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From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-kernel@vger.kernel.org
Cc: "Greg Kroah-Hartman" <gregkh@linuxfoundation.org>,
	stable@vger.kernel.org, "Stefan Mätje" <stefan.maetje@esd.eu>,
	"Bjorn Helgaas" <bhelgaas@google.com>,
	"Andy Shevchenko" <andriy.shevchenko@linux.intel.com>
Subject: [PATCH 4.9 40/53] PCI: Work around Pericom PCIe-to-PCI bridge Retrain Link erratum
Date: Thu, 23 May 2019 21:06:04 +0200	[thread overview]
Message-ID: <20190523181717.257997954@linuxfoundation.org> (raw)
In-Reply-To: <20190523181710.981455400@linuxfoundation.org>

From: Stefan Mätje <stefan.maetje@esd.eu>

commit 4ec73791a64bab25cabf16a6067ee478692e506d upstream.

Due to an erratum in some Pericom PCIe-to-PCI bridges in reverse mode
(conventional PCI on primary side, PCIe on downstream side), the Retrain
Link bit needs to be cleared manually to allow the link training to
complete successfully.

If it is not cleared manually, the link training is continuously restarted
and no devices below the PCI-to-PCIe bridge can be accessed.  That means
drivers for devices below the bridge will be loaded but won't work and may
even crash because the driver is only reading 0xffff.

See the Pericom Errata Sheet PI7C9X111SLB_errata_rev1.2_102711.pdf for
details.  Devices known as affected so far are: PI7C9X110, PI7C9X111SL,
PI7C9X130.

Add a new flag, clear_retrain_link, in struct pci_dev.  Quirks for affected
devices set this bit.

Note that pcie_retrain_link() lives in aspm.c because that's currently the
only place we use it, but this erratum is not specific to ASPM, and we may
retrain links for other reasons in the future.

Signed-off-by: Stefan Mätje <stefan.maetje@esd.eu>
[bhelgaas: apply regardless of CONFIG_PCIEASPM]
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
CC: stable@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/pci/pcie/aspm.c |    9 +++++++++
 drivers/pci/quirks.c    |   17 +++++++++++++++++
 include/linux/pci.h     |    2 ++
 3 files changed, 28 insertions(+)

--- a/drivers/pci/pcie/aspm.c
+++ b/drivers/pci/pcie/aspm.c
@@ -181,6 +181,15 @@ static bool pcie_retrain_link(struct pci
 	pcie_capability_read_word(parent, PCI_EXP_LNKCTL, &reg16);
 	reg16 |= PCI_EXP_LNKCTL_RL;
 	pcie_capability_write_word(parent, PCI_EXP_LNKCTL, reg16);
+	if (parent->clear_retrain_link) {
+		/*
+		 * Due to an erratum in some devices the Retrain Link bit
+		 * needs to be cleared again manually to allow the link
+		 * training to succeed.
+		 */
+		reg16 &= ~PCI_EXP_LNKCTL_RL;
+		pcie_capability_write_word(parent, PCI_EXP_LNKCTL, reg16);
+	}
 
 	/* Wait for link training end. Break out after waiting for timeout */
 	start_jiffies = jiffies;
--- a/drivers/pci/quirks.c
+++ b/drivers/pci/quirks.c
@@ -2046,6 +2046,23 @@ DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_IN
 DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_INTEL, 0x10f4, quirk_disable_aspm_l0s);
 DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_INTEL, 0x1508, quirk_disable_aspm_l0s);
 
+/*
+ * Some Pericom PCIe-to-PCI bridges in reverse mode need the PCIe Retrain
+ * Link bit cleared after starting the link retrain process to allow this
+ * process to finish.
+ *
+ * Affected devices: PI7C9X110, PI7C9X111SL, PI7C9X130.  See also the
+ * Pericom Errata Sheet PI7C9X111SLB_errata_rev1.2_102711.pdf.
+ */
+static void quirk_enable_clear_retrain_link(struct pci_dev *dev)
+{
+	dev->clear_retrain_link = 1;
+	pci_info(dev, "Enable PCIe Retrain Link quirk\n");
+}
+DECLARE_PCI_FIXUP_HEADER(0x12d8, 0xe110, quirk_enable_clear_retrain_link);
+DECLARE_PCI_FIXUP_HEADER(0x12d8, 0xe111, quirk_enable_clear_retrain_link);
+DECLARE_PCI_FIXUP_HEADER(0x12d8, 0xe130, quirk_enable_clear_retrain_link);
+
 static void fixup_rev1_53c810(struct pci_dev *dev)
 {
 	u32 class = dev->class;
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -320,6 +320,8 @@ struct pci_dev {
 	unsigned int	hotplug_user_indicators:1; /* SlotCtl indicators
 						      controlled exclusively by
 						      user sysfs */
+	unsigned int	clear_retrain_link:1;	/* Need to clear Retrain Link
+						   bit manually */
 	unsigned int	d3_delay;	/* D3->D0 transition time in ms */
 	unsigned int	d3cold_delay;	/* D3cold->D0 transition time in ms */
 



  parent reply	other threads:[~2019-05-23 19:09 UTC|newest]

