/*
 * Copyright (C) 2012 ARM Ltd.
 * Author: Marc Zyngier <marc.zyngier@arm.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.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 */

#ifndef __ASM_ARM_KVM_VGIC_H
#define __ASM_ARM_KVM_VGIC_H

#include <linux/kernel.h>
#include <linux/kvm.h>
#include <linux/irqreturn.h>
#include <linux/spinlock.h>
#include <linux/types.h>

#define VGIC_NR_IRQS_LEGACY     256
#define VGIC_NR_SGIS            16
#define VGIC_NR_PPIS            16
#define VGIC_NR_PRIVATE_IRQS    (VGIC_NR_SGIS + VGIC_NR_PPIS)

#define VGIC_V2_MAX_LRS         (1 << 6)
#define VGIC_V3_MAX_LRS         16
#define VGIC_MAX_IRQS           1024
#define VGIC_V2_MAX_CPUS        8

/* Sanity checks... */
#if (KVM_MAX_VCPUS > 255)
#error Too many KVM VCPUs, the VGIC only supports up to 255 VCPUs for now
#endif

#if (VGIC_NR_IRQS_LEGACY & 31)
#error "VGIC_NR_IRQS must be a multiple of 32"
#endif

#if (VGIC_NR_IRQS_LEGACY > VGIC_MAX_IRQS)
#error "VGIC_NR_IRQS must be <= 1024"
#endif

/*
 * The GIC distributor registers describing interrupts have two parts:
 * - 32 per-CPU interrupts (SGI + PPI)
 * - a bunch of shared interrupts (SPI)
 */
struct vgic_bitmap {
        /*
         * - One UL per VCPU for private interrupts (assumes UL is at
         *   least 32 bits)
         * - As many UL as necessary for shared interrupts.
         *
         * The private interrupts are accessed via the "private"
         * field, one UL per vcpu (the state for vcpu n is in
         * private[n]). The shared interrupts are accessed via the
         * "shared" pointer (IRQn state is at bit n-32 in the bitmap).
         */
        unsigned long *private;
        unsigned long *shared;
};

struct vgic_bytemap {
        /*
         * - 8 u32 per VCPU for private interrupts
         * - As many u32 as necessary for shared interrupts.
         *
         * The private interrupts are accessed via the "private"
         * field, (the state for vcpu n is in private[n*8] to
         * private[n*8 + 7]). The shared interrupts are accessed via
         * the "shared" pointer (IRQn state is at byte (n-32)%4 of the
         * shared[(n-32)/4] word).
         */
        u32 *private;
        u32 *shared;
};

struct kvm_vcpu;

enum vgic_type {
        VGIC_V2,                /* Good ol' GICv2 */
        VGIC_V3,                /* New fancy GICv3 */
};

#define LR_STATE_PENDING        (1 << 0)
#define LR_STATE_ACTIVE         (1 << 1)
#define LR_STATE_MASK           (3 << 0)
#define LR_EOI_INT              (1 << 2)

struct vgic_lr {
        u16     irq;
        u8      source;
        u8      state;
};

struct vgic_vmcr {
        u32     ctlr;
        u32     abpr;
        u32     bpr;
        u32     pmr;
};

struct vgic_ops {
        struct vgic_lr  (*get_lr)(const struct kvm_vcpu *, int);
        void    (*set_lr)(struct kvm_vcpu *, int, struct vgic_lr);
        void    (*sync_lr_elrsr)(struct kvm_vcpu *, int, struct vgic_lr);
        u64     (*get_elrsr)(const struct kvm_vcpu *vcpu);
        u64     (*get_eisr)(const struct kvm_vcpu *vcpu);
        void    (*clear_eisr)(struct kvm_vcpu *vcpu);
        u32     (*get_interrupt_status)(const struct kvm_vcpu *vcpu);
        void    (*enable_underflow)(struct kvm_vcpu *vcpu);
        void    (*disable_underflow)(struct kvm_vcpu *vcpu);
        void    (*get_vmcr)(struct kvm_vcpu *vcpu, struct vgic_vmcr *vmcr);
        void    (*set_vmcr)(struct kvm_vcpu *vcpu, struct vgic_vmcr *vmcr);
        void    (*enable)(struct kvm_vcpu *vcpu);
};

struct vgic_params {
        /* vgic type */
        enum vgic_type  type;
        /* Physical address of vgic virtual cpu interface */
        phys_addr_t     vcpu_base;
        /* Number of list registers */
        u32             nr_lr;
        /* Interrupt number */
        unsigned int    maint_irq;
        /* Virtual control interface base address */
        void __iomem    *vctrl_base;
        int             max_gic_vcpus;
        /* Only needed for the legacy KVM_CREATE_IRQCHIP */
        bool            can_emulate_gicv2;
};

struct vgic_vm_ops {
        bool    (*handle_mmio)(struct kvm_vcpu *, struct kvm_run *,
                               struct kvm_exit_mmio *);
        bool    (*queue_sgi)(struct kvm_vcpu *, int irq);
        void    (*add_sgi_source)(struct kvm_vcpu *, int irq, int source);
        int     (*init_model)(struct kvm *);
        int     (*map_resources)(struct kvm *, const struct vgic_params *);
};

struct vgic_dist {
#ifdef CONFIG_KVM_ARM_VGIC
        spinlock_t              lock;
        bool                    in_kernel;
        bool                    ready;

