[PATCH v6 1/1] baseband/acc100: add workaround for deRM corner cases

[Hernan Vargas <hernan.vargas@intel.com>]

Add function to support de-ratematch pre-processing for SW corner cases.
Some specific 5GUL FEC corner cases may cause unintended back pressure
and in some cases a potential stability issue on the ACC100.
To be able to avoid completely such potential issue, the PMD can preempt
such code block configuration so that to process the first level deRM
in SW using the SDK libraries prior to running the rest of the FEC
decoding in HW using an amended code block configuration.
In case meson build system doesn't find such SDK libraries, the fall
method is to run in HW with a warning.

Signed-off-by: Hernan Vargas <hernan.vargas@intel.com>
---
 drivers/baseband/acc/acc_common.h     |   8 ++
 drivers/baseband/acc/meson.build      |  21 +++++
 drivers/baseband/acc/rte_acc100_pmd.c | 108 +++++++++++++++++++++++++-
 3 files changed, 134 insertions(+), 3 deletions(-)

diff --git a/drivers/baseband/acc/acc_common.h b/drivers/baseband/acc/acc_common.h
index eae7eab4e9..5e8972b40a 100644
--- a/drivers/baseband/acc/acc_common.h
+++ b/drivers/baseband/acc/acc_common.h
@@ -123,6 +123,14 @@
 #define ACC_HARQ_ALIGN_64B          64
 #define ACC_MAX_ZC                  384
 
+/* De-ratematch code rate limitation when padding is required */
+#define ACC_LIM_03 2  /* 0.03 */
+#define ACC_LIM_09 6  /* 0.09 */
+#define ACC_LIM_14 9  /* 0.14 */
+#define ACC_LIM_21 14 /* 0.21 */
+#define ACC_LIM_31 20 /* 0.31 */
+#define ACC_MAX_E (128 * 1024 - 2)
+
 /* Helper macro for logging */
 #define rte_acc_log(level, fmt, ...) \
 	rte_log(RTE_LOG_ ## level, RTE_LOG_NOTICE, fmt "\n", \
diff --git a/drivers/baseband/acc/meson.build b/drivers/baseband/acc/meson.build
index 77c393b533..a5fc4fed01 100644
--- a/drivers/baseband/acc/meson.build
+++ b/drivers/baseband/acc/meson.build
@@ -1,6 +1,27 @@
 # SPDX-License-Identifier: BSD-3-Clause
 # Copyright(c) 2020 Intel Corporation
 
+# Check for FlexRAN SDK libraries
+dep_dec5g = dependency('flexran_sdk_ldpc_decoder_5gnr', required: false)
+
+if dep_dec5g.found()
+    ext_deps += cc.find_library('libstdc++', required: true)
+    ext_deps += cc.find_library('libirc', required: true)
+    ext_deps += cc.find_library('libimf', required: true)
+    ext_deps += cc.find_library('libipps', required: true)
+    ext_deps += cc.find_library('libsvml', required: true)
+    ext_deps += dep_dec5g
+    ext_deps += dependency('flexran_sdk_ldpc_encoder_5gnr', required: true)
+    ext_deps += dependency('flexran_sdk_LDPC_ratematch_5gnr', required: true)
+    ext_deps += dependency('flexran_sdk_rate_dematching_5gnr', required: true)
+    ext_deps += dependency('flexran_sdk_turbo', required: true)
+    ext_deps += dependency('flexran_sdk_crc', required: true)
+    ext_deps += dependency('flexran_sdk_rate_matching', required: true)
+    ext_deps += dependency('flexran_sdk_common', required: true)
+    cflags += ['-DRTE_BBDEV_SDK_AVX2']
+    cflags += ['-DRTE_BBDEV_SDK_AVX512']
+endif
+
 deps += ['bbdev', 'bus_pci']
 
 sources = files('rte_acc100_pmd.c', 'rte_acc200_pmd.c')
diff --git a/drivers/baseband/acc/rte_acc100_pmd.c b/drivers/baseband/acc/rte_acc100_pmd.c
index 23bc5d25bb..e8b230e563 100644
--- a/drivers/baseband/acc/rte_acc100_pmd.c
+++ b/drivers/baseband/acc/rte_acc100_pmd.c
@@ -25,6 +25,10 @@
 #include "acc101_pmd.h"
 #include "acc200_cfg.h"
 
