[PATCH v2 3/3] event/cnxk: disable timer resolution estimation

[<pbhagavatula@marvell.com>]

From: Pavan Nikhilesh <pbhagavatula@marvell.com>

Disable timer resolution estimation, read TIM LF clock registers
to get the current running clock counter as estimating causes
time drift.

Signed-off-by: Pavan Nikhilesh <pbhagavatula@marvell.com>
---
 drivers/common/cnxk/hw/tim.h         |   6 ++
 drivers/event/cnxk/cnxk_tim_evdev.c  | 140 +++------------------------
 drivers/event/cnxk/cnxk_tim_evdev.h  |  49 +++++++---
 drivers/event/cnxk/cnxk_tim_worker.c |  18 ----
 drivers/event/cnxk/cnxk_tim_worker.h |   3 +-
 5 files changed, 62 insertions(+), 154 deletions(-)

diff --git a/drivers/common/cnxk/hw/tim.h b/drivers/common/cnxk/hw/tim.h
index a0fe29ddcf..61c38ae175 100644
--- a/drivers/common/cnxk/hw/tim.h
+++ b/drivers/common/cnxk/hw/tim.h
@@ -31,6 +31,12 @@
 #define TIM_LF_INT_VEC_NRSPERR_INT (0x0ull)
 #define TIM_LF_INT_VEC_RAS_INT	   (0x1ull)
 #define TIM_LF_RING_AURA	   (0x0)
+#define TIM_LF_FR_RN_GPIOS	   (0x020)
+#define TIM_LF_FR_RN_GTI	   (0x030)
+#define TIM_LF_FR_RN_PTP	   (0x040)
+#define TIM_LF_FR_RN_TENNS	   (0x050)
+#define TIM_LF_FR_RN_SYNCE	   (0x060)
+#define TIM_LF_FR_RN_BTS	   (0x070)
 #define TIM_LF_RING_BASE	   (0x130)
 #define TIM_LF_NRSPERR_INT	   (0x200)
 #define TIM_LF_NRSPERR_INT_W1S	   (0x208)
diff --git a/drivers/event/cnxk/cnxk_tim_evdev.c b/drivers/event/cnxk/cnxk_tim_evdev.c
index af67235503..f8a536e71a 100644
--- a/drivers/event/cnxk/cnxk_tim_evdev.c
+++ b/drivers/event/cnxk/cnxk_tim_evdev.c
@@ -119,80 +119,6 @@ cnxk_tim_ring_info_get(const struct rte_event_timer_adapter *adptr,
 		   sizeof(struct rte_event_timer_adapter_conf));
 }
 
