git.openwrt.org Git - openwrt/staging/dangole.git/blob

   1 From 7b294e0cd2f7fbfb548a17b8d68d161da19e6592 Mon Sep 17 00:00:00 2001
   2 From: Joakim Zhang <qiangqing.zhang@nxp.com>
   3 Date: Fri, 12 Jul 2019 08:02:56 +0000
   4 Subject: [PATCH] can: flexcan: add Transceiver Delay Compensation suopport
   5
   6 The CAN FD protocol allows the transmission and reception of data at a higher
   7 bit rate than the nominal rate used in the arbitration phase when the message's
   8 BRS bit is set.
   9
  10 The TDC mechanism is effective only during the data phase of FD frames
  11 having BRS bit set. It has no effect either on non-FD frames, or on FD
  12 frames transmitted at normal bit rate.
  13
  14 Signed-off-by: Joakim Zhang <qiangqing.zhang@nxp.com>
  15 Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
  16 ---
  17  drivers/net/can/flexcan.c | 19 ++++++++++++++++++-
  18  1 file changed, 18 insertions(+), 1 deletion(-)
  19
  20 --- a/drivers/net/can/flexcan.c
  21 +++ b/drivers/net/can/flexcan.c
  22 @@ -149,8 +149,11 @@
  23
  24  /* FLEXCAN FD control register (FDCTRL) bits */
  25  #define FLEXCAN_FDCTRL_FDRATE          BIT(31)
  26 +#define FLEXCAN_FDCTRL_TDCEN           BIT(15)
  27 +#define FLEXCAN_FDCTRL_TDCFAIL         BIT(14)
  28  #define FLEXCAN_FDCTRL_MBDSR1(x)       (((x) & 0x3) << 19)
  29  #define FLEXCAN_FDCTRL_MBDSR0(x)       (((x) & 0x3) << 16)
  30 +#define FLEXCAN_FDCTRL_TDCOFF(x)       (((x) & 0x1f) << 8)
  31
  32  /* FLEXCAN FD Bit Timing register (FDCBT) bits */
  33  #define FLEXCAN_FDCBT_FPRESDIV(x)      (((x) & 0x3ff) << 20)
  34 @@ -1102,7 +1105,7 @@ static void flexcan_set_bittiming(struct
  35         struct can_bittiming *bt = &priv->can.bittiming;
  36         struct can_bittiming *dbt = &priv->can.data_bittiming;
  37         struct flexcan_regs __iomem *regs = priv->regs;
  38 -       u32 reg, reg_cbt, reg_fdcbt;
  39 +       u32 reg, reg_cbt, reg_fdcbt, reg_fdctrl;
  40
  41         reg = priv->read(&regs->ctrl);
  42         reg &= ~(FLEXCAN_CTRL_LPB | FLEXCAN_CTRL_SMP | FLEXCAN_CTRL_LOM);
  43 @@ -1174,6 +1177,19 @@ static void flexcan_set_bittiming(struct
  44                                         FLEXCAN_FDCBT_FPROPSEG(dbt->prop_seg);
  45                         priv->write(reg_fdcbt, &regs->fdcbt);
  46
  47 +                       /* enable transceiver delay compensation(TDC) for fd frame.
  48 +                        * TDC must be disabled when Loop Back mode is enabled.
  49 +                        */
  50 +                       reg_fdctrl = priv->read(&regs->fdctrl);
  51 +                       if (!(reg & FLEXCAN_CTRL_LPB)) {
  52 +                               reg_fdctrl |= FLEXCAN_FDCTRL_TDCEN;
  53 +                               reg_fdctrl &= ~FLEXCAN_FDCTRL_TDCOFF(0x1f);
  54 +                               /* for the TDC to work reliably, the offset has to use optimal settings */
  55 +                               reg_fdctrl |= FLEXCAN_FDCTRL_TDCOFF(((dbt->phase_seg1 - 1) + dbt->prop_seg + 2) *
  56 +                                                                   ((dbt->brp -1) + 1));
  57 +                       }
  58 +                       priv->write(reg_fdctrl, &regs->fdctrl);
  59 +
  60                         if (bt->brp != dbt->brp)
  61                                 netdev_warn(dev, "Warning!! data brp = %d and brp = %d don't match.\n"
  62                                             "flexcan may not work. consider using different bitrate or data bitrate\n",
  63 @@ -1325,6 +1341,7 @@ static int flexcan_chip_start(struct net
  64         /* FDCTRL */
  65         if (priv->can.ctrlmode_supported & CAN_CTRLMODE_FD) {
  66                 reg_fdctrl = priv->read(&regs->fdctrl) & ~FLEXCAN_FDCTRL_FDRATE;
  67 +               reg_fdctrl &= ~FLEXCAN_FDCTRL_TDCEN;
  68                 reg_fdctrl &= ~(FLEXCAN_FDCTRL_MBDSR1(0x3) | FLEXCAN_FDCTRL_MBDSR0(0x3));
  69                 reg_mcr = priv->read(&regs->mcr) & ~FLEXCAN_MCR_FDEN;
  70                 reg_ctrl2 = priv->read(&regs->ctrl2) & ~FLEXCAN_CTRL2_ISOCANFDEN;