[PATCH v2 00/17] SoundWire: cadence: add clock stop and fix programming sequences

[PATCH v2 00/17] SoundWire: cadence: add clock stop and fix programming sequences

[Pierre-Louis Bossart]

To make progress with SoundWire support, this patchset provides the
missing support for clock stop modes, and revisits all Cadence Master
register settings. The current code is for some reason not aligned
with internal documentation and hardware recommended flows,
specifically for multi-link operation.

Changes since v1:
Removed log in is_clock_stop(), use the helper in the main
clock_stop() and change return 1->return 0.
Fixed squash issue in patch5 to remove irrelevant udelay() change
Added Patch17 to clear FIFOs and avoid pop noise

Pierre-Louis Bossart (12):
  soundwire: cadence: s/update_config/config_update
  soundwire: cadence: handle error cases with CONFIG_UPDATE
  soundwire: cadence: mask Slave interrupt before stopping clock
  soundwire: cadence: merge routines to clear/set bits
  soundwire: cadence: move clock/SSP related inits to dedicated function
  soundwire: cadence: make SSP interval programmable
  soundwire: cadence: reorder MCP_CONFIG settings
  soundwire: cadence: enable NORMAL operation in cdns_init()
  soundwire: cadence: remove PREQ_DELAY assignment
  soundwire: cadence: remove automatic command retries
  soundwire: cadence: commit changes in the exit_reset() sequence
  soundwire: cadence: multi-link support

Rander Wang (4):
  soundwire: cadence: simplifiy cdns_init()
  soundwire: cadence: add interface to check clock status
  soundwire: cadence: add clock_stop/restart routines
  soundwire: cadence: fix a io timeout issue in S3 test

randerwang (1):
  soundwire: cadence: clear FIFO to avoid pop noise issue on playback
    start

 drivers/soundwire/cadence_master.c | 282 ++++++++++++++++++++++++-----
 drivers/soundwire/cadence_master.h |   9 +-
 drivers/soundwire/intel.c          |   2 +-
 3 files changed, 249 insertions(+), 44 deletions(-)


base-commit: 0b43fef979b4664d51a09dc7e0c430ebb2d18267
-- 
2.20.1

[PATCH v2 01/17] soundwire: cadence: s/update_config/config_update

[Pierre-Louis Bossart]

Somehow we inverted the two, align with register definition to avoid
further confusion.

Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
---
 drivers/soundwire/cadence_master.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/soundwire/cadence_master.c b/drivers/soundwire/cadence_master.c
index 9bec270d0fa4..a1a889d1d7dc 100644
--- a/drivers/soundwire/cadence_master.c
+++ b/drivers/soundwire/cadence_master.c
@@ -235,7 +235,7 @@ static int cdns_clear_bit(struct sdw_cdns *cdns, int offset, u32 value)
  * all changes to the MCP_CONFIG, MCP_CONTROL, MCP_CMDCTRL and MCP_PHYCTRL
  * need to be confirmed with a write to MCP_CONFIG_UPDATE
  */
-static int cdns_update_config(struct sdw_cdns *cdns)
+static int cdns_config_update(struct sdw_cdns *cdns)
 {
 	int ret;
 
@@ -838,7 +838,7 @@ int sdw_cdns_exit_reset(struct sdw_cdns *cdns)
 		     CDNS_MCP_CONFIG_OP_NORMAL);
 
 	/* commit changes */
-	return cdns_update_config(cdns);
+	return cdns_config_update(cdns);
 }
 EXPORT_SYMBOL(sdw_cdns_exit_reset);
 
@@ -1084,7 +1084,7 @@ int sdw_cdns_init(struct sdw_cdns *cdns, bool clock_stop_exit)
 	cdns_writel(cdns, CDNS_MCP_CONFIG, val);
 
 	/* commit changes */
-	return cdns_update_config(cdns);
+	return cdns_config_update(cdns);
 }
 EXPORT_SYMBOL(sdw_cdns_init);
 
-- 
2.20.1

[PATCH v2 02/17] soundwire: cadence: simplifiy cdns_init()

[Pierre-Louis Bossart]

From: Rander Wang <rander.wang@intel.com>

There is no need for the clock_stop_exit argument with the latest
implementation

Signed-off-by: Rander Wang <rander.wang@intel.com>
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
---
 drivers/soundwire/cadence_master.c | 12 +-----------
 drivers/soundwire/cadence_master.h |  2 +-
 drivers/soundwire/intel.c          |  2 +-
 3 files changed, 3 insertions(+), 13 deletions(-)

diff --git a/drivers/soundwire/cadence_master.c b/drivers/soundwire/cadence_master.c
index a1a889d1d7dc..941809ea00a8 100644
--- a/drivers/soundwire/cadence_master.c
+++ b/drivers/soundwire/cadence_master.c
@@ -1018,22 +1018,12 @@ static u32 cdns_set_initial_frame_shape(int n_rows, int n_cols)
  * sdw_cdns_init() - Cadence initialization
  * @cdns: Cadence instance
  */
-int sdw_cdns_init(struct sdw_cdns *cdns, bool clock_stop_exit)
+int sdw_cdns_init(struct sdw_cdns *cdns)
 {
 	struct sdw_bus *bus = &cdns->bus;
 	struct sdw_master_prop *prop = &bus->prop;
 	u32 val;
 	int divider;
-	int ret;
-
-	if (clock_stop_exit) {
-		ret = cdns_clear_bit(cdns, CDNS_MCP_CONTROL,
-				     CDNS_MCP_CONTROL_CLK_STOP_CLR);
-		if (ret < 0) {
-			dev_err(cdns->dev, "Couldn't exit from clock stop\n");
-			return ret;
-		}
-	}
 
