Some PCIe devices take longer time to reach link up state after retrain. This patch polling for link up status after retrain the link. This is to make sure the link is stable and up before we access to configuration space registers after this.
Signed-off-by: Ley Foon Tan <[email protected]> --- drivers/pci/host/pcie-altera.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-) diff --git a/drivers/pci/host/pcie-altera.c b/drivers/pci/host/pcie-altera.c index 78f77e1..a9de2a0 100644 --- a/drivers/pci/host/pcie-altera.c +++ b/drivers/pci/host/pcie-altera.c @@ -61,6 +61,8 @@ #define TLP_LOOP 500 #define RP_DEVFN 0 +#define LINK_UP_TIMEOUT 5000 + #define INTX_NUM 4 #define DWORD_MASK 3 @@ -101,6 +103,7 @@ static void altera_pcie_retrain(struct pci_dev *dev) { u16 linkcap, linkstat; struct altera_pcie *pcie = dev->bus->sysdata; + int timeout = 0; if(!altera_pcie_link_is_up(pcie)) return; @@ -115,9 +118,16 @@ static void altera_pcie_retrain(struct pci_dev *dev) return; pcie_capability_read_word(dev, PCI_EXP_LNKSTA, &linkstat); - if ((linkstat & PCI_EXP_LNKSTA_CLS) == PCI_EXP_LNKSTA_CLS_2_5GB) + if ((linkstat & PCI_EXP_LNKSTA_CLS) == PCI_EXP_LNKSTA_CLS_2_5GB) { pcie_capability_set_word(dev, PCI_EXP_LNKCTL, PCI_EXP_LNKCTL_RL); + while(!altera_pcie_link_is_up(pcie)) { + timeout++; + if (timeout > LINK_UP_TIMEOUT) + break; + udelay(5); + } + } } DECLARE_PCI_FIXUP_EARLY(0x1172, PCI_ANY_ID, altera_pcie_retrain); -- 1.8.2.1
