target/linux/mvebu/patches-4.14/528-arm64-dts-armada-3720-espressobin-set-max-link-to-ge.patch

   1 From 33f8fdcedb01680427328d710594facef7a0092c Mon Sep 17 00:00:00 2001
   2 From: Tomasz Maciej Nowak <tmn505@gmail.com>
   3 Date: Thu, 14 Jun 2018 14:40:26 +0200
   4 Subject: [PATCH 2/2] arm64: dts: armada-3720-espressobin: set max link to gen1
   5
   6 Since the beginning there's been an issue with initializing the Atheros
   7 based MiniPCIe wireless cards. Here's an example of kerenel log:
   8
   9  OF: PCI: host bridge /soc/pcie@d0070000 ranges:
  10  OF: PCI:   MEM 0xe8000000..0xe8ffffff -> 0xe8000000
  11  OF: PCI:    IO 0xe9000000..0xe900ffff -> 0xe9000000
  12  advk-pcie d0070000.pcie: link up
  13  advk-pcie d0070000.pcie: PCI host bridge to bus 0000:00
  14  pci_bus 0000:00: root bus resource [bus 00-ff]
  15  pci_bus 0000:00: root bus resource [mem0xe8000000-0xe8ffffff]
  16  pci_bus 0000:00: root bus resource [io  0x0000-0xffff](bus address [0xe9000000-0xe900ffff])
  17  pci 0000:00:00.0: BAR 0: assigned [mem0xe8000000-0xe801ffff 64bit]
  18  pci 0000:00:00.0: BAR 6: assigned [mem0xe8020000-0xe802ffff pref]
  19  [...]
  20  advk-pcie d0070000.pcie: Posted PIO Response Status: CA,0xe00 @ 0x3c
  21  advk-pcie d0070000.pcie: Posted PIO Response Status: CA,0xe00 @ 0x44
  22  advk-pcie d0070000.pcie: Posted PIO Response Status: CA,0xe00 @ 0x4
  23  ath9k 0000:00:00.0: enabling device (0000 -> 0002)
  24  advk-pcie d0070000.pcie: Posted PIO Response Status: CA,0xe00 @ 0x3c
  25  advk-pcie d0070000.pcie: Posted PIO Response Status: CA,0xe00 @ 0xc
  26  advk-pcie d0070000.pcie: Posted PIO Response Status: CA,0xe00 @ 0x4
  27  advk-pcie d0070000.pcie: Posted PIO Response Status: CA,0xe00 @ 0x40
  28  ath9k 0000:00:00.0: request_irq failed
  29  advk-pcie d0070000.pcie: Posted PIO Response Status: CA,0xe00 @ 0x4
  30  ath9k: probe of 0000:00:00.0 failed with error -22
  31
  32 The same happens for ath5k cards, while ath10k card didn't appear at
  33 all (not detected):
  34
  35  OF: PCI: host bridge /soc/pcie@d0070000 ranges:
  36  OF: PCI:   MEM 0xe8000000..0xe8ffffff -> 0xe8000000
  37  OF: PCI:    IO 0xe9000000..0xe900ffff -> 0xe9000000
  38  advk-pcie d0070000.pcie: link never came up
  39  advk-pcie d0070000.pcie: PCI host bridge to bus 0000:00
  40  pci_bus 0000:00: root bus resource [bus 00-ff]
  41  pci_bus 0000:00: root bus resource [mem0xe8000000-0xe8ffffff]
  42  pci_bus 0000:00: root bus resource [io  0x0000-0xffff](bus address [0xe9000000-0xe900ffff])
  43  advk-pcie d0070000.pcie: config read/write timed out
  44
  45 Following the issue on esppressobin.net forum [1] the workaround seems
  46 to be limiting the speed of PCIe bridge to 1st generation. This fixed
  47 the initialisation of all tested Atheros wireless cards.
  48 The patch in the forum thread swaped registers which would limit speed
  49 for all Armada 3700 based boards. The approach in this patch, in
  50 conjunction with "PCI: aardvark: allow to specify link capability" patch
  51 is less invasive, it only touches the affected board.
  52
  53 For the record, the iwlwifi and mt76 cards were not affected by this
  54 issue.
  55
  56 1. http://espressobin.net/forums/topic/which-pcie-wlan-cards-are-supported
  57
  58 Signed-off-by: Tomasz Maciej Nowak <tmn505@gmail.com>
  59 ---
  60  arch/arm64/boot/dts/marvell/armada-3720-espressobin.dts | 2 ++
  61  1 file changed, 2 insertions(+)
  62
  63 --- a/arch/arm64/boot/dts/marvell/armada-3720-espressobin.dts
  64 +++ b/arch/arm64/boot/dts/marvell/armada-3720-espressobin.dts
  65 @@ -83,6 +83,8 @@
  66  /* J9 */
  67  &pcie0 {
  68         status = "okay";
  69 +
  70 +       max-link-speed = <1>;
  71  };
  72
  73  /* J6 */