diff mbox series

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

Message ID 2b924dcdf8adfe2c0b6b5998e47e836dd8f9e1b1.1713442039.git.matthias.schiffer@ew.tq-group.com (mailing list archive)
State Superseded
Delegated to: Netdev Maintainers
Headers show
Series [net,1/2] net: dsa: mv88e6xxx: Add support for model-specific pre- and post-reset handlers | expand

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netdev/ynl success Generated files up to date; no warnings/errors; no diff in generated;
netdev/fixes_present success Fixes tag present in non-next series
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 926 this patch: 926
netdev/build_tools success No tools touched, skip
netdev/cc_maintainers success CCed 8 of 8 maintainers
netdev/build_clang success Errors and warnings before: 937 this patch: 937
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/deprecated_api success None detected
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success Fixes tag looks correct
netdev/build_allmodconfig_warn success Errors and warnings before: 937 this patch: 937
netdev/checkpatch warning WARNING: line length of 81 exceeds 80 columns WARNING: line length of 82 exceeds 80 columns
netdev/build_clang_rust success No Rust files in patch. Skipping build
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0
netdev/contest success net-next-2024-04-21--03-00 (tests: 995)

Commit Message

Matthias Schiffer April 18, 2024, 12:16 p.m. UTC 
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@ew.tq-group.com>
---

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(-)

Comments

Andrew Lunn April 22, 2024, 1:25 p.m. UTC | #1 
On Thu, Apr 18, 2024 at 02:16:07PM +0200, Matthias Schiffer wrote:
> 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@ew.tq-group.com>
> ---
> 
> 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 _think_ we implement read/write support for all devices which have
the needed registers. Given the large number of ops structures, it is
possible we are missing entries, but nobody has reported any issues.

> 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.
> -		 */

I prefer having the comment here, where it is visible.

>  	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.

I would keep this sentence here.

    Andrew

---
pw-bot: cr
diff mbox series

Patch

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);