If a PIO request is executed while link-down, the whole controller gets stuck in a non-functional state, and even after link comes up again, PIO requests won't work anymore, and a reset of the whole PCIe controller is needed. Therefore we need to prevent sending PIO requests while the link is down.
Signed-off-by: Pali Rohár pali@kernel.org --- drivers/pci/pci-aardvark.c | 38 +++++++++++++++++++++----------------- 1 file changed, 21 insertions(+), 17 deletions(-)
diff --git a/drivers/pci/pci-aardvark.c b/drivers/pci/pci-aardvark.c index 1eb257ea8b4a..ccaeecaca8e3 100644 --- a/drivers/pci/pci-aardvark.c +++ b/drivers/pci/pci-aardvark.c @@ -177,6 +177,23 @@ static inline uint advk_readl(struct pcie_advk *pcie, uint reg) return readl(pcie->base + reg); }
+/** + * pcie_advk_link_up() - Check if PCIe link is up or not + * + * @pcie: The PCI device to access + * + * Return true on link up. + * Return false on link down. + */ +static bool pcie_advk_link_up(struct pcie_advk *pcie) +{ + u32 val, ltssm_state; + + val = advk_readl(pcie, ADVK_LMI_PHY_CFG0); + ltssm_state = (val & ADVK_LMI_PHY_CFG0_LTSSM_MASK) >> ADVK_LMI_PHY_CFG0_LTSSM_SHIFT; + return ltssm_state >= ADVK_LMI_PHY_CFG0_LTSSM_L0 && ltssm_state < ADVK_LMI_PHY_CFG0_LTSSM_DISABLED; +} + /** * pcie_advk_addr_valid() - Check for valid bus address * @@ -195,6 +212,10 @@ static bool pcie_advk_addr_valid(struct pcie_advk *pcie, if (busno == 0 && (dev != 0 || func != 0)) return false;
+ /* Access to other buses is possible when link is up */ + if (busno != 0 && !pcie_advk_link_up(pcie)) + return false; + /* * In PCI-E only a single device (0) can exist on the secondary bus. * Beyond the secondary bus, there might be a Switch and anything is @@ -618,23 +639,6 @@ retry: return ret; }
-/** - * pcie_advk_link_up() - Check if PCIe link is up or not - * - * @pcie: The PCI device to access - * - * Return 1 (true) on link up. - * Return 0 (false) on link down. - */ -static int pcie_advk_link_up(struct pcie_advk *pcie) -{ - u32 val, ltssm_state; - - val = advk_readl(pcie, ADVK_LMI_PHY_CFG0); - ltssm_state = (val & ADVK_LMI_PHY_CFG0_LTSSM_MASK) >> ADVK_LMI_PHY_CFG0_LTSSM_SHIFT; - return ltssm_state >= ADVK_LMI_PHY_CFG0_LTSSM_L0 && ltssm_state < ADVK_LMI_PHY_CFG0_LTSSM_DISABLED; -} - /** * pcie_advk_wait_for_link() - Wait for link training to be accomplished *