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From: Richard Fitzgerald <rf@opensource.cirrus.com>
To: <vkoul@kernel.org>, <yung-chuan.liao@linux.intel.com>,
	<pierre-louis.bossart@linux.intel.com>, <sanyog.r.kale@intel.com>
Cc: <alsa-devel@alsa-project.org>, <linux-kernel@vger.kernel.org>,
	<patches@opensource.cirrus.com>,
	Richard Fitzgerald <rf@opensource.cirrus.com>
Subject: [PATCH 2/2] soundwire: bandwidth allocation: Use hweight32() to calculate set bits
Date: Thu, 2 Feb 2023 15:42:12 +0000	[thread overview]
Message-ID: <20230202154212.1098736-3-rf@opensource.cirrus.com> (raw)
In-Reply-To: <20230202154212.1098736-1-rf@opensource.cirrus.com>

Replace the call to sdw_ch_mask_to_ch() with a call to hweight32().

sdw_ch_mask_to_ch() is counting the number of set bits. The hweight()
family of functions already do this, and they have an advantage of
using a bit-counting instruction if it is available on the target CPU.

Signed-off-by: Richard Fitzgerald <rf@opensource.cirrus.com>
---
 drivers/soundwire/bus.h                          | 11 -----------
 drivers/soundwire/generic_bandwidth_allocation.c |  3 ++-
 2 files changed, 2 insertions(+), 12 deletions(-)

diff --git a/drivers/soundwire/bus.h b/drivers/soundwire/bus.h
index 28bedc919b78..4ce8d708a39c 100644
--- a/drivers/soundwire/bus.h
+++ b/drivers/soundwire/bus.h
@@ -159,17 +159,6 @@ int sdw_transfer_defer(struct sdw_bus *bus, struct sdw_msg *msg,
 int sdw_fill_msg(struct sdw_msg *msg, struct sdw_slave *slave,
 		 u32 addr, size_t count, u16 dev_num, u8 flags, u8 *buf);
 
-/* Retrieve and return channel count from channel mask */
-static inline int sdw_ch_mask_to_ch(unsigned int ch_mask)
-{
-	int c = 0;
-
-	for (c = 0; ch_mask; ch_mask >>= 1)
-		c += ch_mask & 1;
-
-	return c;
-}
-
 /* Fill transport parameter data structure */
 static inline void sdw_fill_xport_params(struct sdw_transport_params *params,
 					 int port_num, bool grp_ctrl_valid,
diff --git a/drivers/soundwire/generic_bandwidth_allocation.c b/drivers/soundwire/generic_bandwidth_allocation.c
index f7c66083a4dd..ea3e8ef408e4 100644
--- a/drivers/soundwire/generic_bandwidth_allocation.c
+++ b/drivers/soundwire/generic_bandwidth_allocation.c
@@ -6,6 +6,7 @@
  *
  */
 
+#include <linux/bitops.h>
 #include <linux/device.h>
 #include <linux/module.h>
 #include <linux/mod_devicetable.h>
@@ -54,7 +55,7 @@ static void sdw_compute_slave_ports(struct sdw_master_runtime *m_rt,
 		slave_total_ch = 0;
 
 		list_for_each_entry(p_rt, &s_rt->port_list, port_node) {
-			ch = sdw_ch_mask_to_ch(p_rt->ch_mask);
+			ch = hweight32(p_rt->ch_mask);
 
 			sdw_fill_xport_params(&p_rt->transport_params,
 					      p_rt->num, false,
-- 
2.30.2


      parent reply	other threads:[~2023-02-02 15:43 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-02-02 15:42 [PATCH 0/2] soundwire: bus: Prevent infinite loop in sdw_ch_mask_to_ch() Richard Fitzgerald
2023-02-02 15:42 ` [PATCH 1/2] " Richard Fitzgerald
2023-02-03 14:35   ` Pierre-Louis Bossart
2023-02-03 16:18     ` Richard Fitzgerald
2023-03-15 13:43       ` Vinod Koul
2023-02-02 15:42 ` Richard Fitzgerald [this message]

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