powerpc: introduce the ePAPR embedded hypervisor vmpic driver

The Freescale ePAPR reference hypervisor provides interrupt controller
services via a hypercall interface, instead of emulating the MPIC
controller.  This is called the VMPIC.

The ePAPR "virtual interrupt controller" provides interrupt controller
services for external interrupts.  External interrupts received by a
partition can come from two sources:

  - Hardware interrupts - hardware interrupts come from external
    interrupt lines or on-chip I/O devices.
  - Virtual interrupts - virtual interrupts are generated by the hypervisor
    as part of some hypervisor service or hypervisor-created virtual device.

Both types of interrupts are processed using the same programming model and
same set of hypercalls.

Signed-off-by: Ashish Kalra <ashish.kalra@freescale.com>
Signed-off-by: Timur Tabi <timur@freescale.com>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>

1 files changed, 302 insertions, 0 deletions

diff --git a/arch/powerpc/sysdev/ehv_pic.c b/arch/powerpc/sysdev/ehv_pic.c
new file mode 100644
index 000000000000..af1a5df46b3e
--- /dev/null
+++ b/arch/powerpc/sysdev/ehv_pic.c
@@ -0,0 +1,302 @@
+/*
+ *  Driver for ePAPR Embedded Hypervisor PIC
+ *
+ *  Copyright 2008-2011 Freescale Semiconductor, Inc.
+ *
+ *  Author: Ashish Kalra <ashish.kalra@freescale.com>
+ *
+ * This file is licensed under the terms of the GNU General Public License
+ * version 2.  This program is licensed "as is" without any warranty of any
+ * kind, whether express or implied.
+ */
+
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/irq.h>
+#include <linux/smp.h>
+#include <linux/interrupt.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+#include <linux/of.h>
+
+#include <asm/io.h>
+#include <asm/irq.h>
+#include <asm/smp.h>
+#include <asm/machdep.h>
+#include <asm/ehv_pic.h>
+#include <asm/fsl_hcalls.h>
+
+#include "../../../kernel/irq/settings.h"
+
+static struct ehv_pic *global_ehv_pic;
+static DEFINE_SPINLOCK(ehv_pic_lock);
+
+static u32 hwirq_intspec[NR_EHV_PIC_INTS];
+static u32 __iomem *mpic_percpu_base_vaddr;
+
+#define IRQ_TYPE_MPIC_DIRECT 4
+#define MPIC_EOI  0x00B0
+
+/*
+ * Linux descriptor level callbacks
+ */
+
+void ehv_pic_unmask_irq(struct irq_data *d)
+{
+	unsigned int src = virq_to_hw(d->irq);
+
+	ev_int_set_mask(src, 0);
+}
+
+void ehv_pic_mask_irq(struct irq_data *d)
+{
+	unsigned int src = virq_to_hw(d->irq);
+
+	ev_int_set_mask(src, 1);
+}
+
+void ehv_pic_end_irq(struct irq_data *d)
+{
+	unsigned int src = virq_to_hw(d->irq);
+
+	ev_int_eoi(src);
+}
+
+void ehv_pic_direct_end_irq(struct irq_data *d)
+{
+	out_be32(mpic_percpu_base_vaddr + MPIC_EOI / 4, 0);
+}
+
+int ehv_pic_set_affinity(struct irq_data *d, const struct cpumask *dest,
+			 bool force)
+{
+	unsigned int src = virq_to_hw(d->irq);
+	unsigned int config, prio, cpu_dest;
+	int cpuid = irq_choose_cpu(dest);
+	unsigned long flags;
+
+	spin_lock_irqsave(&ehv_pic_lock, flags);
