[PATCH net-next v2 8/9] amd-xgbe: Check Rx queue fifos before stopping Rx DMA
From: Tom Lendacky <thomas.lendacky@amd.com>
Date: 2016-02-17 17:49:24
Subsystem:
amd xgbe driver, networking drivers, the rest · Maintainers:
Raju Rangoju, Prashanth Kumar K R, Andrew Lunn, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
Check to be sure that the Rx queue fifos are empty before stopping the Rx DMA channels. Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com> --- drivers/net/ethernet/amd/xgbe/xgbe-common.h | 10 ++++++--- drivers/net/ethernet/amd/xgbe/xgbe-dev.c | 30 +++++++++++++++++++++++++++ 2 files changed, 37 insertions(+), 3 deletions(-)
diff --git a/drivers/net/ethernet/amd/xgbe/xgbe-common.h b/drivers/net/ethernet/amd/xgbe/xgbe-common.h
index b6fa891..bbef959 100644
--- a/drivers/net/ethernet/amd/xgbe/xgbe-common.h
+++ b/drivers/net/ethernet/amd/xgbe/xgbe-common.h@@ -6,7 +6,7 @@ * * License 1: GPLv2 * - * Copyright (c) 2014 Advanced Micro Devices, Inc. + * Copyright (c) 2014-2016 Advanced Micro Devices, Inc. * * This file is free software; you may copy, redistribute and/or modify * it under the terms of the GNU General Public License as published by
@@ -56,7 +56,7 @@ * * License 2: Modified BSD * - * Copyright (c) 2014 Advanced Micro Devices, Inc. + * Copyright (c) 2014-2016 Advanced Micro Devices, Inc. * All rights reserved. * * Redistribution and use in source and binary forms, with or without
@@ -768,12 +768,16 @@ #define MTL_Q_TQDR 0x08 #define MTL_Q_RQOMR 0x40 #define MTL_Q_RQMPOCR 0x44 -#define MTL_Q_RQDR 0x4c +#define MTL_Q_RQDR 0x48 #define MTL_Q_RQFCR 0x50 #define MTL_Q_IER 0x70 #define MTL_Q_ISR 0x74 /* MTL queue register entry bit positions and sizes */ +#define MTL_Q_RQDR_PRXQ_INDEX 16 +#define MTL_Q_RQDR_PRXQ_WIDTH 14 +#define MTL_Q_RQDR_RXQSTS_INDEX 4 +#define MTL_Q_RQDR_RXQSTS_WIDTH 2 #define MTL_Q_RQFCR_RFA_INDEX 1 #define MTL_Q_RQFCR_RFA_WIDTH 6 #define MTL_Q_RQFCR_RFD_INDEX 17
diff --git a/drivers/net/ethernet/amd/xgbe/xgbe-dev.c b/drivers/net/ethernet/amd/xgbe/xgbe-dev.c
index 43273c98..b48c6ec 100644
--- a/drivers/net/ethernet/amd/xgbe/xgbe-dev.c
+++ b/drivers/net/ethernet/amd/xgbe/xgbe-dev.c@@ -2656,6 +2656,32 @@ static void xgbe_disable_tx(struct xgbe_prv_data *pdata) } } +static void xgbe_prepare_rx_stop(struct xgbe_prv_data *pdata, + unsigned int queue) +{ + unsigned int rx_status; + unsigned long rx_timeout; + + /* The Rx engine cannot be stopped if it is actively processing + * packets. Wait for the Rx queue to empty the Rx fifo. Don't + * wait forever though... + */ + rx_timeout = jiffies + (XGBE_DMA_STOP_TIMEOUT * HZ); + while (time_before(jiffies, rx_timeout)) { + rx_status = XGMAC_MTL_IOREAD(pdata, queue, MTL_Q_RQDR); + if ((XGMAC_GET_BITS(rx_status, MTL_Q_RQDR, PRXQ) == 0) && + (XGMAC_GET_BITS(rx_status, MTL_Q_RQDR, RXQSTS) == 0)) + break; + + usleep_range(500, 1000); + } + + if (!time_before(jiffies, rx_timeout)) + netdev_info(pdata->netdev, + "timed out waiting for Rx queue %u to empty\n", + queue); +} + static void xgbe_enable_rx(struct xgbe_prv_data *pdata) { struct xgbe_channel *channel;
@@ -2694,6 +2720,10 @@ static void xgbe_disable_rx(struct xgbe_prv_data *pdata) XGMAC_IOWRITE_BITS(pdata, MAC_RCR, ACS, 0); XGMAC_IOWRITE_BITS(pdata, MAC_RCR, RE, 0); + /* Prepare for Rx DMA channel stop */ + for (i = 0; i < pdata->rx_q_count; i++) + xgbe_prepare_rx_stop(pdata, i); + /* Disable each Rx queue */ XGMAC_IOWRITE(pdata, MAC_RQC0R, 0);