powerpc: introduce ePAPR embedded hypervisor hcall interface

/*

 * 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.

*/

/* List of common clobbered registers.  Do not use this macro. */

#define EV_HCALL_CLOBBERS "r0", "r12", "xer", "ctr", "lr", "cc"

#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"

/*

 * 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.

 */

/**

 * ev_int_set_config - configure the specified interrupt

 * @interrupt: the interrupt number

 * @config: configuration for this interrupt

 * @priority: interrupt priority

 * @destination: destination CPU number

 *

 * Returns 0 for success, or an error code.

 */

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;

}

/**

 * ev_int_get_config - return the config of the specified interrupt

 * @interrupt: the interrupt number

 * @config: returned configuration for this interrupt

 * @priority: returned interrupt priority

 * @destination: returned destination CPU number

 *

 * Returns 0 for success, or an error code.

 */

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;

}

/**

 * ev_int_set_mask - sets the mask for the specified interrupt source

 * @interrupt: the interrupt number

 * @mask: 0=enable interrupts, 1=disable interrupts

 *

 * Returns 0 for success, or an error code.

 */

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;

}

/**

 * ev_int_get_mask - returns the mask for the specified interrupt source

 * @interrupt: the interrupt number

 * @mask: returned mask for this interrupt (0=enabled, 1=disabled)

 *

 * Returns 0 for success, or an error code.

 */

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;

}

/**

 * ev_int_eoi - signal the end of interrupt processing

 * @interrupt: the interrupt number

 *

 * This function signals the end of processing for the the specified

 * interrupt, which must be the interrupt currently in service. By

 * definition, this is also the highest-priority interrupt.

 *

 * Returns 0 for success, or an error code.

 */

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;

}

/**

 * ev_byte_channel_send - send characters to a byte stream

 * @handle: byte stream handle

 * @count: (input) num of chars to send, (output) num chars sent

 * @buffer: pointer to a 16-byte buffer

 *

 * @buffer must be at least 16 bytes long, because all 16 bytes will be

 * read from memory into registers, even if count < 16.

 *

 * Returns 0 for success, or an error code.

 */

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;

}

/**

 * ev_byte_channel_receive - fetch characters from a byte channel

 * @handle: byte channel handle

 * @count: (input) max num of chars to receive, (output) num chars received

 * @buffer: pointer to a 16-byte buffer

 *

 * The size of @buffer must be at least 16 bytes, even if you request fewer

 * than 16 characters, because we always write 16 bytes to @buffer.  This is

 * for performance reasons.

 *

 * Returns 0 for success, or an error code.

 */

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;

}

/**

 * ev_byte_channel_poll - returns the status of the byte channel buffers

 * @handle: byte channel handle

 * @rx_count: returned count of bytes in receive queue

 * @tx_count: returned count of free space in transmit queue

 *

 * This function reports the amount of data in the receive queue (i.e. the

 * number of bytes you can read), and the amount of free space in the transmit

 * queue (i.e. the number of bytes you can write).

 *

 * Returns 0 for success, or an error code.

 */

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;

}

/**

 * ev_int_iack - acknowledge an interrupt

 * @handle: handle to the target interrupt controller

 * @vector: returned interrupt vector

 *

 * If handle is zero, the function returns the next interrupt source

 * number to be handled irrespective of the hierarchy or cascading

 * of interrupt controllers. If non-zero, specifies a handle to the

 * interrupt controller that is the target of the acknowledge.

 *

 * Returns 0 for success, or an error code.

 */

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;

}

/**

 * ev_doorbell_send - send a doorbell to another partition

 * @handle: doorbell send handle

 *

 * Returns 0 for success, or an error code.

 */

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;

}

/**

 * ev_idle -- wait for next interrupt on this core

 *

 * Returns 0 for success, or an error code.

 */

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