From: Shreyas NC shreyas.nc@intel.com
In cases of multiple Masters in a stream, synchronization between multiple Master(s) is achieved by performing bank switch together and using Master methods.
Add sdw_ml_bank_switch() to wait for completion of bank switch.
Signed-off-by: Sanyog Kale sanyog.r.kale@intel.com Signed-off-by: Vinod Koul vkoul@kernel.org Signed-off-by: Shreyas NC shreyas.nc@intel.com --- drivers/soundwire/bus.c | 5 ++ drivers/soundwire/bus.h | 2 + drivers/soundwire/stream.c | 130 ++++++++++++++++++++++++++++++++++++++---- include/linux/soundwire/sdw.h | 4 ++ 4 files changed, 129 insertions(+), 12 deletions(-)
diff --git a/drivers/soundwire/bus.c b/drivers/soundwire/bus.c index dbabd5e69343..1cbfedfc20ef 100644 --- a/drivers/soundwire/bus.c +++ b/drivers/soundwire/bus.c @@ -35,6 +35,11 @@ int sdw_add_bus_master(struct sdw_bus *bus) INIT_LIST_HEAD(&bus->slaves); INIT_LIST_HEAD(&bus->m_rt_list);
+ /* + * Initialize multi_link flag + * TODO: populate this flag by reading property from FW node + */ + bus->multi_link = false; if (bus->ops->read_prop) { ret = bus->ops->read_prop(bus); if (ret < 0) { diff --git a/drivers/soundwire/bus.h b/drivers/soundwire/bus.h index b6cfbdfc47d5..c77de05b8100 100644 --- a/drivers/soundwire/bus.h +++ b/drivers/soundwire/bus.h @@ -4,6 +4,8 @@ #ifndef __SDW_BUS_H #define __SDW_BUS_H
+#define DEFAULT_BANK_SWITCH_TIMEOUT 3000 + #if IS_ENABLED(CONFIG_ACPI) int sdw_acpi_find_slaves(struct sdw_bus *bus); #else diff --git a/drivers/soundwire/stream.c b/drivers/soundwire/stream.c index 539b98ec18d9..6d437eb6a2d3 100644 --- a/drivers/soundwire/stream.c +++ b/drivers/soundwire/stream.c @@ -626,9 +626,10 @@ static int sdw_program_params(struct sdw_bus *bus) return ret; }
-static int sdw_bank_switch(struct sdw_bus *bus) +static int sdw_bank_switch(struct sdw_bus *bus, int m_rt_count) { int col_index, row_index; + bool multi_link; struct sdw_msg *wr_msg; u8 *wbuf = NULL; int ret = 0; @@ -638,6 +639,8 @@ static int sdw_bank_switch(struct sdw_bus *bus) if (!wr_msg) return -ENOMEM;
+ bus->defer_msg.msg = wr_msg; + wbuf = kzalloc(sizeof(*wbuf), GFP_KERNEL); if (!wbuf) { ret = -ENOMEM; @@ -658,17 +661,29 @@ static int sdw_bank_switch(struct sdw_bus *bus) SDW_MSG_FLAG_WRITE, wbuf); wr_msg->ssp_sync = true;
- ret = sdw_transfer(bus, wr_msg); + /* + * Set the multi_link flag only when both the hardware supports + * and there is a stream handled by multiple masters + */ + multi_link = bus->multi_link && (m_rt_count > 1); + + if (multi_link) + ret = sdw_transfer_defer(bus, wr_msg, &bus->defer_msg); + else + ret = sdw_transfer(bus, wr_msg); + if (ret < 0) { dev_err(bus->dev, "Slave frame_ctrl reg write failed"); goto error; }
- kfree(wr_msg); - kfree(wbuf); - bus->defer_msg.msg = NULL; - bus->params.curr_bank = !bus->params.curr_bank; - bus->params.next_bank = !bus->params.next_bank; + if (!bus->multi_link) { + kfree(wr_msg); + kfree(wbuf); + bus->defer_msg.msg = NULL; + bus->params.curr_bank = !bus->params.curr_bank; + bus->params.next_bank = !bus->params.next_bank; + }
return 0;
@@ -679,36 +694,87 @@ static int sdw_bank_switch(struct sdw_bus *bus) return ret; }
