sched_ext: Maintain an online cid mask in the scheduler arenagrafted

Schedulers on the default cid mapping treat [0, nr_online_cids) as the
online set and restart on hotplug. Schedulers that install their own mapping
with scx_bpf_cid_override() have no way to learn which cids are online: the
count no longer identifies members and the CPU-form cpumask is unusable from
cid programs. This is an obvious hole in the cid API.

Add scx_bpf_online_cmask(), a kernel-maintained cmask in the scheduler's
arena, allocated alongside the per-CPU scratch masks and populated after the
cid mapping is finalized and before ops.init(), for child schedulers too.
The pointer stays valid through ops.exit() with no reference to take. It is
the arena offset as a void pointer, the same form struct_ops arena arguments
arrive in. The verifier types the void return as a scalar for the program's
arena cast.

The mask follows the SCX hotplug notifications: seeded from cpu_active_mask
and updated before ops.cid_online/offline() runs, so it lags cpu_online_mask
only inside a hotplug transition. Updates walk the scheduler list under the
lock that also serializes unlinking. Reads are live, not atomic snapshots.
Root initialization excludes hotplug.

v2: Reworded the getter kerneldoc (Andrea Righi).

Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Andrea Righi <arighi@nvidia.com>

1 files changed, 893 insertions, 0 deletions

diff --git a/arch/powerpc/sysdev/ipic.c b/arch/powerpc/sysdev/ipic.c
new file mode 100644
index 000000000..77e6f23c5
--- /dev/null
+++ b/arch/powerpc/sysdev/ipic.c
@@ -0,0 +1,893 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * arch/powerpc/sysdev/ipic.c
+ *
+ * IPIC routines implementations.
+ *
+ * Copyright 2005 Freescale Semiconductor, Inc.
+ */
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/errno.h>
+#include <linux/reboot.h>
+#include <linux/slab.h>
+#include <linux/stddef.h>
+#include <linux/sched.h>
+#include <linux/signal.h>
+#include <linux/syscore_ops.h>
+#include <linux/device.h>
+#include <linux/spinlock.h>
+#include <linux/fsl_devices.h>
+#include <linux/irqdomain.h>
+#include <linux/of_address.h>
+#include <asm/irq.h>
+#include <asm/io.h>
+#include <asm/ipic.h>
+
+#include "ipic.h"
+
+static struct ipic * primary_ipic;
+static struct irq_chip ipic_level_irq_chip, ipic_edge_irq_chip;
+static DEFINE_RAW_SPINLOCK(ipic_lock);
+
+static struct ipic_info ipic_info[] = {
+	[1] = {
+		.mask	= IPIC_SIMSR_H,
+		.prio	= IPIC_SIPRR_C,
+		.force	= IPIC_SIFCR_H,
+		.bit	= 16,
+		.prio_mask = 0,
+	},
+	[2] = {
+		.mask	= IPIC_SIMSR_H,
+		.prio	= IPIC_SIPRR_C,
+		.force	= IPIC_SIFCR_H,
+		.bit	= 17,
+		.prio_mask = 1,
+	},
