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=-10.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,USER_AGENT_GIT autolearn=ham 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 4D351C04EB9 for ; Fri, 30 Nov 2018 02:19:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 036E92086B for ; Fri, 30 Nov 2018 02:19:27 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=chromium.org header.i=@chromium.org header.b="cvuXPhO4" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 036E92086B Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=chromium.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727146AbeK3N1E (ORCPT ); Fri, 30 Nov 2018 08:27:04 -0500 Received: from mail-pf1-f195.google.com ([209.85.210.195]:33440 "EHLO mail-pf1-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726497AbeK3N1E (ORCPT ); Fri, 30 Nov 2018 08:27:04 -0500 Received: by mail-pf1-f195.google.com with SMTP id c123so2009586pfb.0 for ; Thu, 29 Nov 2018 18:19:25 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=v/I8xEX9P8gErGvxWyJaERYOeiDW5zp+tAQouUaMhHc=; b=cvuXPhO44rwL4Er9yGKkDGhp8cXLO/sdmF91tKuU3Gu8z+vhdwguHlJ3N33hiueh/C rX9oPDtxuumqIdEicgCMcTSGF16/GmO1cizGjELrX1Xk35eWwDzGWZEgRBZ5NpFjWsdr NbJlxYz9d06wcynMoKsfQOJlcRoxb88UgVxb4= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=v/I8xEX9P8gErGvxWyJaERYOeiDW5zp+tAQouUaMhHc=; b=mW+KEZGfj3hXwinZkyJNxbbdrWiZJ5j53CieLFEZ8uEOlqf6uNmrN2pbpq38NCAdFY TISmBBgFr9d0AA3JPlyZg1/MW8xTuz47LSHp/iu+yavNnLnbtc/BlRPOzov80eTn7Rk8 v1UshhsWZLUIWsNTmdVpboePl7Tv1MZ09Gb4NNXD3Cdklgjs6J1fNSz4hf/UnrLSrUeY UFTJCm1qj+fHsDgwu5yQXBzKhntV2qQArspQZrPVcuwai8+AHJHnytojVRsJ6pS5ZzoD BW/yjD+bSUPEmLA86i3zKN8ba+UhC4uP1toKii9C87YAlsGWnsK3CceXZXxUwA3YmPli 6sNg== X-Gm-Message-State: AA+aEWagswBXPYWuq3SKU26ARbR+XggGu2/cqqK5xDRGEmXsOABhFaES p5SoD58/nMFCqZEGuDrZACT+ag== X-Google-Smtp-Source: AFSGD/X7MDerg79agx4geQeMWnycHoUwkoTsH5z2cpxQbnQ8G/RDGjqidwrXciiYG0ajAwcFVjixLw== X-Received: by 2002:a62:8a51:: with SMTP id y78mr3771160pfd.35.1543544364803; Thu, 29 Nov 2018 18:19:24 -0800 (PST) Received: from ryandcase.mtv.corp.google.com ([2620:15c:202:201:ed1c:3d1c:9d92:99cb]) by smtp.gmail.com with ESMTPSA id b9sm4678524pfi.118.2018.11.29.18.19.23 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 29 Nov 2018 18:19:24 -0800 (PST) From: Ryan Case To: Greg Kroah-Hartman , Jiri Slaby Cc: Evan Green , Doug Anderson , linux-kernel@vger.kernel.org, linux-serial@vger.kernel.org, Stephen Boyd , Ryan Case Subject: [PATCH v3] tty: serial: qcom_geni_serial: Fix softlock Date: Thu, 29 Nov 2018 18:18:40 -0800 Message-Id: <20181130021840.75861-1-ryandcase@chromium.org> X-Mailer: git-send-email 2.20.0.rc0.387.gc7a69e6b6c-goog MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Transfers were being divided into device FIFO sized (64 byte max) operations which would poll for completion within a spin_lock_irqsave / spin_unlock_irqrestore block. This both made things slow by waiting for the FIFO to completely drain before adding further data and would also result in softlocks on large transmissions. This patch allows larger transfers with continuous FIFO additions as space becomes available and removes polling from the interrupt handler. Signed-off-by: Ryan Case --- Changes in v3: - Reworded comment for clarity - Fixed mips compiler warning Changes in v2: - Addressed nits raised by Stephen drivers/tty/serial/qcom_geni_serial.c | 56 +++++++++++++++++++-------- 1 file changed, 39 insertions(+), 17 deletions(-) diff --git a/drivers/tty/serial/qcom_geni_serial.c b/drivers/tty/serial/qcom_geni_serial.c index 7ded51081add..bbc7d7a5b8b6 100644 --- a/drivers/tty/serial/qcom_geni_serial.c +++ b/drivers/tty/serial/qcom_geni_serial.c @@ -117,6 +117,8 @@ struct qcom_geni_serial_port { u32 *rx_fifo; u32 loopback; bool brk; + + unsigned int tx_remaining; }; static const struct uart_ops qcom_geni_console_pops; @@ -439,6 +441,7 @@ static void qcom_geni_serial_console_write(struct console *co, const char *s, struct qcom_geni_serial_port *port; bool locked = true; unsigned long flags; + u32 geni_status; WARN_ON(co->index < 0 || co->index >= GENI_UART_CONS_PORTS); @@ -452,6 +455,8 @@ static void qcom_geni_serial_console_write(struct console *co, const char *s, else