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author | 2022-09-14 17:02:48 +0100 | |
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committer | 2022-09-20 10:29:31 +0530 | |
commit | 72124f07f0fab446caeea1f545d8c58b7549a899 (patch) | |
tree | 38fda4d9b2a9485c0014a0977aa4b7b1cdb84ed3 /drivers/soundwire/bus.c | |
parent | soundwire: cadence: Fix lost ATTACHED interrupts when enumerating (diff) | |
download | linux-72124f07f0fab446caeea1f545d8c58b7549a899.tar.gz linux-72124f07f0fab446caeea1f545d8c58b7549a899.tar.bz2 linux-72124f07f0fab446caeea1f545d8c58b7549a899.zip |
soundwire: bus: Don't exit early if no device IDs were programmed
Only exit sdw_handle_slave_status() right after calling
sdw_program_device_num() if it actually programmed an ID into at
least one device.
sdw_handle_slave_status() should protect itself against phantom
device #0 ATTACHED indications. In that case there is no actual
device still on #0. The early exit relies on there being a status
change to ATTACHED on the reprogrammed device to trigger another
call to sdw_handle_slave_status() which will then handle the status
of all peripherals. If no device was actually programmed with an
ID there won't be a new ATTACHED indication. This can lead to the
status of other peripherals not being handled.
The status passed to sdw_handle_slave_status() is obviously always
from a point of time in the past, and may indicate accumulated
unhandled events (depending how the bus manager operates). It's
possible that a device ID is reprogrammed but the last PING status
captured state just before that, when it was still reporting on
ID #0. Then sdw_handle_slave_status() is called with this PING info,
just before a new PING status is available showing it now on its new
ID. So sdw_handle_slave_status() will receive a phantom report of a
device on #0, but it will not find one.
Signed-off-by: Richard Fitzgerald <rf@opensource.cirrus.com>
Reviewed-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Link: https://lore.kernel.org/r/20220914160248.1047627-6-rf@opensource.cirrus.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Diffstat (limited to 'drivers/soundwire/bus.c')
-rw-r--r-- | drivers/soundwire/bus.c | 29 |
1 files changed, 21 insertions, 8 deletions
diff --git a/drivers/soundwire/bus.c b/drivers/soundwire/bus.c index 6e569a875a9b..8eded1a55227 100644 --- a/drivers/soundwire/bus.c +++ b/drivers/soundwire/bus.c @@ -729,7 +729,7 @@ void sdw_extract_slave_id(struct sdw_bus *bus, } EXPORT_SYMBOL(sdw_extract_slave_id); -static int sdw_program_device_num(struct sdw_bus *bus) +static int sdw_program_device_num(struct sdw_bus *bus, bool *programmed) { u8 buf[SDW_NUM_DEV_ID_REGISTERS] = {0}; struct sdw_slave *slave, *_s; @@ -739,6 +739,8 @@ static int sdw_program_device_num(struct sdw_bus *bus) int count = 0, ret; u64 addr; + *programmed = false; + /* No Slave, so use raw xfer api */ ret = sdw_fill_msg(&msg, NULL, SDW_SCP_DEVID_0, SDW_NUM_DEV_ID_REGISTERS, 0, SDW_MSG_FLAG_READ, buf); @@ -797,6 +799,8 @@ static int sdw_program_device_num(struct sdw_bus *bus) return ret; } + *programmed = true; + break; } } @@ -1756,7 +1760,7 @@ int sdw_handle_slave_status(struct sdw_bus *bus, { enum sdw_slave_status prev_status; struct sdw_slave *slave; - bool attached_initializing; + bool attached_initializing, id_programmed; int i, ret = 0; /* first check if any Slaves fell off the bus */ @@ -1787,14 +1791,23 @@ int sdw_handle_slave_status(struct sdw_bus *bus, if (status[0] == SDW_SLAVE_ATTACHED) { dev_dbg(bus->dev, "Slave attached, programming device number\n"); - ret = sdw_program_device_num(bus); - if (ret < 0) - dev_err(bus->dev, "Slave attach failed: %d\n", ret); + /* - * programming a device number will have side effects, - * so we deal with other devices at a later time + * Programming a device number will have side effects, + * so we deal with other devices at a later time. + * This relies on those devices reporting ATTACHED, which will + * trigger another call to this function. This will only + * happen if at least one device ID was programmed. + * Error returns from sdw_program_device_num() are currently + * ignored because there's no useful recovery that can be done. + * Returning the error here could result in the current status + * of other devices not being handled, because if no device IDs + * were programmed there's nothing to guarantee a status change + * to trigger another call to this function. */ - return ret; + sdw_program_device_num(bus, &id_programmed); + if (id_programmed) + return 0; } /* Continue to check other slave statuses */ |