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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: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Tested-by: Guenter Roeck <linux@roeck-us.net>
Message-id: 20180703171044.9503-2-peter.maydell@linaro.org
This commit is contained in:
Peter Maydell 2018-07-09 14:51:34 +01:00
parent b78aae9bb6
commit 086ede32af
3 changed files with 49 additions and 7 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

22
hw/core/ptimer.c
View File

@ -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;
}

9
include/hw/ptimer.h
View File

@ -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);

25
tests/ptimer-test.c
View File

@ -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);
}
}