 	/* Set clock divider */
 	divider	= (prop->mclk_freq / prop->max_clk_freq) - 1;
diff --git a/drivers/soundwire/cadence_master.h b/drivers/soundwire/cadence_master.h
index 2de1b2493ffc..44e802bba702 100644
--- a/drivers/soundwire/cadence_master.h
+++ b/drivers/soundwire/cadence_master.h
@@ -138,7 +138,7 @@ extern struct sdw_master_ops sdw_cdns_master_ops;
 irqreturn_t sdw_cdns_irq(int irq, void *dev_id);
 irqreturn_t sdw_cdns_thread(int irq, void *dev_id);
 
-int sdw_cdns_init(struct sdw_cdns *cdns, bool clock_stop_exit);
+int sdw_cdns_init(struct sdw_cdns *cdns);
 int sdw_cdns_pdi_init(struct sdw_cdns *cdns,
 		      struct sdw_cdns_stream_config config);
 int sdw_cdns_exit_reset(struct sdw_cdns *cdns);
diff --git a/drivers/soundwire/intel.c b/drivers/soundwire/intel.c
index a327669c757b..3c83e76c6bf9 100644
--- a/drivers/soundwire/intel.c
+++ b/drivers/soundwire/intel.c
@@ -1077,7 +1077,7 @@ static int intel_init(struct sdw_intel *sdw)
 	intel_link_power_up(sdw);
 	intel_shim_init(sdw);
 
-	return sdw_cdns_init(&sdw->cdns, false);
+	return sdw_cdns_init(&sdw->cdns);
 }
 
 /*
-- 
2.20.1

[PATCH v2 03/17] soundwire: cadence: add interface to check clock status

[Pierre-Louis Bossart]

From: Rander Wang <rander.wang@intel.com>

If master is in clock stop state, driver can't modify registers
in master except the registers for clock stop setting.

Signed-off-by: Rander Wang <rander.wang@intel.com>
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
---
 drivers/soundwire/cadence_master.c | 11 +++++++++++
 drivers/soundwire/cadence_master.h |  2 ++
 2 files changed, 13 insertions(+)

diff --git a/drivers/soundwire/cadence_master.c b/drivers/soundwire/cadence_master.c
index 941809ea00a8..1bfdc1d4fcb1 100644
--- a/drivers/soundwire/cadence_master.c
+++ b/drivers/soundwire/cadence_master.c
@@ -1207,6 +1207,17 @@ static const struct sdw_master_port_ops cdns_port_ops = {
 	.dpn_port_enable_ch = cdns_port_enable,
 };
 
+/**
+ * sdw_cdns_is_clock_stop: Check clock status
+ *
+ * @cdns: Cadence instance
+ */
+bool sdw_cdns_is_clock_stop(struct sdw_cdns *cdns)
+{
+	return !!(cdns_readl(cdns, CDNS_MCP_STAT) & CDNS_MCP_STAT_CLK_STOP);
+}
+EXPORT_SYMBOL(sdw_cdns_is_clock_stop);
+
 /**
  * sdw_cdns_probe() - Cadence probe routine
  * @cdns: Cadence instance
diff --git a/drivers/soundwire/cadence_master.h b/drivers/soundwire/cadence_master.h
index 44e802bba702..691faa386889 100644
--- a/drivers/soundwire/cadence_master.h
+++ b/drivers/soundwire/cadence_master.h
@@ -144,6 +144,8 @@ int sdw_cdns_pdi_init(struct sdw_cdns *cdns,
 int sdw_cdns_exit_reset(struct sdw_cdns *cdns);
 int sdw_cdns_enable_interrupt(struct sdw_cdns *cdns, bool state);
 
+bool sdw_cdns_is_clock_stop(struct sdw_cdns *cdns);
+
 #ifdef CONFIG_DEBUG_FS
 void sdw_cdns_debugfs_init(struct sdw_cdns *cdns, struct dentry *root);
 #endif
-- 
2.20.1

[PATCH v2 04/17] soundwire: cadence: handle error cases with CONFIG_UPDATE

[Pierre-Louis Bossart]

config_update() may time out or cannot be use in ClockStopMode

Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
---
 drivers/soundwire/cadence_master.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/soundwire/cadence_master.c b/drivers/soundwire/cadence_master.c
index 1bfdc1d4fcb1..d7f01d39767b 100644
--- a/drivers/soundwire/cadence_master.c
+++ b/drivers/soundwire/cadence_master.c
@@ -239,6 +239,11 @@ static int cdns_config_update(struct sdw_cdns *cdns)
 {
 	int ret;
 
+	if (sdw_cdns_is_clock_stop(cdns)) {
+		dev_err(cdns->dev, "Cannot program MCP_CONFIG_UPDATE in ClockStopMode\n");
+		return -EINVAL;
+	}
+
 	ret = cdns_clear_bit(cdns, CDNS_MCP_CONFIG_UPDATE,
 			     CDNS_MCP_CONFIG_UPDATE_BIT);
 	if (ret < 0)
-- 
2.20.1

[PATCH v2 05/17] soundwire: cadence: add clock_stop/restart routines

[Pierre-Louis Bossart]

From: Rander Wang <rander.wang@intel.com>

Add support for clock stop and restart, with two configuration
parameters:

1) when entering the ClockStop mode, Slave-initiated wakes can be
prevented.

