707,6 +4714,8 @@ static const struct mv88e6xxx_ops mv88e6190_ops = {
.watchdog_ops = &mv88e6390_watchdog_ops,
.mgmt_rsvd2cpu = mv88e6390_g1_mgmt_rsvd2cpu,
.pot_clear = mv88e6xxx_g2_pot_clear,
+ .hardware_reset_pre = mv88e6xxx_g2_eeprom_wait,
+ .hardware_reset_post = mv88e6xxx_g2_eeprom_wait,
.reset = mv88e6352_g1_reset,
.rmu_disable = mv88e6390_g1_rmu_disable,
.atu_get_hash = mv88e6165_g1_atu_get_hash,
@@ -4765,6 +4774,8 @@ static const struct mv88e6xxx_ops mv88e6190x_ops = {
.watchdog_ops = &mv88e6390_watchdog_ops,
.mgmt_rsvd2cpu = mv88e6390_g1_mgmt_rsvd2cpu,
.pot_clear = mv88e6xxx_g2_pot_clear,
+ .hardware_reset_pre = mv88e6xxx_g2_eeprom_wait,
+ .hardware_reset_post = mv88e6xxx_g2_eeprom_wait,
.reset = mv88e6352_g1_reset,
.rmu_disable = mv88e6390_g1_rmu_disable,
.atu_get_hash = mv88e6165_g1_atu_get_hash,
@@ -4821,6 +4832,8 @@ static const struct mv88e6xxx_ops mv88e6191_ops = {
.watchdog_ops = &mv88e6390_watchdog_ops,
.mgmt_rsvd2cpu = mv88e6390_g1_mgmt_rsvd2cpu,
.pot_clear = mv88e6xxx_g2_pot_clear,
+ .hardware_reset_pre = mv88e6xxx_g2_eeprom_wait,
+ .hardware_reset_post = mv88e6xxx_g2_eeprom_wait,
.reset = mv88e6352_g1_reset,
.rmu_disable = mv88e6390_g1_rmu_disable,
.atu_get_hash = mv88e6165_g1_atu_get_hash,
@@ -4880,6 +4893,8 @@ static const struct mv88e6xxx_ops mv88e6240_ops = {
.watchdog_ops = &mv88e6097_watchdog_ops,
.mgmt_rsvd2cpu = mv88e6352_g2_mgmt_rsvd2cpu,
.pot_clear = mv88e6xxx_g2_pot_clear,
+ .hardware_reset_pre = mv88e6xxx_g2_eeprom_wait,
+ .hardware_reset_post = mv88e6xxx_g2_eeprom_wait,
.reset = mv88e6352_g1_reset,
.rmu_disable = mv88e6352_g1_rmu_disable,
.atu_get_hash = mv88e6165_g1_atu_get_hash,
@@ -4933,6 +4948,8 @@ static const struct mv88e6xxx_ops mv88e6250_ops = {
.watchdog_ops = &mv88e6250_watchdog_ops,
.mgmt_rsvd2cpu = mv88e6352_g2_mgmt_rsvd2cpu,
.pot_clear = mv88e6xxx_g2_pot_clear,
+ .hardware_reset_pre = mv88e6xxx_g2_eeprom_wait,
+ .hardware_reset_post = mv88e6xxx_g2_eeprom_wait,
.reset = mv88e6250_g1_reset,
.vtu_getnext = mv88e6185_g1_vtu_getnext,
.vtu_loadpurge = mv88e6185_g1_vtu_loadpurge,
@@ -4980,6 +4997,8 @@ static const struct mv88e6xxx_ops mv88e6290_ops = {
.watchdog_ops = &mv88e6390_watchdog_ops,
.mgmt_rsvd2cpu = mv88e6390_g1_mgmt_rsvd2cpu,
.pot_clear = mv88e6xxx_g2_pot_clear,
+ .hardware_reset_pre = mv88e6xxx_g2_eeprom_wait,
+ .hardware_reset_post = mv88e6xxx_g2_eeprom_wait,
.reset = mv88e6352_g1_reset,
.rmu_disable = mv88e6390_g1_rmu_disable,
.atu_get_hash = mv88e6165_g1_atu_get_hash,
@@ -5039,6 +5058,8 @@ static const struct mv88e6xxx_ops mv88e6320_ops = {
.watchdog_ops = &mv88e6390_watchdog_ops,
.mgmt_rsvd2cpu = mv88e6352_g2_mgmt_rsvd2cpu,
.pot_clear = mv88e6xxx_g2_pot_clear,
+ .hardware_reset_pre = mv88e6xxx_g2_eeprom_wait,
+ .hardware_reset_post = mv88e6xxx_g2_eeprom_wait,
.reset = mv88e6352_g1_reset,
.vtu_getnext = mv88e6185_g1_vtu_getnext,
.vtu_loadpurge = mv88e6185_g1_vtu_loadpurge,
@@ -5085,6 +5106,8 @@ static const struct mv88e6xxx_ops mv88e6321_ops = {
.set_egress_port = mv88e6095_g1_set_egress_port,
.watchdog_ops = &mv88e6390_watchdog_ops,
.mgmt_rsvd2cpu = mv88e6352_g2_mgmt_rsvd2cpu,
+ .hardware_reset_pre = mv88e6xxx_g2_eeprom_wait,
+ .hardware_reset_post = mv88e6xxx_g2_eeprom_wait,
.reset = mv88e6352_g1_reset,
.vtu_getnext = mv88e6185_g1_vtu_getnext,
