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Sat, 24 Jul 2021 16:18:54 +0800 From: Jitao Shi To: Thierry Reding , Lee Jones , =?UTF-8?q?Uwe=20Kleine-K=C3=B6nig?= , Matthias Brugger CC: , , , , , , , , , , , Jitao Shi Subject: [PATCH v6 4/5] pwm: mtk_disp: fix overflow in period and duty calcalation Date: Sat, 24 Jul 2021 16:18:48 +0800 Message-ID: <20210724081849.182108-5-jitao.shi@mediatek.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20210724081849.182108-1-jitao.shi@mediatek.com> References: <20210724081849.182108-1-jitao.shi@mediatek.com> MIME-Version: 1.0 Content-Type: text/plain X-TM-SNTS-SMTP: 00542DEEE62E7D67BBB1D34FA5DE6387FF294617A841F8A5F6153D1AF11FE15A2000:8 X-MTK: N Content-Transfer-Encoding: base64 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Q3VycmVudCBjYWxjdWxhdGlvbiBmb3IgcGVyaW9kIGFuZCBoaWdoX3dpZHRoIG1heSBoYXZlDQo2 NC1iaXQgb3ZlcmZsb3cuIHN0YXRlLT5wZXJpb2QgYW5kIHJhdGUgYXJlIHU2NC4NCnJhdGUgKiBz dGF0ZS0+cGVyaW9kIHdpbGwgb3ZlcmZsb3cuDQoNCmNsa19kaXYgPSBkaXZfdTY0KHJhdGUgKiBz dGF0ZS0+cGVyaW9kLCBOU0VDX1BFUl9TRUMpDQpwZXJpb2QgPSBkaXY2NF91NjQocmF0ZSAqIHN0 YXRlLT5wZXJpb2QsIGRpdik7DQpoaWdoX3dpZHRoID0gZGl2NjRfdTY0KHJhdGUgKiBzdGF0ZS0+ ZHV0eV9jeWNsZSwgZGl2KTsNCg0KVGhpcyBwYXRjaCBpcyB0byByZXNvbHZlIGl0IGJ5IHVzaW5n IG11bF91NjRfdTY0X2Rpdl91NjQoKS4NCg0KU2lnbmVkLW9mZi1ieTogSml0YW8gU2hpIDxqaXRh by5zaGlAbWVkaWF0ZWsuY29tPg0KLS0tDQogZHJpdmVycy9wd20vcHdtLW10ay1kaXNwLmMgfCA2 ICsrKy0tLQ0KIDEgZmlsZSBjaGFuZ2VkLCAzIGluc2VydGlvbnMoKyksIDMgZGVsZXRpb25zKC0p DQoNCmRpZmYgLS1naXQgYS9kcml2ZXJzL3B3bS9wd20tbXRrLWRpc3AuYyBiL2RyaXZlcnMvcHdt L3B3bS1tdGstZGlzcC5jDQppbmRleCA1OTlkN2RkOGVjYWIuLjRmNmRlNmYyNDQ4NCAxMDA2NDQN Ci0tLSBhL2RyaXZlcnMvcHdtL3B3bS1tdGstZGlzcC5jDQorKysgYi9kcml2ZXJzL3B3bS9wd20t bXRrLWRpc3AuYw0KQEAgLTExNiw3ICsxMTYsNyBAQCBzdGF0aWMgaW50IG10a19kaXNwX3B3bV9h cHBseShzdHJ1Y3QgcHdtX2NoaXAgKmNoaXAsIHN0cnVjdCBwd21fZGV2aWNlICpwd20sDQogCSAq IGhpZ2hfd2lkdGggPSAoUFdNX0NMS19SQVRFICogZHV0eV9ucykgLyAoMTBeOSAqIChjbGtfZGl2 ICsgMSkpDQogCSAqLw0KIAlyYXRlID0gY2xrX2dldF9yYXRlKG1kcC0+Y2xrX21haW4pOw0KLQlj bGtfZGl2ID0gZGl2X3U2NChyYXRlICogc3RhdGUtPnBlcmlvZCwgTlNFQ19QRVJfU0VDKSA+Pg0K KwljbGtfZGl2ID0gbXVsX3U2NF91NjRfZGl2X3U2NChzdGF0ZS0+cGVyaW9kLCByYXRlLCBOU0VD X1BFUl9TRUMpID4+DQogCQkJICBQV01fUEVSSU9EX0JJVF9XSURUSDsNCiAJaWYgKGNsa19kaXYg PiBQV01fQ0xLRElWX01BWCkgew0KIAkJaWYgKCFtZHAtPmVuYWJsZWQpIHsNCkBAIC0xMjcsMTEg KzEyNywxMSBAQCBzdGF0aWMgaW50IG10a19kaXNwX3B3bV9hcHBseShzdHJ1Y3QgcHdtX2NoaXAg KmNoaXAsIHN0cnVjdCBwd21fZGV2aWNlICpwd20sDQogCX0NCiANCiAJZGl2ID0gTlNFQ19QRVJf U0VDICogKGNsa19kaXYgKyAxKTsNCi0JcGVyaW9kID0gZGl2NjRfdTY0KHJhdGUgKiBzdGF0ZS0+ cGVyaW9kLCBkaXYpOw0KKwlwZXJpb2QgPSBtdWxfdTY0X3U2NF9kaXZfdTY0KHN0YXRlLT5wZXJp b2QsIHJhdGUsIGRpdik7DQogCWlmIChwZXJpb2QgPiAwKQ0KIAkJcGVyaW9kLS07DQogDQotCWhp Z2hfd2lkdGggPSBkaXY2NF91NjQocmF0ZSAqIHN0YXRlLT5kdXR5X2N5Y2xlLCBkaXYpOw0KKwlo aWdoX3dpZHRoID0gbXVsX3U2NF91NjRfZGl2X3U2NChzdGF0ZS0+ZHV0eV9jeWNsZSwgcmF0ZSwg ZGl2KTsNCiAJdmFsdWUgPSBwZXJpb2QgfCAoaGlnaF93aWR0aCA8PCBQV01fSElHSF9XSURUSF9T SElGVCk7DQogDQogCW10a19kaXNwX3B3bV91cGRhdGVfYml0cyhtZHAsIG1kcC0+ZGF0YS0+Y29u MCwNCi0tIA0KMi4yNS4xDQo= From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-18.2 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,UNPARSEABLE_RELAY, URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id BC5D4C4338F for ; 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Sat, 24 Jul 2021 16:18:54 +0800 From: Jitao Shi To: Thierry Reding , Lee Jones , =?UTF-8?q?Uwe=20Kleine-K=C3=B6nig?