From patchwork Mon Apr 18 15:27:27 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Maciej W. Rozycki" X-Patchwork-Id: 563260 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 2EF79C433F5 for ; Mon, 18 Apr 2022 15:47:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1345419AbiDRPuN (ORCPT ); Mon, 18 Apr 2022 11:50:13 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60926 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1345709AbiDRPtm (ORCPT ); Mon, 18 Apr 2022 11:49:42 -0400 Received: from angie.orcam.me.uk (angie.orcam.me.uk [IPv6:2001:4190:8020::34]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 83E36E005; Mon, 18 Apr 2022 08:27:28 -0700 (PDT) Received: by angie.orcam.me.uk (Postfix, from userid 500) id E3AC192009E; Mon, 18 Apr 2022 17:27:27 +0200 (CEST) Received: from localhost (localhost [127.0.0.1]) by angie.orcam.me.uk (Postfix) with ESMTP id DC9DC92009C; Mon, 18 Apr 2022 16:27:27 +0100 (BST) Date: Mon, 18 Apr 2022 16:27:27 +0100 (BST) From: "Maciej W. Rozycki" To: Greg Kroah-Hartman , Jiri Slaby cc: Andy Shevchenko , linux-serial@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH v5 4/5] serial: 8250: Export ICR access helpers for internal use In-Reply-To: Message-ID: References: User-Agent: Alpine 2.21 (DEB 202 2017-01-01) MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-serial@vger.kernel.org Make ICR access helpers available outside 8250_port.c, however retain them as ordinary static functions so as not to regress code generation. This is because `serial_icr_write' is currently automatically inlined by GCC, however `serial_icr_read' is not. Making them both static inline would grow code produced, e.g.: $ i386-linux-gnu-size --format=gnu 8250_port-{old,new}.o text data bss total filename 15065 3378 0 18443 8250_port-old.o 15289 3378 0 18667 8250_port-new.o and: $ riscv64-linux-gnu-size --format=gnu 8250_port-{old,new}.o text data bss total filename 16980 5306 0 22286 8250_port-old.o 17124 5306 0 22430 8250_port-new.o while making them external would needlessly add a new module interface and lose the benefit from `serial_icr_write' getting inlined outside 8250_port.o. Signed-off-by: Maciej W. Rozycki Reviewed-by: Andy Shevchenko --- Changes from v4: - Reorder as 4/5 (from 3/5). - Drop `__maybe_unused' from `serial_icr_write'; it's used by `serial_icr_read'. New change in v4, factored out from 5/5. --- drivers/tty/serial/8250/8250.h | 22 ++++++++++++++++++++++ drivers/tty/serial/8250/8250_port.c | 21 --------------------- 2 files changed, 22 insertions(+), 21 deletions(-) linux-serial-8250-icr-access.diff Index: linux-macro/drivers/tty/serial/8250/8250.h =================================================================== --- linux-macro.orig/drivers/tty/serial/8250/8250.h +++ linux-macro/drivers/tty/serial/8250/8250.h @@ -120,6 +120,28 @@ static inline void serial_out(struct uar up->port.serial_out(&up->port, offset, value); } +/* + * For the 16C950 + */ +static void serial_icr_write(struct uart_8250_port *up, int offset, int value) +{ + serial_out(up, UART_SCR, offset); + serial_out(up, UART_ICR, value); +} + +static unsigned int __maybe_unused serial_icr_read(struct uart_8250_port *up, + int offset) +{ + unsigned int value; + + serial_icr_write(up, UART_ACR, up->acr | UART_ACR_ICRRD); + serial_out(up, UART_SCR, offset); + value = serial_in(up, UART_ICR); + serial_icr_write(up, UART_ACR, up->acr); + + return value; +} + void serial8250_clear_and_reinit_fifos(struct uart_8250_port *p); static inline int serial_dl_read(struct uart_8250_port *up) Index: linux-macro/drivers/tty/serial/8250/8250_port.c =================================================================== --- linux-macro.orig/drivers/tty/serial/8250/8250_port.c +++ linux-macro/drivers/tty/serial/8250/8250_port.c @@ -538,27 +538,6 @@ serial_port_out_sync(struct uart_port *p } /* - * For the 16C950 - */ -static void serial_icr_write(struct uart_8250_port *up, int offset, int value) -{ - serial_out(up, UART_SCR, offset); - serial_out(up, UART_ICR, value); -} - -static unsigned int serial_icr_read(struct uart_8250_port *up, int offset) -{ - unsigned int value; - - serial_icr_write(up, UART_ACR, up->acr | UART_ACR_ICRRD); - serial_out(up, UART_SCR, offset); - value = serial_in(up, UART_ICR); - serial_icr_write(up, UART_ACR, up->acr); - - return value; -} - -/* * FIFO support. */ static void serial8250_clear_fifos(struct uart_8250_port *p)