Thread overview: 58+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-05-23 19:05 [PATCH 4.9 00/53] 4.9.179-stable review Greg Kroah-Hartman
2019-05-23 19:05 ` [PATCH 4.9 01/53] net: avoid weird emergency message Greg Kroah-Hartman
2019-05-23 19:05 ` [PATCH 4.9 02/53] net/mlx4_core: Change the error print to info print Greg Kroah-Hartman
2019-05-23 19:05 ` [PATCH 4.9 03/53] ppp: deflate: Fix possible crash in deflate_init Greg Kroah-Hartman
2019-05-23 19:05 ` [PATCH 4.9 04/53] tipc: switch order of device registration to fix a crash Greg Kroah-Hartman
2019-05-23 19:05 ` [PATCH 4.9 05/53] vsock/virtio: free packets during the socket release Greg Kroah-Hartman
2019-05-23 19:05 ` [PATCH 4.9 06/53] tipc: fix modprobe tipc failed after switch order of device registration Greg Kroah-Hartman
2019-05-23 19:05 ` [PATCH 4.9 07/53] vsock/virtio: Initialize core virtio vsock before registering the driver Greg Kroah-Hartman
2019-05-23 19:05 ` [PATCH 4.9 08/53] parisc: Export running_on_qemu symbol for modules Greg Kroah-Hartman
2019-05-23 19:05 ` [PATCH 4.9 09/53] parisc: Skip registering LED when running in QEMU Greg Kroah-Hartman
2019-05-23 19:05 ` [PATCH 4.9 10/53] parisc: Rename LEVEL to PA_ASM_LEVEL to avoid name clash with DRBD code Greg Kroah-Hartman
2019-05-23 19:05 ` [PATCH 4.9 11/53] stm class: Fix channel free in stm output free path Greg Kroah-Hartman
2019-05-23 19:05 ` [PATCH 4.9 12/53] md: add mddev->pers to avoid potential NULL pointer dereference Greg Kroah-Hartman
2019-05-23 19:05 ` [PATCH 4.9 13/53] intel_th: msu: Fix single mode with IOMMU Greg Kroah-Hartman
2019-05-23 19:05 ` [PATCH 4.9 14/53] p54: drop device reference count if fails to enable device Greg Kroah-Hartman
2019-05-23 19:05 ` [PATCH 4.9 15/53] of: fix clang -Wunsequenced for be32_to_cpu() Greg Kroah-Hartman
2019-05-23 19:05 ` [PATCH 4.9 16/53] cifs: fix strcat buffer overflow and reduce raciness in smb21_set_oplock_level() Greg Kroah-Hartman
2019-05-23 19:05 ` [PATCH 4.9 17/53] media: ov6650: Fix sensor possibly not detected on probe Greg Kroah-Hartman
2019-05-23 19:05 ` [PATCH 4.9 18/53] NFS4: Fix v4.0 client state corruption when mount Greg Kroah-Hartman
2019-05-23 19:05 ` [PATCH 4.9 19/53] clk: tegra: Fix PLLM programming on Tegra124+ when PMC overrides divider Greg Kroah-Hartman
2019-05-23 19:05 ` [PATCH 4.9 20/53] fuse: fix writepages on 32bit Greg Kroah-Hartman
2019-05-23 19:05 ` [PATCH 4.9 21/53] fuse: honor RLIMIT_FSIZE in fuse_file_fallocate Greg Kroah-Hartman
2019-05-23 19:05 ` [PATCH 4.9 22/53] iommu/tegra-smmu: Fix invalid ASID bits on Tegra30/114 Greg Kroah-Hartman
2019-05-23 19:05 ` [PATCH 4.9 23/53] ceph: flush dirty inodes before proceeding with remount Greg Kroah-Hartman
2019-05-23 19:05 ` [PATCH 4.9 24/53] tracing: Fix partial reading of trace events id file Greg Kroah-Hartman
2019-05-23 19:05 ` [PATCH 4.9 25/53] memory: tegra: Fix integer overflow on tick value calculation Greg Kroah-Hartman
2019-05-23 19:05 ` [PATCH 4.9 26/53] perf intel-pt: Fix instructions sampling rate Greg Kroah-Hartman
2019-05-23 19:05 ` [PATCH 4.9 27/53] perf intel-pt: Fix improved sample timestamp Greg Kroah-Hartman
