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   1 From 7f3e55a3890fa26d15e2e4e90213962d1a7f6df9 Mon Sep 17 00:00:00 2001
   2 From: =?UTF-8?q?Pali=20Roh=C3=A1r?= <pali@kernel.org>
   3 Date: Fri, 12 Feb 2021 20:32:55 +0100
   4 Subject: [PATCH] PCI: aardvark: Add support for ERR interrupt on emulated
   5  bridge
   6 MIME-Version: 1.0
   7 Content-Type: text/plain; charset=UTF-8
   8 Content-Transfer-Encoding: 8bit
   9
  10 ERR interrupt is triggered when corresponding bit is unmasked in both ISR0
  11 and PCI_EXP_DEVCTL registers. Unmasking ERR bits in PCI_EXP_DEVCTL register
  12 is not enough. This means that currently the ERR interrupt is never
  13 triggered.
  14
  15 Unmask ERR bits in ISR0 register at driver probe time. ERR interrupt is not
  16 triggered until ERR bits are unmasked also in PCI_EXP_DEVCTL register,
  17 which is done by AER driver. So it is safe to unconditionally unmask all
  18 ERR bits in aardvark probe.
  19
  20 Aardvark HW sets PCI_ERR_ROOT_AER_IRQ to zero and when corresponding bits
  21 in ISR0 and PCI_EXP_DEVCTL are enabled, the HW triggers a generic interrupt
  22 on GIC. Chain this interrupt to PCIe interrupt 0 with
  23 generic_handle_domain_irq() to allow processing of ERR interrupts.
  24
  25 Signed-off-by: Pali Rohár <pali@kernel.org>
  26 Signed-off-by: Marek Behún <kabel@kernel.org>
  27 ---
  28  drivers/pci/controller/pci-aardvark.c | 36 ++++++++++++++++++++++++++-
  29  1 file changed, 35 insertions(+), 1 deletion(-)
  30
  31 --- a/drivers/pci/controller/pci-aardvark.c
  32 +++ b/drivers/pci/controller/pci-aardvark.c
  33 @@ -98,6 +98,10 @@
  34  #define PCIE_MSG_PM_PME_MASK                   BIT(7)
  35  #define PCIE_ISR0_MASK_REG                     (CONTROL_BASE_ADDR + 0x44)
  36  #define     PCIE_ISR0_MSI_INT_PENDING          BIT(24)
  37 +#define     PCIE_ISR0_CORR_ERR                 BIT(11)
  38 +#define     PCIE_ISR0_NFAT_ERR                 BIT(12)
  39 +#define     PCIE_ISR0_FAT_ERR                  BIT(13)
  40 +#define     PCIE_ISR0_ERR_MASK                 GENMASK(13, 11)
  41  #define     PCIE_ISR0_INTX_ASSERT(val)         BIT(16 + (val))
  42  #define     PCIE_ISR0_INTX_DEASSERT(val)       BIT(20 + (val))
  43  #define     PCIE_ISR0_ALL_MASK                 GENMASK(31, 0)
  44 @@ -778,11 +782,15 @@ advk_pci_bridge_emul_base_conf_read(stru
  45         case PCI_INTERRUPT_LINE: {
  46                 /*
  47                  * From the whole 32bit register we support reading from HW only
  48 -                * one bit: PCI_BRIDGE_CTL_BUS_RESET.
  49 +                * two bits: PCI_BRIDGE_CTL_BUS_RESET and PCI_BRIDGE_CTL_SERR.
  50                  * Other bits are retrieved only from emulated config buffer.
  51                  */
  52                 __le32 *cfgspace = (__le32 *)&bridge->conf;
  53                 u32 val = le32_to_cpu(cfgspace[PCI_INTERRUPT_LINE / 4]);
  54 +               if (advk_readl(pcie, PCIE_ISR0_MASK_REG) & PCIE_ISR0_ERR_MASK)
  55 +                       val &= ~(PCI_BRIDGE_CTL_SERR << 16);
  56 +               else
  57 +                       val |= PCI_BRIDGE_CTL_SERR << 16;
  58                 if (advk_readl(pcie, PCIE_CORE_CTRL1_REG) & HOT_RESET_GEN)
  59                         val |= PCI_BRIDGE_CTL_BUS_RESET << 16;
  60                 else
  61 @@ -808,6 +816,19 @@ advk_pci_bridge_emul_base_conf_write(str
  62                 break;
  63
  64         case PCI_INTERRUPT_LINE:
  65 +               /*
  66 +                * According to Figure 6-3: Pseudo Logic Diagram for Error
  67 +                * Message Controls in PCIe base specification, SERR# Enable bit
  68 +                * in Bridge Control register enable receiving of ERR_* messages
  69 +                */
  70 +               if (mask & (PCI_BRIDGE_CTL_SERR << 16)) {
  71 +                       u32 val = advk_readl(pcie, PCIE_ISR0_MASK_REG);
  72 +                       if (new & (PCI_BRIDGE_CTL_SERR << 16))
  73 +                               val &= ~PCIE_ISR0_ERR_MASK;
  74 +                       else
  75 +                               val |= PCIE_ISR0_ERR_MASK;
  76 +                       advk_writel(pcie, val, PCIE_ISR0_MASK_REG);
  77 +               }
  78                 if (mask & (PCI_BRIDGE_CTL_BUS_RESET << 16)) {
  79                         u32 val = advk_readl(pcie, PCIE_CORE_CTRL1_REG);
  80                         if (new & (PCI_BRIDGE_CTL_BUS_RESET << 16))
  81 @@ -1457,6 +1478,18 @@ static void advk_pcie_handle_int(struct
  82         isr1_mask = advk_readl(pcie, PCIE_ISR1_MASK_REG);
  83         isr1_status = isr1_val & ((~isr1_mask) & PCIE_ISR1_ALL_MASK);
  84
  85 +       /* Process ERR interrupt */
  86 +       if (isr0_status & PCIE_ISR0_ERR_MASK) {
  87 +               advk_writel(pcie, PCIE_ISR0_ERR_MASK, PCIE_ISR0_REG);
  88 +
  89 +               /*
  90 +                * Aardvark HW returns zero for PCI_ERR_ROOT_AER_IRQ, so use
  91 +                * PCIe interrupt 0
  92 +                */
  93 +               if (generic_handle_domain_irq(pcie->irq_domain, 0) == -EINVAL)
  94 +                       dev_err_ratelimited(&pcie->pdev->dev, "unhandled ERR IRQ\n");
  95 +       }
  96 +
  97         /* Process MSI interrupts */
  98         if (isr0_status & PCIE_ISR0_MSI_INT_PENDING)
  99                 advk_pcie_handle_msi(pcie);