From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 06E14C54FF3 for ; Thu, 27 Feb 2020 14:30:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D2BF224688 for ; Thu, 27 Feb 2020 14:30:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1582813835; bh=WeAnVRuT+eJ3/I9Ri+fo4SZBU5CHsbAcXpVA/xFFqgI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=sg7pYNBIARdgQgbPa/6gF/8HUJCC6w3cQUSI50K+O96I8TZPLVg50qRQYg2scbuVL j/kdLclFKp8w2n7E9LIqgbI0vUj11M+YaTnRiMmTYIiaKDj97BqGGmRZR0biWlTHlv WaUn05pzPxeRlIsyC5cUx6MqWcUEvZizZgtYrHtw= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2387679AbgB0OFB (ORCPT ); Thu, 27 Feb 2020 09:05:01 -0500 Received: from mail.kernel.org ([198.145.29.99]:41220 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1733179AbgB0OEq (ORCPT ); Thu, 27 Feb 2020 09:04:46 -0500 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id ABAAE20578; Thu, 27 Feb 2020 14:04:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1582812286; bh=WeAnVRuT+eJ3/I9Ri+fo4SZBU5CHsbAcXpVA/xFFqgI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=0huLFyY3fyGwoKjOF4N5yGUpKVp1FfCTQczdWoUiJZl5O9j++fn4uC450A54wurEE UbbHho6RcZAsmP3negYi5wb6A1MYNDoIlpZeqI3IP7cYc58Z0BXlukLUwLnoknvFyq FOw6VzUkhXXuRz2inNH68DqxKVYZA9cBTovYK4+Q= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Ryan Case , Douglas Anderson , Sasha Levin Subject: [PATCH 4.19 55/97] tty: serial: qcom_geni_serial: Remove interrupt storm Date: Thu, 27 Feb 2020 14:37:03 +0100 Message-Id: <20200227132223.560905310@linuxfoundation.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20200227132214.553656188@linuxfoundation.org> References: <20200227132214.553656188@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Ryan Case [ Upstream commit 64a428077758383518c258641e81d57fcd454792 ] Disable M_TX_FIFO_WATERMARK_EN after we've sent all data for a given transaction so we don't continue to receive a flurry of free space interrupts while waiting for the M_CMD_DONE notification. Re-enable the watermark when establishing the next transaction. Also clear the watermark interrupt after filling the FIFO so we do not receive notification again prior to actually having free space. Signed-off-by: Ryan Case Reviewed-by: Douglas Anderson Tested-by: Douglas Anderson Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin --- drivers/tty/serial/qcom_geni_serial.c | 25 +++++++++++++++++++++++-- 1 file changed, 23 insertions(+), 2 deletions(-) diff --git a/drivers/tty/serial/qcom_geni_serial.c b/drivers/tty/serial/qcom_geni_serial.c index 2003dfcace5d8..743d877e7ff94 100644 --- a/drivers/tty/serial/qcom_geni_serial.c +++ b/drivers/tty/serial/qcom_geni_serial.c @@ -727,6 +727,7 @@ static void qcom_geni_serial_handle_tx(struct uart_port *uport, bool done, size_t pending; int i; u32 status; + u32 irq_en; unsigned int chunk; int tail; @@ -755,6 +756,11 @@ static void qcom_geni_serial_handle_tx(struct uart_port *uport, bool done, if (!port->tx_remaining) { qcom_geni_serial_setup_tx(uport, pending); port->tx_remaining = pending; + + irq_en = readl_relaxed(uport->membase + SE_GENI_M_IRQ_EN); + if (!(irq_en & M_TX_FIFO_WATERMARK_EN)) + writel_relaxed(irq_en | M_TX_FIFO_WATERMARK_EN, + uport->membase + SE_GENI_M_IRQ_EN); } remaining = chunk; @@ -778,7 +784,23 @@ static void qcom_geni_serial_handle_tx(struct uart_port *uport, bool done, } xmit->tail = tail & (UART_XMIT_SIZE - 1); + + /* + * The tx fifo watermark is level triggered and latched. Though we had + * cleared it in qcom_geni_serial_isr it will have already reasserted + * so we must clear it again here after our writes. + */ + writel_relaxed(M_TX_FIFO_WATERMARK_EN, + uport->membase + SE_GENI_M_IRQ_CLEAR); + out_write_wakeup: + if (!port->tx_remaining) { + irq_en = readl_relaxed(uport->membase + SE_GENI_M_IRQ_EN); + if (irq_en & M_TX_FIFO_WATERMARK_EN) + writel_relaxed(irq_en & ~M_TX_FIFO_WATERMARK_EN, + uport->membase + SE_GENI_M_IRQ_EN); + } + if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS) uart_write_wakeup(uport); } @@ -814,8 +836,7 @@ static irqreturn_t qcom_geni_serial_isr(int isr, void *dev) tty_insert_flip_char(tport, 0, TTY_OVERRUN); } - if (m_irq_status & (M_TX_FIFO_WATERMARK_EN | M_CMD_DONE_EN) && - m_irq_en & (M_TX_FIFO_WATERMARK_EN | M_CMD_DONE_EN)) + if (m_irq_status & m_irq_en & (M_TX_FIFO_WATERMARK_EN | M_CMD_DONE_EN)) qcom_geni_serial_handle_tx(uport, m_irq_status & M_CMD_DONE_EN, geni_status & M_GENI_CMD_ACTIVE); -- 2.20.1