SoundWire: Cirrus Logic fixes #3860
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…D events" This reverts commit 87230e9. Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
This reverts commit 4d77b42. Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
… peripherals The cadence IP explicitly reports slave status changes with bits for each possible change. The function cdns_update_slave_status() attempts to translate this into the current status of each of the slaves. However when there are multiple peripherals on a bus any slave that did not have a status change when the work function ran would not have it's status updated - the array is initialised to a value that equates to UNATTACHED and this can cause spurious reports that slaves had dropped off the bus. In the case where a slave has no status change or has multiple status changes the value from the last PING command is used. Signed-off-by: Simon Trimmer <simont@opensource.cirrus.com> Signed-off-by: Richard Fitzgerald <rf@opensource.cirrus.com> Reviewed-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Ensure that if sdw_handle_slave_status() sees a peripheral has dropped off the bus it reports it to the client driver. If there are any devices reporting on address 0 it bails out after programming the device IDs. So it never reaches the second loop that calls sdw_update_slave_status(). If the missing device is one that is now showing as unenumerated it has been given a device ID so will report as attached next time sdw_handle_slave_status() runs. With the previous code the client driver would only see another ATTACHED notification because the UNATTACHED state was lost when sdw_handle_slave_status() bailed out after programming the device ID. This shows up most when the peripheral has to be reset after downloading updated firmware and there are multiple of these peripherals on the bus. They will all return to unenumerated state after the reset, and then there is a mix of unattached, attached and unenumerated PING states from the peripherals, as each is reset and they reboot. Signed-off-by: Richard Fitzgerald <rf@opensource.cirrus.com> Reviewed-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Don't re-enumerate a peripheral on #0 until we have seen and handled an UNATTACHED notification for that peripheral. Without this, it is possible for the UNATTACHED status to be missed and so the slave->status remains at ATTACHED. If slave->status never changes to UNATTACHED the child driver will never be notified of the UNATTACH, and the code in sdw_handle_slave_status() will skip the second part of enumeration because the slave->status has not changed. This scenario can happen because PINGs are handled in a workqueue function which is working from a snapshot of an old PING, and there is no guarantee when this function will run. A peripheral could report attached in the PING being handled by sdw_handle_slave_status(), but has since reverted to device #0 and is then found in the loop in sdw_program_device_num(). Previously the code would not have updated slave->status to UNATTACHED because it had not yet handled a PING where that peripheral had UNATTACHED. This situation happens fairly frequently with multiple peripherals on a bus that are intentionally reset (for example after downloading firmware). Signed-off-by: Richard Fitzgerald <rf@opensource.cirrus.com> Reviewed-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
The correct way to handle interrupts is to clear the bits we are about to handle _before_ handling them. Thus if the condition then re-asserts during the handling we won't lose it. This patch changes cdns_update_slave_status_work() to do this. The previous code cleared the interrupts after handling them. The problem with this is that when handling enumeration of devices the ATTACH statuses can be accidentally cleared and so some or all of the devices never complete their enumeration. Thus we can have a situation like this: - one or more devices are reverting to ID #0 - accumulated status bits indicate some devices attached and some on ID #0. (Remember: status bits are sticky until they are handled) - Because of device on #0 sdw_handle_slave_status() programs the device ID and exits without handling the other status, expecting to get an ATTACHED from this reprogrammed device. - The device immediately starts reporting ATTACHED in PINGs, which will assert its CDNS_MCP_SLAVE_INTSTAT_ATTACHED bit. - cdns_update_slave_status_work() clears INTSTAT0/1. If the initial status had CDNS_MCP_SLAVE_INTSTAT_ATTACHED bit set it will be cleared. - The ATTACHED change for the device has now been lost. - cdns_update_slave_status_work() clears CDNS_MCP_INT_SLAVE_MASK so if the new ATTACHED state had set it, it will be cleared without ever having been handled. Unless there is some other state change from another device to cause a new interrupt, the ATTACHED state of the reprogrammed device will never cause an interrupt so its enumeration will not be completed. Signed-off-by: Richard Fitzgerald <rf@opensource.cirrus.com> Reviewed-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
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>
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Sep 16, 2022
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