Add a sequence to test if an ASI remains active after receiving
an interrupt.

Signed-off-by: Alexandre Chartre <alexandre.char...@oracle.com>
---
 drivers/staging/asi/asidrv.c | 144 +++++++++++++++++++++++++++++++++--
 drivers/staging/asi/asidrv.h |   5 ++
 2 files changed, 144 insertions(+), 5 deletions(-)

diff --git a/drivers/staging/asi/asidrv.c b/drivers/staging/asi/asidrv.c
index 4231b56db167..a3c7da2bf16e 100644
--- a/drivers/staging/asi/asidrv.c
+++ b/drivers/staging/asi/asidrv.c
@@ -7,6 +7,7 @@
 #include <linux/miscdevice.h>
 #include <linux/module.h>
 #include <linux/slab.h>
+#include <linux/workqueue.h>
 
 #include <asm/asi.h>
 #include <asm/dpt.h>
@@ -19,6 +20,12 @@
 /* Number of read for mem/memmap test sequence */
 #define ASIDRV_MEM_READ_COUNT          1000
 
+/* Timeout for target to be ready to receive an interrupt */
+#define ASIDRV_TIMEOUT_TARGET_READY    1
+
+/* Timeout for receiving an interrupt */
+#define ASIDRV_TIMEOUT_INTERRUPT       5
+
 enum asidrv_state {
        ASIDRV_STATE_NONE,
        ASIDRV_STATE_INTR_WAITING,
@@ -29,6 +36,13 @@ struct asidrv_test {
        struct asi              *asi;   /* ASI for testing */
        struct dpt              *dpt;   /* ASI decorated page-table */
        char                    *buffer; /* buffer for testing */
+
+       /* runtime */
+       atomic_t                state;  /* runtime state */
+       int                     cpu;    /* cpu the test is running on */
+       struct work_struct      work;   /* work for other cpu */
+       bool                    work_set;
+       enum asidrv_run_error   run_error;
 };
 
 struct asidrv_sequence {
@@ -160,6 +174,107 @@ static int asidrv_asi_is_active(struct asi *asi)
        return false;
 }
 
+/*
+ * Wait for an atomic value to be set or the timeout to expire.
+ * Return 0 if the value is set, or -1 if the timeout expires.
+ */
+static enum asidrv_run_error asidrv_wait(struct asidrv_test *test,
+                                        int value, unsigned int timeout)
+{
+       cycles_t start = get_cycles();
+       cycles_t stop = start + timeout * tsc_khz * 1000;
+
+       while (get_cycles() < stop) {
+               if (atomic_read(&test->state) == value ||
+                   test->run_error != ASIDRV_RUN_ERR_NONE)
+                       return test->run_error;
+               cpu_relax();
+       }
+
+       /* timeout reached */
+       return ASIDRV_RUN_ERR_TIMEOUT;
+}
+
+/*
+ * Wait for an atomic value to transition from the initial value (set
+ * on entry) to the final value, or to timeout. Return 0 if the transition
+ * was done, or -1 if the timeout expires.
+ */
+static enum asidrv_run_error asidrv_wait_transition(struct asidrv_test *test,
+                                                   int initial, int final,
+                                                   unsigned int timeout)
+{
+       /* set the initial state value */
+       atomic_set(&test->state, initial);
+
+       /* do an active wait for the state changes */
+       return asidrv_wait(test, final, timeout);
+}
+
+/*
+ * Interrupt Test Sequence
+ */
+
+static void asidrv_intr_handler(void *info)
+{
+       struct asidrv_test *test = info;
+
+       /* ASI should be interrupted by the interrupt */
+       if (asidrv_asi_is_active(test->asi)) {
+               test->run_error = ASIDRV_RUN_ERR_INTR_ASI_ACTIVE;
+               atomic_set(&test->state, ASIDRV_STATE_INTR_RECEIVED);
+               return;
+       }
+
+       pr_debug("Received interrupt\n");
+       atomic_set(&test->state, ASIDRV_STATE_INTR_RECEIVED);
+}
+
+static void asidrv_intr_send(struct work_struct *work)
+{
+       struct asidrv_test *test = container_of(work, struct asidrv_test, work);
+       enum asidrv_run_error err;
+
+       /* wait for cpu target to be ready, then send an interrupt */
+       err = asidrv_wait(test,
+                         ASIDRV_STATE_INTR_WAITING,
+                         ASIDRV_TIMEOUT_TARGET_READY);
+       if (err) {
+               pr_debug("Target cpu %d not ready, interrupt not sent: error 
%d\n",
+                        test->cpu, err);
+               return;
+       }
+
+       pr_debug("Sending interrupt to cpu %d\n", test->cpu);
+       smp_call_function_single(test->cpu, asidrv_intr_handler,
+                                test, false);
+}
+
+static enum asidrv_run_error asidrv_intr_setup(struct asidrv_test *test)
+{
+       /* set work to have another cpu to send us an interrupt */
+       INIT_WORK(&test->work, asidrv_intr_send);
+       test->work_set = true;
+       return ASIDRV_RUN_ERR_NONE;
+}
+
+static enum asidrv_run_error asidrv_intr_run(struct asidrv_test *test)
+{
+       enum asidrv_run_error err;
+
+       /* wait for state changes indicating that an interrupt was received */
+       err = asidrv_wait_transition(test,
+                                    ASIDRV_STATE_INTR_WAITING,
+                                    ASIDRV_STATE_INTR_RECEIVED,
+                                    ASIDRV_TIMEOUT_INTERRUPT);
+       if (err == ASIDRV_RUN_ERR_TIMEOUT) {
+               pr_debug("Interrupt wait timeout\n");
+               err = ASIDRV_RUN_ERR_INTR;
+       }
+
+       return err;
+}
+
 /*
  * Memory Buffer Access Test Sequences
  */
@@ -231,12 +346,18 @@ struct asidrv_sequence asidrv_sequences[] = {
                "memmap",
                asidrv_memmap_setup, asidrv_mem_run, asidrv_memmap_cleanup,
        },
+       [ASIDRV_SEQ_INTERRUPT] = {
+               "interrupt",
+               asidrv_intr_setup, asidrv_intr_run, NULL,
+       },
 };
 
