From patchwork Tue Apr 19 13:37:13 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Arnd Bergmann X-Patchwork-Id: 563508 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 86BADC433EF for ; Tue, 19 Apr 2022 13:44:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S242738AbiDSNqo (ORCPT ); Tue, 19 Apr 2022 09:46:44 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41292 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S243252AbiDSNpW (ORCPT ); Tue, 19 Apr 2022 09:45:22 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D4E1938DA8; Tue, 19 Apr 2022 06:41:34 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 57A0AB81987; Tue, 19 Apr 2022 13:41:33 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7BB39C385A8; Tue, 19 Apr 2022 13:41:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1650375692; bh=tnWw7oBH8X/XBSc06dB4T/Xrxth9FWCIgmXAbL0gUiI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=l353b3xn7RP12XuOF9Cs9zO9tge/orX72WpKCH58E7muL7FyXckbWebpZVTgREpYO 94nj83AEJ8G4ma3/hGOjwiDA7u44mm32sOWTOmedTY1j9E754Khi/eBhNw7sZcR/fP sEELa4g6tqqCHlME51Brhwnr6YLWLyI8Af7wRGM8o8xD8amnnB09engI4zVkiclXXu mCNS0Sb+wp3+DZySStUMonTFolm2Ob9v/CLQNN4JWPX7Aweoh7N2XbyQM1ddcyBgBz 1g2qalhGNLlbW40TdlyWoLmDXnGz4w+LLuOQpSk9G4QwyJjZxE6HKbSgWD1lwNbvb3 UwCXSJ2vUo86g== From: Arnd Bergmann To: linux-omap@vger.kernel.org, tony@atomide.com, aaro.koskinen@iki.fi, jmkrzyszt@gmail.com Cc: Arnd Bergmann , Russell King , Paul Walmsley , Kevin Hilman , Peter Ujfalusi , Vinod Koul , Dmitry Torokhov , Ulf Hansson , Dominik Brodowski , Mark Brown , Felipe Balbi , Alan Stern , Lee Jones , Daniel Thompson , Jingoo Han , Helge Deller , Linus Walleij , Krzysztof Kozlowski , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-usb@vger.kernel.org, dmaengine@vger.kernel.org, linux-input@vger.kernel.org, linux-mmc@vger.kernel.org, linux-serial@vger.kernel.org, dri-devel@lists.freedesktop.org, linux-fbdev@vger.kernel.org, alsa-devel@alsa-project.org Subject: [PATCH 31/41] ARM: OMAP1: clock: Fix early UART rate issues Date: Tue, 19 Apr 2022 15:37:13 +0200 Message-Id: <20220419133723.1394715-32-arnd@kernel.org> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20220419133723.1394715-1-arnd@kernel.org> References: <20220419133723.1394715-1-arnd@kernel.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-fbdev@vger.kernel.org From: Janusz Krzysztofik Commit ef772f2ee31e ("ARM: OMAP: Fix CONFIG_DEBUG_LL") was supposed to fix low level debugging, most possibly by early enabling UART clocks. The fix actually introduced early reset of most bits of MOD_CONF_CTRL_0 register, with the exception of UART1 and UART2 clock related bits which were set high. However, UART1 clock bit can play different roles on different OMAP1 variants. On OMAP1610 it enables the clock as intended, but on OMAP1510 it switches the clock rate from 12 to 48 MHz. Even worth, for UART2 the bit changes its clock rate also on OMAP1610. As a result, UART rates set by a bootloader can be unintentionally changed early on kernel boot and low level debugging broken, not fixed. Besides, reset of all other bits was not justified. Don't touch register bits not related to UART clocks. Also, don't touch the bit of UART2 clock. Make sure UART1 and UART3 are enabled early on relevant OMAP1610 machine types while preserving bootloader UART clock rates on others. Signed-off-by: Janusz Krzysztofik Signed-off-by: Arnd Bergmann --- arch/arm/mach-omap1/clock_data.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) diff --git a/arch/arm/mach-omap1/clock_data.c b/arch/arm/mach-omap1/clock_data.c index 36f04da4b939..57d3752babf8 100644 --- a/arch/arm/mach-omap1/clock_data.c +++ b/arch/arm/mach-omap1/clock_data.c @@ -766,11 +766,11 @@ int __init omap1_clk_init(void) u32 reg; #ifdef CONFIG_DEBUG_LL - /* - * Resets some clocks that may be left on from bootloader, - * but leaves serial clocks on. - */ - omap_writel(0x3 << 29, MOD_CONF_CTRL_0); + /* Make sure UART clocks are enabled early */ + if (cpu_is_omap16xx()) + omap_writel(omap_readl(MOD_CONF_CTRL_0) | + CONF_MOD_UART1_CLK_MODE_R | + CONF_MOD_UART3_CLK_MODE_R, MOD_CONF_CTRL_0); #endif /* USB_REQ_EN will be disabled later if necessary (usb_dc_ck) */