= , Matthias Brugger CC: , , , , , , , , , , , Jitao Shi Subject: [PATCH v6 4/5] pwm: mtk_disp: fix overflow in period and duty calcalation Date: Sat, 24 Jul 2021 16:18:48 +0800 Message-ID: <20210724081849.182108-5-jitao.shi@mediatek.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20210724081849.182108-1-jitao.shi@mediatek.com> References: <20210724081849.182108-1-jitao.shi@mediatek.com> MIME-Version: 1.0 X-TM-SNTS-SMTP: 00542DEEE62E7D67BBB1D34FA5DE6387FF294617A841F8A5F6153D1AF11FE15A2000:8 X-MTK: N X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210724_012913_726412_EB622F15 X-CRM114-Status: GOOD ( 10.44 ) X-BeenThere: linux-mediatek@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "Linux-mediatek" Errors-To: linux-mediatek-bounces+linux-mediatek=archiver.kernel.org@lists.infradead.org Current calculation for period and high_width may have 64-bit overflow. state->period and rate are u64. rate * state->period will overflow. clk_div = div_u64(rate * state->period, NSEC_PER_SEC) period = div64_u64(rate * state->period, div); high_width = div64_u64(rate * state->duty_cycle, div); This patch is to resolve it by using mul_u64_u64_div_u64(). Signed-off-by: Jitao Shi --- drivers/pwm/pwm-mtk-disp.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/drivers/pwm/pwm-mtk-disp.c b/drivers/pwm/pwm-mtk-disp.c index 599d7dd8ecab..4f6de6f24484 100644 --- a/drivers/pwm/pwm-mtk-disp.c +++ b/drivers/pwm/pwm-mtk-disp.c @@ -116,7 +116,7 @@ static int mtk_disp_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm, * high_width = (PWM_CLK_RATE * duty_ns) / (10^9 * (clk_div + 1)) */ rate = clk_get_rate(mdp->clk_main); - clk_div = div_u64(rate * state->period, NSEC_PER_SEC) >> + clk_div = mul_u64_u64_div_u64(state->period, rate, NSEC_PER_SEC) >> PWM_PERIOD_BIT_WIDTH; if (clk_div > PWM_CLKDIV_MAX) { if (!mdp->enabled) { @@ -127,11 +127,11 @@ static int mtk_disp_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm, } div = NSEC_PER_SEC * (clk_div + 1); - period = div64_u64(rate * state->period, div); + period = mul_u64_u64_div_u64(state->period, rate, div); if (period > 0) period--; - high_width = div64_u64(rate * state->duty_cycle, div); + high_width = mul_u64_u64_div_u64(state->duty_cycle, rate, div); value = period | (high_width << PWM_HIGH_WIDTH_SHIFT); mtk_disp_pwm_update_bits(mdp, mdp->data->con0, -- 2.25.1 _______________________________________________ Linux-mediatek mailing list Linux-mediatek@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-mediatek From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-18.2 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,UNPARSEABLE_RELAY, URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id A3311C4338F for ; Sat, 24 Jul 