From: Harald Freudenberger freude@linux.ibm.com
[ Upstream commit 42a87d4103ae365e18c3be1333592ab583b8ad9d ]
Until now there is no way to reset a AP queue or card. Driving a card or queue offline and online again does only toggle the 'software' online state. The only way to trigger a (hardware) reset is by running hot-unplug/hot-plug for example on the HMC.
This patch makes the queue reset attribute in sysfs writable. Writing into this attribute triggers a reset on the AP queue's state machine. So the AP queue is flushed and state machine runs through the initial states which cause a reset (PQAP(RAPQ)) and a re-registration to interrupts (PQAP(AQIC)) if available.
The reset sysfs attribute is writable by root only. So only an administrator is allowed to initiate a reset of AP queues. Please note that the queue's counter values are left untouched by the reset.
Signed-off-by: Harald Freudenberger freude@linux.ibm.com Signed-off-by: Martin Schwidefsky schwidefsky@de.ibm.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/s390/crypto/ap_queue.c | 23 ++++++++++++++++++++++- 1 file changed, 22 insertions(+), 1 deletion(-)
diff --git a/drivers/s390/crypto/ap_queue.c b/drivers/s390/crypto/ap_queue.c index 0aa4b3ccc948c..576ac08777c50 100644 --- a/drivers/s390/crypto/ap_queue.c +++ b/drivers/s390/crypto/ap_queue.c @@ -14,6 +14,9 @@ #include <asm/facility.h>
#include "ap_bus.h" +#include "ap_debug.h" + +static void __ap_flush_queue(struct ap_queue *aq);
/** * ap_queue_enable_interruption(): Enable interruption on an AP queue. @@ -541,7 +544,25 @@ static ssize_t reset_show(struct device *dev, return rc; }
-static DEVICE_ATTR_RO(reset); +static ssize_t reset_store(struct device *dev, + struct device_attribute *attr, + const char *buf, size_t count) +{ + struct ap_queue *aq = to_ap_queue(dev); + + spin_lock_bh(&aq->lock); + __ap_flush_queue(aq); + aq->state = AP_STATE_RESET_START; + ap_wait(ap_sm_event(aq, AP_EVENT_POLL)); + spin_unlock_bh(&aq->lock); + + AP_DBF(DBF_INFO, "reset queue=%02x.%04x triggered by user\n", + AP_QID_CARD(aq->qid), AP_QID_QUEUE(aq->qid)); + + return count; +} + +static DEVICE_ATTR_RW(reset);
static ssize_t interrupt_show(struct device *dev, struct device_attribute *attr, char *buf)