diff options
Diffstat (limited to 'arch/powerpc/sysdev/xics/icp-opal.c')
| -rw-r--r-- | arch/powerpc/sysdev/xics/icp-opal.c | 205 |
1 files changed, 205 insertions, 0 deletions
diff --git a/arch/powerpc/sysdev/xics/icp-opal.c b/arch/powerpc/sysdev/xics/icp-opal.c new file mode 100644 index 000000000..672d8aeda --- /dev/null +++ b/arch/powerpc/sysdev/xics/icp-opal.c @@ -0,0 +1,205 @@ +/* + * Copyright 2016 IBM Corporation. + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version + * 2 of the License, or (at your option) any later version. + */ +#include <linux/types.h> +#include <linux/kernel.h> +#include <linux/irq.h> +#include <linux/smp.h> +#include <linux/interrupt.h> +#include <linux/cpu.h> +#include <linux/of.h> + +#include <asm/smp.h> +#include <asm/irq.h> +#include <asm/errno.h> +#include <asm/xics.h> +#include <asm/io.h> +#include <asm/opal.h> +#include <asm/kvm_ppc.h> + +static void icp_opal_teardown_cpu(void) +{ + int hw_cpu = hard_smp_processor_id(); + + /* Clear any pending IPI */ + opal_int_set_mfrr(hw_cpu, 0xff); +} + +static void icp_opal_flush_ipi(void) +{ + /* + * We take the ipi irq but and never return so we need to EOI the IPI, + * but want to leave our priority 0. + * + * Should we check all the other interrupts too? + * Should we be flagging idle loop instead? + * Or creating some task to be scheduled? + */ + if (opal_int_eoi((0x00 << 24) | XICS_IPI) > 0) + force_external_irq_replay(); +} + +static unsigned int icp_opal_get_xirr(void) +{ + unsigned int kvm_xirr; + __be32 hw_xirr; + int64_t rc; + + /* Handle an interrupt latched by KVM first */ + kvm_xirr = kvmppc_get_xics_latch(); + if (kvm_xirr) + return kvm_xirr; + + /* Then ask OPAL */ + rc = opal_int_get_xirr(&hw_xirr, false); + if (rc < 0) + return 0; + return be32_to_cpu(hw_xirr); +} + +static unsigned int icp_opal_get_irq(void) +{ + unsigned int xirr; + unsigned int vec; + unsigned int irq; + + xirr = icp_opal_get_xirr(); + vec = xirr & 0x00ffffff; + if (vec == XICS_IRQ_SPURIOUS) + return 0; + + irq = irq_find_mapping(xics_host, vec); + if (likely(irq)) { + xics_push_cppr(vec); + return irq; + } + + /* We don't have a linux mapping, so have rtas mask it. */ + xics_mask_unknown_vec(vec); + + /* We might learn about it later, so EOI it */ + if (opal_int_eoi(xirr) > 0) + force_external_irq_replay(); + + return 0; +} + +static void icp_opal_set_cpu_priority(unsigned char cppr) +{ + /* + * Here be dragons. The caller has asked to allow only IPI's and not + * external interrupts. But OPAL XIVE doesn't support that. So instead + * of allowing no interrupts allow all. That's still not right, but + * currently the only caller who does this is xics_migrate_irqs_away() + * and it works in that case. + */ + if (cppr >= DEFAULT_PRIORITY) + cppr = LOWEST_PRIORITY; + + xics_set_base_cppr(cppr); + opal_int_set_cppr(cppr); + iosync(); +} + +static void icp_opal_eoi(struct irq_data *d) +{ + unsigned int hw_irq = (unsigned int)irqd_to_hwirq(d); + int64_t rc; + + iosync(); + rc = opal_int_eoi((xics_pop_cppr() << 24) | hw_irq); + + /* + * EOI tells us whether there are more interrupts to fetch. + * + * Some HW implementations might not be able to send us another + * external interrupt in that case, so we force a replay. + */ + if (rc > 0) + force_external_irq_replay(); +} + +#ifdef CONFIG_SMP + +static void icp_opal_cause_ipi(int cpu) +{ + int hw_cpu = get_hard_smp_processor_id(cpu); + + kvmppc_set_host_ipi(cpu); + opal_int_set_mfrr(hw_cpu, IPI_PRIORITY); +} + +static irqreturn_t icp_opal_ipi_action(int irq, void *dev_id) +{ + int cpu = smp_processor_id(); + + kvmppc_clear_host_ipi(cpu); + opal_int_set_mfrr(get_hard_smp_processor_id(cpu), 0xff); + + return smp_ipi_demux(); +} + +/* + * Called when an interrupt is received on an off-line CPU to + * clear the interrupt, so that the CPU can go back to nap mode. + */ +void icp_opal_flush_interrupt(void) +{ + unsigned int xirr; + unsigned int vec; + + do { + xirr = icp_opal_get_xirr(); + vec = xirr & 0x00ffffff; + if (vec == XICS_IRQ_SPURIOUS) + break; + if (vec == XICS_IPI) { + /* Clear pending IPI */ + int cpu = smp_processor_id(); + kvmppc_clear_host_ipi(cpu); + opal_int_set_mfrr(get_hard_smp_processor_id(cpu), 0xff); + } else { + pr_err("XICS: hw interrupt 0x%x to offline cpu, " + "disabling\n", vec); + xics_mask_unknown_vec(vec); + } + + /* EOI the interrupt */ + } while (opal_int_eoi(xirr) > 0); +} + +#endif /* CONFIG_SMP */ + +static const struct icp_ops icp_opal_ops = { + .get_irq = icp_opal_get_irq, + .eoi = icp_opal_eoi, + .set_priority = icp_opal_set_cpu_priority, + .teardown_cpu = icp_opal_teardown_cpu, + .flush_ipi = icp_opal_flush_ipi, +#ifdef CONFIG_SMP + .ipi_action = icp_opal_ipi_action, + .cause_ipi = icp_opal_cause_ipi, +#endif +}; + +int icp_opal_init(void) +{ + struct device_node *np; + + np = of_find_compatible_node(NULL, NULL, "ibm,opal-intc"); + if (!np) + return -ENODEV; + + icp_ops = &icp_opal_ops; + + printk("XICS: Using OPAL ICP fallbacks\n"); + + of_node_put(np); + return 0; +} + |