target/linux/generic/backport-5.10/610-v5.13-35-net-ethernet-mediatek-ppe-fix-busy-wait-loop.patch

   1 From c5d66587b8900201e1530b7c18d41e87bd5812f4 Mon Sep 17 00:00:00 2001
   2 From: Ilya Lipnitskiy <ilya.lipnitskiy@gmail.com>
   3 Date: Thu, 15 Apr 2021 17:37:48 -0700
   4 Subject: [PATCH] net: ethernet: mediatek: ppe: fix busy wait loop
   5
   6 The intention is for the loop to timeout if the body does not succeed.
   7 The current logic calls time_is_before_jiffies(timeout) which is false
   8 until after the timeout, so the loop body never executes.
   9
  10 Fix by using readl_poll_timeout as a more standard and less error-prone
  11 solution.
  12
  13 Fixes: ba37b7caf1ed ("net: ethernet: mtk_eth_soc: add support for initializing the PPE")
  14 Signed-off-by: Ilya Lipnitskiy <ilya.lipnitskiy@gmail.com>
  15 Cc: Felix Fietkau <nbd@nbd.name>
  16 Reviewed-by: Andrew Lunn <andrew@lunn.ch>
  17 Signed-off-by: David S. Miller <davem@davemloft.net>
  18 ---
  19  drivers/net/ethernet/mediatek/mtk_ppe.c | 20 +++++++++-----------
  20  drivers/net/ethernet/mediatek/mtk_ppe.h |  1 +
  21  2 files changed, 10 insertions(+), 11 deletions(-)
  22
  23 --- a/drivers/net/ethernet/mediatek/mtk_ppe.c
  24 +++ b/drivers/net/ethernet/mediatek/mtk_ppe.c
  25 @@ -2,9 +2,8 @@
  26  /* Copyright (C) 2020 Felix Fietkau <nbd@nbd.name> */
  27
  28  #include <linux/kernel.h>
  29 -#include <linux/jiffies.h>
  30 -#include <linux/delay.h>
  31  #include <linux/io.h>
  32 +#include <linux/iopoll.h>
  33  #include <linux/etherdevice.h>
  34  #include <linux/platform_device.h>
  35  #include "mtk_ppe.h"
  36 @@ -44,18 +43,17 @@ static u32 ppe_clear(struct mtk_ppe *ppe
  37
  38  static int mtk_ppe_wait_busy(struct mtk_ppe *ppe)
  39  {
  40 -       unsigned long timeout = jiffies + HZ;
  41 -
  42 -       while (time_is_before_jiffies(timeout)) {
  43 -               if (!(ppe_r32(ppe, MTK_PPE_GLO_CFG) & MTK_PPE_GLO_CFG_BUSY))
  44 -                       return 0;
  45 +       int ret;
  46 +       u32 val;
  47
  48 -               usleep_range(10, 20);
  49 -       }
  50 +       ret = readl_poll_timeout(ppe->base + MTK_PPE_GLO_CFG, val,
  51 +                                !(val & MTK_PPE_GLO_CFG_BUSY),
  52 +                                20, MTK_PPE_WAIT_TIMEOUT_US);
  53
  54 -       dev_err(ppe->dev, "PPE table busy");
  55 +       if (ret)
  56 +               dev_err(ppe->dev, "PPE table busy");
  57
  58 -       return -ETIMEDOUT;
  59 +       return ret;
  60  }
  61
  62  static void mtk_ppe_cache_clear(struct mtk_ppe *ppe)
  63 --- a/drivers/net/ethernet/mediatek/mtk_ppe.h
  64 +++ b/drivers/net/ethernet/mediatek/mtk_ppe.h
  65 @@ -12,6 +12,7 @@
  66  #define MTK_PPE_ENTRIES_SHIFT          3
  67  #define MTK_PPE_ENTRIES                        (1024 << MTK_PPE_ENTRIES_SHIFT)
  68  #define MTK_PPE_HASH_MASK              (MTK_PPE_ENTRIES - 1)
  69 +#define MTK_PPE_WAIT_TIMEOUT_US                1000000
  70
  71  #define MTK_FOE_IB1_UNBIND_TIMESTAMP   GENMASK(7, 0)
  72  #define MTK_FOE_IB1_UNBIND_PACKETS     GENMASK(23, 8)