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Subject[PATCH AUTOSEL 5.13 008/114] soundwire: bus: only use CLOCK_STOP_MODE0 and fix confusions
Date
From: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>

[ Upstream commit 345e9f5ca798600e44c0843646621f2804eb99f4 ]

Existing devices and implementations only support the required
CLOCK_STOP_MODE0. All the code related to CLOCK_STOP_MODE1 has not
been tested and is highly questionable, with a clear confusion between
CLOCK_STOP_MODE1 and the simple clock stop state machine.

This patch removes all usages of CLOCK_STOP_MODE1 - which has no
impact on any solution - and fixes the use of the simple clock stop
state machine. The resulting code should be a lot more symmetrical and
easier to maintain.

Note that CLOCK_STOP_MODE1 is not supported in the SoundWire Device
Class specification so it's rather unlikely that we need to re-add
this mode later.

Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Reviewed-by: Guennadi Liakhovetski <guennadi.liakhovetski@linux.intel.com>
Reviewed-by: Rander Wang <rander.wang@intel.com>
Signed-off-by: Bard Liao <yung-chuan.liao@linux.intel.com>
Link: https://lore.kernel.org/r/20210511030048.25622-2-yung-chuan.liao@linux.intel.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/soundwire/bus.c | 100 ++++++++++++++--------------------
include/linux/soundwire/sdw.h | 2 -
2 files changed, 40 insertions(+), 62 deletions(-)

diff --git a/drivers/soundwire/bus.c b/drivers/soundwire/bus.c
index a9e0aa72654d..dc4033b6f2e9 100644
--- a/drivers/soundwire/bus.c
+++ b/drivers/soundwire/bus.c
@@ -821,26 +821,6 @@ static void sdw_modify_slave_status(struct sdw_slave *slave,
mutex_unlock(&bus->bus_lock);
}

-static enum sdw_clk_stop_mode sdw_get_clk_stop_mode(struct sdw_slave *slave)
-{
- enum sdw_clk_stop_mode mode;
-
- /*
- * Query for clock stop mode if Slave implements
- * ops->get_clk_stop_mode, else read from property.
- */
- if (slave->ops && slave->ops->get_clk_stop_mode) {
- mode = slave->ops->get_clk_stop_mode(slave);
- } else {
- if (slave->prop.clk_stop_mode1)
- mode = SDW_CLK_STOP_MODE1;
- else
- mode = SDW_CLK_STOP_MODE0;
- }
-
- return mode;
-}
-
static int sdw_slave_clk_stop_callback(struct sdw_slave *slave,
enum sdw_clk_stop_mode mode,
enum sdw_clk_stop_type type)
@@ -933,7 +913,6 @@ static int sdw_bus_wait_for_clk_prep_deprep(struct sdw_bus *bus, u16 dev_num)
*/
int sdw_bus_prep_clk_stop(struct sdw_bus *bus)
{
- enum sdw_clk_stop_mode slave_mode;
bool simple_clk_stop = true;
struct sdw_slave *slave;
bool is_slave = false;
@@ -955,10 +934,8 @@ int sdw_bus_prep_clk_stop(struct sdw_bus *bus)
/* Identify if Slave(s) are available on Bus */
is_slave = true;

- slave_mode = sdw_get_clk_stop_mode(slave);
- slave->curr_clk_stop_mode = slave_mode;
-
- ret = sdw_slave_clk_stop_callback(slave, slave_mode,
+ ret = sdw_slave_clk_stop_callback(slave,
+ SDW_CLK_STOP_MODE0,
SDW_CLK_PRE_PREPARE);
if (ret < 0) {
dev_err(&slave->dev,
@@ -966,22 +943,29 @@ int sdw_bus_prep_clk_stop(struct sdw_bus *bus)
return ret;
}

- ret = sdw_slave_clk_stop_prepare(slave,
- slave_mode, true);
- if (ret < 0) {
- dev_err(&slave->dev,
- "pre-prepare failed:%d", ret);
- return ret;
- }
-
- if (slave_mode == SDW_CLK_STOP_MODE1)
+ /* Only prepare a Slave device if needed */
+ if (!slave->prop.simple_clk_stop_capable) {
simple_clk_stop = false;
+
+ ret = sdw_slave_clk_stop_prepare(slave,
+ SDW_CLK_STOP_MODE0,
+ true);
+ if (ret < 0) {
+ dev_err(&slave->dev,
+ "pre-prepare failed:%d", ret);
+ return ret;
+ }
+ }
}

/* Skip remaining clock stop preparation if no Slave is attached */
if (!is_slave)
return ret;

