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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>
hifive-unleashed-5.1
Gabor Juhos 2012-08-23 15:35:26 +02:00 committed by Ralf Baechle
parent 16cc2cf642
commit a1dca315ce
1 changed files with 22 additions and 0 deletions
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22
arch/mips/pci/pci-ar724x.c
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@ -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);