+	ev_int_get_config(src, &config, &prio, &cpu_dest);
+	ev_int_set_config(src, config, prio, cpuid);
+	spin_unlock_irqrestore(&ehv_pic_lock, flags);
+
+	return 0;
+}
+
+static unsigned int ehv_pic_type_to_vecpri(unsigned int type)
+{
+	/* Now convert sense value */
+
+	switch (type & IRQ_TYPE_SENSE_MASK) {
+	case IRQ_TYPE_EDGE_RISING:
+		return EHV_PIC_INFO(VECPRI_SENSE_EDGE) |
+		       EHV_PIC_INFO(VECPRI_POLARITY_POSITIVE);
+
+	case IRQ_TYPE_EDGE_FALLING:
+	case IRQ_TYPE_EDGE_BOTH:
+		return EHV_PIC_INFO(VECPRI_SENSE_EDGE) |
+		       EHV_PIC_INFO(VECPRI_POLARITY_NEGATIVE);
+
+	case IRQ_TYPE_LEVEL_HIGH:
+		return EHV_PIC_INFO(VECPRI_SENSE_LEVEL) |
+		       EHV_PIC_INFO(VECPRI_POLARITY_POSITIVE);
+
+	case IRQ_TYPE_LEVEL_LOW:
+	default:
+		return EHV_PIC_INFO(VECPRI_SENSE_LEVEL) |
+		       EHV_PIC_INFO(VECPRI_POLARITY_NEGATIVE);
+	}
+}
+
+int ehv_pic_set_irq_type(struct irq_data *d, unsigned int flow_type)
+{
+	unsigned int src = virq_to_hw(d->irq);
+	struct irq_desc *desc = irq_to_desc(d->irq);
+	unsigned int vecpri, vold, vnew, prio, cpu_dest;
+	unsigned long flags;
+
+	if (flow_type == IRQ_TYPE_NONE)
+		flow_type = IRQ_TYPE_LEVEL_LOW;
+
+	irq_settings_clr_level(desc);
+	irq_settings_set_trigger_mask(desc, flow_type);
+	if (flow_type & (IRQ_TYPE_LEVEL_HIGH | IRQ_TYPE_LEVEL_LOW))
+		irq_settings_set_level(desc);
+
+	vecpri = ehv_pic_type_to_vecpri(flow_type);
+
+	spin_lock_irqsave(&ehv_pic_lock, flags);
+	ev_int_get_config(src, &vold, &prio, &cpu_dest);
+	vnew = vold & ~(EHV_PIC_INFO(VECPRI_POLARITY_MASK) |
+			EHV_PIC_INFO(VECPRI_SENSE_MASK));
+	vnew |= vecpri;
+
+	/*
+	 * TODO : Add specific interface call for platform to set
+	 * individual interrupt priorities.
+	 * platform currently using static/default priority for all ints
+	 */
+
+	prio = 8;
+
+	ev_int_set_config(src, vecpri, prio, cpu_dest);
+
+	spin_unlock_irqrestore(&ehv_pic_lock, flags);
+	return 0;
+}
+
+static struct irq_chip ehv_pic_irq_chip = {
+	.irq_mask	= ehv_pic_mask_irq,
+	.irq_unmask	= ehv_pic_unmask_irq,
+	.irq_eoi	= ehv_pic_end_irq,
+	.irq_set_type	= ehv_pic_set_irq_type,
+};
+
+static struct irq_chip ehv_pic_direct_eoi_irq_chip = {
+	.irq_mask	= ehv_pic_mask_irq,
+	.irq_unmask	= ehv_pic_unmask_irq,
+	.irq_eoi	= ehv_pic_direct_end_irq,
+	.irq_set_type	= ehv_pic_set_irq_type,
+};
+
+/* Return an interrupt vector or NO_IRQ if no interrupt is pending. */
+unsigned int ehv_pic_get_irq(void)
+{
+	int irq;
+
+	BUG_ON(global_ehv_pic == NULL);
+
+	if (global_ehv_pic->coreint_flag)
+		irq = mfspr(SPRN_EPR); /* if core int mode */
+	else
+		ev_int_iack(0, &irq); /* legacy mode */
+
+	if (irq == 0xFFFF)    /* 0xFFFF --> no irq is pending */
+		return NO_IRQ;
+
+	/*
+	 * this will also setup revmap[] in the slow path for the first
+	 * time, next calls will always use fast path by indexing revmap
+	 */
+	return irq_linear_revmap(global_ehv_pic->irqhost, irq);
+}
+
+static int ehv_pic_host_match(struct irq_host *h, struct device_node *node)
+{
+	/* Exact match, unless ehv_pic node is NULL */
