From e5fd91f1ef340da553f7a79da9540c3db711c937 Mon Sep 17 00:00:00 2001 From: André Fabian Silva Delgado Date: Tue, 8 Sep 2015 01:01:14 -0300 Subject: Linux-libre 4.2-gnu --- arch/arc/kernel/intc-compact.c | 225 +++++++++++++++++++++++++++++++++++++++++ 1 file changed, 225 insertions(+) create mode 100644 arch/arc/kernel/intc-compact.c (limited to 'arch/arc/kernel/intc-compact.c') diff --git a/arch/arc/kernel/intc-compact.c b/arch/arc/kernel/intc-compact.c new file mode 100644 index 000000000..039fac30b --- /dev/null +++ b/arch/arc/kernel/intc-compact.c @@ -0,0 +1,225 @@ +/* + * Copyright (C) 2011-12 Synopsys, Inc. (www.synopsys.com) + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + * + */ + +#include +#include +#include +#include +#include +#include + +/* + * Early Hardware specific Interrupt setup + * -Platform independent, needed for each CPU (not foldable into init_IRQ) + * -Called very early (start_kernel -> setup_arch -> setup_processor) + * + * what it does ? + * -Optionally, setup the High priority Interrupts as Level 2 IRQs + */ +void arc_init_IRQ(void) +{ + int level_mask = 0; + + /* setup any high priority Interrupts (Level2 in ARCompact jargon) */ + level_mask |= IS_ENABLED(CONFIG_ARC_IRQ3_LV2) << 3; + level_mask |= IS_ENABLED(CONFIG_ARC_IRQ5_LV2) << 5; + level_mask |= IS_ENABLED(CONFIG_ARC_IRQ6_LV2) << 6; + + /* + * Write to register, even if no LV2 IRQs configured to reset it + * in case bootloader had mucked with it + */ + write_aux_reg(AUX_IRQ_LEV, level_mask); + + if (level_mask) + pr_info("Level-2 interrupts bitset %x\n", level_mask); +} + +/* + * ARC700 core includes a simple on-chip intc supporting + * -per IRQ enable/disable + * -2 levels of interrupts (high/low) + * -all interrupts being level triggered + * + * To reduce platform code, we assume all IRQs directly hooked-up into intc. + * Platforms with external intc, hence cascaded IRQs, are free to over-ride + * below, per IRQ. + */ + +static void arc_irq_mask(struct irq_data *data) +{ + unsigned int ienb; + + ienb = read_aux_reg(AUX_IENABLE); + ienb &= ~(1 << data->irq); + write_aux_reg(AUX_IENABLE, ienb); +} + +static void arc_irq_unmask(struct irq_data *data) +{ + unsigned int ienb; + + ienb = read_aux_reg(AUX_IENABLE); + ienb |= (1 << data->irq); + write_aux_reg(AUX_IENABLE, ienb); +} + +static struct irq_chip onchip_intc = { + .name = "ARC In-core Intc", + .irq_mask = arc_irq_mask, + .irq_unmask = arc_irq_unmask, +}; + +static int arc_intc_domain_map(struct irq_domain *d, unsigned int irq, + irq_hw_number_t hw) +{ + /* + * XXX: the IPI IRQ needs to be handled like TIMER too. However ARC core + * code doesn't own it (like TIMER0). ISS IDU / ezchip define it + * in platform header which can't be included here as it goes + * against multi-platform image philisophy + */ + if (irq == TIMER0_IRQ) + irq_set_chip_and_handler(irq, &onchip_intc, handle_percpu_irq); + else + irq_set_chip_and_handler(irq, &onchip_intc, handle_level_irq); + + return 0; +} + +static const struct irq_domain_ops arc_intc_domain_ops = { + .xlate = irq_domain_xlate_onecell, + .map = arc_intc_domain_map, +}; + +static struct irq_domain *root_domain; + +static int __init +init_onchip_IRQ(struct device_node *intc, struct device_node *parent) +{ + if (parent) + panic("DeviceTree incore intc not a root irq controller\n"); + + root_domain = irq_domain_add_legacy(intc, NR_CPU_IRQS, 0, 0, + &arc_intc_domain_ops, NULL); + + if (!root_domain) + panic("root irq domain not avail\n"); + + /* with this