[PATCH v3 12/16] irqchip/armada-370-xp: Configure IPIs as standard interrupts

Marc Zyngier
2020-09-01T14:52:59Z

To introduce IPIs as standard interrupts to the Armada 370-XP
driver, let's allocate a completely separate irqdomain and
irqchip combo that lives parallel to the "standard" one.

This effectively should be modelled as a chained interrupt
controller, but the code is in such a state that it is
pretty hard to shoehorn, as it would require the rewrite
of the MSI layer as well.

Signed-off-by: Marc Zyngier <maz@kernel.org>
---
drivers/irqchip/irq-armada-370-xp.c | 262 +++++++++++++++++++---------
1 file changed, 178 insertions(+), 84 deletions(-)

diff --git a/drivers/irqchip/irq-armada-370-xp.c b/drivers/irqchip/irq-armada-370-xp.c
index c9bdc5221b82..d7eb2e93db8f 100644
--- a/drivers/irqchip/irq-armada-370-xp.c
+++ b/drivers/irqchip/irq-armada-370-xp.c
@@ -310,7 +310,134 @@ static inline int armada_370_xp_msi_init(struct device_node *node,
}
#endif

+static void armada_xp_mpic_perf_init(void)
+{
+ unsigned long cpuid = cpu_logical_map(smp_processor_id());
+
+ /* Enable Performance Counter Overflow interrupts */
+ writel(ARMADA_370_XP_INT_CAUSE_PERF(cpuid),
+ per_cpu_int_base + ARMADA_370_XP_INT_FABRIC_MASK_OFFS);
+}
+
#ifdef CONFIG_SMP
+static struct irq_domain *ipi_domain;
+
+static void armada_370_xp_ipi_mask(struct irq_data *d)
+{
+ u32 reg;
+ reg = readl(per_cpu_int_base + ARMADA_370_XP_IN_DRBEL_MSK_OFFS);
+ reg &= ~BIT(d->hwirq);
+ writel(reg, per_cpu_int_base + ARMADA_370_XP_IN_DRBEL_MSK_OFFS);
+}
+
+static void armada_370_xp_ipi_unmask(struct irq_data *d)
+{
+ u32 reg;
+ reg = readl(per_cpu_int_base + ARMADA_370_XP_IN_DRBEL_MSK_OFFS);
+ reg |= BIT(d->hwirq);
+ writel(reg, per_cpu_int_base + ARMADA_370_XP_IN_DRBEL_MSK_OFFS);
+}
+
+static void armada_370_xp_ipi_send_mask(struct irq_data *d,
+ const struct cpumask *mask)
+{
+ unsigned long map = 0;
+ int cpu;
+
+ /* Convert our logical CPU mask into a physical one. */
+ for_each_cpu(cpu, mask)
+ map |= 1 << cpu_logical_map(cpu);
+
+ /*
+ * Ensure that stores to Normal memory are visible to the
+ * other CPUs before issuing the IPI.
+ */
+ dsb();
+
+ /* submit softirq */
+ writel((map << 8) | d->hwirq, main_int_base +
+ ARMADA_370_XP_SW_TRIG_INT_OFFS);
+}
+
+static void armada_370_xp_ipi_eoi(struct irq_data *d)
+{
+ writel(~BIT(d->hwirq), per_cpu_int_base + ARMADA_370_XP_IN_DRBEL_CAUSE_OFFS);
+}
+
+static struct irq_chip ipi_irqchip = {
+ .name = "IPI",
+ .irq_mask = armada_370_xp_ipi_mask,
+ .irq_unmask = armada_370_xp_ipi_unmask,
+ .irq_eoi = armada_370_xp_ipi_eoi,
+ .ipi_send_mask = armada_370_xp_ipi_send_mask,
+};
+
+static int armada_370_xp_ipi_alloc(struct irq_domain *d,
+ unsigned int virq,
+ unsigned int nr_irqs, void *args)
+{
+ int i;
+
+ for (i = 0; i < nr_irqs; i++) {
+ irq_set_percpu_devid(virq + i);
+ irq_domain_set_info(d, virq + i, i, &ipi_irqchip,
+ d->host_data,
+ handle_percpu_devid_fasteoi_ipi,
+ NULL, NULL);
+ }
+
+ return 0;
+}
+
+static void armada_370_xp_ipi_free(struct irq_domain *d,
+ unsigned int virq,
+ unsigned int nr_irqs)
+{
+ /* Not freeing IPIs */
+}
+
+static const struct irq_domain_ops ipi_domain_ops = {
+ .alloc = armada_370_xp_ipi_alloc,
+ .free = armada_370_xp_ipi_free,
+};
+
+static void ipi_resume(void)
+{
+ int i;
+
+ for (i = 0; i < IPI_DOORBELL_END; i++) {
+ int irq;
+
+ irq = irq_find_mapping(ipi_domain, i);
+ if (irq <= 0)
+ continue;
+ if (irq_percpu_is_enabled(irq)) {
+ struct irq_data *d;
+ d = irq_domain_get_irq_data(ipi_domain, irq);
+ armada_370_xp_ipi_unmask(d);
+ }
+ }
+}
+
+static __init void armada_xp_ipi_init(struct device_node *node)
+{
+ int base_ipi;
+
+ ipi_domain = irq_domain_create_linear(of_node_to_fwnode(node),
+ IPI_DOORBELL_END,
+ &ipi_domain_ops, NULL);
+ if (WARN_ON(!ipi_domain))
+ return;
+
+ irq_domain_update_bus_token(ipi_domain, DOMAIN_BUS_IPI);
+ base_ipi = __irq_domain_alloc_irqs(ipi_domain, -1, IPI_DOORBELL_END,
+ NUMA_NO_NODE, NULL, false, NULL);
+ if (WARN_ON(!base_ipi))
+ return;
+
+ set_smp_ipi_range(base_ipi, IPI_DOORBELL_END);
+}
+
static DEFINE_RAW_SPINLOCK(irq_controller_lock);

