From 5d3df935426271016b895aecaa247101b4bfa35e Mon Sep 17 00:00:00 2001 From: Russell King - ARM Linux Date: Sun, 18 Nov 2012 16:29:44 +0000 Subject: [PATCH 1/3] Dove: Attempt to fix PMU/RTC interrupts Fix the acknowledgement of PMU interrupts on Dove: some Dove hardware has not been sensibly designed so that interrupts can be handled in a race free manner. The PMU is one such instance. The pending (aka 'cause') register is a bunch of RW bits, meaning that these bits can be both cleared and set by software (confirmed on the Armada-510 on the cubox.) Hardware sets the appropriate bit when an interrupt is asserted, and software is required to clear the bits which are to be processed. If we write ~(1 << bit), then we end up asserting every other interrupt except the one we're processing. So, we need to do a read-modify-write cycle to clear the asserted bit. However, any interrupts which occur in the middle of this cycle will also be written back as zero, which will also clear the new interrupts. The upshot of this is: there is _no_ way to safely clear down interrupts in this register (and other similarly behaving interrupt pending registers on this device.) The patch below at least stops us creating new interrupts. Signed-off-by: Russell King Cc: stable@vger.kernel.org Signed-off-by: Jason Cooper --- arch/arm/mach-dove/irq.c | 14 +++++++++++++- 1 file changed, 13 insertions(+), 1 deletion(-) diff --git a/arch/arm/mach-dove/irq.c b/arch/arm/mach-dove/irq.c index 087711524e8a..bc4344aa1009 100644 --- a/arch/arm/mach-dove/irq.c +++ b/arch/arm/mach-dove/irq.c @@ -46,8 +46,20 @@ static void pmu_irq_ack(struct irq_data *d) int pin = irq_to_pmu(d->irq); u32 u; + /* + * The PMU mask register is not RW0C: it is RW. This means that + * the bits take whatever value is written to them; if you write + * a '1', you will set the interrupt. + * + * Unfortunately this means there is NO race free way to clear + * these interrupts. + * + * So, let's structure the code so that the window is as small as + * possible. + */ u = ~(1 << (pin & 31)); - writel(u, PMU_INTERRUPT_CAUSE); + u &= readl_relaxed(PMU_INTERRUPT_CAUSE); + writel_relaxed(u, PMU_INTERRUPT_CAUSE); } static struct irq_chip pmu_irq_chip = { From d356cf5a74afa32b40decca3c9dd88bc3cd63eb5 Mon Sep 17 00:00:00 2001 From: Russell King - ARM Linux Date: Sun, 18 Nov 2012 16:39:32 +0000 Subject: [PATCH 2/3] Dove: Fix irq_to_pmu() PMU interrupts start at IRQ_DOVE_PMU_START, not IRQ_DOVE_PMU_START + 1. Fix the condition. (It may have been less likely to occur had the code been written "if (irq >= IRQ_DOVE_PMU_START" which imho is the easier to understand notation, and matches the normal way of thinking about these things.) Signed-off-by: Russell King Cc: stable@vger.kernel.org Signed-off-by: Jason Cooper --- arch/arm/mach-dove/include/mach/pm.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/arm/mach-dove/include/mach/pm.h b/arch/arm/mach-dove/include/mach/pm.h index 7bcd0dfce4b1..b47f75038686 100644 --- a/arch/arm/mach-dove/include/mach/pm.h +++ b/arch/arm/mach-dove/include/mach/pm.h @@ -63,7 +63,7 @@ static inline int pmu_to_irq(int pin) static inline int irq_to_pmu(int irq) { - if (IRQ_DOVE_PMU_START < irq && irq < NR_IRQS) + if (IRQ_DOVE_PMU_START <= irq && irq < NR_IRQS) return irq - IRQ_DOVE_PMU_START; return -EINVAL; From 1dc831bf53fddcc6443f74a39e72db5bcea4f15d Mon Sep 17 00:00:00 2001 From: Jason Gunthorpe Date: Wed, 21 Nov 2012 00:19:06 -0700 Subject: [PATCH 3/3] ARM: Kirkwood: Update PCI-E fixup - The code relies on rc_pci_fixup being called, which only happens when CONFIG_PCI_QUIRKS is enabled, so add that to Kconfig. Omitting this causes a booting failure with a non-obvious cause. - Update rc_pci_fixup to set the class properly, copying the more modern style from other places - Correct the rc_pci_fixup comment Signed-off-by: Jason Gunthorpe Cc: stable@vger.kernel.org Signed-off-by: Jason Cooper --- arch/arm/Kconfig | 1 + arch/arm/mach-kirkwood/pcie.c | 11 ++++++++--- 2 files changed, 9 insertions(+), 3 deletions(-) diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig index ade7e924bef5..9759fec0b704 100644 --- a/arch/arm/Kconfig +++ b/arch/arm/Kconfig @@ -547,6 +547,7 @@ config ARCH_KIRKWOOD select CPU_FEROCEON select GENERIC_CLOCKEVENTS select PCI + select PCI_QUIRKS select PLAT_ORION_LEGACY help Support for the following Marvell Kirkwood series SoCs: diff --git a/arch/arm/mach-kirkwood/pcie.c b/arch/arm/mach-kirkwood/pcie.c index ec544918b12c..74fc5a074fc4 100644 --- a/arch/arm/mach-kirkwood/pcie.c +++ b/arch/arm/mach-kirkwood/pcie.c @@ -207,14 +207,19 @@ static int __init kirkwood_pcie_setup(int nr, struct pci_sys_data *sys) return 1; } +/* + * The root complex has a hardwired class of PCI_CLASS_MEMORY_OTHER, when it + * is operating as a root complex this needs to be switched to + * PCI_CLASS_BRIDGE_HOST or Linux will errantly try to process the BAR's on + * the device. Decoding setup is handled by the orion code. + */ static void __devinit rc_pci_fixup(struct pci_dev *dev) { - /* - * Prevent enumeration of root complex. - */ if (dev->bus->parent == NULL && dev->devfn == 0) { int i; + dev->class &= 0xff; + dev->class |= PCI_CLASS_BRIDGE_HOST << 8; for (i = 0; i < DEVICE_COUNT_RESOURCE; i++) { dev->resource[i].start = 0; dev->resource[i].end = 0;