+	[3] = {
+		.mask	= IPIC_SIMSR_H,
+		.prio	= IPIC_SIPRR_C,
+		.force	= IPIC_SIFCR_H,
+		.bit	= 18,
+		.prio_mask = 2,
+	},
+	[4] = {
+		.mask	= IPIC_SIMSR_H,
+		.prio	= IPIC_SIPRR_C,
+		.force	= IPIC_SIFCR_H,
+		.bit	= 19,
+		.prio_mask = 3,
+	},
+	[5] = {
+		.mask	= IPIC_SIMSR_H,
+		.prio	= IPIC_SIPRR_C,
+		.force	= IPIC_SIFCR_H,
+		.bit	= 20,
+		.prio_mask = 4,
+	},
+	[6] = {
+		.mask	= IPIC_SIMSR_H,
+		.prio	= IPIC_SIPRR_C,
+		.force	= IPIC_SIFCR_H,
+		.bit	= 21,
+		.prio_mask = 5,
+	},
+	[7] = {
+		.mask	= IPIC_SIMSR_H,
+		.prio	= IPIC_SIPRR_C,
+		.force	= IPIC_SIFCR_H,
+		.bit	= 22,
+		.prio_mask = 6,
+	},
+	[8] = {
+		.mask	= IPIC_SIMSR_H,
+		.prio	= IPIC_SIPRR_C,
+		.force	= IPIC_SIFCR_H,
+		.bit	= 23,
+		.prio_mask = 7,
+	},
+	[9] = {
+		.mask	= IPIC_SIMSR_H,
+		.prio	= IPIC_SIPRR_D,
+		.force	= IPIC_SIFCR_H,
+		.bit	= 24,
+		.prio_mask = 0,
+	},
+	[10] = {
+		.mask	= IPIC_SIMSR_H,
+		.prio	= IPIC_SIPRR_D,
+		.force	= IPIC_SIFCR_H,
+		.bit	= 25,
+		.prio_mask = 1,
+	},
+	[11] = {
+		.mask	= IPIC_SIMSR_H,
+		.prio	= IPIC_SIPRR_D,
+		.force	= IPIC_SIFCR_H,
+		.bit	= 26,
+		.prio_mask = 2,
+	},
+	[12] = {
+		.mask	= IPIC_SIMSR_H,
+		.prio	= IPIC_SIPRR_D,
+		.force	= IPIC_SIFCR_H,
+		.bit	= 27,
+		.prio_mask = 3,
+	},
+	[13] = {
+		.mask	= IPIC_SIMSR_H,
+		.prio	= IPIC_SIPRR_D,
+		.force	= IPIC_SIFCR_H,
+		.bit	= 28,
+		.prio_mask = 4,
+	},
+	[14] = {
+		.mask	= IPIC_SIMSR_H,
+		.prio	= IPIC_SIPRR_D,
+		.force	= IPIC_SIFCR_H,
+		.bit	= 29,
+		.prio_mask = 5,
+	},
+	[15] = {
+		.mask	= IPIC_SIMSR_H,
+		.prio	= IPIC_SIPRR_D,
+		.force	= IPIC_SIFCR_H,
+		.bit	= 30,
+		.prio_mask = 6,
+	},
+	[16] = {
+		.mask	= IPIC_SIMSR_H,
+		.prio	= IPIC_SIPRR_D,
+		.force	= IPIC_SIFCR_H,
+		.bit	= 31,
+		.prio_mask = 7,
+	},
+	[17] = {
+		.ack	= IPIC_SEPNR,
+		.mask	= IPIC_SEMSR,
+		.prio	= IPIC_SMPRR_A,
+		.force	= IPIC_SEFCR,
+		.bit	= 1,
+		.prio_mask = 5,
+	},
+	[18] = {
+		.ack	= IPIC_SEPNR,
+		.mask	= IPIC_SEMSR,
+		.prio	= IPIC_SMPRR_A,
+		.force	= IPIC_SEFCR,
+		.bit	= 2,
+		.prio_mask = 6,
+	},
+	[19] = {
+		.ack	= IPIC_SEPNR,
+		.mask	= IPIC_SEMSR,
+		.prio	= IPIC_SMPRR_A,
+		.force	= IPIC_SEFCR,
+		.bit	= 3,
+		.prio_mask = 7,
+	},
+	[20] = {
+		.ack	= IPIC_SEPNR,
+		.mask	= IPIC_SEMSR,
+		.prio	= IPIC_SMPRR_B,
+		.force	= IPIC_SEFCR,
+		.bit	= 4,
+		.prio_mask = 4,
+	},
+	[21] = {
+		.ack	= IPIC_SEPNR,
+		.mask	= IPIC_SEMSR,
+		.prio	= IPIC_SMPRR_B,
+		.force	= IPIC_SEFCR,
+		.bit	= 5,
+		.prio_mask = 5,
+	},
+	[22] = {
+		.ack	= IPIC_SEPNR,
+		.mask	= IPIC_SEMSR,
+		.prio	= IPIC_SMPRR_B,
+		.force	= IPIC_SEFCR,
+		.bit	= 6,
+		.prio_mask = 6,
+	},
+	[23] = {
+		.ack	= IPIC_SEPNR,
+		.mask	= IPIC_SEMSR,
+		.prio	= IPIC_SMPRR_B,