2) When exiting the ClockStop mode, the caller can request a Bus Reset
(either if all Slaves were configured in ClockStopMode1 or the Master
IP lost context and enumeration is required)

The code handles the case where no Slaves are present by configuring
the IP to treat COMMAND_IGNORED as success.

The exit_reset part can be dealt with in the caller, along with the
required syncArm/syncGo sequence in multi-link mode.

Signed-off-by: Rander Wang <rander.wang@intel.com>
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
---
 drivers/soundwire/cadence_master.c | 157 +++++++++++++++++++++++++++++
 drivers/soundwire/cadence_master.h |   2 +
 2 files changed, 159 insertions(+)

diff --git a/drivers/soundwire/cadence_master.c b/drivers/soundwire/cadence_master.c
index d7f01d39767b..dc29556eaf94 100644
--- a/drivers/soundwire/cadence_master.c
+++ b/drivers/soundwire/cadence_master.c
@@ -231,6 +231,24 @@ static int cdns_clear_bit(struct sdw_cdns *cdns, int offset, u32 value)
 	return -EAGAIN;
 }
 
+static int cdns_set_wait(struct sdw_cdns *cdns, int offset, u32 mask, u32 value)
+{
+	int timeout = 10;
+	u32 reg_read;
+
+	/* Wait for bit to be set */
+	do {
+		reg_read = readl(cdns->registers + offset);
+		if ((reg_read & mask) == value)
+			return 0;
+
+		timeout--;
+		usleep_range(50, 100);
+	} while (timeout != 0);
+
+	return -ETIMEDOUT;
+}
+
 /*
  * all changes to the MCP_CONFIG, MCP_CONTROL, MCP_CMDCTRL and MCP_PHYCTRL
  * need to be confirmed with a write to MCP_CONFIG_UPDATE
@@ -1223,6 +1241,145 @@ bool sdw_cdns_is_clock_stop(struct sdw_cdns *cdns)
 }
 EXPORT_SYMBOL(sdw_cdns_is_clock_stop);
 
+/**
+ * sdw_cdns_clock_stop: Cadence clock stop configuration routine
+ *
+ * @cdns: Cadence instance
+ * @block_wake: prevent wakes if required by the platform
+ */
+int sdw_cdns_clock_stop(struct sdw_cdns *cdns, bool block_wake)
+{
+	bool slave_present = false;
+	struct sdw_slave *slave;
+	int ret;
+
+	/* Check suspend status */
+	if (sdw_cdns_is_clock_stop(cdns)) {
+		dev_dbg(cdns->dev, "Clock is already stopped\n");
+		return 0;
+	}
+
+	/*
+	 * For specific platforms, it is required to be able to put
+	 * master into a state in which it ignores wake-up trials
+	 * in clock stop state
+	 */
+	if (block_wake)
+		cdns_updatel(cdns, CDNS_MCP_CONTROL,
+			     CDNS_MCP_CONTROL_BLOCK_WAKEUP,
+			     CDNS_MCP_CONTROL_BLOCK_WAKEUP);
+
+	list_for_each_entry(slave, &cdns->bus.slaves, node) {
+		if (slave->status == SDW_SLAVE_ATTACHED ||
+		    slave->status == SDW_SLAVE_ALERT) {
+			slave_present = true;
+			break;
+		}
+	}
+
+	/*
+	 * This CMD_ACCEPT should be used when there are no devices
+	 * attached on the link when entering clock stop mode. If this is
+	 * not set and there is a broadcast write then the command ignored
+	 * will be treated as a failure
+	 */
+	if (!slave_present)
+		cdns_updatel(cdns, CDNS_MCP_CONTROL,
+			     CDNS_MCP_CONTROL_CMD_ACCEPT,
+			     CDNS_MCP_CONTROL_CMD_ACCEPT);
+	else
+		cdns_updatel(cdns, CDNS_MCP_CONTROL,
+			     CDNS_MCP_CONTROL_CMD_ACCEPT, 0);
+
+	/* commit changes */
+	ret = cdns_config_update(cdns);
+	if (ret < 0) {
+		dev_err(cdns->dev, "%s: config_update failed\n", __func__);
+		return ret;
+	}
+
+	/* Prepare slaves for clock stop */
+	ret = sdw_bus_prep_clk_stop(&cdns->bus);
+	if (ret < 0) {
+		dev_err(cdns->dev, "prepare clock stop failed %d", ret);
+		return ret;
+	}
+
+	/*
+	 * Enter clock stop mode and only report errors if there are
+	 * Slave devices present (ALERT or ATTACHED)
+	 */
+	ret = sdw_bus_clk_stop(&cdns->bus);
+	if (ret < 0 && slave_present && ret != -ENODATA) {
+		dev_err(cdns->dev, "bus clock stop failed %d", ret);
+		return ret;
+	}
+
+	ret = cdns_set_wait(cdns, CDNS_MCP_STAT,
+			    CDNS_MCP_STAT_CLK_STOP,
+			    CDNS_MCP_STAT_CLK_STOP);
+	if (ret < 0)
+		dev_err(cdns->dev, "Clock stop failed %d\n", ret);
+
+	return ret;
+}
+EXPORT_SYMBOL(sdw_cdns_clock_stop);
+
+/**
+ * sdw_cdns_clock_restart: Cadence PM clock restart configuration routine
+ *
+ * @cdns: Cadence instance
+ * @bus_reset: context may be lost while in low power modes and the bus
+ * may require a Severe Reset and re-enumeration after a wake.
+ */
+int sdw_cdns_clock_restart(struct sdw_cdns *cdns, bool bus_reset)
+{
+	int ret;
+
+	ret = cdns_clear_bit(cdns, CDNS_MCP_CONTROL,
+			     CDNS_MCP_CONTROL_CLK_STOP_CLR);
+	if (ret < 0) {
+		dev_err(cdns->dev, "Couldn't exit from clock stop\n");
+		return ret;
+	}
+
+	ret = cdns_set_wait(cdns, CDNS_MCP_STAT, CDNS_MCP_STAT_CLK_STOP, 0);
+	if (ret < 0) {
+		dev_err(cdns->dev, "clock stop exit failed %d\n", ret);
+		return ret;
+	}
+
+	cdns_updatel(cdns, CDNS_MCP_CONTROL,
+		     CDNS_MCP_CONTROL_BLOCK_WAKEUP, 0);
+
+	/*
+	 * clear CMD_ACCEPT so that the command ignored
+	 * will be treated as a failure during a broadcast write
+	 */
+	cdns_updatel(cdns, CDNS_MCP_CONTROL, CDNS_MCP_CONTROL_CMD_ACCEPT, 0);
+
+	if (!bus_reset) {
+
+		/* enable bus operations with clock and data */
+		cdns_updatel(cdns, CDNS_MCP_CONFIG,
+			     CDNS_MCP_CONFIG_OP,
+			     CDNS_MCP_CONFIG_OP_NORMAL);
+
+		ret = cdns_config_update(cdns);
+		if (ret < 0) {
+			dev_err(cdns->dev, "%s: config_update failed\n", __func__);
+			return ret;
+		}
+
+		ret = sdw_bus_exit_clk_stop(&cdns->bus);
+		if (ret < 0)
+			dev_err(cdns->dev, "bus failed to exit clock stop %d\n", ret);
+	}
+
+	return ret;
+}
+EXPORT_SYMBOL(sdw_cdns_clock_restart);
+
 /**
  * sdw_cdns_probe() - Cadence probe routine
  * @cdns: Cadence instance
diff --git a/drivers/soundwire/cadence_master.h b/drivers/soundwire/cadence_master.h
index 691faa386889..e8fa5c7e09f4 100644
--- a/drivers/soundwire/cadence_master.h
+++ b/drivers/soundwire/cadence_master.h
@@ -145,6 +145,8 @@ int sdw_cdns_exit_reset(struct sdw_cdns *cdns);
 int sdw_cdns_enable_interrupt(struct sdw_cdns *cdns, bool state);
 
