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From:   George Cherian <george.cherian@cavium.com>
To:     linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org
Cc:     bhelgaas@google.com, Jayachandran.Nair@cavium.com,
        Robert.Richter@cavium.com,
        George Cherian <george.cherian@cavium.com>
Subject: [PATCH] PCI: Add quirk for Cavium Thunder-X2 PCIe erratum #173
Date:   Fri,  2 Feb 2018 07:00:46 +0000
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The PCIe Controller on Cavium ThunderX2 processors does not
respond to downstream CFG/ECFG cycles when root port is
in power management D3-hot state.

In our tests the above mentioned errata causes the following crash when
the downstream endpoint config space is accessed, while root port is in
D3 state.

[   12.775202] Unhandled fault: synchronous external abort (0x96000610) at 0x0000000000000000
[   12.783453] Internal error: : 96000610 [#1] SMP
[   12.787971] Modules linked in: aes_neon_blk ablk_helper cryptd
[   12.793799] CPU: 1 PID: 1 Comm: swapper/0 Not tainted 4.8.0-32-generic #34
[   12.800659] Hardware name: Cavium Inc. Unknown/Unknown, BIOS 1.0 01/01/2018
[   12.807607] task: ffff808f346b8d80 task.stack: ffff808f346b4000
[   12.813518] PC is at pci_generic_config_read+0x5c/0xf0
[   12.818643] LR is at pci_generic_config_read+0x48/0xf0
[   12.823767] pc : [<ffff000008506f34>] lr : [<ffff000008506f20>] pstate: 204000c9
[   12.831148] sp : ffff808f346b7bf0
[   12.834449] x29: ffff808f346b7bf0 x28: ffff000008e2b848
[   12.839750] x27: ffff000008dc3070 x26: ffff000008d516c0
[   12.845050] x25: 0000000000000040 x24: ffff00000937a480
[   12.850351] x23: 000000000000006c x22: 0000000000000000
[   12.855651] x21: ffff808f346b7c84 x20: 0000000000000004
[   12.860951] x19: ffff808f31076000 x18: 0000000000000000
[   12.866251] x17: 000000001b3613e6 x16: 000000007f330457
[   12.871551] x15: 0000000067268ad7 x14: 000000005c6254ac
[   12.876851] x13: 00000000f1e100cb x12: 0000000000000030
[   12.882151] x11: 0101010101010101 x10: 7f7f7f7f7f7f7f7f
[   12.887452] x9 : ff656d6e626d686f x8 : 7f7f7f7f7f7f7f7f
[   12.892752] x7 : ffff808f310da108 x6 : 0000000000000000
[   12.898052] x5 : 0000000000000003 x4 : ffff808f3107a800
[   12.903352] x3 : 000000000030006c x2 : 0000000000000014
[   12.908652] x1 : ffff000020000000 x0 : ffff00002030006c
[   12.913952]
[   12.915431] Process swapper/0 (pid: 1, stack limit = 0xffff808f346b4020)
[   12.922118] Stack: (0xffff808f346b7bf0 to 0xffff808f346b8000)
[   12.927850] 7be0:                                   ffff808f346b7c30 ffff000008506e2c
[   12.935665] 7c00: ffff000009185000 000000000000006c ffff808f31076000 ffff808f346b7d14
[   12.943481] 7c20: 0000000000000000 ffff000008309488 ffff808f346b7c90 ffff0000085089f4
[   12.951296] 7c40: 0000000000000004 ffff808f310d4000 0000000000000000 ffff808f346b7d14
[   12.959111] 7c60: 0000000000000068 ffff000008dc3078 ffff000008d604c8 ffff0000085089d8
[   12.966927] 7c80: 0000000000000004 000000000004080b ffff808f346b7cd0 ffff000008513d28
[   12.974742] 7ca0: ffff000009185000 00000000ffffffe7 0000000000000001 ffff808f310d4000
[   12.982557] 7cc0: ffff0000092ae000 ffff808f310d4000 ffff808f346b7d20 ffff0000085142d4
[   12.990372] 7ce0: ffff808f310d4000 ffff808f310d4000 ffff000009214000 ffff808f310d40b0
[   12.998188] 7d00: ffff0000092ae000 ffff808f310d40b0 00000000092ae000 000000000004080b
[   13.006003] 7d20: ffff808f346b7d40 ffff000008518754 0000000000000000 ffff808f310d4000
[   13.013818] 7d40: ffff808f346b7d80 ffff000008d9a974 0000000000000000 ffff808f310d4000
[   13.021634] 7d60: ffff000008d9a93c 0000000000000000 ffff0000092ae000 000000000004080b
[   13.029449] 7d80: ffff808f346b7da0 ffff000008083b4c ffff000009185000 ffff808f346b4000
[   13.037264] 7da0: ffff808f346b7e30 ffff000008d60dfc 00000000000000f5 ffff000009185000
[   13.045079] 7dc0: ffff0000092ae000 0000000000000007 ffff0000092ae000 ffff000008dc3078
[   13.052895] 7de0: ffff000008d604c8 ffff000008d51600 ffff000008dc3070 ffff000008e2b720
[   13.060710] 7e00: ffff0000091a68d8 ffff000008c09678 0000000000000000 0000000700000007
