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Commit a1dca315 authored by Gabor Juhos's avatar Gabor Juhos Committed by Ralf Baechle
Browse files

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: default avatarGabor 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: default avatarRalf Baechle <ralf@linux-mips.org>
parent 16cc2cf6

arch/mips/pci/pci-ar724x.c

+22 −0
Original line number Diff line number Diff line
@@ -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);