static int armada_xp_set_affinity(struct irq_data *d,
@@ -334,43 +461,6 @@ static int armada_xp_set_affinity(struct irq_data *d,

return IRQ_SET_MASK_OK;
}
-#endif
-
-static struct irq_chip armada_370_xp_irq_chip = {
- .name = "MPIC",
- .irq_mask = armada_370_xp_irq_mask,
- .irq_mask_ack = armada_370_xp_irq_mask,
- .irq_unmask = armada_370_xp_irq_unmask,
-#ifdef CONFIG_SMP
- .irq_set_affinity = armada_xp_set_affinity,
-#endif
- .flags = IRQCHIP_SKIP_SET_WAKE | IRQCHIP_MASK_ON_SUSPEND,
-};
-
-static int armada_370_xp_mpic_irq_map(struct irq_domain *h,
- unsigned int virq, irq_hw_number_t hw)
-{
- armada_370_xp_irq_mask(irq_get_irq_data(virq));
- if (!is_percpu_irq(hw))
- writel(hw, per_cpu_int_base +
- ARMADA_370_XP_INT_CLEAR_MASK_OFFS);
- else
- writel(hw, main_int_base + ARMADA_370_XP_INT_SET_ENABLE_OFFS);
- irq_set_status_flags(virq, IRQ_LEVEL);
-
- if (is_percpu_irq(hw)) {
- irq_set_percpu_devid(virq);
- irq_set_chip_and_handler(virq, &armada_370_xp_irq_chip,
- handle_percpu_devid_irq);
- } else {
- irq_set_chip_and_handler(virq, &armada_370_xp_irq_chip,
- handle_level_irq);
- irqd_set_single_target(irq_desc_get_irq_data(irq_to_desc(virq)));
- }
- irq_set_probe(virq);
-
- return 0;
-}

static void armada_xp_mpic_smp_cpu_init(void)
{
@@ -383,48 +473,16 @@ static void armada_xp_mpic_smp_cpu_init(void)
for (i = 0; i < nr_irqs; i++)
writel(i, per_cpu_int_base + ARMADA_370_XP_INT_SET_MASK_OFFS);

+ /* Disable all IPIs */
+ writel(0, per_cpu_int_base + ARMADA_370_XP_IN_DRBEL_MSK_OFFS);
+
/* Clear pending IPIs */
writel(0, per_cpu_int_base + ARMADA_370_XP_IN_DRBEL_CAUSE_OFFS);

- /* Enable first 8 IPIs */
- writel(IPI_DOORBELL_MASK, per_cpu_int_base +
- ARMADA_370_XP_IN_DRBEL_MSK_OFFS);
-
/* Unmask IPI interrupt */
writel(0, per_cpu_int_base + ARMADA_370_XP_INT_CLEAR_MASK_OFFS);
}

-static void armada_xp_mpic_perf_init(void)
-{
- unsigned long cpuid = cpu_logical_map(smp_processor_id());
-
- /* Enable Performance Counter Overflow interrupts */
- writel(ARMADA_370_XP_INT_CAUSE_PERF(cpuid),
- per_cpu_int_base + ARMADA_370_XP_INT_FABRIC_MASK_OFFS);
-}
-
-#ifdef CONFIG_SMP
-static void armada_mpic_send_doorbell(const struct cpumask *mask,
- unsigned int irq)
-{
- int cpu;
- unsigned long map = 0;
-
- /* Convert our logical CPU mask into a physical one. */
- for_each_cpu(cpu, mask)
- map |= 1 << cpu_logical_map(cpu);
-
- /*
- * Ensure that stores to Normal memory are visible to the
- * other CPUs before issuing the IPI.
- */
- dsb();
-
- /* submit softirq */
- writel((map << 8) | irq, main_int_base +
- ARMADA_370_XP_SW_TRIG_INT_OFFS);
-}
-
static void armada_xp_mpic_reenable_percpu(void)
{
unsigned int irq;
@@ -445,6 +503,8 @@ static void armada_xp_mpic_reenable_percpu(void)

