From patchwork Sat Nov 12 21:21:23 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Gabriel L. Somlo" X-Patchwork-Id: 624408 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6C500C433FE for ; Sat, 12 Nov 2022 21:22:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235133AbiKLVWV (ORCPT ); Sat, 12 Nov 2022 16:22:21 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54186 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235145AbiKLVVy (ORCPT ); Sat, 12 Nov 2022 16:21:54 -0500 Received: from mail-qk1-x730.google.com (mail-qk1-x730.google.com [IPv6:2607:f8b0:4864:20::730]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 31D7D18E32; Sat, 12 Nov 2022 13:21:44 -0800 (PST) Received: by mail-qk1-x730.google.com with SMTP id d8so2115611qki.13; Sat, 12 Nov 2022 13:21:44 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=K4iHEj9GzsVhhsWXwgpXJUYpNlSEHLmzm/JsgBx/hzw=; b=EZSQB4szI1sqawbShitBG+hzdiK94qL8rotIka8T4R2AOXMEXnwnsPqjgi0OFSykcR Wj4xQgi5MSxXfhOOaNDiM2udoMgu+tPEn+eygOQeSbf2fE+0isZpODtq5sInTDiNFfye yJ4PG6QLktQy4Tz4QvFL+F2xMu6f05Xzl+PJcOX0PKSwhSE+QuTgeVO4oO1VeG4v/Vio E4KRfk9aL48mSGN+rA0AD4VYJLfISEQP4jrCdHnN/Q3v+QpJum/aX6sb8O3Dgy/210Ld mudcSj1Ci/sDA6Lnp91oChlRxHP9T+ZOtGiDz6lJjqo3Oj0kXH/cEvso/8OtCmyWtNk1 YLJg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=K4iHEj9GzsVhhsWXwgpXJUYpNlSEHLmzm/JsgBx/hzw=; b=42djFdXAMGNw/iua9V+o9Qcz/Tj24F63EFa1kSg/nh3nlaKNaDXANUQI2weQUahW+j HjxPPpzi5Phg35X/ZJW7TYfx6YI6YhqZOaUekeoCjcgGAP9AKjkHyEYFS1ff3dmuGPZs X4gv5Ga9m14rrAOoVROqgxm66ath6f0joAxCJrzjpdE6rhSZ/ttnDAQJpCSiJ3/B3MTp fgbkW1MHGzKI3aw7zyIpc5MeaiFFa+oCF+pxFas//bg/2/vBD8U62/++EwOmF7TUzjog gdomPSytF/UuS4stg9coAkjfIzT0Z5l9ZcLXLOoLWu2HR2WKJ7I/VzqEhkmeaiVxIQsH 4+UA== X-Gm-Message-State: ANoB5pkNPsmea2QhfUoyNXbCOg4GTBkjzFsacdPMDhlEPH54sChTOMVi GlhvL9hD7zKelVe2RUqiiFzAK1YSXYkFDA== X-Google-Smtp-Source: AA0mqf7kqd9AcWKjMOWpFgbx6/iBsL2fXv3FyvWzV6AzGX32D/t7+8FzKy/VHkdItv3i7ioTfW2/Eg== X-Received: by 2002:a37:86c3:0:b0:6fa:d7e:7b4 with SMTP id i186-20020a3786c3000000b006fa0d7e07b4mr6006823qkd.373.1668288103069; Sat, 12 Nov 2022 13:21:43 -0800 (PST) Received: from glsvmlin.ini.cmu.edu (GLSVMLIN.INI.CMU.EDU. [128.2.16.9]) by smtp.gmail.com with ESMTPSA id t8-20020a37ea08000000b006fa313bf185sm3811839qkj.8.2022.11.12.13.21.42 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 12 Nov 2022 13:21:42 -0800 (PST) From: Gabriel Somlo To: linux-kernel@vger.kernel.org Cc: linux-serial@vger.kernel.org, gregkh@linuxfoundation.org, jirislaby@kernel.org, kgugala@antmicro.com, mholenko@antmicro.com, joel@jms.id.au, david.abdurachmanov@gmail.com, florent@enjoy-digital.fr, geert@linux-m68k.org Subject: [PATCH v3 12/14] serial: liteuart: add IRQ support for the RX path Date: Sat, 12 Nov 2022 16:21:23 -0500 Message-Id: <20221112212125.448824-13-gsomlo@gmail.com> X-Mailer: git-send-email 2.37.3 In-Reply-To: <20221112212125.448824-1-gsomlo@gmail.com> References: <20221112212125.448824-1-gsomlo@gmail.