.vtu_loadpurge = mv88e6185_g1_vtu_loadpurge,
@@ -5135,6 +5158,8 @@ static const struct mv88e6xxx_ops mv88e6341_ops = {
.watchdog_ops = &mv88e6390_watchdog_ops,
.mgmt_rsvd2cpu = mv88e6390_g1_mgmt_rsvd2cpu,
.pot_clear = mv88e6xxx_g2_pot_clear,
+ .hardware_reset_pre = mv88e6xxx_g2_eeprom_wait,
+ .hardware_reset_post = mv88e6xxx_g2_eeprom_wait,
.reset = mv88e6352_g1_reset,
.rmu_disable = mv88e6390_g1_rmu_disable,
.atu_get_hash = mv88e6165_g1_atu_get_hash,
@@ -5290,6 +5315,8 @@ static const struct mv88e6xxx_ops mv88e6352_ops = {
.watchdog_ops = &mv88e6097_watchdog_ops,
.mgmt_rsvd2cpu = mv88e6352_g2_mgmt_rsvd2cpu,
.pot_clear = mv88e6xxx_g2_pot_clear,
+ .hardware_reset_pre = mv88e6xxx_g2_eeprom_wait,
+ .hardware_reset_post = mv88e6xxx_g2_eeprom_wait,
.reset = mv88e6352_g1_reset,
.rmu_disable = mv88e6352_g1_rmu_disable,
.atu_get_hash = mv88e6165_g1_atu_get_hash,
@@ -5352,6 +5379,8 @@ static const struct mv88e6xxx_ops mv88e6390_ops = {
.watchdog_ops = &mv88e6390_watchdog_ops,
.mgmt_rsvd2cpu = mv88e6390_g1_mgmt_rsvd2cpu,
.pot_clear = mv88e6xxx_g2_pot_clear,
+ .hardware_reset_pre = mv88e6xxx_g2_eeprom_wait,
+ .hardware_reset_post = mv88e6xxx_g2_eeprom_wait,
.reset = mv88e6352_g1_reset,
.rmu_disable = mv88e6390_g1_rmu_disable,
.atu_get_hash = mv88e6165_g1_atu_get_hash,
@@ -5414,6 +5443,8 @@ static const struct mv88e6xxx_ops mv88e6390x_ops = {
.watchdog_ops = &mv88e6390_watchdog_ops,
.mgmt_rsvd2cpu = mv88e6390_g1_mgmt_rsvd2cpu,
.pot_clear = mv88e6xxx_g2_pot_clear,
+ .hardware_reset_pre = mv88e6xxx_g2_eeprom_wait,
+ .hardware_reset_post = mv88e6xxx_g2_eeprom_wait,
.reset = mv88e6352_g1_reset,
.rmu_disable = mv88e6390_g1_rmu_disable,
.atu_get_hash = mv88e6165_g1_atu_get_hash,
@@ -5479,6 +5510,8 @@ static const struct mv88e6xxx_ops mv88e6393x_ops = {
.watchdog_ops = &mv88e6393x_watchdog_ops,
.mgmt_rsvd2cpu = mv88e6393x_port_mgmt_rsvd2cpu,
.pot_clear = mv88e6xxx_g2_pot_clear,
+ .hardware_reset_pre = mv88e6xxx_g2_eeprom_wait,
+ .hardware_reset_post = mv88e6xxx_g2_eeprom_wait,
.reset = mv88e6352_g1_reset,
.rmu_disable = mv88e6390_g1_rmu_disable,
.atu_get_hash = mv88e6165_g1_atu_get_hash,
diff --git a/drivers/net/dsa/mv88e6xxx/chip.h b/drivers/net/dsa/mv88e6xxx/chip.h
index 85eb293381a7e..363334e1f30b0 100644
--- a/drivers/net/dsa/mv88e6xxx/chip.h
+++ b/drivers/net/dsa/mv88e6xxx/chip.h
@@ -487,6 +487,19 @@ struct mv88e6xxx_ops {
int (*ppu_enable)(struct mv88e6xxx_chip *chip);
int (*ppu_disable)(struct mv88e6xxx_chip *chip);

+ /* Additional handlers to run before and after hard reset, to make sure
+ * that the switch and EEPROM are in a good state.
+ *
+ * If the switch has just been reset and not yet completed loading
+ * EEPROM, the reset may interrupt the I2C transaction mid-byte, causing
+ * the first EEPROM read after the reset from the wrong location
+ * resulting in the switch booting to wrong mode and inoperable. For
+ * this reason, switch families with EEPROM support generally wait for
+ * EEPROM loads to complete as their pre- and post-reset handlers.
+ */
+ int (*hardware_reset_pre)(struct mv88e6xxx_chip *chip);
+ int (*hardware_reset_post)(struct mv88e6xxx_chip *chip);
+
/* Switch Software Reset */
int (*reset)(struct mv88e6xxx_chip *chip);

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