From 865eedea22d0a97d5e5f1e2167f6f9fe6672e25d Mon Sep 17 00:00:00 2001 From: =?utf8?q?Marek=20Beh=C3=BAn?= Date: Mon, 17 Mar 2025 18:32:50 +0100 Subject: [PATCH] net: dsa: mv88e6xxx: workaround RGMII transmit delay erratum for 6320 family MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit commit 1ebc8e1ef906db9c08e9abe9776d85ddec837725 upstream. Implement the workaround for erratum 3.3 RGMII timing may be out of spec when transmit delay is enabled for the 6320 family, which says: When transmit delay is enabled via Port register 1 bit 14 = 1, duty cycle may be out of spec. Under very rare conditions this may cause the attached device receive CRC errors. Signed-off-by: Marek Behún Cc: # 5.4.x Reviewed-by: Andrew Lunn Link: https://patch.msgid.link/20250317173250.28780-8-kabel@kernel.org Signed-off-by: Jakub Kicinski Signed-off-by: Greg Kroah-Hartman --- drivers/net/dsa/mv88e6xxx/chip.c | 17 +++++++++++++++++ 1 file changed, 17 insertions(+) diff --git a/drivers/net/dsa/mv88e6xxx/chip.c b/drivers/net/dsa/mv88e6xxx/chip.c index 4cc60135589d1..e590ea87b6ea2 100644 --- a/drivers/net/dsa/mv88e6xxx/chip.c +++ b/drivers/net/dsa/mv88e6xxx/chip.c @@ -2832,6 +2832,21 @@ static int mv88e6xxx_stats_setup(struct mv88e6xxx_chip *chip) return mv88e6xxx_g1_stats_clear(chip); } +static int mv88e6320_setup_errata(struct mv88e6xxx_chip *chip) +{ + u16 dummy; + int err; + + /* Workaround for erratum + * 3.3 RGMII timing may be out of spec when transmit delay is enabled + */ + err = mv88e6xxx_port_hidden_write(chip, 0, 0xf, 0x7, 0xe000); + if (err) + return err; + + return mv88e6xxx_port_hidden_read(chip, 0, 0xf, 0x7, &dummy); +} + /* Check if the errata has already been applied. */ static bool mv88e6390_setup_errata_applied(struct mv88e6xxx_chip *chip) { @@ -4122,6 +4137,7 @@ static const struct mv88e6xxx_ops mv88e6290_ops = { static const struct mv88e6xxx_ops mv88e6320_ops = { /* MV88E6XXX_FAMILY_6320 */ + .setup_errata = mv88e6320_setup_errata, .ieee_pri_map = mv88e6085_g1_ieee_pri_map, .ip_pri_map = mv88e6085_g1_ip_pri_map, .irl_init_all = mv88e6352_g2_irl_init_all, @@ -4164,6 +4180,7 @@ static const struct mv88e6xxx_ops mv88e6320_ops = { static const struct mv88e6xxx_ops mv88e6321_ops = { /* MV88E6XXX_FAMILY_6320 */ + .setup_errata = mv88e6320_setup_errata, .ieee_pri_map = mv88e6085_g1_ieee_pri_map, .ip_pri_map = mv88e6085_g1_ip_pri_map, .irl_init_all = mv88e6352_g2_irl_init_all, -- 2.47.3