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author | Lucas Stach <l.stach@pengutronix.de> | 2016-01-25 16:50:02 -0600 |
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committer | Bjorn Helgaas <bhelgaas@google.com> | 2016-01-25 16:50:02 -0600 |
commit | 4d107d3b5a686b5834e533a00b73bf7b1cf59df7 (patch) | |
tree | dc851256d8c34ef193b7fa5f75d7c7e0b7b7da9e /drivers/pci/host/pci-imx6.c | |
parent | a77c5422d7586003643377afdb9915e76d07d21c (diff) | |
download | op-kernel-dev-4d107d3b5a686b5834e533a00b73bf7b1cf59df7.zip op-kernel-dev-4d107d3b5a686b5834e533a00b73bf7b1cf59df7.tar.gz |
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 <l.stach@pengutronix.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Diffstat (limited to 'drivers/pci/host/pci-imx6.c')
-rw-r--r-- | drivers/pci/host/pci-imx6.c | 60 |
1 files changed, 22 insertions, 38 deletions
diff --git a/drivers/pci/host/pci-imx6.c b/drivers/pci/host/pci-imx6.c index 6d7dfdc..bd3f7d0 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 = { |