This is a note to let you know that I've just added the patch titled MIPS: pci-rt2880: fix slot 0 configuration to the 5.12-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: mips-pci-rt2880-fix-slot-0-configuration.patch and it can be found in the queue-5.12 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From 8e98b697006d749d745d3b174168a877bb96c500 Mon Sep 17 00:00:00 2001 From: Ilya Lipnitskiy <ilya.lipnitskiy@xxxxxxxxx> Date: Tue, 13 Apr 2021 20:12:33 -0700 Subject: MIPS: pci-rt2880: fix slot 0 configuration From: Ilya Lipnitskiy <ilya.lipnitskiy@xxxxxxxxx> commit 8e98b697006d749d745d3b174168a877bb96c500 upstream. pci_fixup_irqs() used to call pcibios_map_irq on every PCI device, which for RT2880 included bus 0 slot 0. After pci_fixup_irqs() got removed, only slots/funcs with devices attached would be called. While arguably the right thing, that left no chance for this driver to ever initialize slot 0, effectively bricking PCI and USB on RT2880 devices such as the Belkin F5D8235-4 v1. Slot 0 configuration needs to happen after PCI bus enumeration, but before any device at slot 0x11 (func 0 or 1) is talked to. That was determined empirically by testing on a Belkin F5D8235-4 v1 device. A minimal BAR 0 config write followed by read, then setting slot 0 PCI_COMMAND to MASTER | IO | MEMORY is all that seems to be required for proper functionality. Tested by ensuring that full- and high-speed USB devices get enumerated on the Belkin F5D8235-4 v1 (with an out of tree DTS file from OpenWrt). Fixes: 04c81c7293df ("MIPS: PCI: Replace pci_fixup_irqs() call with host bridge IRQ mapping hooks") Signed-off-by: Ilya Lipnitskiy <ilya.lipnitskiy@xxxxxxxxx> Cc: Lorenzo Pieralisi <lorenzo.pieralisi@xxxxxxx> Cc: Tobias Wolf <dev-NTEO@xxxxxxxxx> Cc: <stable@xxxxxxxxxxxxxxx> # v4.14+ Signed-off-by: Thomas Bogendoerfer <tsbogend@xxxxxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- arch/mips/pci/pci-rt2880.c | 37 ++++++++++++++++++++++++------------- 1 file changed, 24 insertions(+), 13 deletions(-) --- a/arch/mips/pci/pci-rt2880.c +++ b/arch/mips/pci/pci-rt2880.c @@ -180,7 +180,6 @@ static inline void rt2880_pci_write_u32( int pcibios_map_irq(const struct pci_dev *dev, u8 slot, u8 pin) { - u16 cmd; int irq = -1; if (dev->bus->number != 0) @@ -188,8 +187,6 @@ int pcibios_map_irq(const struct pci_dev switch (PCI_SLOT(dev->devfn)) { case 0x00: - rt2880_pci_write_u32(PCI_BASE_ADDRESS_0, 0x08000000); - (void) rt2880_pci_read_u32(PCI_BASE_ADDRESS_0); break; case 0x11: irq = RT288X_CPU_IRQ_PCI; @@ -201,16 +198,6 @@ int pcibios_map_irq(const struct pci_dev break; } - pci_write_config_byte((struct pci_dev *) dev, - PCI_CACHE_LINE_SIZE, 0x14); - pci_write_config_byte((struct pci_dev *) dev, PCI_LATENCY_TIMER, 0xFF); - pci_read_config_word((struct pci_dev *) dev, PCI_COMMAND, &cmd); - cmd |= PCI_COMMAND_MASTER | PCI_COMMAND_IO | PCI_COMMAND_MEMORY | - PCI_COMMAND_INVALIDATE | PCI_COMMAND_FAST_BACK | - PCI_COMMAND_SERR | PCI_COMMAND_WAIT | PCI_COMMAND_PARITY; - pci_write_config_word((struct pci_dev *) dev, PCI_COMMAND, cmd); - pci_write_config_byte((struct pci_dev *) dev, PCI_INTERRUPT_LINE, - dev->irq); return irq; } @@ -251,6 +238,30 @@ static int rt288x_pci_probe(struct platf int pcibios_plat_dev_init(struct pci_dev *dev) { + static bool slot0_init; + + /* + * Nobody seems to initialize slot 0, but this platform requires it, so + * do it once when some other slot is being enabled. The PCI subsystem + * should configure other slots properly, so no need to do anything + * special for those. + */ + if (!slot0_init && dev->bus->number == 0) { + u16 cmd; + u32 bar0; + + slot0_init = true; + + pci_bus_write_config_dword(dev->bus, 0, PCI_BASE_ADDRESS_0, + 0x08000000); + pci_bus_read_config_dword(dev->bus, 0, PCI_BASE_ADDRESS_0, + &bar0); + + pci_bus_read_config_word(dev->bus, 0, PCI_COMMAND, &cmd); + cmd |= PCI_COMMAND_MASTER | PCI_COMMAND_IO | PCI_COMMAND_MEMORY; + pci_bus_write_config_word(dev->bus, 0, PCI_COMMAND, cmd); + } + return 0; } Patches currently in stable-queue which might be from ilya.lipnitskiy@xxxxxxxxx are queue-5.12/mips-pci-mt7620-fix-pll-lock-check.patch queue-5.12/mips-pci-rt2880-fix-slot-0-configuration.patch