+#ifdef RTE_BBDEV_SDK_AVX512
+#include <phy_rate_dematching_5gnr.h>
+#endif
+
 #ifdef RTE_LIBRTE_BBDEV_DEBUG
 RTE_LOG_REGISTER_DEFAULT(acc100_logtype, DEBUG);
 #else
@@ -756,6 +760,14 @@ acc100_queue_setup(struct rte_bbdev *dev, uint16_t queue_id,
 		ret = -ENOMEM;
 		goto free_lb_out;
 	}
+	q->derm_buffer = rte_zmalloc_socket(dev->device->driver->name,
+			RTE_BBDEV_TURBO_MAX_CB_SIZE * 10,
+			RTE_CACHE_LINE_SIZE, conf->socket);
+	if (q->derm_buffer == NULL) {
+		rte_bbdev_log(ERR, "Failed to allocate derm_buffer memory");
+		ret = -ENOMEM;
+		goto free_companion_ring_addr;
+	}
 
 	/*
 	 * Software queue ring wraps synchronously with the HW when it reaches
@@ -776,7 +788,7 @@ acc100_queue_setup(struct rte_bbdev *dev, uint16_t queue_id,
 	q_idx = acc100_find_free_queue_idx(dev, conf);
 	if (q_idx == -1) {
 		ret = -EINVAL;
-		goto free_companion_ring_addr;
+		goto free_derm_buffer;
 	}
 
 	q->qgrp_id = (q_idx >> ACC100_GRP_ID_SHIFT) & 0xF;
@@ -804,6 +816,9 @@ acc100_queue_setup(struct rte_bbdev *dev, uint16_t queue_id,
 	dev->data->queues[queue_id].queue_private = q;
 	return 0;
 
+free_derm_buffer:
+	rte_free(q->derm_buffer);
+	q->derm_buffer = NULL;
 free_companion_ring_addr:
 	rte_free(q->companion_ring_addr);
 	q->companion_ring_addr = NULL;
@@ -890,6 +905,7 @@ acc100_queue_release(struct rte_bbdev *dev, uint16_t q_id)
 		/* Mark the Queue as un-assigned */
 		d->q_assigned_bit_map[q->qgrp_id] &= (0xFFFFFFFFFFFFFFFF -
 				(uint64_t) (1 << q->aq_id));
+		rte_free(q->derm_buffer);
 		rte_free(q->companion_ring_addr);
 		rte_free(q->lb_in);
 		rte_free(q->lb_out);
@@ -3111,10 +3127,44 @@ harq_loopback(struct acc_queue *q, struct rte_bbdev_dec_op *op,
 	return 1;
 }
 