 bool sdw_cdns_is_clock_stop(struct sdw_cdns *cdns);
+int sdw_cdns_clock_stop(struct sdw_cdns *cdns, bool block_wake);
+int sdw_cdns_clock_restart(struct sdw_cdns *cdns, bool bus_reset);
 
 #ifdef CONFIG_DEBUG_FS
 void sdw_cdns_debugfs_init(struct sdw_cdns *cdns, struct dentry *root);
-- 
2.20.1

[PATCH v2 06/17] soundwire: cadence: fix a io timeout issue in S3 test

[Pierre-Louis Bossart]

From: Rander Wang <rander.wang@intel.com>

After system resumes from S3, io timeout occurs when setting one
unused master on Comet Lake platform. In this case, the master is
reset to default state, and FIFOLEVEL is reset to default value,
but msg_count used for tracing FIFOLEVEL is still with old value,
so FIFOLEVEL will not be set if a new msg FIFO usage is equal to
the old msg_count.

This patch updates msg_count to default value of FIFOLEVEL when
resetting master.

Tested on Comet Lake platform.

Signed-off-by: Rander Wang <rander.wang@intel.com>
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
---
 drivers/soundwire/cadence_master.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/soundwire/cadence_master.c b/drivers/soundwire/cadence_master.c
index dc29556eaf94..37e16199933c 100644
--- a/drivers/soundwire/cadence_master.c
+++ b/drivers/soundwire/cadence_master.c
@@ -1068,6 +1068,9 @@ int sdw_cdns_init(struct sdw_cdns *cdns)
 	cdns_writel(cdns, CDNS_MCP_SSP_CTRL0, CDNS_DEFAULT_SSP_INTERVAL);
 	cdns_writel(cdns, CDNS_MCP_SSP_CTRL1, CDNS_DEFAULT_SSP_INTERVAL);
 
+	/* reset msg_count to default value of FIFOLEVEL */
+	cdns->msg_count = cdns_readl(cdns, CDNS_MCP_FIFOLEVEL);
+
 	/* flush command FIFOs */
 	cdns_updatel(cdns, CDNS_MCP_CONTROL, CDNS_MCP_CONTROL_CMD_RST,
 		     CDNS_MCP_CONTROL_CMD_RST);
-- 
2.20.1

[PATCH v2 07/17] soundwire: cadence: mask Slave interrupt before stopping clock

[Pierre-Louis Bossart]

Intel QA reported a very rare case, possibly hardware-dependent, where
a Slave can become UNATTACHED during a clock stop sequence, which
leads to timeouts and failed suspend sequences.