        /* vGIC model the kernel emulates for the guest (GICv2 or GICv3) */
        u32                     vgic_model;

        int                     nr_cpus;
        int                     nr_irqs;

        /* Virtual control interface mapping */
        void __iomem            *vctrl_base;

        /* Distributor and vcpu interface mapping in the guest */
        phys_addr_t             vgic_dist_base;
        /* GICv2 and GICv3 use different mapped register blocks */
        union {
                phys_addr_t             vgic_cpu_base;
                phys_addr_t             vgic_redist_base;
        };

        /* Distributor enabled */
        u32                     enabled;

        /* Interrupt enabled (one bit per IRQ) */
        struct vgic_bitmap      irq_enabled;

        /* Level-triggered interrupt external input is asserted */
        struct vgic_bitmap      irq_level;

        /*
         * Interrupt state is pending on the distributor
         */
        struct vgic_bitmap      irq_pending;

        /*
         * Tracks writes to GICD_ISPENDRn and GICD_ICPENDRn for level-triggered
         * interrupts.  Essentially holds the state of the flip-flop in
         * Figure 4-10 on page 4-101 in ARM IHI 0048B.b.
         * Once set, it is only cleared for level-triggered interrupts on
         * guest ACKs (when we queue it) or writes to GICD_ICPENDRn.
         */
        struct vgic_bitmap      irq_soft_pend;

        /* Level-triggered interrupt queued on VCPU interface */
        struct vgic_bitmap      irq_queued;

        /* Interrupt priority. Not used yet. */
        struct vgic_bytemap     irq_priority;

        /* Level/edge triggered */
        struct vgic_bitmap      irq_cfg;

        /*
         * Source CPU per SGI and target CPU:
         *
         * Each byte represent a SGI observable on a VCPU, each bit of
         * this byte indicating if the corresponding VCPU has
         * generated this interrupt. This is a GICv2 feature only.
         *
         * For VCPUn (n < 8), irq_sgi_sources[n*16] to [n*16 + 15] are
         * the SGIs observable on VCPUn.
         */
        u8                      *irq_sgi_sources;

        /*
         * Target CPU for each SPI:
         *
         * Array of available SPI, each byte indicating the target
         * VCPU for SPI. IRQn (n >=32) is at irq_spi_cpu[n-32].
         */
        u8                      *irq_spi_cpu;

        /*
         * Reverse lookup of irq_spi_cpu for faster compute pending:
         *
         * Array of bitmaps, one per VCPU, describing if IRQn is
         * routed to a particular VCPU.
         */
        struct vgic_bitmap      *irq_spi_target;

        /* Target MPIDR for each IRQ (needed for GICv3 IROUTERn) only */
        u32                     *irq_spi_mpidr;

        /* Bitmap indicating which CPU has something pending */
        unsigned long           *irq_pending_on_cpu;

        struct vgic_vm_ops      vm_ops;
#endif
};

struct vgic_v2_cpu_if {
        u32             vgic_hcr;
        u32             vgic_vmcr;
        u32             vgic_misr;      /* Saved only */
        u64             vgic_eisr;      /* Saved only */
        u64             vgic_elrsr;     /* Saved only */
        u32             vgic_apr;
        u32             vgic_lr[VGIC_V2_MAX_LRS];
};

struct vgic_v3_cpu_if {
#ifdef CONFIG_ARM_GIC_V3
        u32             vgic_hcr;
        u32             vgic_vmcr;
        u32             vgic_sre;       /* Restored only, change ignored */
        u32             vgic_misr;      /* Saved only */
        u32             vgic_eisr;      /* Saved only */
        u32             vgic_elrsr;     /* Saved only */
        u32             vgic_ap0r[4];
        u32             vgic_ap1r[4];
        u64             vgic_lr[VGIC_V3_MAX_LRS];
#endif
};

struct vgic_cpu {
#ifdef CONFIG_KVM_ARM_VGIC
        /* per IRQ to LR mapping */
        u8              *vgic_irq_lr_map;

