From c60561014257699d81ab392eb6cb6389ad8907df Mon Sep 17 00:00:00 2001 From: Pierre-Louis Bossart Date: Tue, 23 Aug 2022 12:50:03 +0800 Subject: [PATCH] soundwire: bus: allow device number to be unique at system level The SoundWire specification allows the device number to be allocated at will. When a system includes multiple SoundWire links, the device number scope is limited to the link to which the device is attached. However, for integration/debug it can be convenient to have a unique device number across the system. This patch adds a 'dev_num_ida_min' field at the bus level, which when set will be used to allocate an IDA. The allocation happens when a hardware device reports as ATTACHED. If any error happens during the enumeration, the allocated IDA is not freed - the device number will be reused if/when the device re-joins the bus. The IDA is only freed when the Linux device is unregistered. Signed-off-by: Pierre-Louis Bossart Reviewed-by: Ranjani Sridharan Reviewed-by: Rander Wang Signed-off-by: Bard Liao Link: https://lore.kernel.org/r/20220823045004.2670658-3-yung-chuan.liao@linux.intel.com Signed-off-by: Vinod Koul --- drivers/soundwire/bus.c | 23 +++++++++++++++++------ include/linux/soundwire/sdw.h | 4 ++++ 2 files changed, 21 insertions(+), 6 deletions(-) diff --git a/drivers/soundwire/bus.c b/drivers/soundwire/bus.c index 1823a74..d773eee 100644 --- a/drivers/soundwire/bus.c +++ b/drivers/soundwire/bus.c @@ -12,6 +12,7 @@ #include "sysfs_local.h" static DEFINE_IDA(sdw_bus_ida); +static DEFINE_IDA(sdw_peripheral_ida); static int sdw_get_id(struct sdw_bus *bus) { @@ -156,9 +157,11 @@ static int sdw_delete_slave(struct device *dev, void *data) mutex_lock(&bus->bus_lock); - if (slave->dev_num) /* clear dev_num if assigned */ + if (slave->dev_num) { /* clear dev_num if assigned */ clear_bit(slave->dev_num, bus->assigned); - + if (bus->dev_num_ida_min) + ida_free(&sdw_peripheral_ida, slave->dev_num); + } list_del_init(&slave->node); mutex_unlock(&bus->bus_lock); @@ -638,10 +641,18 @@ static int sdw_get_device_num(struct sdw_slave *slave) { int bit; - bit = find_first_zero_bit(slave->bus->assigned, SDW_MAX_DEVICES); - if (bit == SDW_MAX_DEVICES) { - bit = -ENODEV; - goto err; + if (slave->bus->dev_num_ida_min) { + bit = ida_alloc_range(&sdw_peripheral_ida, + slave->bus->dev_num_ida_min, SDW_MAX_DEVICES, + GFP_KERNEL); + if (bit < 0) + goto err; + } else { + bit = find_first_zero_bit(slave->bus->assigned, SDW_MAX_DEVICES); + if (bit == SDW_MAX_DEVICES) { + bit = -ENODEV; + goto err; + } } /* diff --git a/include/linux/soundwire/sdw.h b/include/linux/soundwire/sdw.h index 39058c8..a2b31d2 100644 --- a/include/linux/soundwire/sdw.h +++ b/include/linux/soundwire/sdw.h @@ -889,6 +889,9 @@ struct sdw_master_ops { * meaningful if multi_link is set. If set to 1, hardware-based * synchronization will be used even if a stream only uses a single * SoundWire segment. + * @dev_num_ida_min: if set, defines the minimum values for the IDA + * used to allocate system-unique device numbers. This value needs to be + * identical across all SoundWire bus in the system. */ struct sdw_bus { struct device *dev; @@ -913,6 +916,7 @@ struct sdw_bus { u32 bank_switch_timeout; bool multi_link; int hw_sync_min_links; + int dev_num_ida_min; }; int sdw_bus_master_add(struct sdw_bus *bus, struct device *parent, -- 2.7.4