From 4d107d3b5a686b5834e533a00b73bf7b1cf59df7 Mon Sep 17 00:00:00 2001 From: Lucas Stach Date: Mon, 25 Jan 2016 16:50:02 -0600 Subject: [PATCH] PCI: imx6: Move link up check into imx6_pcie_wait_for_link() 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 Signed-off-by: Bjorn Helgaas --- drivers/pci/host/pci-imx6.c | 60 ++++++++++++++----------------------- 1 file changed, 22 insertions(+), 38 deletions(-) diff --git a/drivers/pci/host/pci-imx6.c b/drivers/pci/host/pci-imx6.c index 6d7dfdcf4d5c..bd3f7d0ef943 100644 --- a/drivers/pci/host/pci-imx6.c +++ b/drivers/pci/host/pci-imx6.c @@ -349,10 +349,28 @@ static int imx6_pcie_wait_for_link(struct pcie_port *pp) { unsigned int retries; + /* + * 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. + */ for (retries = 0; retries < 200; retries++) { - 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; - usleep_range(100, 1000); + usleep_range(1000, 2000); } return -EINVAL; @@ -467,42 +485,8 @@ static void imx6_pcie_host_init(struct pcie_port *pp) static int imx6_pcie_link_up(struct pcie_port *pp) { - u32 rc; - int count = 5; - - /* - * 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. Reset the PHY and exit. 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) { - rc = readl(pp->dbi_base + PCIE_PHY_DEBUG_R1); - if (!(rc & PCIE_PHY_DEBUG_R1_XMLH_LINK_UP)) - break; - if (!(rc & PCIE_PHY_DEBUG_R1_XMLH_LINK_IN_TRAINING)) - return 1; - if (!count--) - break; - dev_dbg(pp->dev, "Link is up, but still in training\n"); - /* - * Wait a little bit, then re-check if the link finished - * the training. - */ - usleep_range(1000, 2000); - } - - return 0; + return readl(pp->dbi_base + PCIE_PHY_DEBUG_R1) & + PCIE_PHY_DEBUG_R1_XMLH_LINK_UP; } static struct pcie_host_ops imx6_pcie_host_ops = { -- 2.20.1