-static inline void
-sort_multi_array(double ref_arr[], uint64_t arr1[], uint64_t arr2[],
-		 uint64_t arr3[], uint8_t sz)
-{
-	int x;
-
-	for (x = 0; x < sz - 1; x++) {
-		if (ref_arr[x] > ref_arr[x + 1]) {
-			PLT_SWAP(ref_arr[x], ref_arr[x + 1]);
-			PLT_SWAP(arr1[x], arr1[x + 1]);
-			PLT_SWAP(arr2[x], arr2[x + 1]);
-			PLT_SWAP(arr3[x], arr3[x + 1]);
-			x = -1;
-		}
-	}
-}
-
-static inline void
-populate_sample(uint64_t tck[], uint64_t ns[], double diff[], uint64_t dst[],
-		uint64_t req_tck, uint64_t clk_freq, double tck_ns, uint8_t sz,
-		bool mov_fwd)
-{
-	int i;
-
-	for (i = 0; i < sz; i++) {
-		tck[i] = i ? tck[i - 1] : req_tck;
-		do {
-			mov_fwd ? tck[i]++ : tck[i]--;
-			ns[i] = round((double)tck[i] * tck_ns);
-			if (round((double)tck[i] * tck_ns) >
-			    ((double)tck[i] * tck_ns))
-				continue;
-		} while (ns[i] % (uint64_t)cnxk_tim_ns_per_tck(clk_freq));
-		diff[i] = PLT_MAX((double)ns[i], (double)tck[i] * tck_ns) -
-			  PLT_MIN((double)ns[i], (double)tck[i] * tck_ns);
-		dst[i] = mov_fwd ? tck[i] - req_tck : req_tck - tck[i];
-	}
-}
-
-static void
-tim_adjust_resolution(uint64_t *req_ns, uint64_t *req_tck, double tck_ns,
-		      uint64_t clk_freq, uint64_t max_tmo, uint64_t m_tck)
-{
-#define MAX_SAMPLES 5
-	double rmax_diff[MAX_SAMPLES], rmin_diff[MAX_SAMPLES];
-	uint64_t min_tck[MAX_SAMPLES], max_tck[MAX_SAMPLES];
-	uint64_t min_dst[MAX_SAMPLES], max_dst[MAX_SAMPLES];
-	uint64_t min_ns[MAX_SAMPLES], max_ns[MAX_SAMPLES];
-	int i;
-
-	populate_sample(max_tck, max_ns, rmax_diff, max_dst, *req_tck, clk_freq,
-			tck_ns, MAX_SAMPLES, true);
-	sort_multi_array(rmax_diff, max_dst, max_tck, max_ns, MAX_SAMPLES);
-
-	populate_sample(min_tck, min_ns, rmin_diff, min_dst, *req_tck, clk_freq,
-			tck_ns, MAX_SAMPLES, false);
-	sort_multi_array(rmin_diff, min_dst, min_tck, min_ns, MAX_SAMPLES);
-
-	for (i = 0; i < MAX_SAMPLES; i++) {
-		if (min_dst[i] < max_dst[i] && min_tck[i] > m_tck &&
-		    (max_tmo / min_ns[i]) <=
-			    (TIM_MAX_BUCKET_SIZE - TIM_MIN_BUCKET_SIZE)) {
-			*req_tck = min_tck[i];
-			*req_ns = min_ns[i];
-			break;
-		} else if ((max_tmo / max_ns[i]) <
-			   (TIM_MAX_BUCKET_SIZE - TIM_MIN_BUCKET_SIZE)) {
-			*req_tck = max_tck[i];
-			*req_ns = max_ns[i];
-			break;
-		}
-	}
-}
-
 static int
 cnxk_tim_ring_create(struct rte_event_timer_adapter *adptr)
 {
@@ -263,27 +189,7 @@ cnxk_tim_ring_create(struct rte_event_timer_adapter *adptr)
 		goto tim_hw_free;
 	}
 
-	tim_ring->tck_nsec =
-		round(RTE_ALIGN_MUL_NEAR((long double)rcfg->timer_tick_ns,
-					 cnxk_tim_ns_per_tck(clk_freq)));
-	if (log10(clk_freq) - floor(log10(clk_freq)) != 0.0) {
-		uint64_t req_ns, req_tck;
-		double tck_ns;
-
-		req_ns = tim_ring->tck_nsec;
-		tck_ns = NSECPERSEC / clk_freq;
-		req_tck = round(rcfg->timer_tick_ns / tck_ns);
-		tim_adjust_resolution(&req_ns, &req_tck, tck_ns, clk_freq,
-				      rcfg->max_tmo_ns, min_intvl_cyc);
-		if ((tim_ring->tck_nsec != req_ns) &&
-		    !(rcfg->flags & RTE_EVENT_TIMER_ADAPTER_F_ADJUST_RES)) {
-			rc = -ERANGE;
-			goto tim_hw_free;
-		}
-		tim_ring->tck_nsec = ceil(req_tck * tck_ns);
-	}
-
-	tim_ring->tck_int = round((long double)tim_ring->tck_nsec /
+	tim_ring->tck_int = round((double)rcfg->timer_tick_ns /
 				  cnxk_tim_ns_per_tck(clk_freq));
 	tim_ring->tck_nsec =
 		ceil(tim_ring->tck_int * cnxk_tim_ns_per_tck(clk_freq));
@@ -296,6 +202,13 @@ cnxk_tim_ring_create(struct rte_event_timer_adapter *adptr)
 	tim_ring->chunk_sz = dev->chunk_sz;
 	tim_ring->disable_npa = dev->disable_npa;
 	tim_ring->enable_stats = dev->enable_stats;
+	tim_ring->base = roc_tim_lf_base_get(&dev->tim, tim_ring->ring_id);
+	tim_ring->tbase = cnxk_tim_get_tick_base(clk_src, tim_ring->base);
+
+	if (roc_model_is_cn9k() && (tim_ring->clk_src == ROC_TIM_CLK_SRC_GTI))
+		tim_ring->tick_fn = cnxk_tim_cntvct;
+	else
+		tim_ring->tick_fn = cnxk_tim_tick_read;
 
