target/linux/ar71xx/patches-3.3/140-MIPS-pci-ar724x-avoid-data-bus-error-due-to-a-missin.patch

   1 From 9cfa64ddaba49975b420ce5e5020efc3301061ac Mon Sep 17 00:00:00 2001
   2 From: Gabor Juhos <juhosg@openwrt.org>
   3 Date: Tue, 26 Jun 2012 10:19:46 +0200
   4 Subject: [PATCH 01/34] MIPS: pci-ar724x: avoid data bus error due to a missing PCIe module
   5
   6 If the controller has no PCIe module attached,
   7 accessing of the device configuration space
   8 causes a data bus error. Avoid this by checking
   9 the status of the PCIe link in advance, and
  10 indicate an error if the link is down.
  11
  12 Signed-off-by: Gabor Juhos <juhosg@openwrt.org>
  13 ---
  14  arch/mips/pci/pci-ar724x.c |   22 ++++++++++++++++++++++
  15  1 files changed, 22 insertions(+), 0 deletions(-)
  16
  17 --- a/arch/mips/pci/pci-ar724x.c
  18 +++ b/arch/mips/pci/pci-ar724x.c
  19 @@ -23,9 +23,12 @@
  20  #define AR724X_PCI_MEM_BASE    0x10000000
  21  #define AR724X_PCI_MEM_SIZE    0x08000000
  22
  23 +#define AR724X_PCI_REG_RESET           0x18
  24  #define AR724X_PCI_REG_INT_STATUS      0x4c
  25  #define AR724X_PCI_REG_INT_MASK                0x50
  26
  27 +#define AR724X_PCI_RESET_LINK_UP       BIT(0)
  28 +
  29  #define AR724X_PCI_INT_DEV0            BIT(14)
  30
  31  #define AR724X_PCI_IRQ_COUNT           1
  32 @@ -38,6 +41,15 @@ static void __iomem *ar724x_pci_ctrl_bas
  33
  34  static u32 ar724x_pci_bar0_value;
  35  static bool ar724x_pci_bar0_is_cached;
  36 +static bool ar724x_pci_link_up;
  37 +
  38 +static inline bool ar724x_pci_check_link(void)
  39 +{
  40 +       u32 reset;
  41 +
  42 +       reset = __raw_readl(ar724x_pci_ctrl_base + AR724X_PCI_REG_RESET);
  43 +       return reset & AR724X_PCI_RESET_LINK_UP;
  44 +}
  45
  46  static int ar724x_pci_read(struct pci_bus *bus, unsigned int devfn, int where,
  47                             int size, uint32_t *value)
  48 @@ -46,6 +58,9 @@ static int ar724x_pci_read(struct pci_bu
  49         void __iomem *base;
  50         u32 data;
  51
  52 +       if (!ar724x_pci_link_up)
  53 +               return PCIBIOS_DEVICE_NOT_FOUND;
  54 +
  55         if (devfn)
  56                 return PCIBIOS_DEVICE_NOT_FOUND;
  57
  58 @@ -96,6 +111,9 @@ static int ar724x_pci_write(struct pci_b
  59         u32 data;
  60         int s;
  61
  62 +       if (!ar724x_pci_link_up)
  63 +               return PCIBIOS_DEVICE_NOT_FOUND;
  64 +
  65         if (devfn)
  66                 return PCIBIOS_DEVICE_NOT_FOUND;
  67
  68 @@ -280,6 +298,10 @@ int __init ar724x_pcibios_init(int irq)
  69         if (ar724x_pci_ctrl_base == NULL)
  70                 goto err_unmap_devcfg;
  71
  72 +       ar724x_pci_link_up = ar724x_pci_check_link();
  73 +       if (!ar724x_pci_link_up)
  74 +               pr_warn("ar724x: PCIe link is down\n");
  75 +
  76         ar724x_pci_irq_init(irq);
  77         register_pci_controller(&ar724x_pci_controller);
  78