2021 08:30:58 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 6422A60E8B for ; 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Sat, 24 Jul 2021 01:29:06 -0700 Received: from MTKMBS33N1.mediatek.inc (172.27.4.75) by MTKMBS62DR.mediatek.inc (172.29.94.18) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Sat, 24 Jul 2021 01:19:04 -0700 Received: from MTKCAS36.mediatek.inc (172.27.4.186) by MTKMBS33N1.mediatek.inc (172.27.4.75) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Sat, 24 Jul 2021 16:18:55 +0800 Received: from mszsdclx1018.gcn.mediatek.inc (10.16.6.18) by MTKCAS36.mediatek.inc (172.27.4.170) with Microsoft SMTP Server id 15.0.1497.2 via Frontend Transport; Sat, 24 Jul 2021 16:18:54 +0800 From: Jitao Shi To: Thierry Reding , Lee Jones , =?UTF-8?q?Uwe=20Kleine-K=C3=B6nig?= , Matthias Brugger CC: , , , , , , , , , , , Jitao Shi Subject: [PATCH v6 4/5] pwm: mtk_disp: fix overflow in period and duty calcalation Date: Sat, 24 Jul 2021 16:18:48 +0800 Message-ID: <20210724081849.182108-5-jitao.shi@mediatek.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20210724081849.182108-1-jitao.shi@mediatek.com> References: <20210724081849.182108-1-jitao.shi@mediatek.com> MIME-Version: 1.0 X-TM-SNTS-SMTP: 00542DEEE62E7D67BBB1D34FA5DE6387FF294617A841F8A5F6153D1AF11FE15A2000:8 X-MTK: N X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210724_012913_726412_EB622F15 X-CRM114-Status: GOOD ( 10.44 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org Current calculation for period and high_width may have 64-bit overflow. state->period and rate are u64. rate * state->period will overflow. clk_div = div_u64(rate * state->period, NSEC_PER_SEC) period = div64_u64(rate * state->period, div); high_width = div64_u64(rate * state->duty_cycle, div); This patch is to resolve it by using mul_u64_u64_div_u64(). Signed-off-by: Jitao Shi --- drivers/pwm/pwm-mtk-disp.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/drivers/pwm/pwm-mtk-disp.c b/drivers/pwm/pwm-mtk-disp.c index 599d7dd8ecab..4f6de6f24484 100644 --- a/drivers/pwm/pwm-mtk-disp.c +++ b/drivers/pwm/pwm-mtk-disp.c @@ -116,7 +116,7 @@ static int mtk_disp_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm, * high_width = (PWM_CLK_RATE * duty_ns) / (10^9 * (clk_div + 1)) */ rate = clk_get_rate(mdp->clk_main); - clk_div = div_u64(rate * state->period, NSEC_PER_SEC) >> + clk_div = mul_u64_u64_div_u64(state->period, rate, NSEC_PER_SEC) >> PWM_PERIOD_BIT_WIDTH; if (clk_div > PWM_CLKDIV_MAX) { if (!mdp->enabled) { @@ -127,11 +127,11 @@ static int mtk_disp_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm, } div = NSEC_PER_SEC * (clk_div + 1); - period = div64_u64(rate * state->period, div); + period = mul_u64_u64_div_u64(state->period, rate, div); if (period > 0) period--; - high_width = div64_u64(rate * state->duty_cycle, div); + high_width = mul_u64_u64_div_u64(state->duty_cycle, rate, div); value = period | (high_width << PWM_HIGH_WIDTH_SHIFT); mtk_disp_pwm_update_bits(mdp, mdp->data->con0, -- 2.25.1 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel