epapr_hcalls.h

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/*
 * ePAPR hcall interface
 *
 * Copyright 2008-2011 Freescale Semiconductor, Inc.
 *
 * Author: Timur Tabi <timur@freescale.com>
 *
 * This file is provided under a dual BSD/GPL license.  When using or
 * redistributing this file, you may do so under either license.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *     * Redistributions of source code must retain the above copyright
 *       notice, this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above copyright
 *       notice, this list of conditions and the following disclaimer in the
 *       documentation and/or other materials provided with the distribution.
 *     * Neither the name of Freescale Semiconductor nor the
 *       names of its contributors may be used to endorse or promote products
 *       derived from this software without specific prior written permission.
 *
 *
 * ALTERNATIVELY, this software may be distributed under the terms of the
 * GNU General Public License ("GPL") as published by the Free Software
 * Foundation, either version 2 of that License or (at your option) any
 * later version.
 *
 * THIS SOFTWARE IS PROVIDED BY Freescale Semiconductor ``AS IS'' AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL Freescale Semiconductor BE LIABLE FOR ANY
 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

/* A "hypercall" is an "sc 1" instruction.  This header file file provides C
 * wrapper functions for the ePAPR hypervisor interface.  It is inteded
 * for use by Linux device drivers and other operating systems.
 *
 * The hypercalls are implemented as inline assembly, rather than assembly
 * language functions in a .S file, for optimization.  It allows
 * the caller to issue the hypercall instruction directly, improving both
 * performance and memory footprint.
 */

#ifndef _EPAPR_HCALLS_H
#define _EPAPR_HCALLS_H

#include <linux/types.h>
#include <linux/errno.h>
#include <asm/byteorder.h>

#define EV_BYTE_CHANNEL_SEND        1
#define EV_BYTE_CHANNEL_RECEIVE     2
#define EV_BYTE_CHANNEL_POLL        3
#define EV_INT_SET_CONFIG       4
#define EV_INT_GET_CONFIG       5
#define EV_INT_SET_MASK         6
#define EV_INT_GET_MASK         7
#define EV_INT_IACK         9
#define EV_INT_EOI          10
#define EV_INT_SEND_IPI         11
#define EV_INT_SET_TASK_PRIORITY    12
#define EV_INT_GET_TASK_PRIORITY    13
#define EV_DOORBELL_SEND        14
#define EV_MSGSND           15
#define EV_IDLE             16

/* vendor ID: epapr */
#define EV_LOCAL_VENDOR_ID      0   /* for private use */
#define EV_EPAPR_VENDOR_ID      1
#define EV_FSL_VENDOR_ID        2   /* Freescale Semiconductor */
#define EV_IBM_VENDOR_ID        3   /* IBM */
#define EV_GHS_VENDOR_ID        4   /* Green Hills Software */
#define EV_ENEA_VENDOR_ID       5   /* Enea */
#define EV_WR_VENDOR_ID         6   /* Wind River Systems */
#define EV_AMCC_VENDOR_ID       7   /* Applied Micro Circuits */
#define EV_KVM_VENDOR_ID        42  /* KVM */

/* The max number of bytes that a byte channel can send or receive per call */
#define EV_BYTE_CHANNEL_MAX_BYTES   16


#define _EV_HCALL_TOKEN(id, num) (((id) << 16) | (num))
#define EV_HCALL_TOKEN(hcall_num) _EV_HCALL_TOKEN(EV_EPAPR_VENDOR_ID, hcall_num)

/* epapr error codes */
#define EV_EPERM        1   /* Operation not permitted */
#define EV_ENOENT       2   /*  Entry Not Found */
#define EV_EIO          3   /* I/O error occured */
#define EV_EAGAIN       4   /* The operation had insufficient
                     * resources to complete and should be
                     * retried
                     */
#define EV_ENOMEM       5   /* There was insufficient memory to
                     * complete the operation */
#define EV_EFAULT       6   /* Bad guest address */
#define EV_ENODEV       7   /* No such device */
#define EV_EINVAL       8   /* An argument supplied to the hcall
                       was out of range or invalid */
#define EV_INTERNAL     9   /* An internal error occured */
#define EV_CONFIG       10  /* A configuration error was detected */
#define EV_INVALID_STATE    11  /* The object is in an invalid state */
#define EV_UNIMPLEMENTED    12  /* Unimplemented hypercall */
#define EV_BUFFER_OVERFLOW  13  /* Caller-supplied buffer too small */