+		.force	= IPIC_SEFCR,
+		.bit	= 7,
+		.prio_mask = 7,
+	},
+	[32] = {
+		.mask	= IPIC_SIMSR_H,
+		.prio	= IPIC_SIPRR_A,
+		.force	= IPIC_SIFCR_H,
+		.bit	= 0,
+		.prio_mask = 0,
+	},
+	[33] = {
+		.mask	= IPIC_SIMSR_H,
+		.prio	= IPIC_SIPRR_A,
+		.force	= IPIC_SIFCR_H,
+		.bit	= 1,
+		.prio_mask = 1,
+	},
+	[34] = {
+		.mask	= IPIC_SIMSR_H,
+		.prio	= IPIC_SIPRR_A,
+		.force	= IPIC_SIFCR_H,
+		.bit	= 2,
+		.prio_mask = 2,
+	},
+	[35] = {
+		.mask	= IPIC_SIMSR_H,
+		.prio	= IPIC_SIPRR_A,
+		.force	= IPIC_SIFCR_H,
+		.bit	= 3,
+		.prio_mask = 3,
+	},
+	[36] = {
+		.mask	= IPIC_SIMSR_H,
+		.prio	= IPIC_SIPRR_A,
+		.force	= IPIC_SIFCR_H,
+		.bit	= 4,
+		.prio_mask = 4,
+	},
+	[37] = {
+		.mask	= IPIC_SIMSR_H,
+		.prio	= IPIC_SIPRR_A,
+		.force	= IPIC_SIFCR_H,
+		.bit	= 5,
+		.prio_mask = 5,
+	},
+	[38] = {
+		.mask	= IPIC_SIMSR_H,
+		.prio	= IPIC_SIPRR_A,
+		.force	= IPIC_SIFCR_H,
+		.bit	= 6,
+		.prio_mask = 6,
+	},
+	[39] = {
+		.mask	= IPIC_SIMSR_H,
+		.prio	= IPIC_SIPRR_A,
+		.force	= IPIC_SIFCR_H,
+		.bit	= 7,
+		.prio_mask = 7,
+	},
+	[40] = {
+		.mask	= IPIC_SIMSR_H,
+		.prio	= IPIC_SIPRR_B,
+		.force	= IPIC_SIFCR_H,
+		.bit	= 8,
+		.prio_mask = 0,
+	},
+	[41] = {
+		.mask	= IPIC_SIMSR_H,
+		.prio	= IPIC_SIPRR_B,
+		.force	= IPIC_SIFCR_H,
+		.bit	= 9,
+		.prio_mask = 1,
+	},
+	[42] = {
+		.mask	= IPIC_SIMSR_H,
+		.prio	= IPIC_SIPRR_B,
+		.force	= IPIC_SIFCR_H,
+		.bit	= 10,
+		.prio_mask = 2,
+	},
+	[43] = {
+		.mask	= IPIC_SIMSR_H,
+		.prio	= IPIC_SIPRR_B,
+		.force	= IPIC_SIFCR_H,
+		.bit	= 11,
+		.prio_mask = 3,
+	},
+	[44] = {
+		.mask	= IPIC_SIMSR_H,
+		.prio	= IPIC_SIPRR_B,
+		.force	= IPIC_SIFCR_H,
+		.bit	= 12,
+		.prio_mask = 4,
+	},
+	[45] = {
+		.mask	= IPIC_SIMSR_H,
+		.prio	= IPIC_SIPRR_B,
+		.force	= IPIC_SIFCR_H,
+		.bit	= 13,
+		.prio_mask = 5,
+	},
+	[46] = {
+		.mask	= IPIC_SIMSR_H,
+		.prio	= IPIC_SIPRR_B,
+		.force	= IPIC_SIFCR_H,
+		.bit	= 14,
+		.prio_mask = 6,
+	},
+	[47] = {
+		.mask	= IPIC_SIMSR_H,
+		.prio	= IPIC_SIPRR_B,
+		.force	= IPIC_SIFCR_H,
+		.bit	= 15,
+		.prio_mask = 7,
+	},
+	[48] = {
+		.ack	= IPIC_SEPNR,
+		.mask	= IPIC_SEMSR,
+		.prio	= IPIC_SMPRR_A,
+		.force	= IPIC_SEFCR,
+		.bit	= 0,
+		.prio_mask = 4,
+	},
+	[64] = {
+		.mask	= IPIC_SIMSR_L,
+		.prio	= IPIC_SMPRR_A,
+		.force	= IPIC_SIFCR_L,
+		.bit	= 0,
+		.prio_mask = 0,
+	},
+	[65] = {
+		.mask	= IPIC_SIMSR_L,
+		.prio	= IPIC_SMPRR_A,
+		.force	= IPIC_SIFCR_L,
+		.bit	= 1,
+		.prio_mask = 1,
+	},
+	[66] = {
+		.mask	= IPIC_SIMSR_L,
+		.prio	= IPIC_SMPRR_A,
+		.force	= IPIC_SIFCR_L,
+		.bit	= 2,
+		.prio_mask = 2,
+	},
+	[67] = {
+		.mask	= IPIC_SIMSR_L,
+		.prio	= IPIC_SMPRR_A,
+		.force	= IPIC_SIFCR_L,
+		.bit	= 3,
+		.prio_mask = 3,
