From patchwork Fri Aug 5 08:17:52 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Geert Uytterhoeven X-Patchwork-Id: 9264883 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 7A5A96048B for ; Fri, 5 Aug 2016 08:18:17 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 6DCC6212BE for ; Fri, 5 Aug 2016 08:18:17 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 61F7428410; Fri, 5 Aug 2016 08:18:17 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.9 required=2.0 tests=BAYES_00,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id C040928138 for ; Fri, 5 Aug 2016 08:18:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934833AbcHEISP (ORCPT ); Fri, 5 Aug 2016 04:18:15 -0400 Received: from michel.telenet-ops.be ([195.130.137.88]:52809 "EHLO michel.telenet-ops.be" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934750AbcHEISM (ORCPT ); Fri, 5 Aug 2016 04:18:12 -0400 Received: from ayla.of.borg ([84.193.137.253]) by michel.telenet-ops.be with bizsmtp id TLJA1t00b5UCtCs06LJAy4; Fri, 05 Aug 2016 10:18:11 +0200 Received: from ramsan.of.borg ([192.168.97.29] helo=ramsan) by ayla.of.borg with esmtp (Exim 4.82) (envelope-from ) id 1bVaKY-0006Ib-Dl; Fri, 05 Aug 2016 10:18:10 +0200 Received: from geert by ramsan with local (Exim 4.82) (envelope-from ) id 1bVaKY-0000Lt-Hy; Fri, 05 Aug 2016 10:18:10 +0200 From: Geert Uytterhoeven To: Mark Brown Cc: Magnus Damm , Nobuhiro Iwamatsu , Ulrich Hecht , linux-spi@vger.kernel.org, linux-renesas-soc@vger.kernel.org, Geert Uytterhoeven Subject: [PATCH] spi: sh-msiof: Avoid invalid clock generator parameters Date: Fri, 5 Aug 2016 10:17:52 +0200 Message-Id: <1470385072-1313-1-git-send-email-geert+renesas@glider.be> X-Mailer: git-send-email 1.9.1 Sender: linux-spi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-spi@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP The conversion from a look-up table to a calculation for clock generator parameters forgot to take into account that BRDV x 1/1 is valid only if BRPS is x 1/1 or x 1/2, leading to undefined behavior (e.g. arbitrary clock rates). This limitation is documented for the MSIOF module in all supported SH/R-Mobile and R-Car Gen2/Gen3 ARM SoCs. Tested on r8a7791/koelsch and r8a7795/salvator-x. Fixes: 65d5665bb260b034 ("spi: sh-msiof: Update calculation of frequency dividing") Signed-off-by: Geert Uytterhoeven --- I think this is suitable for stable, so please add Cc: stable@vger.kernel.org when applying. drivers/spi/spi-sh-msiof.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/spi/spi-sh-msiof.c b/drivers/spi/spi-sh-msiof.c index 8d1120931f343776..91dc730880264fe8 100644 --- a/drivers/spi/spi-sh-msiof.c +++ b/drivers/spi/spi-sh-msiof.c @@ -301,6 +301,9 @@ static void sh_msiof_spi_set_clk_regs(struct sh_msiof_spi_priv *p, for (k = 0; k < ARRAY_SIZE(sh_msiof_spi_div_table); k++) { brps = DIV_ROUND_UP(div, sh_msiof_spi_div_table[k].div); + /* SCR_BRDV_DIV_1 is valid only if BRPS is x 1/1 or x 1/2 */ + if (sh_msiof_spi_div_table[k].div == 1 && brps > 2) + continue; if (brps <= 32) /* max of brdv is 32 */ break; }