powerpc/pseries/vas: Add hcall wrappers for VAS handling

// SPDX-License-Identifier: GPL-2.0-or-later

/*

 * Copyright 2020-21 IBM Corp.

 */

#define pr_fmt(fmt) "vas: " fmt

#include <linux/module.h>

#include <linux/kernel.h>

#include <linux/export.h>

#include <linux/types.h>

#include <linux/delay.h>

#include <asm/hvcall.h>

#include <asm/plpar_wrappers.h>

#include <asm/vas.h>

#include "vas.h"

#define VAS_INVALID_WIN_ADDRESS	0xFFFFFFFFFFFFFFFFul

#define VAS_DEFAULT_DOMAIN_ID	0xFFFFFFFFFFFFFFFFul

/* The hypervisor allows one credit per window right now */

#define DEF_WIN_CREDS		1

static long hcall_return_busy_check(long rc)

{

	/* Check if we are stalled for some time */

	if (H_IS_LONG_BUSY(rc)) {

		msleep(get_longbusy_msecs(rc));

		rc = H_BUSY;

	} else if (rc == H_BUSY) {

		cond_resched();

	}

	return rc;

}

/*

 * Allocate VAS window hcall

 */

static int h_allocate_vas_window(struct pseries_vas_window *win, u64 *domain,

				     u8 wintype, u16 credits)

{

	long retbuf[PLPAR_HCALL9_BUFSIZE] = {0};

	long rc;

	do {

		rc = plpar_hcall9(H_ALLOCATE_VAS_WINDOW, retbuf, wintype,

				  credits, domain[0], domain[1], domain[2],

				  domain[3], domain[4], domain[5]);

		rc = hcall_return_busy_check(rc);

	} while (rc == H_BUSY);

	if (rc == H_SUCCESS) {

		if (win->win_addr == VAS_INVALID_WIN_ADDRESS) {

			pr_err("H_ALLOCATE_VAS_WINDOW: COPY/PASTE is not supported\n");

			return -ENOTSUPP;

		}

		win->vas_win.winid = retbuf[0];

		win->win_addr = retbuf[1];

		win->complete_irq = retbuf[2];

		win->fault_irq = retbuf[3];

		return 0;

	}

	pr_err("H_ALLOCATE_VAS_WINDOW error: %ld, wintype: %u, credits: %u\n",

		rc, wintype, credits);

	return -EIO;

}

/*

 * Deallocate VAS window hcall.

 */

static int h_deallocate_vas_window(u64 winid)

{

	long rc;

	do {

		rc = plpar_hcall_norets(H_DEALLOCATE_VAS_WINDOW, winid);

		rc = hcall_return_busy_check(rc);

	} while (rc == H_BUSY);

	if (rc == H_SUCCESS)

		return 0;

	pr_err("H_DEALLOCATE_VAS_WINDOW error: %ld, winid: %llu\n",

		rc, winid);

	return -EIO;

}

/*

 * Modify VAS window.

 * After the window is opened with allocate window hcall, configure it

 * with flags and LPAR PID before using.

 */

static int h_modify_vas_window(struct pseries_vas_window *win)

{

	long rc;

	u32 lpid = mfspr(SPRN_PID);

	/*

	 * AMR value is not supported in Linux VAS implementation.

	 * The hypervisor ignores it if 0 is passed.

	 */

	do {

		rc = plpar_hcall_norets(H_MODIFY_VAS_WINDOW,

					win->vas_win.winid, lpid, 0,

					VAS_MOD_WIN_FLAGS, 0);

		rc = hcall_return_busy_check(rc);

	} while (rc == H_BUSY);

	if (rc == H_SUCCESS)

		return 0;

	pr_err("H_MODIFY_VAS_WINDOW error: %ld, winid %u lpid %u\n",

			rc, win->vas_win.winid, lpid);

	return -EIO;

}

/*

 * This hcall is used to determine the capabilities from the hypervisor.

 * @hcall: H_QUERY_VAS_CAPABILITIES or H_QUERY_NX_CAPABILITIES

 * @query_type: If 0 is passed, the hypervisor returns the overall

 *		capabilities which provides all feature(s) that are

 *		available. Then query the hypervisor to get the

 *		corresponding capabilities for the specific feature.

 *		Example: H_QUERY_VAS_CAPABILITIES provides VAS GZIP QoS

 *			and VAS GZIP Default capabilities.

 *			H_QUERY_NX_CAPABILITIES provides NX GZIP

 *			capabilities.

 * @result: Return buffer to save capabilities.

 */

int h_query_vas_capabilities(const u64 hcall, u8 query_type, u64 result)

{

	long rc;

	rc = plpar_hcall_norets(hcall, query_type, result);

	if (rc == H_SUCCESS)

		return 0;

	pr_err("HCALL(%llx) error %ld, query_type %u, result buffer 0x%llx\n",

			hcall, rc, query_type, result);

	return -EIO;

}