/*
 * Hypercall register clobber list
 *
 * These macros are used to define the list of clobbered registers during a
 * hypercall.  Technically, registers r0 and r3-r12 are always clobbered,
 * but the gcc inline assembly syntax does not allow us to specify registers
 * on the clobber list that are also on the input/output list.  Therefore,
 * the lists of clobbered registers depends on the number of register
 * parmeters ("+r" and "=r") passed to the hypercall.
 *
 * Each assembly block should use one of the HCALL_CLOBBERSx macros.  As a
 * general rule, 'x' is the number of parameters passed to the assembly
 * block *except* for r11.
 *
 * If you're not sure, just use the smallest value of 'x' that does not
 * generate a compilation error.  Because these are static inline functions,
 * the compiler will only check the clobber list for a function if you
 * compile code that calls that function.
 *
 * r3 and r11 are not included in any clobbers list because they are always
 * listed as output registers.
 *
 * XER, CTR, and LR are currently listed as clobbers because it's uncertain
 * whether they will be clobbered.
 *
 * Note that r11 can be used as an output parameter.
 *
 * The "memory" clobber is only necessary for hcalls where the Hypervisor
 * will read or write guest memory. However, we add it to all hcalls because
 * the impact is minimal, and we want to ensure that it's present for the
 * hcalls that need it.
*/

/* List of common clobbered registers.  Do not use this macro. */
#define EV_HCALL_CLOBBERS "r0", "r12", "xer", "ctr", "lr", "cc", "memory"

#define EV_HCALL_CLOBBERS8 EV_HCALL_CLOBBERS
#define EV_HCALL_CLOBBERS7 EV_HCALL_CLOBBERS8, "r10"
#define EV_HCALL_CLOBBERS6 EV_HCALL_CLOBBERS7, "r9"
#define EV_HCALL_CLOBBERS5 EV_HCALL_CLOBBERS6, "r8"
#define EV_HCALL_CLOBBERS4 EV_HCALL_CLOBBERS5, "r7"
#define EV_HCALL_CLOBBERS3 EV_HCALL_CLOBBERS4, "r6"
#define EV_HCALL_CLOBBERS2 EV_HCALL_CLOBBERS3, "r5"
#define EV_HCALL_CLOBBERS1 EV_HCALL_CLOBBERS2, "r4"

extern bool epapr_paravirt_enabled;
extern u32 epapr_hypercall_start[];

/*
 * We use "uintptr_t" to define a register because it's guaranteed to be a
 * 32-bit integer on a 32-bit platform, and a 64-bit integer on a 64-bit
 * platform.
 *
 * All registers are either input/output or output only.  Registers that are
 * initialized before making the hypercall are input/output.  All
 * input/output registers are represented with "+r".  Output-only registers
 * are represented with "=r".  Do not specify any unused registers.  The
 * clobber list will tell the compiler that the hypercall modifies those
 * registers, which is good enough.
 */

static inline unsigned int ev_int_set_config(unsigned int interrupt,
    uint32_t config, unsigned int priority, uint32_t destination)
{
    register uintptr_t r11 __asm__("r11");
    register uintptr_t r3 __asm__("r3");
    register uintptr_t r4 __asm__("r4");
    register uintptr_t r5 __asm__("r5");
    register uintptr_t r6 __asm__("r6");

    r11 = EV_HCALL_TOKEN(EV_INT_SET_CONFIG);
    r3  = interrupt;
    r4  = config;
    r5  = priority;
    r6  = destination;

    __asm__ __volatile__ ("sc 1"
        : "+r" (r11), "+r" (r3), "+r" (r4), "+r" (r5), "+r" (r6)
        : : EV_HCALL_CLOBBERS4
    );

    return r3;
}

static inline unsigned int ev_int_get_config(unsigned int interrupt,
    uint32_t *config, unsigned int *priority, uint32_t *destination)
{
    register uintptr_t r11 __asm__("r11");
    register uintptr_t r3 __asm__("r3");
    register uintptr_t r4 __asm__("r4");
    register uintptr_t r5 __asm__("r5");
    register uintptr_t r6 __asm__("r6");

    r11 = EV_HCALL_TOKEN(EV_INT_GET_CONFIG);
    r3 = interrupt;

    __asm__ __volatile__ ("sc 1"
        : "+r" (r11), "+r" (r3), "=r" (r4), "=r" (r5), "=r" (r6)
        : : EV_HCALL_CLOBBERS4
    );

    *config = r4;
    *priority = r5;
    *destination = r6;

    return r3;
}

static inline unsigned int ev_int_set_mask(unsigned int interrupt,
    unsigned int mask)
{
    register uintptr_t r11 __asm__("r11");
    register uintptr_t r3 __asm__("r3");
    register uintptr_t r4 __asm__("r4");

    r11 = EV_HCALL_TOKEN(EV_INT_SET_MASK);
    r3 = interrupt;
    r4 = mask;

    __asm__ __volatile__ ("sc 1"
        : "+r" (r11), "+r" (r3), "+r" (r4)
        : : EV_HCALL_CLOBBERS2
    );

    return r3;
}

static inline unsigned int ev_int_get_mask(unsigned int interrupt,
    unsigned int *mask)
{
    register uintptr_t r11 __asm__("r11");
    register uintptr_t r3 __asm__("r3");
    register uintptr_t r4 __asm__("r4");

    r11 = EV_HCALL_TOKEN(EV_INT_GET_MASK);
    r3 = interrupt;

