target/linux/generic/backport-5.10/762-v5.11-net-dsa-mt7530-support-setting-MTU.patch

   1 From 9470174e7581e75a8ebd78964997314dfc2e706c Mon Sep 17 00:00:00 2001
   2 From: DENG Qingfang <dqfext@gmail.com>
   3 Date: Tue, 3 Nov 2020 13:06:18 +0800
   4 Subject: [PATCH] net: dsa: mt7530: support setting MTU
   5
   6 MT7530/7531 has a global RX packet length register, which can be used
   7 to set MTU.
   8
   9 Supported packet length values are 1522 (1518 if untagged), 1536,
  10 1552, and multiple of 1024 (from 2048 to 15360).
  11
  12 Signed-off-by: DENG Qingfang <dqfext@gmail.com>
  13 Link: https://lore.kernel.org/r/20201103050618.11419-1-dqfext@gmail.com
  14 Signed-off-by: Jakub Kicinski <kuba@kernel.org>
  15 ---
  16  drivers/net/dsa/mt7530.c | 49 ++++++++++++++++++++++++++++++++++++++++
  17  drivers/net/dsa/mt7530.h | 12 ++++++++++
  18  2 files changed, 61 insertions(+)
  19
  20 --- a/drivers/net/dsa/mt7530.c
  21 +++ b/drivers/net/dsa/mt7530.c
  22 @@ -1015,6 +1015,53 @@ mt7530_port_disable(struct dsa_switch *d
  23         mutex_unlock(&priv->reg_mutex);
  24  }
  25
  26 +static int
  27 +mt7530_port_change_mtu(struct dsa_switch *ds, int port, int new_mtu)
  28 +{
  29 +       struct mt7530_priv *priv = ds->priv;
  30 +       struct mii_bus *bus = priv->bus;
  31 +       int length;
  32 +       u32 val;
  33 +
  34 +       /* When a new MTU is set, DSA always set the CPU port's MTU to the
  35 +        * largest MTU of the slave ports. Because the switch only has a global
  36 +        * RX length register, only allowing CPU port here is enough.
  37 +        */
  38 +       if (!dsa_is_cpu_port(ds, port))
  39 +               return 0;
  40 +
  41 +       mutex_lock_nested(&bus->mdio_lock, MDIO_MUTEX_NESTED);
  42 +
  43 +       val = mt7530_mii_read(priv, MT7530_GMACCR);
  44 +       val &= ~MAX_RX_PKT_LEN_MASK;
  45 +
  46 +       /* RX length also includes Ethernet header, MTK tag, and FCS length */
  47 +       length = new_mtu + ETH_HLEN + MTK_HDR_LEN + ETH_FCS_LEN;
  48 +       if (length <= 1522) {
  49 +               val |= MAX_RX_PKT_LEN_1522;
  50 +       } else if (length <= 1536) {
  51 +               val |= MAX_RX_PKT_LEN_1536;
  52 +       } else if (length <= 1552) {
  53 +               val |= MAX_RX_PKT_LEN_1552;
  54 +       } else {
  55 +               val &= ~MAX_RX_JUMBO_MASK;
  56 +               val |= MAX_RX_JUMBO(DIV_ROUND_UP(length, 1024));
  57 +               val |= MAX_RX_PKT_LEN_JUMBO;
  58 +       }
  59 +
  60 +       mt7530_mii_write(priv, MT7530_GMACCR, val);
  61 +
  62 +       mutex_unlock(&bus->mdio_lock);
  63 +
  64 +       return 0;
  65 +}
  66 +
  67 +static int
  68 +mt7530_port_max_mtu(struct dsa_switch *ds, int port)
  69 +{
  70 +       return MT7530_MAX_MTU;
  71 +}
  72 +
  73  static void
  74  mt7530_stp_state_set(struct dsa_switch *ds, int port, u8 state)
  75  {
  76 @@ -2653,6 +2700,8 @@ static const struct dsa_switch_ops mt753
  77         .get_sset_count         = mt7530_get_sset_count,
  78         .port_enable            = mt7530_port_enable,
  79         .port_disable           = mt7530_port_disable,
  80 +       .port_change_mtu        = mt7530_port_change_mtu,
  81 +       .port_max_mtu           = mt7530_port_max_mtu,
  82         .port_stp_state_set     = mt7530_stp_state_set,
  83         .port_bridge_join       = mt7530_port_bridge_join,
  84         .port_bridge_leave      = mt7530_port_bridge_leave,
  85 --- a/drivers/net/dsa/mt7530.h
  86 +++ b/drivers/net/dsa/mt7530.h
  87 @@ -11,6 +11,9 @@
  88  #define MT7530_NUM_FDB_RECORDS         2048
  89  #define MT7530_ALL_MEMBERS             0xff
  90
  91 +#define MTK_HDR_LEN    4
  92 +#define MT7530_MAX_MTU (15 * 1024 - ETH_HLEN - ETH_FCS_LEN - MTK_HDR_LEN)
  93 +
  94  enum mt753x_id {
  95         ID_MT7530 = 0,
  96         ID_MT7621 = 1,
  97 @@ -301,6 +304,15 @@ enum mt7530_vlan_port_attr {
  98  #define MT7531_DBG_CNT(x)              (0x3018 + (x) * 0x100)
  99  #define  MT7531_DIS_CLR                        BIT(31)
 100
 101 +#define MT7530_GMACCR                  0x30e0
 102 +#define  MAX_RX_JUMBO(x)               ((x) << 2)
 103 +#define  MAX_RX_JUMBO_MASK             GENMASK(5, 2)
 104 +#define  MAX_RX_PKT_LEN_MASK           GENMASK(1, 0)
 105 +#define  MAX_RX_PKT_LEN_1522           0x0
 106 +#define  MAX_RX_PKT_LEN_1536           0x1
 107 +#define  MAX_RX_PKT_LEN_1552           0x2
 108 +#define  MAX_RX_PKT_LEN_JUMBO          0x3
 109 +
 110  /* Register for MIB */
 111  #define MT7530_PORT_MIB_COUNTER(x)     (0x4000 + (x) * 0x100)
 112  #define MT7530_MIB_CCR                 0x4fe0