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| author | Gabor Juhos <juhosg@openwrt.org> | 2012-08-23 17:35:26 +0400 |
|---|---|---|
| committer | Ralf Baechle <ralf@linux-mips.org> | 2012-08-23 17:44:47 +0400 |
| commit | a1dca315ce3f78347bca8ce8befe3cc71ae63b7e (patch) | |
| tree | d86f7a45cb7c631e0e2c295e3f70d1bed1d849f7 /arch/mips/pci/pci-ar724x.c | |
| parent | 16cc2cf642eb73978a3ebde66dc94d24d46b4798 (diff) | |
| download | linux-a1dca315ce3f78347bca8ce8befe3cc71ae63b7e.tar.xz | |
MIPS: pci-ar724x: avoid data bus error due to a missing PCIe module
If the controller has no PCIe module attached, accessing of the device
configuration space causes a data bus error. Avoid this by checking the
status of the PCIe link in advance, and indicate an error if the link
is down.
Signed-off-by: Gabor Juhos <juhosg@openwrt.org>
Cc: stable@vger.kernel.org
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/4293/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Diffstat (limited to 'arch/mips/pci/pci-ar724x.c')
| -rw-r--r-- | arch/mips/pci/pci-ar724x.c | 22 |
1 files changed, 22 insertions, 0 deletions
diff --git a/arch/mips/pci/pci-ar724x.c b/arch/mips/pci/pci-ar724x.c index 414a7459858d..86d77a666458 100644 --- a/arch/mips/pci/pci-ar724x.c +++ b/arch/mips/pci/pci-ar724x.c @@ -23,9 +23,12 @@ #define AR724X_PCI_MEM_BASE 0x10000000 #define AR724X_PCI_MEM_SIZE 0x08000000 +#define AR724X_PCI_REG_RESET 0x18 #define AR724X_PCI_REG_INT_STATUS 0x4c #define AR724X_PCI_REG_INT_MASK 0x50 +#define AR724X_PCI_RESET_LINK_UP BIT(0) + #define AR724X_PCI_INT_DEV0 BIT(14) #define AR724X_PCI_IRQ_COUNT 1 @@ -38,6 +41,15 @@ static void __iomem *ar724x_pci_ctrl_base; static u32 ar724x_pci_bar0_value; static bool ar724x_pci_bar0_is_cached; +static bool ar724x_pci_link_up; + +static inline bool ar724x_pci_check_link(void) +{ + u32 reset; + + reset = __raw_readl(ar724x_pci_ctrl_base + AR724X_PCI_REG_RESET); + return reset & AR724X_PCI_RESET_LINK_UP; +} static int ar724x_pci_read(struct pci_bus *bus, unsigned int devfn, int where, int size, uint32_t *value) @@ -46,6 +58,9 @@ static int ar724x_pci_read(struct pci_bus *bus, unsigned int devfn, int where, void __iomem *base; u32 data; + if (!ar724x_pci_link_up) + return PCIBIOS_DEVICE_NOT_FOUND; + if (devfn) return PCIBIOS_DEVICE_NOT_FOUND; @@ -96,6 +111,9 @@ static int ar724x_pci_write(struct pci_bus *bus, unsigned int devfn, int where, u32 data; int s; + if (!ar724x_pci_link_up) + return PCIBIOS_DEVICE_NOT_FOUND; + if (devfn) return PCIBIOS_DEVICE_NOT_FOUND; @@ -280,6 +298,10 @@ int __init ar724x_pcibios_init(int irq) if (ar724x_pci_ctrl_base == NULL) goto err_unmap_devcfg; + ar724x_pci_link_up = ar724x_pci_check_link(); + if (!ar724x_pci_link_up) + pr_warn("ar724x: PCIe link is down\n"); + ar724x_pci_irq_init(irq); register_pci_controller(&ar724x_pci_controller); |