+	},
+	[68] = {
+		.mask	= IPIC_SIMSR_L,
+		.prio	= IPIC_SMPRR_B,
+		.force	= IPIC_SIFCR_L,
+		.bit	= 4,
+		.prio_mask = 0,
+	},
+	[69] = {
+		.mask	= IPIC_SIMSR_L,
+		.prio	= IPIC_SMPRR_B,
+		.force	= IPIC_SIFCR_L,
+		.bit	= 5,
+		.prio_mask = 1,
+	},
+	[70] = {
+		.mask	= IPIC_SIMSR_L,
+		.prio	= IPIC_SMPRR_B,
+		.force	= IPIC_SIFCR_L,
+		.bit	= 6,
+		.prio_mask = 2,
+	},
+	[71] = {
+		.mask	= IPIC_SIMSR_L,
+		.prio	= IPIC_SMPRR_B,
+		.force	= IPIC_SIFCR_L,
+		.bit	= 7,
+		.prio_mask = 3,
+	},
+	[72] = {
+		.mask	= IPIC_SIMSR_L,
+		.prio	= 0,
+		.force	= IPIC_SIFCR_L,
+		.bit	= 8,
+	},
+	[73] = {
+		.mask	= IPIC_SIMSR_L,
+		.prio	= 0,
+		.force	= IPIC_SIFCR_L,
+		.bit	= 9,
+	},
+	[74] = {
+		.mask	= IPIC_SIMSR_L,
+		.prio	= 0,
+		.force	= IPIC_SIFCR_L,
+		.bit	= 10,
+	},
+	[75] = {
+		.mask	= IPIC_SIMSR_L,
+		.prio	= 0,
+		.force	= IPIC_SIFCR_L,
+		.bit	= 11,
+	},
+	[76] = {
+		.mask	= IPIC_SIMSR_L,
+		.prio	= 0,
+		.force	= IPIC_SIFCR_L,
+		.bit	= 12,
+	},
+	[77] = {
+		.mask	= IPIC_SIMSR_L,
+		.prio	= 0,
+		.force	= IPIC_SIFCR_L,
+		.bit	= 13,
+	},
+	[78] = {
+		.mask	= IPIC_SIMSR_L,
+		.prio	= 0,
+		.force	= IPIC_SIFCR_L,
+		.bit	= 14,
+	},
+	[79] = {
+		.mask	= IPIC_SIMSR_L,
+		.prio	= 0,
+		.force	= IPIC_SIFCR_L,
+		.bit	= 15,
+	},
+	[80] = {
+		.mask	= IPIC_SIMSR_L,
+		.prio	= 0,
+		.force	= IPIC_SIFCR_L,
+		.bit	= 16,
+	},
+	[81] = {
+		.mask	= IPIC_SIMSR_L,
+		.prio	= 0,
+		.force	= IPIC_SIFCR_L,
+		.bit	= 17,
+	},
+	[82] = {
+		.mask	= IPIC_SIMSR_L,
+		.prio	= 0,
+		.force	= IPIC_SIFCR_L,
+		.bit	= 18,
+	},
+	[83] = {
+		.mask	= IPIC_SIMSR_L,
+		.prio	= 0,
+		.force	= IPIC_SIFCR_L,
+		.bit	= 19,
+	},
+	[84] = {
+		.mask	= IPIC_SIMSR_L,
+		.prio	= 0,
+		.force	= IPIC_SIFCR_L,
+		.bit	= 20,
+	},
+	[85] = {
+		.mask	= IPIC_SIMSR_L,
+		.prio	= 0,
+		.force	= IPIC_SIFCR_L,
+		.bit	= 21,
+	},
+	[86] = {
+		.mask	= IPIC_SIMSR_L,
+		.prio	= 0,
+		.force	= IPIC_SIFCR_L,
+		.bit	= 22,
+	},
+	[87] = {
+		.mask	= IPIC_SIMSR_L,
+		.prio	= 0,
+		.force	= IPIC_SIFCR_L,
+		.bit	= 23,
+	},
+	[88] = {
+		.mask	= IPIC_SIMSR_L,
+		.prio	= 0,
+		.force	= IPIC_SIFCR_L,
+		.bit	= 24,
+	},
+	[89] = {
+		.mask	= IPIC_SIMSR_L,
+		.prio	= 0,
+		.force	= IPIC_SIFCR_L,
+		.bit	= 25,
+	},
+	[90] = {
+		.mask	= IPIC_SIMSR_L,
+		.prio	= 0,
+		.force	= IPIC_SIFCR_L,
+		.bit	= 26,
+	},
+	[91] = {
+		.mask	= IPIC_SIMSR_L,
+		.prio	= 0,
+		.force	= IPIC_SIFCR_L,
+		.bit	= 27,
+	},
+	[94] = {
+		.mask	= IPIC_SIMSR_L,
+		.prio	= 0,
+		.force	= IPIC_SIFCR_L,
+		.bit	= 30,
+	},
+};
+
+static inline u32 ipic_read(volatile u32 __iomem *base, unsigned int reg)
+{
+	return in_be32(base + (reg >> 2));
+}
+
+static inline void ipic_write(volatile u32 __iomem *base, unsigned int reg, u32 value)
