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Date: Tue, 13 Feb 2024 21:05:01 +0300
From: Dan Carpenter <dan.carpenter@linaro.org>
To: Philipp Stanner <pstanner@redhat.com>
Cc: Laurentiu Palcu <laurentiu.palcu@oss.nxp.com>,
	Lucas Stach <l.stach@pengutronix.de>,
	Maarten Lankhorst <maarten.lankhorst@linux.intel.com>,
	Maxime Ripard <mripard@kernel.org>,
	Thomas Zimmermann <tzimmermann@suse.de>,
	David Airlie <airlied@gmail.com>, Daniel Vetter <daniel@ffwll.ch>,
	Shawn Guo <shawnguo@kernel.org>,
	Sascha Hauer <s.hauer@pengutronix.de>,
	Pengutronix Kernel Team <kernel@pengutronix.de>,
	Fabio Estevam <festevam@gmail.com>,
	NXP Linux Team <linux-imx@nxp.com>, dri-devel@lists.freedesktop.org,
	linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org,
	kernel-janitors@vger.kernel.org
Subject: [PATCH] drm/imx/dcss: fix resource size calculation
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The resource is inclusive of the ->start and ->end addresses so this
calculation is not correct.  It should be "res->end - res->start + 1".
Use the resource_size() to do the calculation.

Fixes: 90393c9b5408 ("drm/imx/dcss: request memory region")
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
---
From static analysis.  Not tested.

 drivers/gpu/drm/imx/dcss/dcss-dev.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/imx/dcss/dcss-dev.c b/drivers/gpu/drm/imx/dcss/dcss-dev.c
index 597e9b7bd4bf..7fd0c4c14205 100644
--- a/drivers/gpu/drm/imx/dcss/dcss-dev.c
+++ b/drivers/gpu/drm/imx/dcss/dcss-dev.c
@@ -167,7 +167,6 @@ struct dcss_dev *dcss_dev_create(struct device *dev, bool hdmi_output)
 	struct resource *res;
 	struct dcss_dev *dcss;
 	const struct dcss_type_data *devtype;
-	resource_size_t res_len;
 
 	devtype = of_device_get_match_data(dev);
 	if (!devtype) {
@@ -181,8 +180,7 @@ struct dcss_dev *dcss_dev_create(struct device *dev, bool hdmi_output)
 		return ERR_PTR(-EINVAL);
 	}
 
-	res_len = res->end - res->start;
-	if (!devm_request_mem_region(dev, res->start, res_len, "dcss")) {
+	if (!devm_request_mem_region(dev, res->start, resource_size(res), "dcss")) {
 		dev_err(dev, "cannot request memory region\n");
 		return ERR_PTR(-EBUSY);
 	}
-- 
2.43.0