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

alpha/PCI: Fix noname IRQ level detection

to the 4.14-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: alpha-pci-fix-noname-irq-level-detection.patch and it can be found in the queue-4.14 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 86be89939d11a84800f66e2a283b915b704bf33d Mon Sep 17 00:00:00 2001

From: Lorenzo Pieralisi lorenzo.pieralisi@arm.com Date: Tue, 16 Jan 2018 11:52:59 +0000 Subject: alpha/PCI: Fix noname IRQ level detection

From: Lorenzo Pieralisi lorenzo.pieralisi@arm.com

commit 86be89939d11a84800f66e2a283b915b704bf33d upstream.

The conversion of the alpha architecture PCI host bridge legacy IRQ mapping/swizzling to the new PCI host bridge map/swizzle hooks carried out through:

commit 0e4c2eeb758a ("alpha/PCI: Replace pci_fixup_irqs() call with host bridge IRQ mapping hooks")

implies that IRQ for devices are now allocated through pci_assign_irq() function in pci_device_probe() that is called when a driver matching a device is found in order to probe the device through the device driver.

Alpha noname platforms required IRQ level programming to be executed in sio_fixup_irq_levels(), that is called in noname_init_pci(), a platform hook called within a subsys_initcall.

In noname_init_pci(), present IRQs are detected through sio_collect_irq_levels() that check the struct pci_dev->irq number to detect if an IRQ has been allocated for the device.

By the time sio_collect_irq_levels() is called, some devices may still have not a matching driver loaded to match them (eg loadable module) therefore their IRQ allocation is still pending - which means that sio_collect_irq_levels() does not programme the correct IRQ level for those devices, causing their IRQ handling to be broken when the device driver is actually loaded and the device is probed.

Fix the issue by adding code in the noname map_irq() function (noname_map_irq()) that, whilst mapping/swizzling the IRQ line, it also ensures that the correct IRQ level programming is executed at platform level, fixing the issue.

Fixes: 0e4c2eeb758a ("alpha/PCI: Replace pci_fixup_irqs() call with host bridge IRQ mapping hooks") Reported-by: Mikulas Patocka mpatocka@redhat.com Signed-off-by: Lorenzo Pieralisi lorenzo.pieralisi@arm.com Cc: Bjorn Helgaas bhelgaas@google.com Cc: Richard Henderson rth@twiddle.net Cc: Ivan Kokshaysky ink@jurassic.park.msu.ru Cc: Mikulas Patocka mpatocka@redhat.com Cc: Meelis Roos mroos@linux.ee Signed-off-by: Matt Turner mattst88@gmail.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org

--- arch/alpha/kernel/sys_sio.c | 35 +++++++++++++++++++++++++++++------ 1 file changed, 29 insertions(+), 6 deletions(-)

--- a/arch/alpha/kernel/sys_sio.c +++ b/arch/alpha/kernel/sys_sio.c @@ -102,6 +102,15 @@ sio_pci_route(void) alpha_mv.sys.sio.route_tab); }

+static bool sio_pci_dev_irq_needs_level(const struct pci_dev *dev) +{ + if ((dev->class >> 16 == PCI_BASE_CLASS_BRIDGE) && + (dev->class >> 8 != PCI_CLASS_BRIDGE_PCMCIA)) + return false; + + return true; +} + static unsigned int __init sio_collect_irq_levels(void) { @@ -110,8 +119,7 @@ sio_collect_irq_levels(void)

/* Iterate through the devices, collecting IRQ levels. */ for_each_pci_dev(dev) { - if ((dev->class >> 16 == PCI_BASE_CLASS_BRIDGE) && - (dev->class >> 8 != PCI_CLASS_BRIDGE_PCMCIA)) + if (!sio_pci_dev_irq_needs_level(dev)) continue;

if (dev->irq) @@ -120,8 +128,7 @@ sio_collect_irq_levels(void) return level_bits; }

-static void __init -sio_fixup_irq_levels(unsigned int level_bits) +static void __sio_fixup_irq_levels(unsigned int level_bits, bool reset) { unsigned int old_level_bits;

@@ -139,12 +146,21 @@ sio_fixup_irq_levels(unsigned int level_ */ old_level_bits = inb(0x4d0) | (inb(0x4d1) << 8);

- level_bits |= (old_level_bits & 0x71ff); + if (reset) + old_level_bits &= 0x71ff; + + level_bits |= old_level_bits;

outb((level_bits >> 0) & 0xff, 0x4d0); outb((level_bits >> 8) & 0xff, 0x4d1); }

+static inline void +sio_fixup_irq_levels(unsigned int level_bits) +{ + __sio_fixup_irq_levels(level_bits, true); +} + static inline int noname_map_irq(const struct pci_dev *dev, u8 slot, u8 pin) { @@ -181,7 +197,14 @@ noname_map_irq(const struct pci_dev *dev const long min_idsel = 6, max_idsel = 14, irqs_per_slot = 5; int irq = COMMON_TABLE_LOOKUP, tmp; tmp = __kernel_extbl(alpha_mv.sys.sio.route_tab, irq); - return irq >= 0 ? tmp : -1; + + irq = irq >= 0 ? tmp : -1; + + /* Fixup IRQ level if an actual IRQ mapping is detected */ + if (sio_pci_dev_irq_needs_level(dev) && irq >= 0) + __sio_fixup_irq_levels(1 << irq, false); + + return irq; }

static inline int

Patches currently in stable-queue which might be from lorenzo.pieralisi@arm.com are

queue-4.14/alpha-pci-fix-noname-irq-level-detection.patch