From: Devarsh Thakkar <devarsht@ti.com>
To: <mchehab@kernel.org>, <hverkuil-cisco@xs4all.nl>,
<linux-media@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
<benjamin.gaignard@collabora.com>,
<sebastian.fricke@collabora.com>, <akpm@linux-foundation.org>,
<gregkh@linuxfoundation.org>, <andriy.shevchenko@linux.intel.com>,
<adobriyan@gmail.com>, <jani.nikula@intel.com>,
<p.zabel@pengutronix.de>, <airlied@gmail.com>, <daniel@ffwll.ch>,
<dri-devel@lists.freedesktop.org>
Cc: <laurent.pinchart@ideasonboard.com>, <praneeth@ti.com>,
<nm@ti.com>, <vigneshr@ti.com>, <a-bhatia1@ti.com>,
<j-luthra@ti.com>, <b-brnich@ti.com>, <detheridge@ti.com>,
<p-mantena@ti.com>, <vijayp@ti.com>, <devarsht@ti.com>,
<andrzej.p@collabora.com>, <nicolas@ndufresne.ca>
Subject: [PATCH v7 6/8] math.h Add macros to round to closest specified power of 2
Date: Fri, 10 May 2024 00:09:52 +0530 [thread overview]
Message-ID: <20240509183952.4064331-1-devarsht@ti.com> (raw)
Add macros to round to nearest specified power of 2. Two macros are added :
round_closest_up and round_closest_down which round up to nearest multiple
of 2 with a preference to round up or round down respectively if there are
two possible nearest values to the given number.
This patch is inspired from the Mentor Graphics IPU driver [1] which uses
similar macro locally and which can be updated to use this generic macro
instead along with other drivers having similar requirements.
[1]:
https://elixir.bootlin.com/linux/v6.8.9/source/drivers/gpu/ipu-v3/ipu-image-convert.c#L480
Signed-off-by: Devarsh Thakkar <devarsht@ti.com>
---
V1->V6 (No change, patch introduced in V7)
---
include/linux/math.h | 36 ++++++++++++++++++++++++++++++++++++
1 file changed, 36 insertions(+)
diff --git a/include/linux/math.h b/include/linux/math.h
index dd4152711de7..82ee3265c910 100644
--- a/include/linux/math.h
+++ b/include/linux/math.h
@@ -34,6 +34,42 @@
*/
#define round_down(x, y) ((x) & ~__round_mask(x, y))
+/**
+ * round_closest_up - round to nearest specified power of 2 with preference
+ * to rounding up
+ * @x: the value to round
+ * @y: multiple to round to (must be a power of 2)
+ *
+ * Rounds @x to nearest multiple of @y (which must be a power of 2).
+ * The rounded value can be greater than or less than @x depending
+ * upon it's nearness to @x. If there are two nearest possible values,
+ * then preference will be given to the greater value.
+ *
+ * Examples :
+ * round_closest_up(17, 4) = 16
+ * round_closest_up(15, 4) = 16
+ * round_closest_up(14, 4) = 16
+ */
+#define round_closest_up(x, y) round_down((x) + (y) / 2, (y))
+
+/**
+ * round_closest_down - round to nearest specified power of 2 with preference
+ * to rounding down
+ * @x: the value to round
+ * @y: multiple to round down to (must be a power of 2)
+ *
+ * Rounds @x to nearest multiple of @y (which must be a power of 2).
+ * The rounded value can be greater than or less than @x depending
+ * upon it's nearness to @x. If there are two nearest possible values,
+ * then preference will be given to the lesser value.
+ *
+ * Examples :
+ * round_closest_down(17, 4) = 16
+ * round_closest_down(15, 4) = 16
+ * round_closest_down(14, 4) = 12
+ */
+#define round_closest_down(x, y) round_up((x) - (y) / 2, (y))
+
#define DIV_ROUND_UP __KERNEL_DIV_ROUND_UP
#define DIV_ROUND_DOWN_ULL(ll, d) \
--
2.39.1
next reply other threads:[~2024-05-09 18:40 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-05-09 18:39 Devarsh Thakkar [this message]
2024-05-10 15:01 ` [PATCH v7 6/8] math.h Add macros to round to closest specified power of 2 Andy Shevchenko
2024-05-10 15:15 ` Jani Nikula
2024-05-10 15:28 ` Andy Shevchenko
2024-05-11 17:41 ` Devarsh Thakkar
2024-05-13 8:59 ` Andy Shevchenko
2024-05-13 11:25 ` Devarsh Thakkar
2024-05-13 12:25 ` Andy Shevchenko
2024-05-13 13:04 ` Devarsh Thakkar
2024-05-13 13:14 ` Andy Shevchenko
2024-05-11 17:26 ` Devarsh Thakkar
2024-05-12 4:46 ` Alexey Dobriyan
2024-05-13 8:55 ` Andy Shevchenko
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