2019-05-23 19:05 ` [PATCH 4.9 28/53] perf intel-pt: Fix sample timestamp wrt non-taken branches Greg Kroah-Hartman
2019-05-23 19:05 ` [PATCH 4.9 29/53] objtool: Allow AR to be overridden with HOSTAR Greg Kroah-Hartman
2019-05-23 19:05 ` [PATCH 4.9 30/53] fbdev: sm712fb: fix brightness control on reboot, dont set SR30 Greg Kroah-Hartman
2019-05-23 19:05 ` [PATCH 4.9 31/53] fbdev: sm712fb: fix VRAM detection, dont set SR70/71/74/75 Greg Kroah-Hartman
2019-05-23 19:05 ` [PATCH 4.9 32/53] fbdev: sm712fb: fix white screen of death on reboot, dont set CR3B-CR3F Greg Kroah-Hartman
2019-05-23 19:05 ` [PATCH 4.9 33/53] fbdev: sm712fb: fix boot screen glitch when sm712fb replaces VGA Greg Kroah-Hartman
2019-05-23 19:05 ` [PATCH 4.9 34/53] fbdev: sm712fb: fix crashes during framebuffer writes by correctly mapping VRAM Greg Kroah-Hartman
2019-05-23 19:05 ` [PATCH 4.9 35/53] fbdev: sm712fb: fix support for 1024x768-16 mode Greg Kroah-Hartman
2019-05-23 19:06 ` [PATCH 4.9 36/53] fbdev: sm712fb: use 1024x768 by default on non-MIPS, fix garbled display Greg Kroah-Hartman
2019-05-23 19:06 ` [PATCH 4.9 37/53] fbdev: sm712fb: fix crashes and garbled display during DPMS modesetting Greg Kroah-Hartman
2019-05-23 19:06 ` [PATCH 4.9 38/53] PCI: Mark Atheros AR9462 to avoid bus reset Greg Kroah-Hartman
2019-05-23 19:06 ` [PATCH 4.9 39/53] PCI: Factor out pcie_retrain_link() function Greg Kroah-Hartman
2019-05-23 19:06 ` Greg Kroah-Hartman [this message]
2019-05-23 19:06 ` [PATCH 4.9 41/53] dm delay: fix a crash when invalid device is specified Greg Kroah-Hartman
2019-05-23 19:06 ` [PATCH 4.9 42/53] xfrm: policy: Fix out-of-bound array accesses in __xfrm_policy_unlink Greg Kroah-Hartman
2019-05-23 19:06 ` [PATCH 4.9 43/53] xfrm6_tunnel: Fix potential panic when unloading xfrm6_tunnel module Greg Kroah-Hartman
2019-05-23 19:06 ` [PATCH 4.9 44/53] vti4: ipip tunnel deregistration fixes Greg Kroah-Hartman
2019-05-23 19:06 ` [PATCH 4.9 45/53] xfrm4: Fix uninitialized memory read in _decode_session4 Greg Kroah-Hartman
2019-05-23 19:06 ` [PATCH 4.9 46/53] mac80211: Fix kernel panic due to use of txq after free Greg Kroah-Hartman
2019-05-23 19:06 ` [PATCH 4.9 47/53] KVM: arm/arm64: Ensure vcpu target is unset on reset failure Greg Kroah-Hartman
2019-05-23 19:06 ` [PATCH 4.9 48/53] power: supply: sysfs: prevent endless uevent loop with CONFIG_POWER_SUPPLY_DEBUG Greg Kroah-Hartman
2019-05-23 19:06 ` [PATCH 4.9 49/53] ufs: fix braino in ufs_get_inode_gid() for solaris UFS flavour Greg Kroah-Hartman
2019-05-23 19:06 ` [PATCH 4.9 50/53] perf bench numa: Add define for RUSAGE_THREAD if not present Greg Kroah-Hartman
2019-05-23 19:06 ` [PATCH 4.9 51/53] Revert "Dont jump to compute_result state from check_result state" Greg Kroah-Hartman
2019-05-23 19:06 ` [PATCH 4.9 52/53] md/raid: raid5 preserve the writeback action after the parity check Greg Kroah-Hartman
2019-05-23 19:06 ` [PATCH 4.9 53/53] btrfs: Honour FITRIM range constraints during free space trim Greg Kroah-Hartman
2019-05-24  5:28 ` [PATCH 4.9 00/53] 4.9.179-stable review kernelci.org bot
2019-05-24  8:43 ` Naresh Kamboju
2019-05-24 11:04 ` Jon Hunter
2019-05-24 18:56 ` shuah

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