spin_lock_irqsave(&uport->lock, flags); + geni_status = readl_relaxed(uport->membase + SE_GENI_STATUS); + /* Cancel the current write to log the fault */ if (!locked) { geni_se_cancel_m_cmd(&port->se); @@ -465,9 +470,19 @@ static void qcom_geni_serial_console_write(struct console *co, const char *s, } writel_relaxed(M_CMD_CANCEL_EN, uport->membase + SE_GENI_M_IRQ_CLEAR); + } else if ((geni_status & M_GENI_CMD_ACTIVE) && !port->tx_remaining) { + /* + * It seems we can't interrupt existing transfers if all data + * has been sent, in which case we need to look for done first. + */ + qcom_geni_serial_poll_tx_done(uport); } __qcom_geni_serial_console_write(uport, s, count); + + if (port->tx_remaining) + qcom_geni_serial_setup_tx(uport, port->tx_remaining); + if (locked) spin_unlock_irqrestore(&uport->lock, flags); } @@ -701,40 +716,45 @@ static void qcom_geni_serial_handle_rx(struct uart_port *uport, bool drop) port->handle_rx(uport, total_bytes, drop); } -static void qcom_geni_serial_handle_tx(struct uart_port *uport) +static void qcom_geni_serial_handle_tx(struct uart_port *uport, bool done, + bool active) { struct qcom_geni_serial_port *port = to_dev_port(uport, uport); struct circ_buf *xmit = &uport->state->xmit; size_t avail; size_t remaining; + size_t pending; int i; u32 status; unsigned int chunk; int tail; - u32 irq_en; - chunk = uart_circ_chars_pending(xmit); status = readl_relaxed(uport->membase + SE_GENI_TX_FIFO_STATUS); - /* Both FIFO and framework buffer are drained */ - if (!chunk && !status) { + + /* Complete the current tx command before taking newly added data */ + if (active) + pending = port->tx_remaining; + else + pending = uart_circ_chars_pending(xmit); + + /* All data has been transmitted and acknowledged as received */ + if (!pending && !status && done) { qcom_geni_serial_stop_tx(uport); goto out_write_wakeup; } - if (!uart_console(uport)) { - irq_en = readl_relaxed(uport->membase + SE_GENI_M_IRQ_EN); - irq_en &= ~(M_TX_FIFO_WATERMARK_EN); - writel_relaxed(0, uport->membase + SE_GENI_TX_WATERMARK_REG); - writel_relaxed(irq_en, uport->membase + SE_GENI_M_IRQ_EN); - } + avail = port->tx_fifo_depth - (status & TX_FIFO_WC); + avail *= port->tx_bytes_pw; - avail = (port->tx_fifo_depth - port->tx_wm) * port->tx_bytes_pw; tail = xmit->tail; - chunk = min3((size_t)chunk, (size_t)(UART_XMIT_SIZE - tail), avail); + chunk = min3(avail, pending, (size_t)(UART_XMIT_SIZE - tail)); if (!chunk) goto out_write_wakeup; - qcom_geni_serial_setup_tx(uport, chunk); + if (!port->tx_remaining) { + qcom_geni_serial_setup_tx(uport, pending); + port->tx_remaining = pending; + } remaining = chunk; for (i = 0; i < chunk; ) { @@ -753,11 +773,10 @@ static void qcom_geni_serial_handle_tx(struct uart_port *uport) tail += tx_bytes; uport->icount.tx += tx_bytes; remaining -= tx_bytes; + port->tx_remaining -= tx_bytes; } xmit->tail = tail & (UART_XMIT_SIZE - 1); - if (uart_console(uport)) - qcom_geni_serial_poll_tx_done(uport); out_write_wakeup: if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS) uart_write_wakeup(uport); @@ -767,6 +786,7 @@ static irqreturn_t qcom_geni_serial_isr(int isr, void *dev) { unsigned int m_irq_status; unsigned int s_irq_status; + unsigned int geni_status; struct uart_port *uport = dev; unsigned long flags; unsigned int m_irq_en; @@ -780,6 +800,7 @@ static irqreturn_t qcom_geni_serial_isr(int isr, void *dev) spin_lock_irqsave(&uport->lock, flags); m_irq_status = readl_relaxed(uport->membase + SE_GENI_M_IRQ_STATUS); s_irq_status = readl_relaxed(uport->membase + SE_GENI_S_IRQ_STATUS); + geni_status = readl_relaxed(uport->membase + SE_GENI_STATUS); m_irq_en = readl_relaxed(uport->membase + SE_GENI_M_IRQ_EN); writel_relaxed(m_irq_status, uport->membase + SE_GENI_M_IRQ_CLEAR); writel_relaxed(s_irq_status, uport->membase + SE_GENI_S_IRQ_CLEAR); @@ -794,7 +815,8 @@ static irqreturn_t qcom_geni_serial_isr(int isr, void *dev) 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)) - qcom_geni_serial_handle_tx(uport); + qcom_geni_serial_handle_tx(uport, m_irq_status & M_CMD_DONE_EN, + geni_status & M_GENI_CMD_ACTIVE); if (s_irq_status & S_GP_IRQ_0_EN || s_irq_status & S_GP_IRQ_1_EN) { if (s_irq_status & S_GP_IRQ_0_EN) -- 2.20.0.rc0.387.gc7a69e6b6c-goog