    __asm__ __volatile__ ("sc 1"
        : "+r" (r11), "+r" (r3), "=r" (r4)
        : : EV_HCALL_CLOBBERS2
    );

    *mask = r4;

    return r3;
}

static inline unsigned int ev_int_eoi(unsigned int interrupt)
{
    register uintptr_t r11 __asm__("r11");
    register uintptr_t r3 __asm__("r3");

    r11 = EV_HCALL_TOKEN(EV_INT_EOI);
    r3 = interrupt;

    __asm__ __volatile__ ("sc 1"
        : "+r" (r11), "+r" (r3)
        : : EV_HCALL_CLOBBERS1
    );

    return r3;
}

static inline unsigned int ev_byte_channel_send(unsigned int handle,
    unsigned int *count, const char buffer[EV_BYTE_CHANNEL_MAX_BYTES])
{
    register uintptr_t r11 __asm__("r11");
    register uintptr_t r3 __asm__("r3");
    register uintptr_t r4 __asm__("r4");
    register uintptr_t r5 __asm__("r5");
    register uintptr_t r6 __asm__("r6");
    register uintptr_t r7 __asm__("r7");
    register uintptr_t r8 __asm__("r8");
    const uint32_t *p = (const uint32_t *) buffer;

    r11 = EV_HCALL_TOKEN(EV_BYTE_CHANNEL_SEND);
    r3 = handle;
    r4 = *count;
    r5 = be32_to_cpu(p[0]);
    r6 = be32_to_cpu(p[1]);
    r7 = be32_to_cpu(p[2]);
    r8 = be32_to_cpu(p[3]);

    __asm__ __volatile__ ("sc 1"
        : "+r" (r11), "+r" (r3),
          "+r" (r4), "+r" (r5), "+r" (r6), "+r" (r7), "+r" (r8)
        : : EV_HCALL_CLOBBERS6
    );

    *count = r4;

    return r3;
}

static inline unsigned int ev_byte_channel_receive(unsigned int handle,
    unsigned int *count, char buffer[EV_BYTE_CHANNEL_MAX_BYTES])
{
    register uintptr_t r11 __asm__("r11");
    register uintptr_t r3 __asm__("r3");
    register uintptr_t r4 __asm__("r4");
    register uintptr_t r5 __asm__("r5");
    register uintptr_t r6 __asm__("r6");
    register uintptr_t r7 __asm__("r7");
    register uintptr_t r8 __asm__("r8");
    uint32_t *p = (uint32_t *) buffer;

    r11 = EV_HCALL_TOKEN(EV_BYTE_CHANNEL_RECEIVE);
    r3 = handle;
    r4 = *count;

    __asm__ __volatile__ ("sc 1"
        : "+r" (r11), "+r" (r3), "+r" (r4),
          "=r" (r5), "=r" (r6), "=r" (r7), "=r" (r8)
        : : EV_HCALL_CLOBBERS6
    );

    *count = r4;
    p[0] = cpu_to_be32(r5);
    p[1] = cpu_to_be32(r6);
    p[2] = cpu_to_be32(r7);
    p[3] = cpu_to_be32(r8);

    return r3;
}

static inline unsigned int ev_byte_channel_poll(unsigned int handle,
    unsigned int *rx_count, unsigned int *tx_count)
{
    register uintptr_t r11 __asm__("r11");
    register uintptr_t r3 __asm__("r3");
    register uintptr_t r4 __asm__("r4");
    register uintptr_t r5 __asm__("r5");

    r11 = EV_HCALL_TOKEN(EV_BYTE_CHANNEL_POLL);
    r3 = handle;

    __asm__ __volatile__ ("sc 1"
        : "+r" (r11), "+r" (r3), "=r" (r4), "=r" (r5)
        : : EV_HCALL_CLOBBERS3
    );

    *rx_count = r4;
    *tx_count = r5;

    return r3;
}

static inline unsigned int ev_int_iack(unsigned int handle,
    unsigned int *vector)
{
    register uintptr_t r11 __asm__("r11");
    register uintptr_t r3 __asm__("r3");
    register uintptr_t r4 __asm__("r4");

    r11 = EV_HCALL_TOKEN(EV_INT_IACK);
    r3 = handle;

    __asm__ __volatile__ ("sc 1"
        : "+r" (r11), "+r" (r3), "=r" (r4)
        : : EV_HCALL_CLOBBERS2
    );

    *vector = r4;

    return r3;
}

static inline unsigned int ev_doorbell_send(unsigned int handle)
{
    register uintptr_t r11 __asm__("r11");
    register uintptr_t r3 __asm__("r3");

    r11 = EV_HCALL_TOKEN(EV_DOORBELL_SEND);
    r3 = handle;

    __asm__ __volatile__ ("sc 1"
        : "+r" (r11), "+r" (r3)
        : : EV_HCALL_CLOBBERS1
    );

    return r3;
}

static inline unsigned int ev_idle(void)
{
    register uintptr_t r11 __asm__("r11");
    register uintptr_t r3 __asm__("r3");

    r11 = EV_HCALL_TOKEN(EV_IDLE);

    __asm__ __volatile__ ("sc 1"
        : "+r" (r11), "=r" (r3)
        : : EV_HCALL_CLOBBERS1
    );

    return r3;
}

#endif