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=-7.0 required=3.0 tests=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED 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 BB5ACC282C2 for ; Thu, 7 Feb 2019 11:27:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 80B4921902 for ; Thu, 7 Feb 2019 11:27:02 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=baylibre-com.20150623.gappssmtp.com header.i=@baylibre-com.20150623.gappssmtp.com header.b="lpGa0Grw" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727003AbfBGL1A (ORCPT ); Thu, 7 Feb 2019 06:27:00 -0500 Received: from mail-ed1-f67.google.com ([209.85.208.67]:38276 "EHLO mail-ed1-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726561AbfBGL1A (ORCPT ); Thu, 7 Feb 2019 06:27:00 -0500 Received: by mail-ed1-f67.google.com with SMTP id h50so8690596ede.5 for ; Thu, 07 Feb 2019 03:26:59 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=baylibre-com.20150623.gappssmtp.com; s=20150623; h=from:to:cc:subject:date:references:reply-to:message-id:mime-version; bh=obC/o0x/Of+oiYvDNo+3FmUgPGJAQl+NE5x85eXAQHI=; b=lpGa0Grw3h/abtMaXn8NhnwSyAc4gkosLOJN3rQecVmu/PUkG6561GanDZRktd8Nca SmSdGAm7PK7OLr+TV0dpGPi2QnPfRciLmalt04YeQub95QaqfKMzO5nMopKi6EA51LaA HHqzvMmE6uovrowLcZJf0bK4COmQu/hZ+bfPRRyVE9vJ8tJkjSc/LYeRHaFXueQ5Pfov MMFTeIH4v1IvyDhmAIWOIqikUDlDabQZvovVAWtgJ8/qAynFQH1PCB6a7bbSIrfjKWVf 7v2rQY2Z66S9UFvsAue90atnXEAbwYSrw/JY08p1V/2cCbKHOUWq4l0DVZqZdXHKM66c gKzA== 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:references:reply-to :message-id:mime-version; bh=obC/o0x/Of+oiYvDNo+3FmUgPGJAQl+NE5x85eXAQHI=; b=D48qxjOhtRGtWKKwR/Obf6UXb6CxHz6MHxk2KHHsLu47HnqMNSFwkJVOKd7VbkVRCh B5DZQ1lAEaq3OL6D00cPhgLQ0tZfLqFH2QfwIAzAcoHrZPVoA9t/50VDklKTCbgcD0Hi LAA50BCF9T8tEe71hDFEB4wh6i8zfazbQsnDUWYPqeo5jMLCwUPJMQnCO/CnlMyJlim8 XE+jQcTJuk+soNwn5opZ+LIK/spCSOQ7lJ0CTn3eMsHRbRvol56zFwONuHw+njuFRwTK UN9wX+8PcgUNJjSNb52Nmg6KGmVKwa7VFzbqBRK0JaCnYfIWl1iJdxREtX3ScXBskX2b z8eg== X-Gm-Message-State: AHQUAuYHi3lFmWg+MXoVEnQ6u6oJkGcJDXoYmJEApgzcvpgu7Nf3feoE FczdamTHtUmw8GX41j30P9h+ww== X-Google-Smtp-Source: AHgI3IaacZRmJNMHtyYLIrXWsYmX+kBY4nCl0BEnTm3g+kmpaGvMP3TR483tFqfu5leYPUmmyCMgkg== X-Received: by 2002:aa7:c0c8:: with SMTP id j8mr4962862edp.94.1549538818755; Thu, 07 Feb 2019 03:26:58 -0800 (PST) Received: from localhost ([2620:10d:c092:180::1:a0f9]) by smtp.gmail.com with ESMTPSA id e26sm3239012eja.9.2019.02.07.03.26.57 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 07 Feb 2019 03:26:58 -0800 (PST) From: Julien Masson To: Kevin Hilman , Greg Kroah-Hartman Cc: linux-amlogic@lists.infradead.org, linux-arm-kernel@lists.infradead.org, linux-serial@vger.kernel.org, Jiri Slaby , Julien Masson , linux-kernel@vger.kernel.org Subject: [PATCH 1/2] tty: serial: meson_uart: Add support for kernel debugger Date: Thu, 7 Feb 2019 12:26:16 +0100 References: <86h8dfx2jv.fsf@gmail.com> Reply-To: <86h8dfx2jv.fsf@gmail.com> Message-ID: <86ftszx2im.fsf@gmail.com> MIME-Version: 1.0 Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The kgdb invokes the poll_put_char and poll_get_char when communicating with the host. This patch implement the serial polling hooks for the meson_uart to be used for KGDB debugging over serial line. Signed-off-by: Julien Masson --- drivers/tty/serial/meson_uart.c | 46 +++++++++++++++++++++++++++++++++++++++++ 1 file changed, 46 insertions(+) diff --git a/drivers/tty/serial/meson_uart.c b/drivers/tty/serial/meson_uart.c index 8a84259..49b20da 100644 --- a/drivers/tty/serial/meson_uart.c +++ b/drivers/tty/serial/meson_uart.c @@ -426,6 +426,48 @@ static void meson_uart_config_port(struct uart_port *port, int flags) } } +#ifdef CONFIG_CONSOLE_POLL +/* + * Console polling routines for writing and reading from the uart while + * in an interrupt or debug context (i.e. kgdb). + */ + +static int meson_uart_poll_get_char(struct uart_port *port) +{ + u32 c; + unsigned long flags; + + spin_lock_irqsave(&port->lock, flags); + + if (readl(port->membase + AML_UART_STATUS) & AML_UART_RX_EMPTY) + c = NO_POLL_CHAR; + else + c = readl(port->membase + AML_UART_RFIFO); + + spin_unlock_irqrestore(&port->lock, flags); + + return c; +} + +static void meson_uart_poll_put_char(struct uart_port *port, unsigned char c) +{ + unsigned long flags; + + spin_lock_irqsave(&port->lock, flags); + + while (!(readl(port->membase + AML_UART_STATUS) & AML_UART_TX_EMPTY)) + cpu_relax(); + + writel(c, port->membase + AML_UART_WFIFO); + + while (!(readl(port->membase + AML_UART_STATUS) & AML_UART_TX_EMPTY)) + cpu_relax(); + + spin_unlock_irqrestore(&port->lock, flags); +} + +#endif /* CONFIG_CONSOLE_POLL */ + static const struct uart_ops meson_uart_ops = { .set_mctrl = meson_uart_set_mctrl, .get_mctrl = meson_uart_get_mctrl, @@ -441,6 +483,10 @@ static const struct uart_ops meson_uart_ops = { .request_port = meson_uart_request_port, .release_port = meson_uart_release_port, .verify_port = meson_uart_verify_port, +#ifdef CONFIG_CONSOLE_POLL + .poll_get_char = meson_uart_poll_get_char, + .poll_put_char = meson_uart_poll_put_char, +#endif }; #ifdef CONFIG_SERIAL_MESON_CONSOLE -- 2.7.4