target/linux/mediatek/patches-4.4/0095-net-next-mediatek-add-IRQ-locking.patch

   1 From dd08d1ac4cfc86fbea5ee207b9615922ede88ec6 Mon Sep 17 00:00:00 2001
   2 From: John Crispin <john@phrozen.org>
   3 Date: Tue, 17 May 2016 06:01:45 +0200
   4 Subject: [PATCH 095/102] 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: Sean Wang <keyhaede@gmail.com>
  14 Signed-off-by: John Crispin <john@phrozen.org>
  15 ---
  16  drivers/net/ethernet/mediatek/mtk_eth_soc.c |    7 +++++++
  17  drivers/net/ethernet/mediatek/mtk_eth_soc.h |    1 +
  18  2 files changed, 8 insertions(+)
  19
  20 --- a/drivers/net/ethernet/mediatek/mtk_eth_soc.c
  21 +++ b/drivers/net/ethernet/mediatek/mtk_eth_soc.c
  22 @@ -331,18 +331,24 @@ static void mtk_mdio_cleanup(struct mtk_
  23
  24  static inline void mtk_irq_disable(struct mtk_eth *eth, u32 mask)
  25  {
  26 +       unsigned long flags;
  27         u32 val;
  28
  29 +       spin_lock_irqsave(&eth->irq_lock, flags);
  30         val = mtk_r32(eth, MTK_QDMA_INT_MASK);
  31         mtk_w32(eth, val & ~mask, MTK_QDMA_INT_MASK);
  32 +       spin_unlock_irqrestore(&eth->irq_lock, flags);
  33  }
  34
  35  static inline void mtk_irq_enable(struct mtk_eth *eth, u32 mask)
  36  {
  37 +       unsigned long flags;
  38         u32 val;
  39
  40 +       spin_lock_irqsave(&eth->irq_lock, flags);
  41         val = mtk_r32(eth, MTK_QDMA_INT_MASK);
  42         mtk_w32(eth, val | mask, MTK_QDMA_INT_MASK);
  43 +       spin_unlock_irqrestore(&eth->irq_lock, flags);
  44  }
  45
  46  static int mtk_set_mac_address(struct net_device *dev, void *p)
  47 @@ -1771,6 +1777,7 @@ static int mtk_probe(struct platform_dev
  48                 return -EADDRNOTAVAIL;
  49
  50         spin_lock_init(&eth->page_lock);
  51 +       spin_lock_init(&eth->irq_lock);
  52
  53         eth->ethsys = syscon_regmap_lookup_by_phandle(pdev->dev.of_node,
  54                                                       "mediatek,ethsys");
  55 --- a/drivers/net/ethernet/mediatek/mtk_eth_soc.h
  56 +++ b/drivers/net/ethernet/mediatek/mtk_eth_soc.h
  57 @@ -373,6 +373,7 @@ struct mtk_eth {
  58         void __iomem                    *base;
  59         struct reset_control            *rstc;
  60         spinlock_t                      page_lock;
  61 +       spinlock_t                      irq_lock;
  62         struct net_device               dummy_dev;
  63         struct net_device               *netdev[MTK_MAX_DEVS];
  64         struct mtk_mac                  *mac[MTK_MAX_DEVS];