armada_370_xp_irq_unmask(data);
}
+
+ ipi_resume();
}

static int armada_xp_mpic_starting_cpu(unsigned int cpu)
@@ -462,7 +522,46 @@ static int mpic_cascaded_starting_cpu(unsigned int cpu)
enable_percpu_irq(parent_irq, IRQ_TYPE_NONE);
return 0;
}
+#else
+static void armada_xp_mpic_smp_cpu_init(void) {}
+static void ipi_resume(void) {}
+#endif
+
+static struct irq_chip armada_370_xp_irq_chip = {
+ .name = "MPIC",
+ .irq_mask = armada_370_xp_irq_mask,
+ .irq_mask_ack = armada_370_xp_irq_mask,
+ .irq_unmask = armada_370_xp_irq_unmask,
+#ifdef CONFIG_SMP
+ .irq_set_affinity = armada_xp_set_affinity,
#endif
+ .flags = IRQCHIP_SKIP_SET_WAKE | IRQCHIP_MASK_ON_SUSPEND,
+};
+
+static int armada_370_xp_mpic_irq_map(struct irq_domain *h,
+ unsigned int virq, irq_hw_number_t hw)
+{
+ armada_370_xp_irq_mask(irq_get_irq_data(virq));
+ if (!is_percpu_irq(hw))
+ writel(hw, per_cpu_int_base +
+ ARMADA_370_XP_INT_CLEAR_MASK_OFFS);
+ else
+ writel(hw, main_int_base + ARMADA_370_XP_INT_SET_ENABLE_OFFS);
+ irq_set_status_flags(virq, IRQ_LEVEL);
+
+ if (is_percpu_irq(hw)) {
+ irq_set_percpu_devid(virq);
+ irq_set_chip_and_handler(virq, &armada_370_xp_irq_chip,
+ handle_percpu_devid_irq);
+ } else {
+ irq_set_chip_and_handler(virq, &armada_370_xp_irq_chip,
+ handle_level_irq);
+ irqd_set_single_target(irq_desc_get_irq_data(irq_to_desc(virq)));
+ }
+ irq_set_probe(virq);
+
+ return 0;
+}

static const struct irq_domain_ops armada_370_xp_mpic_irq_ops = {
.map = armada_370_xp_mpic_irq_map,
@@ -562,22 +661,15 @@ armada_370_xp_handle_irq(struct pt_regs *regs)
#ifdef CONFIG_SMP
/* IPI Handling */
if (irqnr == 0) {
- u32 ipimask, ipinr;
+ unsigned long ipimask;
+ int ipi;

ipimask = readl_relaxed(per_cpu_int_base +
ARMADA_370_XP_IN_DRBEL_CAUSE_OFFS)
& IPI_DOORBELL_MASK;

- writel(~ipimask, per_cpu_int_base +
- ARMADA_370_XP_IN_DRBEL_CAUSE_OFFS);
-
- /* Handle all pending doorbells */
- for (ipinr = IPI_DOORBELL_START;
- ipinr < IPI_DOORBELL_END; ipinr++) {
- if (ipimask & (0x1 << ipinr))
- handle_IPI(ipinr, regs);
- }
- continue;
+ for_each_set_bit(ipi, &ipimask, IPI_DOORBELL_END)
+ handle_domain_irq(ipi_domain, ipi, regs);
}
#endif

@@ -636,6 +728,8 @@ static void armada_370_xp_mpic_resume(void)
writel(0, per_cpu_int_base + ARMADA_370_XP_INT_CLEAR_MASK_OFFS);
if (doorbell_mask_reg & PCI_MSI_DOORBELL_MASK)
writel(1, per_cpu_int_base + ARMADA_370_XP_INT_CLEAR_MASK_OFFS);
+
+ ipi_resume();
}

static struct syscore_ops armada_370_xp_mpic_syscore_ops = {
@@ -691,7 +785,7 @@ static int __init armada_370_xp_mpic_of_init(struct device_node *node,
irq_set_default_host(armada_370_xp_mpic_domain);
set_handle_irq(armada_370_xp_handle_irq);
#ifdef CONFIG_SMP
- set_smp_cross_call(armada_mpic_send_doorbell);
+ armada_xp_ipi_init(node);
cpuhp_setup_state_nocalls(CPUHP_AP_IRQ_ARMADA_XP_STARTING,
"irqchip/armada/ipi:starting",
armada_xp_mpic_starting_cpu, NULL);
--
2.27.0