From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932938AbcECARF (ORCPT ); Mon, 2 May 2016 20:17:05 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:59772 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932866AbcECAQn (ORCPT ); Mon, 2 May 2016 20:16:43 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Keerthy , Tony Lindgren , Linus Walleij Subject: [PATCH 4.4 060/163] pinctrl: single: Fix pcs_parse_bits_in_pinctrl_entry to use __ffs than ffs Date: Mon, 2 May 2016 17:11:28 -0700 Message-Id: <20160503000510.501268250@linuxfoundation.org> X-Mailer: git-send-email 2.8.2 In-Reply-To: <20160503000508.556845508@linuxfoundation.org> References: <20160503000508.556845508@linuxfoundation.org> User-Agent: quilt/0.64 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 4.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Keerthy commit 56b367c0cd67d4c3006738e7dc9dda9273fd2bfe upstream. pcs_parse_bits_in_pinctrl_entry uses ffs which gives bit indices ranging from 1 to MAX. This leads to a corner case where we try to request the pin number = MAX and fails. bit_pos value is being calculted using ffs. pin_num_from_lsb uses bit_pos value. pins array is populated with: pin + pin_num_from_lsb. The above is 1 more than usual bit indices as bit_pos uses ffs to compute first set bit. Hence the last of the pins array is populated with the MAX value and not MAX - 1 which causes error when we call pin_request. mask_pos is rightly calculated as ((pcs->fmask) << (bit_pos - 1)) Consequently val_pos and submask are correct. Hence use __ffs which gives (ffs(x) - 1) as the first bit set. fixes: 4e7e8017a8 ("pinctrl: pinctrl-single: enhance to configure multiple pins of different modules") Signed-off-by: Keerthy Acked-by: Tony Lindgren Signed-off-by: Linus Walleij Signed-off-by: Greg Kroah-Hartman --- drivers/pinctrl/pinctrl-single.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) --- a/drivers/pinctrl/pinctrl-single.c +++ b/drivers/pinctrl/pinctrl-single.c @@ -1273,9 +1273,9 @@ static int pcs_parse_bits_in_pinctrl_ent /* Parse pins in each row from LSB */ while (mask) { - bit_pos = ffs(mask); + bit_pos = __ffs(mask); pin_num_from_lsb = bit_pos / pcs->bits_per_pin; - mask_pos = ((pcs->fmask) << (bit_pos - 1)); + mask_pos = ((pcs->fmask) << bit_pos); val_pos = val & mask_pos; submask = mask & mask_pos; @@ -1847,7 +1847,7 @@ static int pcs_probe(struct platform_dev ret = of_property_read_u32(np, "pinctrl-single,function-mask", &pcs->fmask); if (!ret) { - pcs->fshift = ffs(pcs->fmask) - 1; + pcs->fshift = __ffs(pcs->fmask); pcs->fmax = pcs->fmask >> pcs->fshift; } else { /* If mask property doesn't exist, function mux is invalid. */