Port of a Linux commit 4d107d3b5a686b5834e533a00b73bf7b1cf59df7 imx6_pcie_link_up() previously used usleep_range() to wait for the link to come up. Since it may be called while holding the config spinlock, the sleep causes a "BUG: scheduling while atomic" error. Instead of waiting for the link to come up in imx6_pcie_link_up(), do the waiting in imx6_pcie_wait_for_link(), where we're not holding a lock and sleeping is allowed. [bhelgaas: changelog, references to bugzilla and f95d3ae77191] Link: https://bugzilla.kernel.org/show_bug.cgi?id=100031 Fixes: f95d3ae77191 ("PCI: imx6: Wait for retraining") Signed-off-by: Lucas Stach <l.stach@xxxxxxxxxxxxxx> Signed-off-by: Bjorn Helgaas <bhelgaas@xxxxxxxxxx> Signed-off-by: Andrey Smirnov <andrew.smirnov@xxxxxxxxx> --- drivers/pci/pci-imx6.c | 20 +++++++++++++++++++- 1 file changed, 19 insertions(+), 1 deletion(-) diff --git a/drivers/pci/pci-imx6.c b/drivers/pci/pci-imx6.c index fc56a0d14..53d767824 100644 --- a/drivers/pci/pci-imx6.c +++ b/drivers/pci/pci-imx6.c @@ -399,8 +399,26 @@ static int imx6_pcie_wait_for_link(struct pcie_port *pp) { uint64_t start = get_time_ns(); + /* + * Test if the PHY reports that the link is up and also that the LTSSM + * training finished. There are three possible states of the link when + * this code is called: + * 1) The link is DOWN (unlikely) + * The link didn't come up yet for some reason. This usually means + * we have a real problem somewhere, if it happens with a peripheral + * connected. This state calls for inspection of the DEBUG registers. + * 2) The link is UP, but still in LTSSM training + * Wait for the training to finish, which should take a very short + * time. If the training does not finish, we have a problem and we + * need to inspect the DEBUG registers. If the training does finish, + * the link is up and operating correctly. + * 3) The link is UP and no longer in LTSSM training + * The link is up and operating correctly. + */ while (1) { - if (dw_pcie_link_up(pp)) + u32 reg = readl(pp->dbi_base + PCIE_PHY_DEBUG_R1); + if ((reg & PCIE_PHY_DEBUG_R1_XMLH_LINK_UP) && + !(reg & PCIE_PHY_DEBUG_R1_XMLH_LINK_IN_TRAINING)) return 0; if (!is_timeout(start, SECOND)) -- 2.19.1 _______________________________________________ barebox mailing list barebox@xxxxxxxxxxxxxxxxxxx http://lists.infradead.org/mailman/listinfo/barebox