+{
+	out_be32(base + (reg >> 2), value);
+}
+
+static inline struct ipic * ipic_from_irq(unsigned int virq)
+{
+	return primary_ipic;
+}
+
+static void ipic_unmask_irq(struct irq_data *d)
+{
+	struct ipic *ipic = ipic_from_irq(d->irq);
+	unsigned int src = irqd_to_hwirq(d);
+	unsigned long flags;
+	u32 temp;
+
+	raw_spin_lock_irqsave(&ipic_lock, flags);
+
+	temp = ipic_read(ipic->regs, ipic_info[src].mask);
+	temp |= (1 << (31 - ipic_info[src].bit));
+	ipic_write(ipic->regs, ipic_info[src].mask, temp);
+
+	raw_spin_unlock_irqrestore(&ipic_lock, flags);
+}
+
+static void ipic_mask_irq(struct irq_data *d)
+{
+	struct ipic *ipic = ipic_from_irq(d->irq);
+	unsigned int src = irqd_to_hwirq(d);
+	unsigned long flags;
+	u32 temp;
+
+	raw_spin_lock_irqsave(&ipic_lock, flags);
+
+	temp = ipic_read(ipic->regs, ipic_info[src].mask);
+	temp &= ~(1 << (31 - ipic_info[src].bit));
+	ipic_write(ipic->regs, ipic_info[src].mask, temp);
+
+	/* mb() can't guarantee that masking is finished.  But it does finish
+	 * for nearly all cases. */
+	mb();
+
+	raw_spin_unlock_irqrestore(&ipic_lock, flags);
+}
+
+static void ipic_ack_irq(struct irq_data *d)
+{
+	struct ipic *ipic = ipic_from_irq(d->irq);
+	unsigned int src = irqd_to_hwirq(d);
+	unsigned long flags;
+	u32 temp;
+
+	raw_spin_lock_irqsave(&ipic_lock, flags);
+
+	temp = 1 << (31 - ipic_info[src].bit);
+	ipic_write(ipic->regs, ipic_info[src].ack, temp);
+
+	/* mb() can't guarantee that ack is finished.  But it does finish
+	 * for nearly all cases. */
+	mb();
+
+	raw_spin_unlock_irqrestore(&ipic_lock, flags);
+}
+
+static void ipic_mask_irq_and_ack(struct irq_data *d)
+{
+	struct ipic *ipic = ipic_from_irq(d->irq);
+	unsigned int src = irqd_to_hwirq(d);
+	unsigned long flags;
+	u32 temp;
+
+	raw_spin_lock_irqsave(&ipic_lock, flags);
+
+	temp = ipic_read(ipic->regs, ipic_info[src].mask);
+	temp &= ~(1 << (31 - ipic_info[src].bit));
+	ipic_write(ipic->regs, ipic_info[src].mask, temp);
+
+	temp = 1 << (31 - ipic_info[src].bit);
+	ipic_write(ipic->regs, ipic_info[src].ack, temp);
+
+	/* mb() can't guarantee that ack is finished.  But it does finish
+	 * for nearly all cases. */
+	mb();
+
+	raw_spin_unlock_irqrestore(&ipic_lock, flags);
+}
+
+static int ipic_set_irq_type(struct irq_data *d, unsigned int flow_type)
+{
+	struct ipic *ipic = ipic_from_irq(d->irq);
+	unsigned int src = irqd_to_hwirq(d);
+	unsigned int vold, vnew, edibit;
+
+	if (flow_type == IRQ_TYPE_NONE)
+		flow_type = IRQ_TYPE_LEVEL_LOW;
+
+	/* ipic supports only low assertion and high-to-low change senses
+	 */
+	if (!(flow_type & (IRQ_TYPE_LEVEL_LOW | IRQ_TYPE_EDGE_FALLING))) {