+ /*
+ * Don't wait for all Slaves to be ready if they follow the simple
+ * state machine
+ */
if (!simple_clk_stop) {
ret = sdw_bus_wait_for_clk_prep_deprep(bus,
SDW_BROADCAST_DEV_NUM);
@@ -998,17 +982,13 @@ int sdw_bus_prep_clk_stop(struct sdw_bus *bus)
slave->status != SDW_SLAVE_ALERT)
continue;

- slave_mode = slave->curr_clk_stop_mode;
-
- if (slave_mode == SDW_CLK_STOP_MODE1) {
- ret = sdw_slave_clk_stop_callback(slave,
- slave_mode,
- SDW_CLK_POST_PREPARE);
+ ret = sdw_slave_clk_stop_callback(slave,
+ SDW_CLK_STOP_MODE0,
+ SDW_CLK_POST_PREPARE);

- if (ret < 0) {
- dev_err(&slave->dev,
- "post-prepare failed:%d", ret);
- }
+ if (ret < 0) {
+ dev_err(&slave->dev,
+ "post-prepare failed:%d", ret);
}
}

@@ -1059,7 +1039,6 @@ EXPORT_SYMBOL(sdw_bus_clk_stop);
*/
int sdw_bus_exit_clk_stop(struct sdw_bus *bus)
{
- enum sdw_clk_stop_mode mode;
bool simple_clk_stop = true;
struct sdw_slave *slave;
bool is_slave = false;
@@ -1081,31 +1060,33 @@ int sdw_bus_exit_clk_stop(struct sdw_bus *bus)
/* Identify if Slave(s) are available on Bus */
is_slave = true;

- mode = slave->curr_clk_stop_mode;
-
- if (mode == SDW_CLK_STOP_MODE1) {
- simple_clk_stop = false;
- continue;
- }
-
- ret = sdw_slave_clk_stop_callback(slave, mode,
+ ret = sdw_slave_clk_stop_callback(slave, SDW_CLK_STOP_MODE0,
SDW_CLK_PRE_DEPREPARE);
if (ret < 0)
dev_warn(&slave->dev,
"clk stop deprep failed:%d", ret);

- ret = sdw_slave_clk_stop_prepare(slave, mode,
- false);
+ /* Only de-prepare a Slave device if needed */
+ if (!slave->prop.simple_clk_stop_capable) {
+ simple_clk_stop = false;

- if (ret < 0)
- dev_warn(&slave->dev,
- "clk stop deprep failed:%d", ret);
+ ret = sdw_slave_clk_stop_prepare(slave, SDW_CLK_STOP_MODE0,
+ false);
+
+ if (ret < 0)
+ dev_warn(&slave->dev,
+ "clk stop deprep failed:%d", ret);
+ }
}

/* Skip remaining clock stop de-preparation if no Slave is attached */
if (!is_slave)
return 0;

+ /*
+ * Don't wait for all Slaves to be ready if they follow the simple
+ * state machine
+ */
if (!simple_clk_stop)
sdw_bus_wait_for_clk_prep_deprep(bus, SDW_BROADCAST_DEV_NUM);

@@ -1117,8 +1098,7 @@ int sdw_bus_exit_clk_stop(struct sdw_bus *bus)
slave->status != SDW_SLAVE_ALERT)
continue;

- mode = slave->curr_clk_stop_mode;
- sdw_slave_clk_stop_callback(slave, mode,
+ sdw_slave_clk_stop_callback(slave, SDW_CLK_STOP_MODE0,
SDW_CLK_POST_DEPREPARE);
}

diff --git a/include/linux/soundwire/sdw.h b/include/linux/soundwire/sdw.h
index ced07f8fde87..5d93d9949653 100644
--- a/include/linux/soundwire/sdw.h
+++ b/include/linux/soundwire/sdw.h
@@ -624,7 +624,6 @@ struct sdw_slave_ops {
int (*port_prep)(struct sdw_slave *slave,
struct sdw_prepare_ch *prepare_ch,
enum sdw_port_prep_ops pre_ops);
- int (*get_clk_stop_mode)(struct sdw_slave *slave);
int (*clk_stop)(struct sdw_slave *slave,
enum sdw_clk_stop_mode mode,
enum sdw_clk_stop_type type);
@@ -675,7 +674,6 @@ struct sdw_slave {
struct list_head node;
struct completion port_ready[SDW_MAX_PORTS];
unsigned int m_port_map[SDW_MAX_PORTS];
- enum sdw_clk_stop_mode curr_clk_stop_mode;
u16 dev_num;
u16 dev_num_sticky;
bool probed;
--
2.30.2
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