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5d3df93542
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 <rmk+kernel@arm.linux.org.uk> Cc: stable@vger.kernel.org Signed-off-by: Jason Cooper <jason@lakedaemon.net>
143 lines
3.0 KiB
C
143 lines
3.0 KiB
C
/*
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* arch/arm/mach-dove/irq.c
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*
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* Dove IRQ handling.
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*
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* This file is licensed under the terms of the GNU General Public
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* License version 2. This program is licensed "as is" without any
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* warranty of any kind, whether express or implied.
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*/
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#include <linux/kernel.h>
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#include <linux/init.h>
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#include <linux/irq.h>
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#include <linux/gpio.h>
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#include <linux/io.h>
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#include <asm/mach/arch.h>
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#include <plat/irq.h>
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#include <asm/mach/irq.h>
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#include <mach/pm.h>
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#include <mach/bridge-regs.h>
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#include <plat/orion-gpio.h>
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#include "common.h"
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static void pmu_irq_mask(struct irq_data *d)
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{
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int pin = irq_to_pmu(d->irq);
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u32 u;
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u = readl(PMU_INTERRUPT_MASK);
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u &= ~(1 << (pin & 31));
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writel(u, PMU_INTERRUPT_MASK);
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}
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static void pmu_irq_unmask(struct irq_data *d)
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{
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int pin = irq_to_pmu(d->irq);
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u32 u;
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u = readl(PMU_INTERRUPT_MASK);
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u |= 1 << (pin & 31);
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writel(u, PMU_INTERRUPT_MASK);
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}
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static void pmu_irq_ack(struct irq_data *d)
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{
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int pin = irq_to_pmu(d->irq);
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u32 u;
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/*
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* The PMU mask register is not RW0C: it is RW. This means that
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* the bits take whatever value is written to them; if you write
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* a '1', you will set the interrupt.
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*
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* Unfortunately this means there is NO race free way to clear
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* these interrupts.
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*
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* So, let's structure the code so that the window is as small as
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* possible.
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*/
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u = ~(1 << (pin & 31));
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u &= readl_relaxed(PMU_INTERRUPT_CAUSE);
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writel_relaxed(u, PMU_INTERRUPT_CAUSE);
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}
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static struct irq_chip pmu_irq_chip = {
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.name = "pmu_irq",
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.irq_mask = pmu_irq_mask,
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.irq_unmask = pmu_irq_unmask,
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.irq_ack = pmu_irq_ack,
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};
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static void pmu_irq_handler(unsigned int irq, struct irq_desc *desc)
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{
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unsigned long cause = readl(PMU_INTERRUPT_CAUSE);
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cause &= readl(PMU_INTERRUPT_MASK);
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if (cause == 0) {
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do_bad_IRQ(irq, desc);
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return;
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}
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for (irq = 0; irq < NR_PMU_IRQS; irq++) {
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if (!(cause & (1 << irq)))
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continue;
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irq = pmu_to_irq(irq);
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generic_handle_irq(irq);
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}
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}
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static int __initdata gpio0_irqs[4] = {
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IRQ_DOVE_GPIO_0_7,
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IRQ_DOVE_GPIO_8_15,
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IRQ_DOVE_GPIO_16_23,
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IRQ_DOVE_GPIO_24_31,
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};
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static int __initdata gpio1_irqs[4] = {
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IRQ_DOVE_HIGH_GPIO,
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0,
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0,
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0,
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};
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static int __initdata gpio2_irqs[4] = {
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0,
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0,
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0,
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0,
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};
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void __init dove_init_irq(void)
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{
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int i;
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orion_irq_init(0, IRQ_VIRT_BASE + IRQ_MASK_LOW_OFF);
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orion_irq_init(32, IRQ_VIRT_BASE + IRQ_MASK_HIGH_OFF);
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/*
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* Initialize gpiolib for GPIOs 0-71.
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*/
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orion_gpio_init(NULL, 0, 32, DOVE_GPIO_LO_VIRT_BASE, 0,
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IRQ_DOVE_GPIO_START, gpio0_irqs);
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orion_gpio_init(NULL, 32, 32, DOVE_GPIO_HI_VIRT_BASE, 0,
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IRQ_DOVE_GPIO_START + 32, gpio1_irqs);
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orion_gpio_init(NULL, 64, 8, DOVE_GPIO2_VIRT_BASE, 0,
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IRQ_DOVE_GPIO_START + 64, gpio2_irqs);
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/*
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* Mask and clear PMU interrupts
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*/
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writel(0, PMU_INTERRUPT_MASK);
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writel(0, PMU_INTERRUPT_CAUSE);
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for (i = IRQ_DOVE_PMU_START; i < NR_IRQS; i++) {
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irq_set_chip_and_handler(i, &pmu_irq_chip, handle_level_irq);
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irq_set_status_flags(i, IRQ_LEVEL);
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set_irq_flags(i, IRQF_VALID);
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}
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irq_set_chained_handler(IRQ_DOVE_PMU, pmu_irq_handler);
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}
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