+		printk(KERN_ERR "ipic: sense type 0x%x not supported\n",
+			flow_type);
+		return -EINVAL;
+	}
+	/* ipic supports only edge mode on external interrupts */
+	if ((flow_type & IRQ_TYPE_EDGE_FALLING) && !ipic_info[src].ack) {
+		printk(KERN_ERR "ipic: edge sense not supported on internal "
+				"interrupts\n");
+		return -EINVAL;
+
+	}
+
+	irqd_set_trigger_type(d, flow_type);
+	if (flow_type & IRQ_TYPE_LEVEL_LOW)  {
+		irq_set_handler_locked(d, handle_level_irq);
+		d->chip = &ipic_level_irq_chip;
+	} else {
+		irq_set_handler_locked(d, handle_edge_irq);
+		d->chip = &ipic_edge_irq_chip;
+	}
+
+	/* only EXT IRQ senses are programmable on ipic
+	 * internal IRQ senses are LEVEL_LOW
+	 */
+	if (src == IPIC_IRQ_EXT0)
+		edibit = 15;
+	else
+		if (src >= IPIC_IRQ_EXT1 && src <= IPIC_IRQ_EXT7)
+			edibit = (14 - (src - IPIC_IRQ_EXT1));
+		else
+			return (flow_type & IRQ_TYPE_LEVEL_LOW) ? 0 : -EINVAL;
+
+	vold = ipic_read(ipic->regs, IPIC_SECNR);
+	if ((flow_type & IRQ_TYPE_SENSE_MASK) == IRQ_TYPE_EDGE_FALLING) {
+		vnew = vold | (1 << edibit);
+	} else {
+		vnew = vold & ~(1 << edibit);
+	}
+	if (vold != vnew)
+		ipic_write(ipic->regs, IPIC_SECNR, vnew);
+	return IRQ_SET_MASK_OK_NOCOPY;
+}
+
+/* level interrupts and edge interrupts have different ack operations */
+static struct irq_chip ipic_level_irq_chip = {
+	.name		= "IPIC",
+	.irq_unmask	= ipic_unmask_irq,
+	.irq_mask	= ipic_mask_irq,
+	.irq_mask_ack	= ipic_mask_irq,
+	.irq_set_type	= ipic_set_irq_type,
+};
+
+static struct irq_chip ipic_edge_irq_chip = {
+	.name		= "IPIC",
+	.irq_unmask	= ipic_unmask_irq,
+	.irq_mask	= ipic_mask_irq,
+	.irq_mask_ack	= ipic_mask_irq_and_ack,
+	.irq_ack	= ipic_ack_irq,
+	.irq_set_type	= ipic_set_irq_type,
+};
+
+static int ipic_host_match(struct irq_domain *h, struct device_node *node,
+			   enum irq_domain_bus_token bus_token)
+{
+	/* Exact match, unless ipic node is NULL */
+	struct device_node *of_node = irq_domain_get_of_node(h);
+	return of_node == NULL || of_node == node;
+}
+
+static int ipic_host_map(struct irq_domain *h, unsigned int virq,
+			 irq_hw_number_t hw)
+{
+	struct ipic *ipic = h->host_data;
+
+	irq_set_chip_data(virq, ipic);
+	irq_set_chip_and_handler(virq, &ipic_level_irq_chip, handle_level_irq);
+
+	/* Set default irq type */
+	irq_set_irq_type(virq, IRQ_TYPE_NONE);
+
+	return 0;
+}
+
+static const struct irq_domain_ops ipic_host_ops = {
+	.match	= ipic_host_match,
+	.map	= ipic_host_map,
+	.xlate	= irq_domain_xlate_onetwocell,
+};
+
+struct ipic * __init ipic_init(struct device_node *node, unsigned int flags)
+{
+	struct ipic	*ipic;
+	struct resource res;
+	u32 temp = 0, ret;
+
+	ret = of_address_to_resource(node, 0, &res);
+	if (ret)
+		return NULL;
