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| author | Andrey Smirnov <andrew.smirnov@gmail.com> | 2018-12-16 21:18:33 -0800 |
|---|---|---|
| committer | Sascha Hauer <s.hauer@pengutronix.de> | 2019-01-08 16:28:47 +0100 |
| commit | 0aa89c9deaebf3d1258814f38930abd8ec0987ab (patch) | |
| tree | 100734478d7b496e764eebc197c70d2a9fbd50d7 /drivers/pci/pci-imx6.c | |
| parent | 5a7a0ec30661559c65c8085c8949cab1ec3bccd6 (diff) | |
| download | barebox-0aa89c9deaebf3d1258814f38930abd8ec0987ab.tar.gz barebox-0aa89c9deaebf3d1258814f38930abd8ec0987ab.tar.xz | |
PCI: imx6: Move link up check into imx6_pcie_wait_for_link()
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@pengutronix.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Diffstat (limited to 'drivers/pci/pci-imx6.c')
| -rw-r--r-- | drivers/pci/pci-imx6.c | 20 |
1 files changed, 19 insertions, 1 deletions
diff --git a/drivers/pci/pci-imx6.c b/drivers/pci/pci-imx6.c index fc56a0d14a..53d767824a 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)) |