Commit 086ede32 authored by Peter Maydell's avatar Peter Maydell
Browse files

ptimer: Add TRIGGER_ONLY_ON_DECREMENT policy option 



The CMSDK timer behaviour is that an interrupt is triggered when the
counter counts down from 1 to 0; however one is not triggered if the
counter is manually set to 0 by a guest write to the counter register.
Currently ptimer can't handle this; add a policy option to allow
a ptimer user to request this behaviour.

Signed-off-by: default avatarPeter Maydell <peter.maydell@linaro.org>
Reviewed-by: default avatarRichard Henderson <richard.henderson@linaro.org>
Tested-by: default avatarGuenter Roeck <linux@roeck-us.net>
Message-id: 20180703171044.9503-2-peter.maydell@linaro.org
parent b78aae9b

hw/core/ptimer.c

+21 −1
Original line number Diff line number Diff line
@@ -45,8 +45,20 @@ static void ptimer_reload(ptimer_state *s, int delta_adjust) 
    uint32_t period_frac = s->period_frac;

    uint64_t period = s->period;

    uint64_t delta = s->delta;

    bool suppress_trigger = false;



    if (delta == 0 && !(s->policy_mask & PTIMER_POLICY_NO_IMMEDIATE_TRIGGER)) {

    /*

     * Note that if delta_adjust is 0 then we must be here because of

     * a count register write or timer start, not because of timer expiry.

     * In that case the policy might require us to suppress the timer trigger

     * that we would otherwise generate for a zero delta.

     */

    if (delta_adjust == 0 &&

        (s->policy_mask & PTIMER_POLICY_TRIGGER_ONLY_ON_DECREMENT)) {

        suppress_trigger = true;

    }

    if (delta == 0 && !(s->policy_mask & PTIMER_POLICY_NO_IMMEDIATE_TRIGGER)

        && !suppress_trigger) {

        ptimer_trigger(s);

    }
@@ -353,6 +365,14 @@ ptimer_state *ptimer_init(QEMUBH *bh, uint8_t policy_mask) 
    s->bh = bh;

    s->timer = timer_new_ns(QEMU_CLOCK_VIRTUAL, ptimer_tick, s);

    s->policy_mask = policy_mask;



    /*

     * These two policies are incompatible -- trigger-on-decrement implies

     * a timer trigger when the count becomes 0, but no-immediate-trigger

     * implies a trigger when the count stops being 0.

     */

    assert(!((policy_mask & PTIMER_POLICY_TRIGGER_ONLY_ON_DECREMENT) &&

             (policy_mask & PTIMER_POLICY_NO_IMMEDIATE_TRIGGER)));

    return s;

}

include/hw/ptimer.h

+9 −0
Original line number Diff line number Diff line
@@ -69,6 +69,15 @@ 
 * not the one less.  */

#define PTIMER_POLICY_NO_COUNTER_ROUND_DOWN (1 << 4)



/*

 * Starting to run with a zero counter, or setting the counter to "0" via

 * ptimer_set_count() or ptimer_set_limit() will not trigger the timer

 * (though it will cause a reload). Only a counter decrement to "0"

 * will cause a trigger. Not compatible with NO_IMMEDIATE_TRIGGER;

 * ptimer_init() will assert() that you don't set both.

 */

#define PTIMER_POLICY_TRIGGER_ONLY_ON_DECREMENT (1 << 5)



/* ptimer.c */

typedef struct ptimer_state ptimer_state;

typedef void (*ptimer_cb)(void *opaque);

tests/ptimer-test.c

+19 −6
Original line number Diff line number Diff line
@@ -208,6 +208,7 @@ static void check_periodic(gconstpointer arg) 
    bool no_immediate_trigger = (*policy & PTIMER_POLICY_NO_IMMEDIATE_TRIGGER);

    bool no_immediate_reload = (*policy & PTIMER_POLICY_NO_IMMEDIATE_RELOAD);

    bool no_round_down = (*policy & PTIMER_POLICY_NO_COUNTER_ROUND_DOWN);

    bool trig_only_on_dec = (*policy & PTIMER_POLICY_TRIGGER_ONLY_ON_DECREMENT);



    triggered = false;
@@ -311,7 +312,7 @@ static void check_periodic(gconstpointer arg) 
    g_assert_cmpuint(ptimer_get_count(ptimer), ==,

                     no_immediate_reload ? 0 : 10);



    if (no_immediate_trigger) {

    if (no_immediate_trigger || trig_only_on_dec) {

        g_assert_false(triggered);