+/** + * sdw_ml_sync_bank_switch: Multilink register bank switch + * + * @bus: SDW bus instance + * + * Caller function should free the buffers on error + */ +static int sdw_ml_sync_bank_switch(struct sdw_bus *bus) +{ + unsigned long time_left; + + if (!bus->multi_link) + return 0; + + /* Wait for completion of transfer */ + time_left = wait_for_completion_timeout(&bus->defer_msg.complete, + bus->bank_switch_timeout); + + if (!time_left) { + dev_err(bus->dev, "Controller Timed out on bank switch"); + return -ETIMEDOUT; + } + + bus->params.curr_bank = !bus->params.curr_bank; + bus->params.next_bank = !bus->params.next_bank; + + if (bus->defer_msg.msg) { + kfree(bus->defer_msg.msg->buf); + kfree(bus->defer_msg.msg); + } + + return 0; +} + static int do_bank_switch(struct sdw_stream_runtime *stream) { struct sdw_master_runtime *m_rt = NULL; const struct sdw_master_ops *ops; struct sdw_bus *bus = NULL; + bool multi_link = false; int ret = 0;
- list_for_each_entry(m_rt, &stream->master_list, stream_node) { bus = m_rt->bus; ops = bus->ops;
+ if (bus->multi_link) { + multi_link = true; + mutex_lock(&bus->msg_lock); + } + /* Pre-bank switch */ if (ops->pre_bank_switch) { ret = ops->pre_bank_switch(bus); if (ret < 0) { dev_err(bus->dev, "Pre bank switch op failed: %d", ret); - return ret; + goto msg_unlock; } }
- /* Bank switch */ - ret = sdw_bank_switch(bus); + /* + * Perform Bank switch operation. + * For multi link cases, the actual bank switch is + * synchronized across all Masters and happens later as a + * part of post_bank_switch ops. + */ + ret = sdw_bank_switch(bus, stream->m_rt_count); if (ret < 0) { dev_err(bus->dev, "Bank switch failed: %d", ret); - return ret; + goto error; + } }
+ /* + * For multi link cases, it is expected that the bank switch is + * triggered by the post_bank_switch for the first Master in the list + * and for the other Masters the post_bank_switch() should return doing + * nothing. + */ list_for_each_entry(m_rt, &stream->master_list, stream_node) { bus = m_rt->bus; ops = bus->ops; @@ -719,7 +785,47 @@ static int do_bank_switch(struct sdw_stream_runtime *stream) if (ret < 0) { dev_err(bus->dev, "Post bank switch op failed: %d", ret); + goto error; } + } else if (bus->multi_link && stream->m_rt_count > 1) { + dev_err(bus->dev, + "Post bank switch ops not implemented"); + goto error; + } + + /* Set the bank switch timeout to default, if not set */ + if (!bus->bank_switch_timeout) + bus->bank_switch_timeout = DEFAULT_BANK_SWITCH_TIMEOUT; + + /* Check if bank switch was successful */ + ret = sdw_ml_sync_bank_switch(bus); + if (ret < 0) { + dev_err(bus->dev, + "multi link bank switch failed: %d", ret); + goto error; + } + + mutex_unlock(&bus->msg_lock); + } + + return ret; + +error: + list_for_each_entry(m_rt, &stream->master_list, stream_node) { + + bus = m_rt->bus; + + kfree(bus->defer_msg.msg->buf); + kfree(bus->defer_msg.msg); + } + +msg_unlock: + + if (multi_link) { + list_for_each_entry(m_rt, &stream->master_list, stream_node) { + bus = m_rt->bus; + if (mutex_is_locked(&bus->msg_lock)) + mutex_unlock(&bus->msg_lock); } }
diff --git a/include/linux/soundwire/sdw.h b/include/linux/soundwire/sdw.h index 214e14604d9f..df313913e856 100644 --- a/include/linux/soundwire/sdw.h +++ b/include/linux/soundwire/sdw.h @@ -678,6 +678,9 @@ struct sdw_master_ops { * @defer_msg: Defer message * @clk_stop_timeout: Clock stop timeout computed * @bank_switch_timeout: Bank switch timeout computed + * @multi_link: Store bus property that indicates if multi links + * are supported. This flag is populated by drivers after reading + * appropriate firmware (ACPI/DT). */ struct sdw_bus { struct device *dev; @@ -694,6 +697,7 @@ struct sdw_bus { struct sdw_defer defer_msg; unsigned int clk_stop_timeout; u32 bank_switch_timeout; + bool multi_link; };
int sdw_add_bus_master(struct sdw_bus *bus);