drivers/gpu/drm/xe/xe_mert.c

// SPDX-License-Identifier: MIT
/*
 * Copyright(c) 2025, Intel Corporation. All rights reserved.
 */

#include "regs/xe_irq_regs.h"
#include "regs/xe_mert_regs.h"

#include "xe_device.h"
#include "xe_mert.h"
#include "xe_mmio.h"
#include "xe_sriov_printk.h"
#include "xe_tile.h"

/**
 * xe_mert_init_early() - Initialize MERT data
 * @xe: the &xe_device with MERT to init
 */
void xe_mert_init_early(struct xe_device *xe)
{
	struct xe_tile *tile = xe_device_get_root_tile(xe);
	struct xe_mert *mert = &tile->mert;

	spin_lock_init(&mert->lock);
	init_completion(&mert->tlb_inv_done);
}

/**
 * xe_mert_invalidate_lmtt() - Invalidate MERT LMTT
 * @xe: the &xe_device with MERT
 *
 * Trigger invalidation of the MERT LMTT and wait for completion.
 *
 * Return: 0 on success or -ETIMEDOUT in case of a timeout.
 */
int xe_mert_invalidate_lmtt(struct xe_device *xe)
{
	struct xe_tile *tile = xe_device_get_root_tile(xe);
	struct xe_mert *mert = &tile->mert;
	const long timeout = HZ / 4;
	unsigned long flags;

	xe_assert(xe, xe_device_has_mert(xe));

	spin_lock_irqsave(&mert->lock, flags);
	if (!mert->tlb_inv_triggered) {
		mert->tlb_inv_triggered = true;
		reinit_completion(&mert->tlb_inv_done);
		xe_mmio_write32(&tile->mmio, MERT_TLB_INV_DESC_A, MERT_TLB_INV_DESC_A_VALID);
	}
	spin_unlock_irqrestore(&mert->lock, flags);

	if (!wait_for_completion_timeout(&mert->tlb_inv_done, timeout))
		return -ETIMEDOUT;

	return 0;
}

static void mert_handle_cat_error(struct xe_device *xe)
{
	struct xe_tile *tile = xe_device_get_root_tile(xe);
	u32 reg_val, vfid, code;

	reg_val = xe_mmio_read32(&tile->mmio, MERT_TLB_CT_INTR_ERR_ID_PORT);
	if (!reg_val)
		return;
	xe_mmio_write32(&tile->mmio, MERT_TLB_CT_INTR_ERR_ID_PORT, 0);

	vfid = FIELD_GET(CATERR_VFID, reg_val);
	code = FIELD_GET(CATERR_CODES, reg_val);

	switch (code) {
	case CATERR_NO_ERROR:
		break;
	case CATERR_UNMAPPED_GGTT:
		xe_sriov_err(xe, "MERT: CAT_ERR: Access to an unmapped GGTT!\n");
		xe_device_declare_wedged(xe);
		break;
	case CATERR_LMTT_FAULT:
		xe_sriov_dbg(xe, "MERT: CAT_ERR: VF%u LMTT fault!\n", vfid);
		/* XXX: track/report malicious VF activity */
		break;
	default:
		xe_sriov_err(xe, "MERT: Unexpected CAT_ERR code=%#x!\n", code);
		xe_device_declare_wedged(xe);
		break;
	}
}

/**
 * xe_mert_irq_handler - Handler for MERT interrupts
 * @xe: the &xe_device
 * @master_ctl: interrupt register
 *
 * Handle interrupts generated by MERT.
 */
void xe_mert_irq_handler(struct xe_device *xe, u32 master_ctl)
{
	struct xe_tile *tile = xe_device_get_root_tile(xe);
	struct xe_mert *mert = &tile->mert;
	unsigned long flags;
	u32 reg_val;

	if (!(master_ctl & SOC_H2DMEMINT_IRQ))
		return;

	mert_handle_cat_error(xe);

	spin_lock_irqsave(&mert->lock, flags);
	if (mert->tlb_inv_triggered) {
		reg_val = xe_mmio_read32(&tile->mmio, MERT_TLB_INV_DESC_A);
		if (!(reg_val & MERT_TLB_INV_DESC_A_VALID)) {
			mert->tlb_inv_triggered = false;
			complete_all(&mert->tlb_inv_done);
		}
	}
	spin_unlock_irqrestore(&mert->lock, flags);
}