From patchwork Mon Mar 3 13:54:32 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Marc Kleine-Budde X-Patchwork-Id: 325833 X-Patchwork-Delegate: davem@davemloft.net Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id F13982C00CE for ; Tue, 4 Mar 2014 00:55:10 +1100 (EST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754317AbaCCNyv (ORCPT ); Mon, 3 Mar 2014 08:54:51 -0500 Received: from metis.ext.pengutronix.de ([92.198.50.35]:43425 "EHLO metis.ext.pengutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754522AbaCCNys (ORCPT ); Mon, 3 Mar 2014 08:54:48 -0500 Received: from gallifrey.ext.pengutronix.de ([2001:6f8:1178:4:5054:ff:fe8d:eefb] helo=hardanger.do.blackshift.org) by metis.ext.pengutronix.de with esmtp (Exim 4.72) (envelope-from ) id 1WKTKQ-0005aV-54; Mon, 03 Mar 2014 14:54:46 +0100 From: Marc Kleine-Budde To: netdev@vger.kernel.org Cc: davem@davemloft.net, linux-can@vger.kernel.org, kernel@pengutronix.de, Marc Kleine-Budde , linux-stable Subject: [PATCH 5/8] can: flexcan: fix transition from and to freeze mode in chip_{, un}freeze Date: Mon, 3 Mar 2014 14:54:32 +0100 Message-Id: <1393854875-8171-6-git-send-email-mkl@pengutronix.de> X-Mailer: git-send-email 1.9.0 In-Reply-To: <1393854875-8171-1-git-send-email-mkl@pengutronix.de> References: <1393854875-8171-1-git-send-email-mkl@pengutronix.de> X-SA-Exim-Connect-IP: 2001:6f8:1178:4:5054:ff:fe8d:eefb X-SA-Exim-Mail-From: mkl@pengutronix.de X-SA-Exim-Scanned: No (on metis.ext.pengutronix.de); SAEximRunCond expanded to false X-PTX-Original-Recipient: netdev@vger.kernel.org Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org This patch factors out freeze and unfreeze of the CAN core into seperate functions. Experiments have shown that the transition from and to freeze mode may take several microseconds, especially the time entering the freeze mode depends on the current bitrate. This patch adds a while loop which polls the Freeze Mode ACK bit (FRZ_ACK) that indicates a successfull mode change. If the function runs into a timeout a error value is returned. Cc: linux-stable Signed-off-by: Marc Kleine-Budde --- drivers/net/can/flexcan.c | 60 ++++++++++++++++++++++++++++++++++++++--------- 1 file changed, 49 insertions(+), 11 deletions(-) diff --git a/drivers/net/can/flexcan.c b/drivers/net/can/flexcan.c index 6b0fecd..330b5b9 100644 --- a/drivers/net/can/flexcan.c +++ b/drivers/net/can/flexcan.c @@ -325,6 +325,44 @@ static int flexcan_chip_disable(struct flexcan_priv *priv) return 0; } +static int flexcan_chip_freeze(struct flexcan_priv *priv) +{ + struct flexcan_regs __iomem *regs = priv->base; + unsigned int timeout = 1000 * 1000 * 10 / priv->can.bittiming.bitrate; + u32 reg; + + reg = flexcan_read(®s->mcr); + reg |= FLEXCAN_MCR_HALT; + flexcan_write(reg, ®s->mcr); + + while (timeout-- && !(flexcan_read(®s->mcr) & FLEXCAN_MCR_FRZ_ACK)) + usleep_range(100, 200); + + if (!(flexcan_read(®s->mcr) & FLEXCAN_MCR_FRZ_ACK)) + return -ETIMEDOUT; + + return 0; +} + +static int flexcan_chip_unfreeze(struct flexcan_priv *priv) +{ + struct flexcan_regs __iomem *regs = priv->base; + unsigned int timeout = FLEXCAN_TIMEOUT_US / 10; + u32 reg; + + reg = flexcan_read(®s->mcr); + reg &= ~FLEXCAN_MCR_HALT; + flexcan_write(reg, ®s->mcr); + + while (timeout-- && (flexcan_read(®s->mcr) & FLEXCAN_MCR_FRZ_ACK)) + usleep_range(10, 20); + + if (flexcan_read(®s->mcr) & FLEXCAN_MCR_FRZ_ACK) + return -ETIMEDOUT; + + return 0; +} + static int flexcan_get_berr_counter(const struct net_device *dev, struct can_berr_counter *bec) { @@ -756,7 +794,7 @@ static int flexcan_chip_start(struct net_device *dev) netdev_err(dev, "Failed to softreset can module (mcr=0x%08x)\n", reg_mcr); err = -ENODEV; - goto out; + goto out_chip_disable; } flexcan_set_bittiming(dev); @@ -826,12 +864,12 @@ static int flexcan_chip_start(struct net_device *dev) err = flexcan_transceiver_enable(priv); if (err) - goto out; + goto out_chip_disable; /* synchronize with the can bus */ - reg_mcr = flexcan_read(®s->mcr); - reg_mcr &= ~FLEXCAN_MCR_HALT; - flexcan_write(reg_mcr, ®s->mcr); + err = flexcan_chip_unfreeze(priv); + if (err) + goto out_transceiver_disable; priv->can.state = CAN_STATE_ERROR_ACTIVE; @@ -844,7 +882,9 @@ static int flexcan_chip_start(struct net_device *dev) return 0; - out: + out_transceiver_disable: + flexcan_transceiver_disable(priv); + out_chip_disable: flexcan_chip_disable(priv); return err; } @@ -859,12 +899,10 @@ static void flexcan_chip_stop(struct net_device *dev) { struct flexcan_priv *priv = netdev_priv(dev); struct flexcan_regs __iomem *regs = priv->base; - u32 reg; - /* Disable + halt module */ - reg = flexcan_read(®s->mcr); - reg |= FLEXCAN_MCR_MDIS | FLEXCAN_MCR_HALT; - flexcan_write(reg, ®s->mcr); + /* freeze + disable module */ + flexcan_chip_freeze(priv); + flexcan_chip_disable(priv); /* Disable all interrupts */ flexcan_write(0, ®s->imask1);