 	for (i = 0; i < dev->ring_ctl_cnt; i++) {
 		struct cnxk_tim_ctl *ring_ctl = &dev->ring_ctl_data[i];
@@ -342,7 +255,6 @@ cnxk_tim_ring_create(struct rte_event_timer_adapter *adptr)
 		goto tim_chnk_free;
 	}
 
-	tim_ring->base = roc_tim_lf_base_get(&dev->tim, tim_ring->ring_id);
 	plt_write64((uint64_t)tim_ring->bkt, tim_ring->base + TIM_LF_RING_BASE);
 	plt_write64(tim_ring->aura, tim_ring->base + TIM_LF_RING_AURA);
 
@@ -391,31 +303,6 @@ cnxk_tim_ring_free(struct rte_event_timer_adapter *adptr)
 	return 0;
 }
 
-static void
-cnxk_tim_calibrate_start_tsc(struct cnxk_tim_ring *tim_ring)
-{
-#define CNXK_TIM_CALIB_ITER 1E6
-	uint32_t real_bkt, bucket;
-	int icount, ecount = 0;
-	uint64_t bkt_cyc;
-
-	for (icount = 0; icount < CNXK_TIM_CALIB_ITER; icount++) {
-		real_bkt = plt_read64(tim_ring->base + TIM_LF_RING_REL) >> 44;
-		bkt_cyc = cnxk_tim_cntvct();
-		bucket = (bkt_cyc - tim_ring->ring_start_cyc) /
-			 tim_ring->tck_int;
-		bucket = bucket % (tim_ring->nb_bkts);
-		tim_ring->ring_start_cyc =
-			bkt_cyc - (real_bkt * tim_ring->tck_int);
-		if (bucket != real_bkt)
-			ecount++;
-	}
-	tim_ring->last_updt_cyc = bkt_cyc;
-	plt_tim_dbg("Bucket mispredict %3.2f distance %d\n",
-		    100 - (((double)(icount - ecount) / (double)icount) * 100),
-		    bucket - real_bkt);
-}
-
 static int
 cnxk_tim_ring_start(const struct rte_event_timer_adapter *adptr)
 {
@@ -431,12 +318,16 @@ cnxk_tim_ring_start(const struct rte_event_timer_adapter *adptr)
 	if (rc < 0)
 		return rc;
 
-	tim_ring->tot_int = tim_ring->tck_int * tim_ring->nb_bkts;
 	tim_ring->fast_div = rte_reciprocal_value_u64(tim_ring->tck_int);
 	tim_ring->fast_bkt = rte_reciprocal_value_u64(tim_ring->nb_bkts);
 
-	cnxk_tim_calibrate_start_tsc(tim_ring);
+	if (roc_model_is_cn9k() && (tim_ring->clk_src == ROC_TIM_CLK_SRC_GTI)) {
+		uint64_t start_diff;
 
+		start_diff = cnxk_tim_cntvct(tim_ring->tbase) -
+			     cnxk_tim_tick_read(tim_ring->tbase);
+		tim_ring->ring_start_cyc += start_diff;
+	}
 	return rc;
 }
 
@@ -462,7 +353,8 @@ cnxk_tim_stats_get(const struct rte_event_timer_adapter *adapter,
 		   struct rte_event_timer_adapter_stats *stats)
 {
 	struct cnxk_tim_ring *tim_ring = adapter->data->adapter_priv;
-	uint64_t bkt_cyc = cnxk_tim_cntvct() - tim_ring->ring_start_cyc;
+	uint64_t bkt_cyc =
+		tim_ring->tick_fn(tim_ring->tbase) - tim_ring->ring_start_cyc;
 
 	stats->evtim_exp_count =
 		__atomic_load_n(&tim_ring->arm_cnt, __ATOMIC_RELAXED);
diff --git a/drivers/event/cnxk/cnxk_tim_evdev.h b/drivers/event/cnxk/cnxk_tim_evdev.h
index 91a90ee2ce..0fda9f4f13 100644
--- a/drivers/event/cnxk/cnxk_tim_evdev.h
+++ b/drivers/event/cnxk/cnxk_tim_evdev.h
@@ -24,14 +24,14 @@
 