+
+	ipic = kzalloc_obj(*ipic);
+	if (ipic == NULL)
+		return NULL;
+
+	ipic->irqhost = irq_domain_create_linear(of_fwnode_handle(node),
+						 NR_IPIC_INTS,
+						 &ipic_host_ops, ipic);
+	if (ipic->irqhost == NULL) {
+		kfree(ipic);
+		return NULL;
+	}
+
+	ipic->regs = ioremap(res.start, resource_size(&res));
+
+	/* init hw */
+	ipic_write(ipic->regs, IPIC_SICNR, 0x0);
+
+	/* default priority scheme is grouped. If spread mode is required
+	 * configure SICFR accordingly */
+	if (flags & IPIC_SPREADMODE_GRP_A)
+		temp |= SICFR_IPSA;
+	if (flags & IPIC_SPREADMODE_GRP_B)
+		temp |= SICFR_IPSB;
+	if (flags & IPIC_SPREADMODE_GRP_C)
+		temp |= SICFR_IPSC;
+	if (flags & IPIC_SPREADMODE_GRP_D)
+		temp |= SICFR_IPSD;
+	if (flags & IPIC_SPREADMODE_MIX_A)
+		temp |= SICFR_MPSA;
+	if (flags & IPIC_SPREADMODE_MIX_B)
+		temp |= SICFR_MPSB;
+
+	ipic_write(ipic->regs, IPIC_SICFR, temp);
+
+	/* handle MCP route */
+	temp = 0;
+	if (flags & IPIC_DISABLE_MCP_OUT)
+		temp = SERCR_MCPR;
+	ipic_write(ipic->regs, IPIC_SERCR, temp);
+
+	/* handle routing of IRQ0 to MCP */
+	temp = ipic_read(ipic->regs, IPIC_SEMSR);
+
+	if (flags & IPIC_IRQ0_MCP)
+		temp |= SEMSR_SIRQ0;
+	else
+		temp &= ~SEMSR_SIRQ0;
+
+	ipic_write(ipic->regs, IPIC_SEMSR, temp);
+
+	primary_ipic = ipic;
+	irq_set_default_domain(primary_ipic->irqhost);
+
+	ipic_write(ipic->regs, IPIC_SIMSR_H, 0);
+	ipic_write(ipic->regs, IPIC_SIMSR_L, 0);
+
+	pr_info("IPIC (%d IRQ sources) at MMIO %pa\n", NR_IPIC_INTS, &res.start);
+
+	return ipic;
+}
+
+void __init ipic_set_default_priority(void)
+{
+	ipic_write(primary_ipic->regs, IPIC_SIPRR_A, IPIC_PRIORITY_DEFAULT);
+	ipic_write(primary_ipic->regs, IPIC_SIPRR_B, IPIC_PRIORITY_DEFAULT);
+	ipic_write(primary_ipic->regs, IPIC_SIPRR_C, IPIC_PRIORITY_DEFAULT);
+	ipic_write(primary_ipic->regs, IPIC_SIPRR_D, IPIC_PRIORITY_DEFAULT);
+	ipic_write(primary_ipic->regs, IPIC_SMPRR_A, IPIC_PRIORITY_DEFAULT);
+	ipic_write(primary_ipic->regs, IPIC_SMPRR_B, IPIC_PRIORITY_DEFAULT);
+}
+
+u32 ipic_get_mcp_status(void)
+{
+	return primary_ipic ? ipic_read(primary_ipic->regs, IPIC_SERSR) : 0;
+}
+
+void ipic_clear_mcp_status(u32 mask)
+{
+	ipic_write(primary_ipic->regs, IPIC_SERSR, mask);
+}
+
+/* Return an interrupt vector or 0 if no interrupt is pending. */
+unsigned int ipic_get_irq(void)
+{
+	int irq;
+
+	BUG_ON(primary_ipic == NULL);
+
+#define IPIC_SIVCR_VECTOR_MASK	0x7f
+	irq = ipic_read(primary_ipic->regs, IPIC_SIVCR) & IPIC_SIVCR_VECTOR_MASK;
+
+	if (irq == 0)    /* 0 --> no irq is pending */
+		return 0;
+
+	return irq_find_mapping(primary_ipic->irqhost, irq);
+}
+
+#ifdef CONFIG_SUSPEND
+static struct {
+	u32 sicfr;
+	u32 siprr[2];
+	u32 simsr[2];