we don't need to export root_domain */ + irq_set_default_host(root_domain); + + return 0; +} + +IRQCHIP_DECLARE(arc_intc, "snps,arc700-intc", init_onchip_IRQ); + +/* + * arch_local_irq_enable - Enable interrupts. + * + * 1. Explicitly called to re-enable interrupts + * 2. Implicitly called from spin_unlock_irq, write_unlock_irq etc + * which maybe in hard ISR itself + * + * Semantics of this function change depending on where it is called from: + * + * -If called from hard-ISR, it must not invert interrupt priorities + * e.g. suppose TIMER is high priority (Level 2) IRQ + * Time hard-ISR, timer_interrupt( ) calls spin_unlock_irq several times. + * Here local_irq_enable( ) shd not re-enable lower priority interrupts + * -If called from soft-ISR, it must re-enable all interrupts + * soft ISR are low prioity jobs which can be very slow, thus all IRQs + * must be enabled while they run. + * Now hardware context wise we may still be in L2 ISR (not done rtie) + * still we must re-enable both L1 and L2 IRQs + * Another twist is prev scenario with flow being + * L1 ISR ==> interrupted by L2 ISR ==> L2 soft ISR + * here we must not re-enable Ll as prev Ll Interrupt's h/w context will get + * over-written (this is deficiency in ARC700 Interrupt mechanism) + */ + +#ifdef CONFIG_ARC_COMPACT_IRQ_LEVELS /* Complex version for 2 IRQ levels */ + +void arch_local_irq_enable(void) +{ + + unsigned long flags = arch_local_save_flags(); + + /* Allow both L1 and L2 at the onset */ + flags |= (STATUS_E1_MASK | STATUS_E2_MASK); + + /* Called from hard ISR (between irq_enter and irq_exit) */ + if (in_irq()) { + + /* If in L2 ISR, don't re-enable any further IRQs as this can + * cause IRQ priorities to get upside down. e.g. it could allow + * L1 be taken while in L2 hard ISR which is wrong not only in + * theory, it can also cause the dreaded L1-L2-L1 scenario + */ + if (flags & STATUS_A2_MASK) + flags &= ~(STATUS_E1_MASK | STATUS_E2_MASK); + + /* Even if in L1 ISR, allowe Higher prio L2 IRQs */ + else if (flags & STATUS_A1_MASK) + flags &= ~(STATUS_E1_MASK); + } + + /* called from soft IRQ, ideally we want to re-enable all levels */ + + else if (in_softirq()) { + + /* However if this is case of L1 interrupted by L2, + * re-enabling both may cause whaco L1-L2-L1 scenario + * because ARC700 allows level 1 to interrupt an active L2 ISR + * Thus we disable both + * However some code, executing in soft ISR wants some IRQs + * to be enabled so we re-enable L2 only + * + * How do we determine L1 intr by L2 + * -A2 is set (means in L2 ISR) + * -E1 is set in this ISR's pt_regs->status32 which is + * saved copy of status32_l2 when l2 ISR happened + */ + struct pt_regs *pt = get_irq_regs(); + + if ((flags & STATUS_A2_MASK) && pt && + (pt->status32 & STATUS_A1_MASK)) { + /*flags &= ~(STATUS_E1_MASK | STATUS_E2_MASK); */ + flags &= ~(STATUS_E1_MASK); + } + } + + arch_local_irq_restore(flags); +} + +#else /* ! CONFIG_ARC_COMPACT_IRQ_LEVELS */ + +/* + * Simpler version for only 1 level of interrupt + * Here we only Worry about Level 1 Bits + */ +void arch_local_irq_enable(void) +{ + unsigned long flags; + + /* + * ARC IDE Drivers tries to re-enable interrupts from hard-isr + * context which is simply wrong + */ + if (in_irq()) { + WARN_ONCE(1, "IRQ enabled from hard-isr"); + return; + } + + flags = arch_local_save_flags(); + flags |= (STATUS_E1_MASK | STATUS_E2_MASK); + arch_local_irq_restore(flags); +} +#endif +EXPORT_SYMBOL(arch_local_irq_enable); -- cgit v1.2.3-54-g00ecf