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-serial@vger.kernel.org Add support for IRQ-driven RX. Support for the TX path will be added in a separate commit. Signed-off-by: Gabriel Somlo --- drivers/tty/serial/liteuart.c | 61 +++++++++++++++++++++++++++++++---- 1 file changed, 54 insertions(+), 7 deletions(-) diff --git a/drivers/tty/serial/liteuart.c b/drivers/tty/serial/liteuart.c index cf1ce597b45e..e30adb30277f 100644 --- a/drivers/tty/serial/liteuart.c +++ b/drivers/tty/serial/liteuart.c @@ -6,6 +6,7 @@ */ #include +#include #include #include #include @@ -130,13 +131,29 @@ static void liteuart_rx_chars(struct uart_port *port) tty_flip_buffer_push(&port->state->port); } +static irqreturn_t liteuart_interrupt(int irq, void *data) +{ + struct liteuart_port *uart = data; + struct uart_port *port = &uart->port; + u8 isr = litex_read8(port->membase + OFF_EV_PENDING); + + /* for now, only rx path triggers interrupts */ + isr &= EV_RX; + + spin_lock(&port->lock); + if (isr & EV_RX) + liteuart_rx_chars(port); + spin_unlock(&port->lock); + + return IRQ_RETVAL(isr); +} + static void liteuart_timer(struct timer_list *t) { struct liteuart_port *uart = from_timer(uart, t, timer); struct uart_port *port = &uart->port; - liteuart_rx_chars(port); - + liteuart_interrupt(0, port); mod_timer(&uart->timer, jiffies + uart_poll_timeout(port)); } @@ -162,19 +179,42 @@ static unsigned int liteuart_get_mctrl(struct uart_port *port) static int liteuart_startup(struct uart_port *port) { struct liteuart_port *uart = to_liteuart_port(port); + int ret; + u8 irq_mask = 0; - /* disable events */ - litex_write8(port->membase + OFF_EV_ENABLE, 0); + if (port->irq) { + ret = request_irq(port->irq, liteuart_interrupt, 0, + KBUILD_MODNAME, uart); + if (ret == 0) { + /* only enable rx interrupts at this time */ + irq_mask = EV_RX; + } else { + pr_err(pr_fmt("line %d irq %d failed: using polling\n"), + port->line, port->irq); + port->irq = 0; + } + } - /* prepare timer for polling */ - timer_setup(&uart->timer, liteuart_timer, 0); - mod_timer(&uart->timer, jiffies + uart_poll_timeout(port)); + if (!port->irq) { + timer_setup(&uart->timer, liteuart_timer, 0); + mod_timer(&uart->timer, jiffies + uart_poll_timeout(port)); + } + + litex_write8(port->membase + OFF_EV_ENABLE, irq_mask); return 0; } static void liteuart_shutdown(struct uart_port *port) { + struct liteuart_port *uart = to_liteuart_port(port); + + litex_write8(port->membase + OFF_EV_ENABLE, 0); + + if (port->irq) + free_irq(port->irq, port); + else + del_timer_sync(&uart->timer); } static void liteuart_set_termios(struct uart_port *port, struct ktermios *new, @@ -263,6 +303,13 @@ static int liteuart_probe(struct platform_device *pdev) goto err_erase_id; } + /* get irq */ + ret = platform_get_irq_optional(pdev, 0); + if (ret < 0 && ret != -ENXIO) + return ret; + if (ret > 0) + port->irq = ret; + /* values not from device tree */ port->dev = &pdev->dev; port->iotype = UPIO_MEM;