 #define CNXK_TIM_EVDEV_NAME	    cnxk_tim_eventdev
 #define CNXK_TIM_MAX_BUCKETS	    (0xFFFFF)
-#define CNXK_TIM_RING_DEF_CHUNK_SZ  (4096)
+#define CNXK_TIM_RING_DEF_CHUNK_SZ  (256)
 #define CNXK_TIM_CHUNK_ALIGNMENT    (16)
 #define CNXK_TIM_MAX_BURST	    \
 			(RTE_CACHE_LINE_SIZE / CNXK_TIM_CHUNK_ALIGNMENT)
 #define CNXK_TIM_NB_CHUNK_SLOTS(sz) (((sz) / CNXK_TIM_CHUNK_ALIGNMENT) - 1)
 #define CNXK_TIM_MIN_CHUNK_SLOTS    (0x1)
 #define CNXK_TIM_MAX_CHUNK_SLOTS    (0x1FFE)
-#define CNXK_TIM_MAX_POOL_CACHE_SZ  (128)
+#define CNXK_TIM_MAX_POOL_CACHE_SZ  (16)
 
 #define CN9K_TIM_MIN_TMO_TKS (256)
 
@@ -119,18 +119,18 @@ struct cnxk_tim_bkt {
 };
 
 struct cnxk_tim_ring {
-	uintptr_t base;
 	uint16_t nb_chunk_slots;
 	uint32_t nb_bkts;
-	uint64_t last_updt_cyc;
+	uintptr_t tbase;
+	uint64_t (*tick_fn)(uint64_t tbase);
 	uint64_t ring_start_cyc;
-	uint64_t tck_int;
-	uint64_t tot_int;
 	struct cnxk_tim_bkt *bkt;
 	struct rte_mempool *chunk_pool;
 	struct rte_reciprocal_u64 fast_div;
 	struct rte_reciprocal_u64 fast_bkt;
+	uint64_t tck_int;
 	uint64_t arm_cnt;
+	uintptr_t base;
 	uint8_t prod_type_sp;
 	uint8_t enable_stats;
 	uint8_t disable_npa;
@@ -163,19 +163,19 @@ cnxk_tim_priv_get(void)
 	return mz->addr;
 }
 
-static inline long double
+static inline double
 cnxk_tim_ns_per_tck(uint64_t freq)
 {
-	return (long double)NSECPERSEC / freq;
+	return (double)NSECPERSEC / freq;
 }
 
 #ifdef RTE_ARCH_ARM64
 static inline uint64_t
-cnxk_tim_cntvct(void)
+cnxk_tim_cntvct(uint64_t base __rte_unused)
 {
 	uint64_t tsc;
 
-	asm volatile("mrs %0, cntvct_el0" : "=r"(tsc));
+	asm volatile("mrs %0, CNTVCT_EL0" : "=r"(tsc)::"memory");
 	return tsc;
 }
 
@@ -189,7 +189,7 @@ cnxk_tim_cntfrq(void)
 }
 #else
 static inline uint64_t
-cnxk_tim_cntvct(void)
+cnxk_tim_cntvct(uint64_t base __rte_unused)
 {
 	return 0;
 }
@@ -201,6 +201,12 @@ cnxk_tim_cntfrq(void)
 }
 #endif
 
+static inline uint64_t
+cnxk_tim_tick_read(uint64_t tick_base)
+{
+	return plt_read64(tick_base);
+}
+
 static inline enum roc_tim_clk_src
 cnxk_tim_convert_clk_src(enum rte_event_timer_adapter_clk_src clk_src)
 {
@@ -221,6 +227,27 @@ cnxk_tim_convert_clk_src(enum rte_event_timer_adapter_clk_src clk_src)
 	}
 }
 