 static enum asidrv_run_error asidrv_run_init(struct asidrv_test *test)
 {
        int err;
 
+       test->run_error = ASIDRV_RUN_ERR_NONE;
+
        /*
         * Map the current stack, we need it to enter ASI.
         */
@@ -272,18 +393,31 @@ static void asidrv_run_fini(struct asidrv_test *test)
 static enum asidrv_run_error asidrv_run_setup(struct asidrv_test *test,
                                              struct asidrv_sequence *sequence)
 {
-       int run_err = ASIDRV_RUN_ERR_NONE;
+       unsigned int other_cpu;
+       int run_err;
+
+       test->work_set = false;
 
        if (sequence->setup) {
                run_err = sequence->setup(test);
                if (run_err)
-                       goto failed;
+                       return run_err;
        }
 
-       return ASIDRV_RUN_ERR_NONE;
+       if (test->work_set) {
+               other_cpu = cpumask_any_but(cpu_online_mask, test->cpu);
+               if (other_cpu == test->cpu) {
+                       pr_debug("Sequence %s requires an extra online cpu\n",
+                                sequence->name);
+                       asidrv_run_cleanup(test, sequence);
+                       return ASIDRV_RUN_ERR_NCPUS;
+               }
 
-failed:
-       return run_err;
+               atomic_set(&test->state, ASIDRV_STATE_NONE);
+               schedule_work_on(other_cpu, &test->work);
+       }
+
+       return ASIDRV_RUN_ERR_NONE;
 }
 
 static void asidrv_run_cleanup(struct asidrv_test *test,
diff --git a/drivers/staging/asi/asidrv.h b/drivers/staging/asi/asidrv.h
index 1e820cc64f13..8055d96a0058 100644
--- a/drivers/staging/asi/asidrv.h
+++ b/drivers/staging/asi/asidrv.h
@@ -10,6 +10,7 @@ enum asidrv_seqnum {
        ASIDRV_SEQ_PRINTK,      /* printk sequence */
        ASIDRV_SEQ_MEM,         /* access unmapped memory */
        ASIDRV_SEQ_MEMMAP,      /* access mapped memory */
+       ASIDRV_SEQ_INTERRUPT,   /* interrupt sequence */
 };
 
 enum asidrv_run_error {
@@ -20,6 +21,10 @@ enum asidrv_run_error {
        ASIDRV_RUN_ERR_ENTER,   /* failed to enter ASI */
        ASIDRV_RUN_ERR_ACTIVE,  /* ASI is not active after entering ASI */
        ASIDRV_RUN_ERR_MAP_BUFFER, /* failed to map buffer */
+       ASIDRV_RUN_ERR_NCPUS,   /* not enough active cpus */
+       ASIDRV_RUN_ERR_INTR,    /* no interrupt received */
+       ASIDRV_RUN_ERR_INTR_ASI_ACTIVE, /* ASI active in interrupt handler */
+       ASIDRV_RUN_ERR_TIMEOUT,
 };
 
 #define ASIDRV_IOCTL_RUN_SEQUENCE      _IOWR('a', 1, struct asidrv_run_param)
-- 
2.18.2

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