[   13.068526] 7e20: 0000000000000000 000000000004080b ffff808f346b7ea0 ffff000008980d90
[   13.076342] 7e40: ffff000008980d78 0000000000000000 0000000000000000 0000000000000000
[   13.084157] 7e60: 0000000000000000 0000000000000000 0000000000000000 0000000000000000
[   13.091972] 7e80: 0000000000000000 0000000000000000 0000000000000000 000000000004080b
[   13.099788] 7ea0: 0000000000000000 ffff000008083690 ffff000008980d78 0000000000000000
[   13.107603] 7ec0: 0000000000000000 0000000000000000 0000000000000000 0000000000000000
[   13.115418] 7ee0: 0000000000000000 0000000000000000 0000000000000000 0000000000000000
[   13.123233] 7f00: 0000000000000000 0000000000000000 0000000000000000 0000000000000000
[   13.131048] 7f20: 0000000000000000 0000000000000000 0000000000000000 0000000000000000
[   13.138864] 7f40: 0000000000000000 0000000000000000 0000000000000000 0000000000000000
[   13.146679] 7f60: 0000000000000000 0000000000000000 0000000000000000 0000000000000000
[   13.154494] 7f80: 0000000000000000 0000000000000000 0000000000000000 0000000000000000
[   13.162309] 7fa0: 0000000000000000 0000000000000000 0000000000000000 0000000000000000
[   13.170125] 7fc0: 0000000000000000 0000000000000005 0000000000000000 0000000000000000
[   13.177940] 7fe0: 0000000000000000 0000000000000000 0000000000000000 0000000000000000
[   13.185755] Call trace:
[   13.188190] Exception stack(0xffff808f346b7a00 to 0xffff808f346b7b30)
[   13.194616] 7a00: ffff808f31076000 0001000000000000 ffff808f346b7bf0 ffff000008506f34
[   13.202432] 7a20: 00000000204000c9 0000000000000003 ffff000009660000 0000000000000007
[   13.210247] 7a40: ffff000000000000 0000000000000000 ffff0000092c2d3b 414d48203a6d7665
[   13.218062] 7a60: 3a73727474612043 0000000000000024 0000000005f5e0ff 0000000000000006
[   13.225878] 7a80: 0000000000000007 ffff0000092c2d25 ffff808f346b7aa0 ffff00000849bc1c
[   13.233693] 7aa0: ffff808f346b7b20 ffff00000849c100 0000000000000000 000000000004080b
[   13.241508] 7ac0: ffff00002030006c ffff000020000000 0000000000000014 000000000030006c
[   13.249323] 7ae0: ffff808f3107a800 0000000000000003 0000000000000000 ffff808f310da108
[   13.257139] 7b00: 7f7f7f7f7f7f7f7f ff656d6e626d686f 7f7f7f7f7f7f7f7f 0101010101010101
[   13.264953] 7b20: 0000000000000030 00000000f1e100cb
[   13.269819] [<ffff000008506f34>] pci_generic_config_read+0x5c/0xf0
[   13.275987] [<ffff000008506e2c>] pci_bus_read_config_dword+0xb4/0xd8
[   13.282328] [<ffff0000085089f4>] pcie_capability_read_dword+0x64/0xb8
[   13.288757] [<ffff000008513d28>] __pci_dev_reset+0x90/0x328
[   13.294317] [<ffff0000085142d4>] pci_probe_reset_function+0x24/0x30
[   13.300571] [<ffff000008518754>] pci_create_sysfs_dev_files+0x18c/0x2a0
[   13.307173] [<ffff000008d9a974>] pci_sysfs_init+0x38/0x60
[   13.312560] [<ffff000008083b4c>] do_one_initcall+0x5c/0x170
[   13.318122] [<ffff000008d60dfc>] kernel_init_freeable+0x1c0/0x27c
[   13.324205] [<ffff000008980d90>] kernel_init+0x18/0x110
[   13.329416] [<ffff000008083690>] ret_from_fork+0x10/0x40
[   13.334716] Code: 7100069f 540003c0 71000a9f 54000240 (b9400001)
[   13.340805] ---[ end trace fc992038acd29ec3 ]---

Fix this by adding a quirk that prevents the root port from 
entering D3 state. This is seen on both Ax/Bx variants of the processor.

Signed-off-by: George Cherian <george.cherian@cavium.com>
---
 drivers/pci/quirks.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
index 10684b1..2eb08a8 100644
--- a/drivers/pci/quirks.c
+++ b/drivers/pci/quirks.c
@@ -1154,6 +1154,18 @@ static void quirk_ide_samemode(struct pci_dev *pdev)
 DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_82801CA_10, quirk_ide_samemode);
 
 /*
+ * Cavium's Thunder-X2 Processors root port doesnot handle cfg/ecfg access to
+ * downstream properly if root port is put into D3
+ */
+
+static void quirk_no_rootport_d3(struct pci_dev *pdev)
+{
+	pdev->dev_flags |= PCI_DEV_FLAGS_NO_D3;
+}
+DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_BROADCOM, 0x9084, quirk_no_rootport_d3);
+DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_CAVIUM, 0xaf84, quirk_no_rootport_d3);
+
+/*
  * Some ATA devices break if put into D3
  */
 
-- 
2.1.4