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

   1 From 4ff9304355036d4a00bdf0e47e869fc770ba1cc5 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 87/91] 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 --- a/drivers/net/ethernet/mediatek/mtk_eth_soc.c
  20 +++ b/drivers/net/ethernet/mediatek/mtk_eth_soc.c
  21 @@ -316,22 +316,28 @@ static void mtk_mdio_cleanup(struct mtk_
  22
  23  static inline void mtk_irq_disable(struct mtk_eth *eth, u32 mask)
  24  {
  25 +       unsigned long flags;
  26         u32 val;
  27
  28 +       spin_lock_irqsave(&eth->irq_lock, flags);
  29         val = mtk_r32(eth, MTK_QDMA_INT_MASK);
  30         mtk_w32(eth, val & ~mask, MTK_QDMA_INT_MASK);
  31         /* flush write */
  32         mtk_r32(eth, MTK_QDMA_INT_MASK);
  33 +       spin_unlock_irqrestore(&eth->irq_lock, flags);
  34  }
  35
  36  static inline void mtk_irq_enable(struct mtk_eth *eth, u32 mask)
  37  {
  38 +       unsigned long flags;
  39         u32 val;
  40
  41 +       spin_lock_irqsave(&eth->irq_lock, flags);
  42         val = mtk_r32(eth, MTK_QDMA_INT_MASK);
  43         mtk_w32(eth, val | mask, MTK_QDMA_INT_MASK);
  44         /* flush write */
  45         mtk_r32(eth, MTK_QDMA_INT_MASK);
  46 +       spin_unlock_irqrestore(&eth->irq_lock, flags);
  47  }
  48
  49  static int mtk_set_mac_address(struct net_device *dev, void *p)
  50 @@ -1752,6 +1758,7 @@ static int mtk_probe(struct platform_dev
  51                 return -EADDRNOTAVAIL;
  52
  53         spin_lock_init(&eth->page_lock);
  54 +       spin_lock_init(&eth->irq_lock);
  55
  56         eth->ethsys = syscon_regmap_lookup_by_phandle(pdev->dev.of_node,
  57                                                       "mediatek,ethsys");
  58 --- a/drivers/net/ethernet/mediatek/mtk_eth_soc.h
  59 +++ b/drivers/net/ethernet/mediatek/mtk_eth_soc.h
  60 @@ -372,6 +372,7 @@ struct mtk_eth {
  61         void __iomem                    *base;
  62         struct reset_control            *rstc;
  63         spinlock_t                      page_lock;
  64 +       spinlock_t                      irq_lock;
  65         struct net_device               dummy_dev;
  66         struct net_device               *netdev[MTK_MAX_DEVS];
  67         struct mtk_mac                  *mac[MTK_MAX_DEVS];