target/linux/layerscape/patches-5.4/809-jailhouse-0018-ivshmem-net-Refactor-and-comment-ivshm_net_state_cha.patch

   1 From 5192fa99f0d267eb7bd1c79e556430ea8911ae38 Mon Sep 17 00:00:00 2001
   2 From: Jan Kiszka <jan.kiszka@siemens.com>
   3 Date: Sun, 4 Mar 2018 13:50:24 +0100
   4 Subject: [PATCH] ivshmem-net: Refactor and comment ivshm_net_state_change
   5
   6 This should make the state transitioning logic clearer. Also avoid the
   7 harmless but redundant netif_carrier_on/ivshm_net_run in RUN state.
   8
   9 Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
  10 (cherry picked from commit 8539efe70fbdf4a0bea75a97c1628fbb38b6590b)
  11 ---
  12  drivers/net/ivshmem-net.c | 23 ++++++++++++++++++++---
  13  1 file changed, 20 insertions(+), 3 deletions(-)
  14
  15 --- a/drivers/net/ivshmem-net.c
  16 +++ b/drivers/net/ivshmem-net.c
  17 @@ -575,14 +575,21 @@ static void ivshm_net_state_change(struc
  18         struct net_device *ndev = in->napi.dev;
  19         u32 rstate = readl(&in->ivshm_regs->rstate);
  20
  21 -
  22         switch (in->lstate) {
  23         case IVSHM_NET_STATE_RESET:
  24 +               /*
  25 +                * Wait for the remote to leave READY/RUN before transitioning
  26 +                * to INIT.
  27 +                */
  28                 if (rstate < IVSHM_NET_STATE_READY)
  29                         ivshm_net_set_state(in, IVSHM_NET_STATE_INIT);
  30                 break;
  31
  32         case IVSHM_NET_STATE_INIT:
  33 +               /*
  34 +                * Wait for the remote to leave RESET before performing the
  35 +                * initialization and moving to READY.
  36 +                */
  37                 if (rstate > IVSHM_NET_STATE_RESET) {
  38                         ivshm_net_init_queues(ndev);
  39                         ivshm_net_set_state(in, IVSHM_NET_STATE_READY);
  40 @@ -594,11 +601,21 @@ static void ivshm_net_state_change(struc
  41                 break;
  42
  43         case IVSHM_NET_STATE_READY:
  44 -       case IVSHM_NET_STATE_RUN:
  45 +               /*
  46 +                * Link is up and we are running once the remote is in READY or
  47 +                * RUN.
  48 +                */
  49                 if (rstate >= IVSHM_NET_STATE_READY) {
  50                         netif_carrier_on(ndev);
  51                         ivshm_net_run(ndev);
  52 -               } else if (rstate == IVSHM_NET_STATE_RESET) {
  53 +                       break;
  54 +               }
  55 +               /* fall through */
  56 +       case IVSHM_NET_STATE_RUN:
  57 +               /*
  58 +                * If the remote goes to RESET, we need to follow immediately.
  59 +                */
  60 +               if (rstate == IVSHM_NET_STATE_RESET) {
  61                         netif_carrier_off(ndev);
  62                         ivshm_net_do_stop(ndev);
  63                 }