target/linux/mediatek/patches-4.4/0087-net-next-mediatek-add-IRQ-locking.patch

   1 From f74d752da12c1b63bf2bbfa220aab5e2dd644157 Mon Sep 17 00:00:00 2001
   2 From: John Crispin <blogic@openwrt.org>
   3 Date: Wed, 20 Apr 2016 16:18:07 +0200
   4 Subject: [PATCH 87/90] net-next: mediatek: add IRQ locking
   5
   6 The code that enables and disables IRQs is missing proper locking. After
   7 adding the IRQ separation patch and routing the putting the RX and TX IRQs
   8 on different cores we experienced IRQ stalls. Fix this by adding proper
   9 locking. We use a dedicated lock to reduce the latency if the IRQ code.
  10 Otherwise it might wait for bottom code to finish before reenabling or
  11 disabling IRQs.
  12
  13 Signed-off-by: John Crispin <blogic@openwrt.org>
  14 ---
  15  drivers/net/ethernet/mediatek/mtk_eth_soc.c |    7 +++++++
  16  drivers/net/ethernet/mediatek/mtk_eth_soc.h |    1 +
  17  2 files changed, 8 insertions(+)
  18
  19 diff --git a/drivers/net/ethernet/mediatek/mtk_eth_soc.c b/drivers/net/ethernet/mediatek/mtk_eth_soc.c
  20 index 24a4179..f86d551 100644
  21 --- a/drivers/net/ethernet/mediatek/mtk_eth_soc.c
  22 +++ b/drivers/net/ethernet/mediatek/mtk_eth_soc.c
  23 @@ -316,22 +316,28 @@ static void mtk_mdio_cleanup(struct mtk_eth *eth)
  24
  25  static inline void mtk_irq_disable(struct mtk_eth *eth, u32 mask)
  26  {
  27 +       unsigned long flags;
  28         u32 val;
  29
  30 +       spin_lock_irqsave(&eth->irq_lock, flags);
  31         val = mtk_r32(eth, MTK_QDMA_INT_MASK);
  32         mtk_w32(eth, val & ~mask, MTK_QDMA_INT_MASK);
  33         /* flush write */
  34         mtk_r32(eth, MTK_QDMA_INT_MASK);
  35 +       spin_unlock_irqrestore(&eth->irq_lock, flags);
  36  }
  37
  38  static inline void mtk_irq_enable(struct mtk_eth *eth, u32 mask)
  39  {
  40 +       unsigned long flags;
  41         u32 val;
  42
  43 +       spin_lock_irqsave(&eth->irq_lock, flags);
  44         val = mtk_r32(eth, MTK_QDMA_INT_MASK);
  45         mtk_w32(eth, val | mask, MTK_QDMA_INT_MASK);
  46         /* flush write */
  47         mtk_r32(eth, MTK_QDMA_INT_MASK);
  48 +       spin_unlock_irqrestore(&eth->irq_lock, flags);
  49  }
  50
  51  static int mtk_set_mac_address(struct net_device *dev, void *p)
  52 @@ -1752,6 +1758,7 @@ static int mtk_probe(struct platform_device *pdev)
  53                 return -EADDRNOTAVAIL;
  54
  55         spin_lock_init(&eth->page_lock);
  56 +       spin_lock_init(&eth->irq_lock);
  57
  58         eth->ethsys = syscon_regmap_lookup_by_phandle(pdev->dev.of_node,
  59                                                       "mediatek,ethsys");
  60 diff --git a/drivers/net/ethernet/mediatek/mtk_eth_soc.h b/drivers/net/ethernet/mediatek/mtk_eth_soc.h
  61 index 57f7e8a..8220275 100644
  62 --- a/drivers/net/ethernet/mediatek/mtk_eth_soc.h
  63 +++ b/drivers/net/ethernet/mediatek/mtk_eth_soc.h
  64 @@ -372,6 +372,7 @@ struct mtk_eth {
  65         void __iomem                    *base;
  66         struct reset_control            *rstc;
  67         spinlock_t                      page_lock;
  68 +       spinlock_t                      irq_lock;
  69         struct net_device               dummy_dev;
  70         struct net_device               *netdev[MTK_MAX_DEVS];
  71         struct mtk_mac                  *mac[MTK_MAX_DEVS];
  72 --
  73 1.7.10.4
  74