        /* Pending interrupts on this VCPU */
        DECLARE_BITMAP( pending_percpu, VGIC_NR_PRIVATE_IRQS);
        unsigned long   *pending_shared;

        /* Bitmap of used/free list registers */
        DECLARE_BITMAP( lr_used, VGIC_V2_MAX_LRS);

        /* Number of list registers on this CPU */
        int             nr_lr;

        /* CPU vif control registers for world switch */
        union {
                struct vgic_v2_cpu_if   vgic_v2;
                struct vgic_v3_cpu_if   vgic_v3;
        };
#endif
};

#define LR_EMPTY        0xff

#define INT_STATUS_EOI          (1 << 0)
#define INT_STATUS_UNDERFLOW    (1 << 1)

struct kvm;
struct kvm_vcpu;
struct kvm_run;
struct kvm_exit_mmio;

#ifdef CONFIG_KVM_ARM_VGIC
int kvm_vgic_addr(struct kvm *kvm, unsigned long type, u64 *addr, bool write);
int kvm_vgic_hyp_init(void);
int kvm_vgic_map_resources(struct kvm *kvm);
int kvm_vgic_get_max_vcpus(void);
int kvm_vgic_create(struct kvm *kvm, u32 type);
void kvm_vgic_destroy(struct kvm *kvm);
void kvm_vgic_vcpu_destroy(struct kvm_vcpu *vcpu);
void kvm_vgic_flush_hwstate(struct kvm_vcpu *vcpu);
void kvm_vgic_sync_hwstate(struct kvm_vcpu *vcpu);
int kvm_vgic_inject_irq(struct kvm *kvm, int cpuid, unsigned int irq_num,
                        bool level);
void vgic_v3_dispatch_sgi(struct kvm_vcpu *vcpu, u64 reg);
int kvm_vgic_vcpu_pending_irq(struct kvm_vcpu *vcpu);
bool vgic_handle_mmio(struct kvm_vcpu *vcpu, struct kvm_run *run,
                      struct kvm_exit_mmio *mmio);

#define irqchip_in_kernel(k)    (!!((k)->arch.vgic.in_kernel))
#define vgic_initialized(k)     (!!((k)->arch.vgic.nr_cpus))
#define vgic_ready(k)           ((k)->arch.vgic.ready)

int vgic_v2_probe(struct device_node *vgic_node,
                  const struct vgic_ops **ops,
                  const struct vgic_params **params);
#ifdef CONFIG_ARM_GIC_V3
int vgic_v3_probe(struct device_node *vgic_node,
                  const struct vgic_ops **ops,
                  const struct vgic_params **params);
#else
static inline int vgic_v3_probe(struct device_node *vgic_node,
                                const struct vgic_ops **ops,
                                const struct vgic_params **params)
{
        return -ENODEV;
}
#endif

#else
static inline int kvm_vgic_hyp_init(void)
{
        return 0;
}

static inline int kvm_vgic_set_addr(struct kvm *kvm, unsigned long type, u64 addr)
{
        return 0;
}

static inline int kvm_vgic_addr(struct kvm *kvm, unsigned long type, u64 *addr, bool write)
{
        return -ENXIO;
}

static inline int kvm_vgic_map_resources(struct kvm *kvm)
{
        return 0;
}

static inline int kvm_vgic_create(struct kvm *kvm, u32 type)
{
        return 0;
}

static inline void kvm_vgic_destroy(struct kvm *kvm)
{
}

static inline void kvm_vgic_vcpu_destroy(struct kvm_vcpu *vcpu)
{
}

static inline int kvm_vgic_vcpu_init(struct kvm_vcpu *vcpu)
{
        return 0;
}

static inline void kvm_vgic_flush_hwstate(struct kvm_vcpu *vcpu) {}
static inline void kvm_vgic_sync_hwstate(struct kvm_vcpu *vcpu) {}

static inline int kvm_vgic_inject_irq(struct kvm *kvm, int cpuid,
                                      unsigned int irq_num, bool level)
{
        return 0;
}

static inline int kvm_vgic_vcpu_pending_irq(struct kvm_vcpu *vcpu)
{
        return 0;
}

static inline bool vgic_handle_mmio(struct kvm_vcpu *vcpu, struct kvm_run *run,
                                    struct kvm_exit_mmio *mmio)
{
        return false;
}

static inline int irqchip_in_kernel(struct kvm *kvm)
{
        return 0;
}

static inline bool vgic_initialized(struct kvm *kvm)
{
        return true;
}

static inline bool vgic_ready(struct kvm *kvm)
{
        return true;
}

static inline int kvm_vgic_get_max_vcpus(void)
{
        return KVM_MAX_VCPUS;
}
#endif

#endif