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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 747DBC4332F for ; Fri, 18 Nov 2022 14:30:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S242387AbiKROa3 (ORCPT ); Fri, 18 Nov 2022 09:30:29 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59574 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S242377AbiKROaV (ORCPT ); Fri, 18 Nov 2022 09:30:21 -0500 Received: from mga01.intel.com (mga01.intel.com [192.55.52.88]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3AB4C23154; Fri, 18 Nov 2022 06:30:20 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1668781820; x=1700317820; h=date:from:to:cc:subject:in-reply-to:message-id: references:mime-version; bh=pWaMMlXuz5fP2ZoBJcXFxbvy5ntANJ8RsM8x308UVC4=; b=HjT+wYjMyVVSx9Ko6uMsO73nUEcAtbTSsZxE7XuDZWxnQ2VOj/VfBWS0 m9dFPa3JVZrjbaIfTFb13rA3dWmaJQtQkQHzC4QSagjynwKYyMXxp4cIB F0q/vedewOb8vfmV0YJVe57lXqqOPsG0/z0f2ky5AFOvbsuPLKhdmrEmn UauIfKdw6LXFs36eQ+9tmHDJHz3YTnwiI0qfpinU0GlRRA6XqfC/c8/11 Pdt+Lw5H/xqfk+mlo56q41mMf8a38C34kJrVL/+xUwHdUq7Yy3/lN1/9q TSH8vrHWjBm34HTN/Hrlj+oFS/4pIkB4MiFr80ExoQRJrs3rUukjMOJeq w==; X-IronPort-AV: E=McAfee;i="6500,9779,10535"; a="339984867" X-IronPort-AV: E=Sophos;i="5.96,174,1665471600"; d="scan'208";a="339984867" Received: from orsmga006.jf.intel.com ([10.7.209.51]) by fmsmga101.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 18 Nov 2022 06:30:19 -0800 X-IronPort-AV: E=McAfee;i="6500,9779,10535"; a="618026604" X-IronPort-AV: E=Sophos;i="5.96,174,1665471600"; d="scan'208";a="618026604" Received: from amulyuko-mobl1.ccr.corp.intel.com ([10.252.35.83]) by orsmga006-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 18 Nov 2022 06:30:16 -0800 Date: Fri, 18 Nov 2022 16:30:15 +0200 (EET) From: =?ISO-8859-15?Q?Ilpo_J=E4rvinen?= To: "Gabriel L. Somlo" cc: LKML , linux-serial , Greg Kroah-Hartman , Jiri Slaby , kgugala@antmicro.com, mholenko@antmicro.com, joel@jms.id.au, david.abdurachmanov@gmail.com, florent@enjoy-digital.fr, geert@linux-m68k.org Subject: Re: [PATCH v4 12/14] serial: liteuart: add IRQ support for the RX path In-Reply-To: Message-ID: <26f43d54-7ee6-d05e-5c1c-4bc37f06077@linux.intel.com> References: <20221116144908.234154-1-gsomlo@gmail.com> <20221116144908.234154-13-gsomlo@gmail.com> <6629539b-c5a7-4edc-7ab1-5c977f7319@linux.intel.com> MIME-Version: 1.0 Content-Type: multipart/mixed; boundary="8323329-1000769402-1668781820=:3952" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This message is in MIME format. The first part should be readable text, while the remaining parts are likely unreadable without MIME-aware tools. --8323329-1000769402-1668781820=:3952 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: 8BIT On Fri, 18 Nov 2022, Gabriel L. Somlo wrote: > On Fri, Nov 18, 2022 at 03:58:47PM +0200, Ilpo Järvinen wrote: > > On Wed, 16 Nov 2022, Gabriel Somlo wrote: > > > > > Add support for IRQ-driven RX. Support for the TX path will be added > > > in a separate commit. > > > > > > Signed-off-by: Gabriel Somlo > > > --- > > > > > > Changes from v3: > > > - add shadow irq register to support polling mode and avoid reading > > > hardware mmio irq register to learn which irq flags are enabled > > > - this also simplifies both liteuart_interrupt() and liteuart_startup() > > > > > > drivers/tty/serial/liteuart.c | 76 +++++++++++++++++++++++++++++++---- > > > 1 file changed, 69 insertions(+), 7 deletions(-) > > > > > > diff --git a/drivers/tty/serial/liteuart.c b/drivers/tty/serial/liteuart.c > > > index 8a6e176be08e..fad778578986 100644 > > > --- a/drivers/tty/serial/liteuart.c > > > +++ b/drivers/tty/serial/liteuart.c > > > @@ -7,6 +7,7 @@ > > > > > > #include > > > #include > > > +#include > > > #include > > > #include > > > #include > > > @@ -46,6 +47,7 @@ struct liteuart_port { > > > struct uart_port port; > > > struct timer_list timer; > > > u32 id; > > > + u8 irq_reg; > > > }; > > > > > > #define to_liteuart_port(port) container_of(port, struct liteuart_port, port) > > > @@ -76,6 +78,19 @@ static void liteuart_putchar(struct uart_port *port, unsigned char ch) > > > litex_write8(port->membase + OFF_RXTX, ch); > > > } > > > > > > +static void liteuart_update_irq_reg(struct uart_port *port, bool set, u8 mask) > > > +{ > > > + struct liteuart_port *uart = to_liteuart_port(port); > > > + > > > + if (set) > > > + uart->irq_reg |= mask; > > > + else > > > + uart->irq_reg &= ~mask; > > > + > > > + if (port->irq) > > > + litex_write8(port->membase + OFF_EV_ENABLE, uart->irq_reg); > > > +} > > > + > > > static void liteuart_stop_tx(struct uart_port *port) > > > { > > > } > > > @@ -129,13 +144,27 @@ 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; > > > + > > > + spin_lock(&port->lock); > > > + isr = litex_read8(port->membase + OFF_EV_PENDING) & uart->irq_reg; > > > + 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)); > > > } > > > > > > @@ -161,19 +190,45 @@ 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); > > > + unsigned long flags; > > > + int ret; > > > > > > - /* 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) { > > > + pr_err(pr_fmt("line %d irq %d failed: using polling\n"), > > > + port->line, port->irq); > > > > dev_err() seems more appropriate here. > > Makes sense, good thing `struct uart_port` has a `dev` field :) > I've made the change, and lined it up for the upcoming v5 of the > series. Also that pr_fmt() should be dropped (in case you didn't already). It was in my mind ealier but should have stated it explicitly. -- i. --8323329-1000769402-1668781820=:3952--