From patchwork Tue Apr 2 21:06:21 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: =?utf-8?q?Jernej_=C5=A0krabec?= X-Patchwork-Id: 10882343 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 8013D1575 for ; Tue, 2 Apr 2019 21:07:21 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 66124288BA for ; Tue, 2 Apr 2019 21:07:21 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 5A0FC28913; Tue, 2 Apr 2019 21:07:21 +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=-5.2 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,MAILING_LIST_MULTI,RCVD_IN_DNSWL_MED autolearn=unavailable version=3.3.1 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id D21F4288BA for ; Tue, 2 Apr 2019 21:07:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Message-Id:Date:Subject:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=NNXV9SIfv62fpibSfz77Q9ialcspJnhEFS0eIYCS9oo=; b=dZTw44GZl/EqvT RkqYx5ht0pp6Wkqxs7ONhpMtcL2WdH3hIpRqRE1I0r4sxcObLbA5abEDT+IcHPq59M82ETdo/Pv0V VzLTzdKCg94+/JJydccPN/N8U7sQv0u5cYDHunw5mfFg9LtLwaz0AAn1eKfksMIblp8j5/7Ls0WUg VGQF2Y5xmLPTeIMg4OauABlsQbSP5PfSEvhYUFaY8DpmCZgpOlAkg3m5vXDcXYXuNx3jFrvLeYgzx zmAVsVGpyiqAw4Hpv39EkxFw7WFGPv8HKREsFDLXHhCqaj0ITK4+XdgqZceNvG33NTjsVOslO55mf crdeV+2muEZiCsbT36gg==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1hBQco-0000nn-D0; Tue, 02 Apr 2019 21:07:18 +0000 Received: from mailoutvs50.siol.net ([185.57.226.241] helo=mail.siol.net) by bombadil.infradead.org with esmtps (Exim 4.90_1 #2 (Red Hat Linux)) id 1hBQcC-0008Rl-Rs for linux-arm-kernel@lists.infradead.org; Tue, 02 Apr 2019 21:06:44 +0000 Received: from localhost (localhost [127.0.0.1]) by mail.siol.net (Zimbra) with ESMTP id 0B975521A88; Tue, 2 Apr 2019 23:06:33 +0200 (CEST) X-Virus-Scanned: amavisd-new at psrvmta12.zcs-production.pri Received: from mail.siol.net ([127.0.0.1]) by localhost (psrvmta12.zcs-production.pri [127.0.0.1]) (amavisd-new, port 10032) with ESMTP id kSv2RTOv067m; Tue, 2 Apr 2019 23:06:32 +0200 (CEST) Received: from mail.siol.net (localhost [127.0.0.1]) by mail.siol.net (Zimbra) with ESMTPS id 75FFC521A6C; Tue, 2 Apr 2019 23:06:32 +0200 (CEST) Received: from localhost.localdomain (cpe-86-58-52-202.static.triera.net [86.58.52.202]) (Authenticated sender: 031275009) by mail.siol.net (Zimbra) with ESMTPSA id C8FA6521A88; Tue, 2 Apr 2019 23:06:29 +0200 (CEST) From: Jernej Skrabec To: maxime.ripard@bootlin.com, wens@csie.org Subject: [PATCH 1/3] clk: sunxi-ng: nkmp: Avoid GENMASK(-1, 0) Date: Tue, 2 Apr 2019 23:06:21 +0200 Message-Id: <20190402210623.14988-2-jernej.skrabec@siol.net> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20190402210623.14988-1-jernej.skrabec@siol.net> References: <20190402210623.14988-1-jernej.skrabec@siol.net> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20190402_140641_283163_3A4B5B02 X-CRM114-Status: GOOD ( 14.05 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: jernej.skrabec@siol.net, sboyd@kernel.org, mturquette@baylibre.com, linux-kernel@vger.kernel.org, linux-clk@vger.kernel.org, linux-arm-kernel@lists.infradead.org Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Virus-Scanned: ClamAV using ClamSMTP Sometimes one of the nkmp factors is unused. This means that one of the factors shift and width values are set to 0. Current nkmp clock code generates a mask for each factor with GENMASK(width + shift - 1, shift). For unused factor this translates to GENMASK(-1, 0). This code is further expanded by C preprocessor to final version: (((~0UL) - (1UL << (0)) + 1) & (~0UL >> (BITS_PER_LONG - 1 - (-1)))) or a bit simplified: (~0UL & (~0UL >> BITS_PER_LONG)) It turns out that result of the second part (~0UL >> BITS_PER_LONG) is actually undefined by C standard, which clearly specifies: "If the value of the right operand is negative or is greater than or equal to the width of the promoted left operand, the behavior is undefined." Additionally, compiling kernel with aarch64-linux-gnu-gcc 8.3.0 gave different results whether literals or variables with same values as literals were used. GENMASK with literals -1 and 0 gives zero and with variables gives 0xFFFFFFFFFFFFFFF (~0UL). Because nkmp driver uses GENMASK with variables as parameter, expression calculates mask as ~0UL instead of 0. This has further consequences that LSB in register is always set to 1 (1 is neutral value for a factor and shift is 0). For example, H6 pll-de clock is set to 600 MHz by sun4i-drm driver, but due to this bug ends up being 300 MHz. Additionally, 300 MHz seems to be too low because following warning can be found in dmesg: [ 1.752763] WARNING: CPU: 2 PID: 41 at drivers/clk/sunxi-ng/ccu_common.c:41 ccu_helper_wait_for_lock.part.0+0x6c/0x90 [ 1.763378] Modules linked in: [ 1.766441] CPU: 2 PID: 41 Comm: kworker/2:1 Not tainted 5.1.0-rc2-next-20190401 #138 [ 1.774269] Hardware name: Pine H64 (DT) [ 1.778200] Workqueue: events deferred_probe_work_func [ 1.783341] pstate: 40000005 (nZcv daif -PAN -UAO) [ 1.788135] pc : ccu_helper_wait_for_lock.part.0+0x6c/0x90 [ 1.793623] lr : ccu_helper_wait_for_lock.part.0+0x48/0x90 [ 1.799107] sp : ffff000010f93840 [ 1.802422] x29: ffff000010f93840 x28: 0000000000000000 [ 1.807735] x27: ffff800073ce9d80 x26: ffff000010afd1b8 [ 1.813049] x25: ffffffffffffffff x24: 00000000ffffffff [ 1.818362] x23: 0000000000000001 x22: ffff000010abd5c8 [ 1.823675] x21: 0000000010000000 x20: 00000000685f367e [ 1.828987] x19: 0000000000001801 x18: 0000000000000001 [ 1.834300] x17: 0000000000000001 x16: 0000000000000000 [ 1.839613] x15: 0000000000000000 x14: ffff000010789858 [ 1.844926] x13: 0000000000000000 x12: 0000000000000001 [ 1.850239] x11: 0000000000000000 x10: 0000000000000970 [ 1.855551] x9 : ffff000010f936c0 x8 : ffff800074cec0d0 [ 1.860864] x7 : 0000800067117000 x6 : 0000000115c30b41 [ 1.866177] x5 : 00ffffffffffffff x4 : 002c959300bfe500 [ 1.871490] x3 : 0000000000000018 x2 : 0000000029aaaaab [ 1.876802] x1 : 00000000000002e6 x0 : 00000000686072bc [ 1.882114] Call trace: [ 1.884565] ccu_helper_wait_for_lock.part.0+0x6c/0x90 [ 1.889705] ccu_helper_wait_for_lock+0x10/0x20 [ 1.894236] ccu_nkmp_set_rate+0x244/0x2a8 [ 1.898334] clk_change_rate+0x144/0x290 [ 1.902258] clk_core_set_rate_nolock+0x180/0x1b8 [ 1.906963] clk_set_rate+0x34/0xa0 [ 1.910455] sun8i_mixer_bind+0x484/0x558 [ 1.914466] component_bind_all+0x10c/0x230 [ 1.918651] sun4i_drv_bind+0xc4/0x1a0 [ 1.922401] try_to_bring_up_master+0x164/0x1c0 [ 1.926932] __component_add+0xa0/0x168 [ 1.930769] component_add+0x10/0x18 [ 1.934346] sun8i_dw_hdmi_probe+0x18/0x20 [ 1.938443] platform_drv_probe+0x50/0xa0 [ 1.942455] really_probe+0xcc/0x280 [ 1.946032] driver_probe_device+0x54/0xe8 [ 1.950130] __device_attach_driver+0x80/0xb8 [ 1.954488] bus_for_each_drv+0x78/0xc8 [ 1.958326] __device_attach+0xd4/0x130 [ 1.962163] device_initial_probe+0x10/0x18 [ 1.966348] bus_probe_device+0x90/0x98 [ 1.970185] deferred_probe_work_func+0x6c/0xa0 [ 1.974720] process_one_work+0x1e0/0x320 [ 1.978732] worker_thread+0x228/0x428 [ 1.982484] kthread+0x120/0x128 [ 1.985714] ret_from_fork+0x10/0x18 [ 1.989290] ---[ end trace 9babd42e1ca4b84f ]--- This commit solves the issue by first checking value of the factor width. If it is equal to 0 (unused factor), mask is set to 0, otherwise GENMASK() macro is used as before. Fixes: d897ef56faf9 ("clk: sunxi-ng: Mask nkmp factors when setting register") Signed-off-by: Jernej Skrabec --- drivers/clk/sunxi-ng/ccu_nkmp.c | 18 +++++++++++++----- 1 file changed, 13 insertions(+), 5 deletions(-) diff --git a/drivers/clk/sunxi-ng/ccu_nkmp.c b/drivers/clk/sunxi-ng/ccu_nkmp.c index 9b49adb20d07..69dfc6de1c4e 100644 --- a/drivers/clk/sunxi-ng/ccu_nkmp.c +++ b/drivers/clk/sunxi-ng/ccu_nkmp.c @@ -167,7 +167,7 @@ static int ccu_nkmp_set_rate(struct clk_hw *hw, unsigned long rate, unsigned long parent_rate) { struct ccu_nkmp *nkmp = hw_to_ccu_nkmp(hw); - u32 n_mask, k_mask, m_mask, p_mask; + u32 n_mask = 0, k_mask = 0, m_mask = 0, p_mask = 0; struct _ccu_nkmp _nkmp; unsigned long flags; u32 reg; @@ -186,10 +186,18 @@ static int ccu_nkmp_set_rate(struct clk_hw *hw, unsigned long rate, ccu_nkmp_find_best(parent_rate, rate, &_nkmp); - n_mask = GENMASK(nkmp->n.width + nkmp->n.shift - 1, nkmp->n.shift); - k_mask = GENMASK(nkmp->k.width + nkmp->k.shift - 1, nkmp->k.shift); - m_mask = GENMASK(nkmp->m.width + nkmp->m.shift - 1, nkmp->m.shift); - p_mask = GENMASK(nkmp->p.width + nkmp->p.shift - 1, nkmp->p.shift); + if (nkmp->n.width) + n_mask = GENMASK(nkmp->n.width + nkmp->n.shift - 1, + nkmp->n.shift); + if (nkmp->k.width) + k_mask = GENMASK(nkmp->k.width + nkmp->k.shift - 1, + nkmp->k.shift); + if (nkmp->m.width) + m_mask = GENMASK(nkmp->m.width + nkmp->m.shift - 1, + nkmp->m.shift); + if (nkmp->p.width) + p_mask = GENMASK(nkmp->p.width + nkmp->p.shift - 1, + nkmp->p.shift); spin_lock_irqsave(nkmp->common.lock, flags);