This is a note to let you know that I've just added the patch titled

PCI: mvebu: Handle changes to the bridge windows while enabled

to the 4.4-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...

The filename of the patch is: pci-mvebu-handle-changes-to-the-bridge-windows-while-enabled.patch and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let stable@vger.kernel.org know about it.

From foo@baz Thu Nov 9 18:22:51 CET 2017

From: Jason Gunthorpe jgunthorpe@obsidianresearch.com Date: Mon, 12 Dec 2016 11:30:20 -0700 Subject: PCI: mvebu: Handle changes to the bridge windows while enabled

From: Jason Gunthorpe jgunthorpe@obsidianresearch.com

[ Upstream commit d9bf28e2650fe3eeefed7e34841aea07d10c6543 ]

The PCI core will write to the bridge window config multiple times while they are enabled. This can lead to mbus failures like this:

mvebu_mbus: cannot add window '4:e8', conflicts with another window mvebu-pcie mbus:pex@e0000000: Could not create MBus window at [mem 0xe0000000-0xe00fffff]: -22

For me this is happening during a hotplug cycle. The PCI core is not changing the values, just writing them twice while active.

The patch addresses the general case of any change to an active window, but not atomically. The code is slightly refactored so io and mem can share more of the window logic.

Signed-off-by: Jason Gunthorpe jgunthorpe@obsidianresearch.com Signed-off-by: Bjorn Helgaas bhelgaas@google.com Acked-by: Jason Cooper jason@lakedaemon.net Signed-off-by: Sasha Levin alexander.levin@verizon.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/pci/host/pci-mvebu.c | 101 +++++++++++++++++++++++++------------------ 1 file changed, 60 insertions(+), 41 deletions(-)

--- a/drivers/pci/host/pci-mvebu.c +++ b/drivers/pci/host/pci-mvebu.c @@ -131,6 +131,12 @@ struct mvebu_pcie { int nports; };

+struct mvebu_pcie_window { + phys_addr_t base; + phys_addr_t remap; + size_t size; +}; + /* Structure representing one PCIe interface */ struct mvebu_pcie_port { char *name; @@ -148,10 +154,8 @@ struct mvebu_pcie_port { struct mvebu_sw_pci_bridge bridge; struct device_node *dn; struct mvebu_pcie *pcie; - phys_addr_t memwin_base; - size_t memwin_size; - phys_addr_t iowin_base; - size_t iowin_size; + struct mvebu_pcie_window memwin; + struct mvebu_pcie_window iowin; u32 saved_pcie_stat; };

@@ -377,23 +381,45 @@ static void mvebu_pcie_add_windows(struc } }

+static void mvebu_pcie_set_window(struct mvebu_pcie_port *port, + unsigned int target, unsigned int attribute, + const struct mvebu_pcie_window *desired, + struct mvebu_pcie_window *cur) +{ + if (desired->base == cur->base && desired->remap == cur->remap && + desired->size == cur->size) + return; + + if (cur->size != 0) { + mvebu_pcie_del_windows(port, cur->base, cur->size); + cur->size = 0; + cur->base = 0; + + /* + * If something tries to change the window while it is enabled + * the change will not be done atomically. That would be + * difficult to do in the general case. + */ + } + + if (desired->size == 0) + return; + + mvebu_pcie_add_windows(port, target, attribute, desired->base, + desired->size, desired->remap); + *cur = *desired; +} + static void mvebu_pcie_handle_iobase_change(struct mvebu_pcie_port *port) { - phys_addr_t iobase; + struct mvebu_pcie_window desired = {};

/* Are the new iobase/iolimit values invalid? */ if (port->bridge.iolimit < port->bridge.iobase || port->bridge.iolimitupper < port->bridge.iobaseupper || !(port->bridge.command & PCI_COMMAND_IO)) { - - /* If a window was configured, remove it */ - if (port->iowin_base) { - mvebu_pcie_del_windows(port, port->iowin_base, - port->iowin_size); - port->iowin_base = 0; - port->iowin_size = 0; - } - + mvebu_pcie_set_window(port, port->io_target, port->io_attr, + &desired, &port->iowin); return; }

@@ -410,32 +436,27 @@ static void mvebu_pcie_handle_iobase_cha * specifications. iobase is the bus address, port->iowin_base * is the CPU address. */ - iobase = ((port->bridge.iobase & 0xF0) << 8) | - (port->bridge.iobaseupper << 16); - port->iowin_base = port->pcie->io.start + iobase; - port->iowin_size = ((0xFFF | ((port->bridge.iolimit & 0xF0) << 8) | - (port->bridge.iolimitupper << 16)) - - iobase) + 1; - - mvebu_pcie_add_windows(port, port->io_target, port->io_attr, - port->iowin_base, port->iowin_size, - iobase); + desired.remap = ((port->bridge.iobase & 0xF0) << 8) | + (port->bridge.iobaseupper << 16); + desired.base = port->pcie->io.start + desired.remap; + desired.size = ((0xFFF | ((port->bridge.iolimit & 0xF0) << 8) | + (port->bridge.iolimitupper << 16)) - + desired.remap) + + 1; + + mvebu_pcie_set_window(port, port->io_target, port->io_attr, &desired, + &port->iowin); }

static void mvebu_pcie_handle_membase_change(struct mvebu_pcie_port *port) { + struct mvebu_pcie_window desired = {.remap = MVEBU_MBUS_NO_REMAP}; + /* Are the new membase/memlimit values invalid? */ if (port->bridge.memlimit < port->bridge.membase || !(port->bridge.command & PCI_COMMAND_MEMORY)) { - - /* If a window was configured, remove it */ - if (port->memwin_base) { - mvebu_pcie_del_windows(port, port->memwin_base, - port->memwin_size); - port->memwin_base = 0; - port->memwin_size = 0; - } - + mvebu_pcie_set_window(port, port->mem_target, port->mem_attr, + &desired, &port->memwin); return; }

@@ -445,14 +466,12 @@ static void mvebu_pcie_handle_membase_ch * window to setup, according to the PCI-to-PCI bridge * specifications. */ - port->memwin_base = ((port->bridge.membase & 0xFFF0) << 16); - port->memwin_size = - (((port->bridge.memlimit & 0xFFF0) << 16) | 0xFFFFF) - - port->memwin_base + 1; - - mvebu_pcie_add_windows(port, port->mem_target, port->mem_attr, - port->memwin_base, port->memwin_size, - MVEBU_MBUS_NO_REMAP); + desired.base = ((port->bridge.membase & 0xFFF0) << 16); + desired.size = (((port->bridge.memlimit & 0xFFF0) << 16) | 0xFFFFF) - + desired.base + 1; + + mvebu_pcie_set_window(port, port->mem_target, port->mem_attr, &desired, + &port->memwin); }

/*

Patches currently in stable-queue which might be from jgunthorpe@obsidianresearch.com are

queue-4.4/pci-mvebu-handle-changes-to-the-bridge-windows-while-enabled.patch