This patch suppresses the handling of all Slave events while this
transition happens. The two cases that matter are:

a) alerts: if the Slave wants to signal an alert condition, it can do
so using the in-band wake, so there's almost no impact with this
patch.

b) sync loss or imp-def reset: in those cases, bringing back the Slave
to functional state requires a complete re-enumeration. It's better to
just ignore this case and restart cleanly, rather than attempt a
'clean' suspend.

Validation results show the timeouts no longer visible with this patch.

GitHub issue: https://github.com/thesofproject/linux/issues/1678
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
---
 drivers/soundwire/cadence_master.c | 28 ++++++++++++++++++++++++++++
 1 file changed, 28 insertions(+)

diff --git a/drivers/soundwire/cadence_master.c b/drivers/soundwire/cadence_master.c
index 37e16199933c..613c63359413 100644
--- a/drivers/soundwire/cadence_master.c
+++ b/drivers/soundwire/cadence_master.c
@@ -865,6 +865,24 @@ int sdw_cdns_exit_reset(struct sdw_cdns *cdns)
 }
 EXPORT_SYMBOL(sdw_cdns_exit_reset);
 
+/**
+ * sdw_cdns_enable_slave_interrupt() - Enable SDW slave interrupts
+ * @cdns: Cadence instance
+ * @state: boolean for true/false
+ */
+static void cdns_enable_slave_interrupts(struct sdw_cdns *cdns, bool state)
+{
+	u32 mask;
+
+	mask = cdns_readl(cdns, CDNS_MCP_INTMASK);
+	if (state)
+		mask |= CDNS_MCP_INT_SLAVE_MASK;
+	else
+		mask &= ~CDNS_MCP_INT_SLAVE_MASK;
+
+	cdns_writel(cdns, CDNS_MCP_INTMASK, mask);
+}
+
 /**
  * sdw_cdns_enable_interrupt() - Enable SDW interrupts
  * @cdns: Cadence instance
@@ -1262,6 +1280,13 @@ int sdw_cdns_clock_stop(struct sdw_cdns *cdns, bool block_wake)
 		return 0;
 	}
 
+	/*
+	 * Before entering clock stop we mask the Slave
+	 * interrupts. This helps avoid having to deal with e.g. a
+	 * Slave becoming UNATTACHED while the clock is being stopped
+	 */
+	cdns_enable_slave_interrupts(cdns, false);
+
 	/*
 	 * For specific platforms, it is required to be able to put
 	 * master into a state in which it ignores wake-up trials
@@ -1339,6 +1364,9 @@ int sdw_cdns_clock_restart(struct sdw_cdns *cdns, bool bus_reset)
 {
 	int ret;
 
+	/* unmask Slave interrupts that were masked when stopping the clock */
+	cdns_enable_slave_interrupts(cdns, true);
+
 	ret = cdns_clear_bit(cdns, CDNS_MCP_CONTROL,
 			     CDNS_MCP_CONTROL_CLK_STOP_CLR);
 	if (ret < 0) {
-- 
2.20.1

[PATCH v2 08/17] soundwire: cadence: merge routines to clear/set bits

[Pierre-Louis Bossart]

Use a single loop to wait for hardware to set/clear fields.

Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
---
 drivers/soundwire/cadence_master.c | 28 ++++++++--------------------
 1 file changed, 8 insertions(+), 20 deletions(-)

diff --git a/drivers/soundwire/cadence_master.c b/drivers/soundwire/cadence_master.c
index 613c63359413..7d9fc2c645e3 100644
--- a/drivers/soundwire/cadence_master.c
+++ b/drivers/soundwire/cadence_master.c
@@ -211,26 +211,6 @@ static inline void cdns_updatel(struct sdw_cdns *cdns,
 	cdns_writel(cdns, offset, tmp);
 }
 
-static int cdns_clear_bit(struct sdw_cdns *cdns, int offset, u32 value)
-{
-	int timeout = 10;
-	u32 reg_read;
-
-	writel(value, cdns->registers + offset);
-
-	/* Wait for bit to be self cleared */
-	do {
-		reg_read = readl(cdns->registers + offset);
-		if ((reg_read & value) == 0)
-			return 0;
-
-		timeout--;
-		udelay(50);
-	} while (timeout != 0);
-
-	return -EAGAIN;
-}
-
 static int cdns_set_wait(struct sdw_cdns *cdns, int offset, u32 mask, u32 value)
 {
 	int timeout = 10;
@@ -249,6 +229,14 @@ static int cdns_set_wait(struct sdw_cdns *cdns, int offset, u32 mask, u32 value)
 	return -ETIMEDOUT;
 }
 
+static int cdns_clear_bit(struct sdw_cdns *cdns, int offset, u32 value)
+{
+	writel(value, cdns->registers + offset);
+
+	/* Wait for bit to be self cleared */
+	return cdns_set_wait(cdns, offset, value, 0);
+}
+
 /*
  * all changes to the MCP_CONFIG, MCP_CONTROL, MCP_CMDCTRL and MCP_PHYCTRL
  * need to be confirmed with a write to MCP_CONFIG_UPDATE
-- 
2.20.1

[PATCH v2 09/17] soundwire: cadence: move clock/SSP related inits to dedicated function

[Pierre-Louis Bossart]