+	return h->of_node == NULL || h->of_node == node;
+}
+
+static int ehv_pic_host_map(struct irq_host *h, unsigned int virq,
+			 irq_hw_number_t hw)
+{
+	struct ehv_pic *ehv_pic = h->host_data;
+	struct irq_chip *chip;
+
+	/* Default chip */
+	chip = &ehv_pic->hc_irq;
+
+	if (mpic_percpu_base_vaddr)
+		if (hwirq_intspec[hw] & IRQ_TYPE_MPIC_DIRECT)
+			chip = &ehv_pic_direct_eoi_irq_chip;
+
+	irq_set_chip_data(virq, chip);
+	/*
+	 * using handle_fasteoi_irq as our irq handler, this will
+	 * only call the eoi callback and suitable for the MPIC
+	 * controller which set ISR/IPR automatically and clear the
+	 * highest priority active interrupt in ISR/IPR when we do
+	 * a specific eoi
+	 */
+	irq_set_chip_and_handler(virq, chip, handle_fasteoi_irq);
+
+	/* Set default irq type */
+	irq_set_irq_type(virq, IRQ_TYPE_NONE);
+
+	return 0;
+}
+
+static int ehv_pic_host_xlate(struct irq_host *h, struct device_node *ct,
+			   const u32 *intspec, unsigned int intsize,
+			   irq_hw_number_t *out_hwirq, unsigned int *out_flags)
+
+{
+	/*
+	 * interrupt sense values coming from the guest device tree
+	 * interrupt specifiers can have four possible sense and
+	 * level encoding information and they need to
+	 * be translated between firmware type & linux type.
+	 */
+
+	static unsigned char map_of_senses_to_linux_irqtype[4] = {
+		IRQ_TYPE_EDGE_FALLING,
+		IRQ_TYPE_EDGE_RISING,
+		IRQ_TYPE_LEVEL_LOW,
+		IRQ_TYPE_LEVEL_HIGH,
+	};
+
+	*out_hwirq = intspec[0];
+	if (intsize > 1) {
+		hwirq_intspec[intspec[0]] = intspec[1];
+		*out_flags = map_of_senses_to_linux_irqtype[intspec[1] &
+							~IRQ_TYPE_MPIC_DIRECT];
+	} else {
+		*out_flags = IRQ_TYPE_NONE;
+	}
+
+	return 0;
+}
+
+static struct irq_host_ops ehv_pic_host_ops = {
+	.match = ehv_pic_host_match,
+	.map = ehv_pic_host_map,
+	.xlate = ehv_pic_host_xlate,
+};
+
+void __init ehv_pic_init(void)
+{
+	struct device_node *np, *np2;
+	struct ehv_pic *ehv_pic;
+	int coreint_flag = 1;
+
+	np = of_find_compatible_node(NULL, NULL, "epapr,hv-pic");
+	if (!np) {
+		pr_err("ehv_pic_init: could not find epapr,hv-pic node\n");
+		return;
+	}
+
+	if (!of_find_property(np, "has-external-proxy", NULL))
+		coreint_flag = 0;
+
+	ehv_pic = kzalloc(sizeof(struct ehv_pic), GFP_KERNEL);
+	if (!ehv_pic) {
+		of_node_put(np);
+		return;
+	}
+
+	ehv_pic->irqhost = irq_alloc_host(np, IRQ_HOST_MAP_LINEAR,
+		NR_EHV_PIC_INTS, &ehv_pic_host_ops, 0);
+
+	if (!ehv_pic->irqhost) {
+		of_node_put(np);
+		return;
+	}
+
+	np2 = of_find_compatible_node(NULL, NULL, "fsl,hv-mpic-per-cpu");
+	if (np2) {
+		mpic_percpu_base_vaddr = of_iomap(np2, 0);
+		if (!mpic_percpu_base_vaddr)
+			pr_err("ehv_pic_init: of_iomap failed\n");
+
+		of_node_put(np2);
+	}
+
+	ehv_pic->irqhost->host_data = ehv_pic;
+	ehv_pic->hc_irq = ehv_pic_irq_chip;
+	ehv_pic->hc_irq.irq_set_affinity = ehv_pic_set_affinity;
+	ehv_pic->coreint_flag = coreint_flag;
+
+	global_ehv_pic = ehv_pic;
+	irq_set_default_host(global_ehv_pic->irqhost);
+}