+static inline uintptr_t
+cnxk_tim_get_tick_base(enum roc_tim_clk_src clk_src, uintptr_t base)
+{
+	switch (clk_src) {
+	case ROC_TIM_CLK_SRC_GTI:
+		return base + TIM_LF_FR_RN_GTI;
+	case ROC_TIM_CLK_SRC_GPIO:
+		return base + TIM_LF_FR_RN_GPIOS;
+	case ROC_TIM_CLK_SRC_10NS:
+		return base + TIM_LF_FR_RN_TENNS;
+	case ROC_TIM_CLK_SRC_PTP:
+		return base + TIM_LF_FR_RN_PTP;
+	case ROC_TIM_CLK_SRC_SYNCE:
+		return base + TIM_LF_FR_RN_SYNCE;
+	case ROC_TIM_CLK_SRC_BTS:
+		return base + TIM_LF_FR_RN_BTS;
+	default:
+		return ROC_TIM_CLK_SRC_INVALID;
+	}
+}
+
 static inline int
 cnxk_tim_get_clk_freq(struct cnxk_tim_evdev *dev, enum roc_tim_clk_src clk_src,
 		      uint64_t *freq)
diff --git a/drivers/event/cnxk/cnxk_tim_worker.c b/drivers/event/cnxk/cnxk_tim_worker.c
index dfcfbdc797..923a72093b 100644
--- a/drivers/event/cnxk/cnxk_tim_worker.c
+++ b/drivers/event/cnxk/cnxk_tim_worker.c
@@ -39,22 +39,6 @@ cnxk_tim_format_event(const struct rte_event_timer *const tim,
 	entry->wqe = tim->ev.u64;
 }
 
-static inline void
-cnxk_tim_sync_start_cyc(struct cnxk_tim_ring *tim_ring)
-{
-	uint64_t cur_cyc = cnxk_tim_cntvct();
-	uint32_t real_bkt;
-
-	if (cur_cyc - tim_ring->last_updt_cyc > tim_ring->tot_int) {
-		real_bkt = plt_read64(tim_ring->base + TIM_LF_RING_REL) >> 44;
-		cur_cyc = cnxk_tim_cntvct();
-
-		tim_ring->ring_start_cyc =
-			cur_cyc - (real_bkt * tim_ring->tck_int);
-		tim_ring->last_updt_cyc = cur_cyc;
-	}
-}
-
 static __rte_always_inline uint16_t
 cnxk_tim_timer_arm_burst(const struct rte_event_timer_adapter *adptr,
 			 struct rte_event_timer **tim, const uint16_t nb_timers,
@@ -65,7 +49,6 @@ cnxk_tim_timer_arm_burst(const struct rte_event_timer_adapter *adptr,
 	uint16_t index;
 	int ret = 0;
 
-	cnxk_tim_sync_start_cyc(tim_ring);
 	for (index = 0; index < nb_timers; index++) {
 		if (cnxk_tim_arm_checks(tim_ring, tim[index]))
 			break;
@@ -127,7 +110,6 @@ cnxk_tim_timer_arm_tmo_brst(const struct rte_event_timer_adapter *adptr,
 		return 0;
 	}
 
-	cnxk_tim_sync_start_cyc(tim_ring);
 	while (arr_idx < nb_timers) {
 		for (idx = 0; idx < CNXK_TIM_MAX_BURST && (arr_idx < nb_timers);
 		     idx++, arr_idx++) {
diff --git a/drivers/event/cnxk/cnxk_tim_worker.h b/drivers/event/cnxk/cnxk_tim_worker.h
index 0c9f29cfbe..8d8ed1d3a1 100644
--- a/drivers/event/cnxk/cnxk_tim_worker.h
+++ b/drivers/event/cnxk/cnxk_tim_worker.h
@@ -131,7 +131,8 @@ cnxk_tim_get_target_bucket(struct cnxk_tim_ring *const tim_ring,
 			   const uint32_t rel_bkt, struct cnxk_tim_bkt **bkt,
 			   struct cnxk_tim_bkt **mirr_bkt)
 {
-	const uint64_t bkt_cyc = cnxk_tim_cntvct() - tim_ring->ring_start_cyc;
+	const uint64_t bkt_cyc =
+		tim_ring->tick_fn(tim_ring->tbase) - tim_ring->ring_start_cyc;
 	uint64_t bucket =
 		rte_reciprocal_divide_u64(bkt_cyc, &tim_ring->fast_div) +
 		rel_bkt;
-- 
2.25.1