+	u32 sicnr;
+	u32 smprr[2];
+	u32 semsr;
+	u32 secnr;
+	u32 sermr;
+	u32 sercr;
+} ipic_saved_state;
+
+static int ipic_suspend(void *data)
+{
+	struct ipic *ipic = primary_ipic;
+
+	ipic_saved_state.sicfr = ipic_read(ipic->regs, IPIC_SICFR);
+	ipic_saved_state.siprr[0] = ipic_read(ipic->regs, IPIC_SIPRR_A);
+	ipic_saved_state.siprr[1] = ipic_read(ipic->regs, IPIC_SIPRR_D);
+	ipic_saved_state.simsr[0] = ipic_read(ipic->regs, IPIC_SIMSR_H);
+	ipic_saved_state.simsr[1] = ipic_read(ipic->regs, IPIC_SIMSR_L);
+	ipic_saved_state.sicnr = ipic_read(ipic->regs, IPIC_SICNR);
+	ipic_saved_state.smprr[0] = ipic_read(ipic->regs, IPIC_SMPRR_A);
+	ipic_saved_state.smprr[1] = ipic_read(ipic->regs, IPIC_SMPRR_B);
+	ipic_saved_state.semsr = ipic_read(ipic->regs, IPIC_SEMSR);
+	ipic_saved_state.secnr = ipic_read(ipic->regs, IPIC_SECNR);
+	ipic_saved_state.sermr = ipic_read(ipic->regs, IPIC_SERMR);
+	ipic_saved_state.sercr = ipic_read(ipic->regs, IPIC_SERCR);
+
+	if (fsl_deep_sleep()) {
+		/* In deep sleep, make sure there can be no
+		 * pending interrupts, as this can cause
+		 * problems on 831x.
+		 */
+		ipic_write(ipic->regs, IPIC_SIMSR_H, 0);
+		ipic_write(ipic->regs, IPIC_SIMSR_L, 0);
+		ipic_write(ipic->regs, IPIC_SEMSR, 0);
+		ipic_write(ipic->regs, IPIC_SERMR, 0);
+	}
+
+	return 0;
+}
+
+static void ipic_resume(void *data)
+{
+	struct ipic *ipic = primary_ipic;
+
+	ipic_write(ipic->regs, IPIC_SICFR, ipic_saved_state.sicfr);
+	ipic_write(ipic->regs, IPIC_SIPRR_A, ipic_saved_state.siprr[0]);
+	ipic_write(ipic->regs, IPIC_SIPRR_D, ipic_saved_state.siprr[1]);
+	ipic_write(ipic->regs, IPIC_SIMSR_H, ipic_saved_state.simsr[0]);
+	ipic_write(ipic->regs, IPIC_SIMSR_L, ipic_saved_state.simsr[1]);
+	ipic_write(ipic->regs, IPIC_SICNR, ipic_saved_state.sicnr);
+	ipic_write(ipic->regs, IPIC_SMPRR_A, ipic_saved_state.smprr[0]);
+	ipic_write(ipic->regs, IPIC_SMPRR_B, ipic_saved_state.smprr[1]);
+	ipic_write(ipic->regs, IPIC_SEMSR, ipic_saved_state.semsr);
+	ipic_write(ipic->regs, IPIC_SECNR, ipic_saved_state.secnr);
+	ipic_write(ipic->regs, IPIC_SERMR, ipic_saved_state.sermr);
+	ipic_write(ipic->regs, IPIC_SERCR, ipic_saved_state.sercr);
+}
+#else
+#define ipic_suspend NULL
+#define ipic_resume NULL
+#endif
+
+static const struct syscore_ops ipic_syscore_ops = {
+	.suspend = ipic_suspend,
+	.resume = ipic_resume,
+};
+
+static struct syscore ipic_syscore = {
+	.ops = &ipic_syscore_ops,
+};
+
+static int __init init_ipic_syscore(void)
+{
+	if (!primary_ipic || !primary_ipic->regs)
+		return -ENODEV;
+
+	printk(KERN_DEBUG "Registering ipic system core operations\n");
+	register_syscore(&ipic_syscore);
+
+	return 0;
+}
+
+subsys_initcall(init_ipic_syscore);