    } else {

        g_assert_true(triggered);
@@ -506,6 +507,7 @@ static void check_run_with_delta_0(gconstpointer arg) 
    bool no_immediate_trigger = (*policy & PTIMER_POLICY_NO_IMMEDIATE_TRIGGER);

    bool no_immediate_reload = (*policy & PTIMER_POLICY_NO_IMMEDIATE_RELOAD);

    bool no_round_down = (*policy & PTIMER_POLICY_NO_COUNTER_ROUND_DOWN);

    bool trig_only_on_dec = (*policy & PTIMER_POLICY_TRIGGER_ONLY_ON_DECREMENT);



    triggered = false;
@@ -515,7 +517,7 @@ static void check_run_with_delta_0(gconstpointer arg) 
    g_assert_cmpuint(ptimer_get_count(ptimer), ==,

                     no_immediate_reload ? 0 : 99);



    if (no_immediate_trigger) {

    if (no_immediate_trigger || trig_only_on_dec) {

        g_assert_false(triggered);

    } else {

        g_assert_true(triggered);
@@ -563,7 +565,7 @@ static void check_run_with_delta_0(gconstpointer arg) 
    g_assert_cmpuint(ptimer_get_count(ptimer), ==,

                     no_immediate_reload ? 0 : 99);



    if (no_immediate_trigger) {

    if (no_immediate_trigger || trig_only_on_dec) {

        g_assert_false(triggered);

    } else {

        g_assert_true(triggered);
@@ -609,6 +611,7 @@ static void check_periodic_with_load_0(gconstpointer arg) 
    ptimer_state *ptimer = ptimer_init(bh, *policy);

    bool continuous_trigger = (*policy & PTIMER_POLICY_CONTINUOUS_TRIGGER);

    bool no_immediate_trigger = (*policy & PTIMER_POLICY_NO_IMMEDIATE_TRIGGER);

    bool trig_only_on_dec = (*policy & PTIMER_POLICY_TRIGGER_ONLY_ON_DECREMENT);



    triggered = false;
@@ -617,7 +620,7 @@ static void check_periodic_with_load_0(gconstpointer arg) 


    g_assert_cmpuint(ptimer_get_count(ptimer), ==, 0);



    if (no_immediate_trigger) {

    if (no_immediate_trigger || trig_only_on_dec) {

        g_assert_false(triggered);

    } else {

        g_assert_true(triggered);
@@ -667,6 +670,7 @@ static void check_oneshot_with_load_0(gconstpointer arg) 
    QEMUBH *bh = qemu_bh_new(ptimer_trigger, NULL);

    ptimer_state *ptimer = ptimer_init(bh, *policy);

    bool no_immediate_trigger = (*policy & PTIMER_POLICY_NO_IMMEDIATE_TRIGGER);

    bool trig_only_on_dec = (*policy & PTIMER_POLICY_TRIGGER_ONLY_ON_DECREMENT);



    triggered = false;
@@ -675,7 +679,7 @@ static void check_oneshot_with_load_0(gconstpointer arg) 


    g_assert_cmpuint(ptimer_get_count(ptimer), ==, 0);



    if (no_immediate_trigger) {

    if (no_immediate_trigger || trig_only_on_dec) {

        g_assert_false(triggered);

    } else {

        g_assert_true(triggered);
@@ -725,6 +729,10 @@ static void add_ptimer_tests(uint8_t policy) 
        g_strlcat(policy_name, "no_counter_rounddown,", 256);

    }



    if (policy & PTIMER_POLICY_TRIGGER_ONLY_ON_DECREMENT) {

        g_strlcat(policy_name, "trigger_only_on_decrement,", 256);

    }



    g_test_add_data_func_full(

        tmp = g_strdup_printf("/ptimer/set_count policy=%s", policy_name),

        g_memdup(&policy, 1), check_set_count, g_free);
@@ -790,10 +798,15 @@ static void add_ptimer_tests(uint8_t policy) 


static void add_all_ptimer_policies_comb_tests(void)

{

    int last_policy = PTIMER_POLICY_NO_COUNTER_ROUND_DOWN;

    int last_policy = PTIMER_POLICY_TRIGGER_ONLY_ON_DECREMENT;

    int policy = PTIMER_POLICY_DEFAULT;



    for (; policy < (last_policy << 1); policy++) {

        if ((policy & PTIMER_POLICY_TRIGGER_ONLY_ON_DECREMENT) &&

            (policy & PTIMER_POLICY_NO_IMMEDIATE_TRIGGER)) {

            /* Incompatible policy flag settings -- don't try to test them */

            continue;

        }

        add_ptimer_tests(policy);

    }

}