+/** Assess whether a work around is required for the deRM corner cases */
+static inline bool
+derm_workaround_required(struct rte_bbdev_op_ldpc_dec *ldpc_dec, struct acc_queue *q)
+{
+	if (!is_acc100(q))
+		return false;
+	int32_t e = ldpc_dec->cb_params.e;
+	int q_m = ldpc_dec->q_m;
+	int z_c = ldpc_dec->z_c;
+	int K = (ldpc_dec->basegraph == 1 ? ACC_K_ZC_1 : ACC_K_ZC_2)
+			* z_c;
+
+	bool required = false;
+	if (ldpc_dec->basegraph == 1) {
+		if ((q_m == 4) && (z_c >= 320) && (e * ACC_LIM_31 > K * 64))
+			required = true;
+		else if ((e * ACC_LIM_21 > K * 64))
+			required = true;
+	} else {
+		if (q_m <= 2) {
+			if ((z_c >= 208) && (e * ACC_LIM_09 > K * 64))
+				required = true;
+			else if ((z_c < 208) && (e * ACC_LIM_03 > K * 64))
+				required = true;
+		} else if (e * ACC_LIM_14 > K * 64)
+			required = true;
+	}
+	if (required)
+		rte_bbdev_log(INFO, "Running deRM pre-processing in SW");
+
+	return required;
+}
+
 /** Enqueue one decode operations for ACC100 device in CB mode */
 static inline int
 enqueue_ldpc_dec_one_op_cb(struct acc_queue *q, struct rte_bbdev_dec_op *op,
-		uint16_t total_enqueued_cbs, bool same_op)
+		uint16_t total_enqueued_cbs, bool same_op,
+		struct rte_bbdev_queue_data *q_data)
 {
 	int ret;
 	if (unlikely(check_bit(op->ldpc_dec.op_flags,
@@ -3168,6 +3218,58 @@ enqueue_ldpc_dec_one_op_cb(struct acc_queue *q, struct rte_bbdev_dec_op *op,
 	} else {
 		struct acc_fcw_ld *fcw;
 		uint32_t seg_total_left;
+
+		if (derm_workaround_required(&op->ldpc_dec, q)) {
+			#ifdef RTE_BBDEV_SDK_AVX512
+			struct rte_bbdev_op_ldpc_dec *dec = &op->ldpc_dec;
+			struct bblib_rate_dematching_5gnr_request derm_req;
+			struct bblib_rate_dematching_5gnr_response derm_resp;
+			uint8_t *in;
+
+			/* Checking input size is matching with E */
+			if (dec->input.data->data_len < dec->cb_params.e) {
+				rte_bbdev_log(ERR, "deRM: Input size mismatch");
+				return -EFAULT;
+			}
+			/* Run first deRM processing in SW */
+			in = rte_pktmbuf_mtod_offset(dec->input.data, uint8_t *, in_offset);
+			derm_req.p_in = (int8_t *) in;
+			derm_req.p_harq = (int8_t *) q->derm_buffer;
+			derm_req.base_graph = dec->basegraph;
+			derm_req.zc = dec->z_c;
+			derm_req.ncb = dec->n_cb;
+			derm_req.e = dec->cb_params.e;
+			if (derm_req.e > ACC_MAX_E) {
+				rte_bbdev_log(WARNING,
+						"deRM: E %d > %d max",
+						derm_req.e, ACC_MAX_E);
+				derm_req.e = ACC_MAX_E;
+			}
+			derm_req.k0 = 0; /* Actual output from SDK */
+			derm_req.isretx = false;
+			derm_req.rvid = dec->rv_index;
+			derm_req.modulation_order = dec->q_m;
+			derm_req.start_null_index =
+					(dec->basegraph == 1 ? 22 : 10)
+					* dec->z_c - 2 * dec->z_c
+					- dec->n_filler;
+			derm_req.num_of_null = dec->n_filler;
+			bblib_rate_dematching_5gnr(&derm_req, &derm_resp);
+			/* Force back the HW DeRM */
+			dec->q_m = 1;
+			dec->cb_params.e = dec->n_cb - dec->n_filler;
+			dec->rv_index = 0;
+			rte_memcpy(in, q->derm_buffer, dec->cb_params.e);
+			/* Capture counter when pre-processing is used */
+			q_data->queue_stats.enqueue_warn_count++;
+			#else
+			RTE_SET_USED(q_data);
+			rte_bbdev_log(WARNING,
+				"Corner case may require deRM pre-processing in SDK"
+				);
+			#endif
+		}
+
 		fcw = &desc->req.fcw_ld;
 		q->d->fcw_ld_fill(op, fcw, harq_layout);
 
@@ -3721,7 +3823,7 @@ acc100_enqueue_ldpc_dec_cb(struct rte_bbdev_queue_data *q_data,
 			ops[i]->ldpc_dec.n_cb, ops[i]->ldpc_dec.q_m,
 			ops[i]->ldpc_dec.n_filler, ops[i]->ldpc_dec.cb_params.e,
 			same_op);
-		ret = enqueue_ldpc_dec_one_op_cb(q, ops[i], i, same_op);
+		ret = enqueue_ldpc_dec_one_op_cb(q, ops[i], i, same_op, q_data);
 		if (ret < 0) {
 			acc_enqueue_invalid(q_data);
 			break;
-- 
2.37.1