This helps isolate code and align with recommended programming flows

Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
---
 drivers/soundwire/cadence_master.c | 18 +++++++++++++-----
 1 file changed, 13 insertions(+), 5 deletions(-)

diff --git a/drivers/soundwire/cadence_master.c b/drivers/soundwire/cadence_master.c
index 7d9fc2c645e3..fb697ff665f5 100644
--- a/drivers/soundwire/cadence_master.c
+++ b/drivers/soundwire/cadence_master.c
@@ -1043,11 +1043,7 @@ static u32 cdns_set_initial_frame_shape(int n_rows, int n_cols)
 	return val;
 }
 
-/**
- * sdw_cdns_init() - Cadence initialization
- * @cdns: Cadence instance
- */
-int sdw_cdns_init(struct sdw_cdns *cdns)
+static void cdns_init_clock_ctrl(struct sdw_cdns *cdns)
 {
 	struct sdw_bus *bus = &cdns->bus;
 	struct sdw_master_prop *prop = &bus->prop;
@@ -1073,6 +1069,18 @@ int sdw_cdns_init(struct sdw_cdns *cdns)
 	/* Set SSP interval to default value */
 	cdns_writel(cdns, CDNS_MCP_SSP_CTRL0, CDNS_DEFAULT_SSP_INTERVAL);
 	cdns_writel(cdns, CDNS_MCP_SSP_CTRL1, CDNS_DEFAULT_SSP_INTERVAL);
+}
+
+/**
+ * sdw_cdns_init() - Cadence initialization
+ * @cdns: Cadence instance
+ */
+int sdw_cdns_init(struct sdw_cdns *cdns)
+{
+	u32 val;
+	int ret;
+
+	cdns_init_clock_ctrl(cdns);
 
 	/* reset msg_count to default value of FIFOLEVEL */
 	cdns->msg_count = cdns_readl(cdns, CDNS_MCP_FIFOLEVEL);
-- 
2.20.1

[PATCH v2 10/17] soundwire: cadence: make SSP interval programmable

[Pierre-Louis Bossart]

In multi-master mode, the IP will only accept SSP intervals with
integer relationships between the frame rate and the gsync frequency.

E.g for a 48kHz frame rate and 4 kHz gsync signal, the SSP interval
can only be 1, 2, 3, 4, 6, 12.

To simplify we only allow one SSP per gsync interval.

Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
---
 drivers/soundwire/cadence_master.c | 7 ++++---
 drivers/soundwire/cadence_master.h | 3 +++
 2 files changed, 7 insertions(+), 3 deletions(-)

diff --git a/drivers/soundwire/cadence_master.c b/drivers/soundwire/cadence_master.c
index fb697ff665f5..773341568d7e 100644
--- a/drivers/soundwire/cadence_master.c
+++ b/drivers/soundwire/cadence_master.c
@@ -183,7 +183,6 @@ MODULE_PARM_DESC(cdns_mcp_int_mask, "Cadence MCP IntMask");
 #define CDNS_PDI_CONFIG_PORT			GENMASK(4, 0)
 
 /* Driver defaults */
-#define CDNS_DEFAULT_SSP_INTERVAL		0x18
 #define CDNS_TX_TIMEOUT				2000
 
 #define CDNS_SCP_RX_FIFOLEVEL			0x2
@@ -1048,6 +1047,7 @@ static void cdns_init_clock_ctrl(struct sdw_cdns *cdns)
 	struct sdw_bus *bus = &cdns->bus;
 	struct sdw_master_prop *prop = &bus->prop;
 	u32 val;
+	u32 ssp_interval;
 	int divider;
 
 	/* Set clock divider */
@@ -1067,8 +1067,9 @@ static void cdns_init_clock_ctrl(struct sdw_cdns *cdns)
 	cdns_writel(cdns, CDNS_MCP_FRAME_SHAPE_INIT, val);
 
 	/* Set SSP interval to default value */
-	cdns_writel(cdns, CDNS_MCP_SSP_CTRL0, CDNS_DEFAULT_SSP_INTERVAL);
-	cdns_writel(cdns, CDNS_MCP_SSP_CTRL1, CDNS_DEFAULT_SSP_INTERVAL);
+	ssp_interval = prop->default_frame_rate / SDW_CADENCE_GSYNC_HZ;
+	cdns_writel(cdns, CDNS_MCP_SSP_CTRL0, ssp_interval);
+	cdns_writel(cdns, CDNS_MCP_SSP_CTRL1, ssp_interval);
 }
 
 /**
diff --git a/drivers/soundwire/cadence_master.h b/drivers/soundwire/cadence_master.h
index e8fa5c7e09f4..b410656f8194 100644
--- a/drivers/soundwire/cadence_master.h
+++ b/drivers/soundwire/cadence_master.h
@@ -5,6 +5,9 @@
 #ifndef __SDW_CADENCE_H
 #define __SDW_CADENCE_H
 
+#define SDW_CADENCE_GSYNC_KHZ		4 /* 4 kHz */
+#define SDW_CADENCE_GSYNC_HZ		(SDW_CADENCE_GSYNC_KHZ * 1000)
+
 /**
  * struct sdw_cdns_pdi: PDI (Physical Data Interface) instance
  *
-- 
2.20.1

[PATCH v2 11/17] soundwire: cadence: reorder MCP_CONFIG settings

[Pierre-Louis Bossart]

Follow hardware programming flows and add placeholder comment for
multi-master mode.

Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
---
 drivers/soundwire/cadence_master.c | 18 ++++++++++--------
 1 file changed, 10 insertions(+), 8 deletions(-)

diff --git a/drivers/soundwire/cadence_master.c b/drivers/soundwire/cadence_master.c
index 773341568d7e..9afce1f32076 100644
--- a/drivers/soundwire/cadence_master.c
+++ b/drivers/soundwire/cadence_master.c
@@ -1097,20 +1097,22 @@ int sdw_cdns_init(struct sdw_cdns *cdns)
 	/* Configure mcp config */
 	val = cdns_readl(cdns, CDNS_MCP_CONFIG);
 
-	/* Set Max cmd retry to 15 */
-	val |= CDNS_MCP_CONFIG_MCMD_RETRY;
+	/* Set cmd mode for Tx and Rx cmds */
+	val &= ~CDNS_MCP_CONFIG_CMD;
 
-	/* Set frame delay between PREQ and ping frame to 15 frames */
-	val |= 0xF << SDW_REG_SHIFT(CDNS_MCP_CONFIG_MPREQ_DELAY);
+	/* Disable sniffer mode */
+	val &= ~CDNS_MCP_CONFIG_SNIFFER;
 
 	/* Disable auto bus release */
 	val &= ~CDNS_MCP_CONFIG_BUS_REL;
 
-	/* Disable sniffer mode */
-	val &= ~CDNS_MCP_CONFIG_SNIFFER;
+	/* Multi-master support to be added here */
 
-	/* Set cmd mode for Tx and Rx cmds */
-	val &= ~CDNS_MCP_CONFIG_CMD;
+	/* Set frame delay between PREQ and ping frame to 15 frames */
+	val |= 0xF << SDW_REG_SHIFT(CDNS_MCP_CONFIG_MPREQ_DELAY);
+
+	/* Set Max cmd retry to 15 */
+	val |= CDNS_MCP_CONFIG_MCMD_RETRY;
 
 	cdns_writel(cdns, CDNS_MCP_CONFIG, val);
 
-- 
2.20.1

[PATCH v2 12/17] soundwire: cadence: enable NORMAL operation in cdns_init()

[Pierre-Louis Bossart]

Follow recommended programming sequences, this needs to be enabled
before the reset sequence.

Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
---
 drivers/soundwire/cadence_master.c | 9 ++++-----
 1 file changed, 4 insertions(+), 5 deletions(-)

diff --git a/drivers/soundwire/cadence_master.c b/drivers/soundwire/cadence_master.c
index 9afce1f32076..6adf41e3fdcf 100644
--- a/drivers/soundwire/cadence_master.c
+++ b/drivers/soundwire/cadence_master.c
@@ -842,11 +842,6 @@ int sdw_cdns_exit_reset(struct sdw_cdns *cdns)
 		     CDNS_MCP_CONTROL_HW_RST,
 		     CDNS_MCP_CONTROL_HW_RST);
 
-	/* enable bus operations with clock and data */
-	cdns_updatel(cdns, CDNS_MCP_CONFIG,
-		     CDNS_MCP_CONFIG_OP,
-		     CDNS_MCP_CONFIG_OP_NORMAL);
-
 	/* commit changes */
 	return cdns_config_update(cdns);
 }
@@ -1097,6 +1092,10 @@ int sdw_cdns_init(struct sdw_cdns *cdns)
 	/* Configure mcp config */
 	val = cdns_readl(cdns, CDNS_MCP_CONFIG);
 
+	/* enable bus operations with clock and data */
+	val &= ~CDNS_MCP_CONFIG_OP;
+	val |= CDNS_MCP_CONFIG_OP_NORMAL;
+
 	/* Set cmd mode for Tx and Rx cmds */
 	val &= ~CDNS_MCP_CONFIG_CMD;
 
-- 
2.20.1

[PATCH v2 13/17] soundwire: cadence: remove PREQ_DELAY assignment

[Pierre-Louis Bossart]

The hardware default is 0x1F, and the existing code does an OR with 0xF.
This is a no-op, remove.

Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
---
 drivers/soundwire/cadence_master.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/soundwire/cadence_master.c b/drivers/soundwire/cadence_master.c
index 6adf41e3fdcf..420ad23c5530 100644
--- a/drivers/soundwire/cadence_master.c
+++ b/drivers/soundwire/cadence_master.c
@@ -1107,8 +1107,7 @@ int sdw_cdns_init(struct sdw_cdns *cdns)
 
 	/* Multi-master support to be added here */
 
-	/* Set frame delay between PREQ and ping frame to 15 frames */
-	val |= 0xF << SDW_REG_SHIFT(CDNS_MCP_CONFIG_MPREQ_DELAY);
+	/* leave frame delay to hardware default of 0x1F */
 
 	/* Set Max cmd retry to 15 */
 	val |= CDNS_MCP_CONFIG_MCMD_RETRY;
-- 
2.20.1

[PATCH v2 14/17] soundwire: cadence: remove automatic command retries

[Pierre-Louis Bossart]

This is a good idea on paper, but it's not recommended at all when
operating in multi-master mode. It's also not recommended when doing
bank switches, since the retransmission would happen at the next SSP,
and the command protocol is stuck in the mean time.

Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
---
 drivers/soundwire/cadence_master.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/soundwire/cadence_master.c b/drivers/soundwire/cadence_master.c
index 420ad23c5530..c9fdd4deb4f5 100644
--- a/drivers/soundwire/cadence_master.c
+++ b/drivers/soundwire/cadence_master.c
@@ -1109,8 +1109,7 @@ int sdw_cdns_init(struct sdw_cdns *cdns)
 
 	/* leave frame delay to hardware default of 0x1F */
 
-	/* Set Max cmd retry to 15 */
-	val |= CDNS_MCP_CONFIG_MCMD_RETRY;
+	/* leave command retry to hardware default of 0 */
 
 	cdns_writel(cdns, CDNS_MCP_CONFIG, val);
 
-- 
2.20.1

[PATCH v2 15/17] soundwire: cadence: commit changes in the exit_reset() sequence

[Pierre-Louis Bossart]

Follow recommended flows, the BUS_RESET must be programmed before the
UPDATE_CONFIG.

Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
---
 drivers/soundwire/cadence_master.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/drivers/soundwire/cadence_master.c b/drivers/soundwire/cadence_master.c
index c9fdd4deb4f5..55cf219cc908 100644
--- a/drivers/soundwire/cadence_master.c
+++ b/drivers/soundwire/cadence_master.c
@@ -1074,7 +1074,6 @@ static void cdns_init_clock_ctrl(struct sdw_cdns *cdns)
 int sdw_cdns_init(struct sdw_cdns *cdns)
 {
 	u32 val;
-	int ret;
 
 	cdns_init_clock_ctrl(cdns);
 
@@ -1113,8 +1112,8 @@ int sdw_cdns_init(struct sdw_cdns *cdns)
 
 	cdns_writel(cdns, CDNS_MCP_CONFIG, val);
 
-	/* commit changes */
-	return cdns_config_update(cdns);
+	/* changes will be committed later */
+	return 0;
 }
 EXPORT_SYMBOL(sdw_cdns_init);
 
-- 
2.20.1

[PATCH v2 16/17] soundwire: cadence: multi-link support

[Pierre-Louis Bossart]

Enable multi-link (aka multi-master configuration). In this
configuration, updates and commands with the 'ssp_sync' tag will be
deferred and controlled by the gsync hardware signal.

Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
---
 drivers/soundwire/cadence_master.c | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/drivers/soundwire/cadence_master.c b/drivers/soundwire/cadence_master.c
index 55cf219cc908..eedc4cefdab0 100644
--- a/drivers/soundwire/cadence_master.c
+++ b/drivers/soundwire/cadence_master.c
@@ -843,7 +843,13 @@ int sdw_cdns_exit_reset(struct sdw_cdns *cdns)
 		     CDNS_MCP_CONTROL_HW_RST);
 
 	/* commit changes */
-	return cdns_config_update(cdns);
+	cdns_updatel(cdns, CDNS_MCP_CONFIG_UPDATE,
+		     CDNS_MCP_CONFIG_UPDATE_BIT,
+		     CDNS_MCP_CONFIG_UPDATE_BIT);
+
+	/* don't wait here */
+	return 0;
+
 }
 EXPORT_SYMBOL(sdw_cdns_exit_reset);
 
@@ -1104,7 +1110,9 @@ int sdw_cdns_init(struct sdw_cdns *cdns)
 	/* Disable auto bus release */
 	val &= ~CDNS_MCP_CONFIG_BUS_REL;
 
-	/* Multi-master support to be added here */
+	if (cdns->bus.multi_link)
+		/* Set Multi-master mode to take gsync into account */
+		val |= CDNS_MCP_CONFIG_MMASTER;
 
 	/* leave frame delay to hardware default of 0x1F */
 
-- 
2.20.1

[PATCH v2 17/17] soundwire: cadence: clear FIFO to avoid pop noise issue on playback start

[Pierre-Louis Bossart]

From: randerwang <rander.wang@linux.intel.com>

Driver should clear FIFO in PDI, or the previously stored sample data
in FIFO will generate pop noise when stream is started. The soft reset
bit will clear all the FIFO to zero and is self-cleared after that.

Signed-off-by: randerwang <rander.wang@linux.intel.com>
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
---
 drivers/soundwire/cadence_master.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/soundwire/cadence_master.c b/drivers/soundwire/cadence_master.c
index eedc4cefdab0..ecd357d1c63d 100644
--- a/drivers/soundwire/cadence_master.c
+++ b/drivers/soundwire/cadence_master.c
@@ -1503,6 +1503,7 @@ void sdw_cdns_config_stream(struct sdw_cdns *cdns,
 	cdns_updatel(cdns, offset, CDNS_PORTCTRL_DIRN, val);
 
 	val = pdi->num;
+	val |= CDNS_PDI_CONFIG_SOFT_RESET;
 	val |= ((1 << ch) - 1) << SDW_REG_SHIFT(CDNS_PDI_CONFIG_CHANNEL);
 	cdns_writel(cdns, CDNS_PDI_CONFIG(pdi->num), val);
 }
-- 
2.20.1

Re: [PATCH v2 00/17] SoundWire: cadence: add clock stop and fix programming sequences

[Vinod Koul]

On 17-03-20, 11:33, Pierre-Louis Bossart wrote:
> To make progress with SoundWire support, this patchset provides the
> missing support for clock stop modes, and revisits all Cadence Master
> register settings. The current code is for some reason not aligned
> with internal documentation and hardware recommended flows,
> specifically for multi-link operation.

Applied, thanks

-- 
~Vinod