soundwire: bandwidth allocation: Use hweight32() to calculate set bits

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.
This also fixes a potential infinite loop bug in the implementation of
sdw_ch_mask_to_ch().

Signed-off-by: Richard Fitzgerald <rf@opensource.cirrus.com>
Link: https://lore.kernel.org/r/20230315145051.2299822-1-rf@opensource.cirrus.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

diff --git a/drivers/soundwire/bus.h b/drivers/soundwire/bus.h
index 96927a14379689b2df116d50a8a1e48b7e59962f..f0a59e5df631cea3f4d779e06b5f28db31fb70dd 100644 (file)
--- a/drivers/soundwire/bus.h
+++ b/drivers/soundwire/bus.h
@@ -158,17 +158,6 @@ 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(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 f7c66083a4dd5e9e2f4a3f896bb4d0f5e9be1bc0..ea3e8ef408e476f9e823c3e7642fe1eb0233d383 100644 (file)
--- 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,