drivers/net/ethernet/intel/igc/igc_base.c

// SPDX-License-Identifier: GPL-2.0
/* Copyright (c)  2018 Intel Corporation */

#include <linux/delay.h>

#include "igc_hw.h"
#include "igc_i225.h"

/**
 * igc_rx_fifo_flush_base - Clean rx fifo after Rx enable
 * @hw: pointer to the HW structure
 *
 * After Rx enable, if manageability is enabled then there is likely some
 * bad data at the start of the fifo and possibly in the DMA fifo.  This
 * function clears the fifos and flushes any packets that came in as rx was
 * being enabled.
 */
void igc_rx_fifo_flush_base(struct igc_hw *hw)
{
	u32 rctl, rlpml, rxdctl[4], rfctl, temp_rctl, rx_enabled;
	int i, ms_wait;

	/* disable IPv6 options as per hardware errata */
	rfctl = rd32(IGC_RFCTL);
	rfctl |= IGC_RFCTL_IPV6_EX_DIS;
	wr32(IGC_RFCTL, rfctl);

	if (!(rd32(IGC_MANC) & IGC_MANC_RCV_TCO_EN))
		return;

	/* Disable all Rx queues */
	for (i = 0; i < 4; i++) {
		rxdctl[i] = rd32(IGC_RXDCTL(i));
		wr32(IGC_RXDCTL(i),
		     rxdctl[i] & ~IGC_RXDCTL_QUEUE_ENABLE);
	}
	/* Poll all queues to verify they have shut down */
	for (ms_wait = 0; ms_wait < 10; ms_wait++) {
		usleep_range(1000, 2000);
		rx_enabled = 0;
		for (i = 0; i < 4; i++)
			rx_enabled |= rd32(IGC_RXDCTL(i));
		if (!(rx_enabled & IGC_RXDCTL_QUEUE_ENABLE))
			break;
	}

	if (ms_wait == 10)
		pr_debug("Queue disable timed out after 10ms\n");

	/* Clear RLPML, RCTL.SBP, RFCTL.LEF, and set RCTL.LPE so that all
	 * incoming packets are rejected.  Set enable and wait 2ms so that
	 * any packet that was coming in as RCTL.EN was set is flushed
	 */
	wr32(IGC_RFCTL, rfctl & ~IGC_RFCTL_LEF);

	rlpml = rd32(IGC_RLPML);
	wr32(IGC_RLPML, 0);

	rctl = rd32(IGC_RCTL);
	temp_rctl = rctl & ~(IGC_RCTL_EN | IGC_RCTL_SBP);
	temp_rctl |= IGC_RCTL_LPE;

	wr32(IGC_RCTL, temp_rctl);
	wr32(IGC_RCTL, temp_rctl | IGC_RCTL_EN);
	wrfl();
	usleep_range(2000, 3000);

	/* Enable Rx queues that were previously enabled and restore our
	 * previous state
	 */
	for (i = 0; i < 4; i++)
		wr32(IGC_RXDCTL(i), rxdctl[i]);
	wr32(IGC_RCTL, rctl);
	wrfl();

	wr32(IGC_RLPML, rlpml);
	wr32(IGC_RFCTL, rfctl);

	/* Flush receive errors generated by workaround */
	rd32(IGC_ROC);
	rd32(IGC_RNBC);
	rd32(IGC_MPC);
}