// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (C) 2018-2020 Oplus. All rights reserved.
 */

#include "ufs_latency_hist.h"
#include <linux/math64.h>
/*
 * Blk IO latency support. We want this to be as cheap as possible, so doing
 * this lockless (and avoiding atomics), a few off by a few errors in this
 * code is not harmful, and we don't want to do anything that is
 * perf-impactful.
 * TODO : If necessary, we can make the histograms per-cpu and aggregate
 * them when printing them out.
 */
ssize_t
io_latency_hist_show(char* name, struct io_latency_state *s, char *buf,
		int buf_size)
{
   int i;
   int bytes_written = 0;
   u_int64_t num_elem, elem;
   int pct;
   u_int64_t average;

   num_elem = s->latency_elems;
   if (num_elem > 0) {
	   average = div64_u64(s->latency_sum, s->latency_elems);
	   bytes_written += scnprintf(buf + bytes_written,
	      buf_size - bytes_written,
		   "IO %s(count = %llu,"
		   " average = %lluus)\t0\t4k\t8k\t8-32k\t32-64k\t64-128k\t128-256k\t>256k:\n", name, num_elem, average);
	   for (i = 0;i < ARRAY_SIZE(latency_x_axis_us);i++) {
		   elem = s->latency_y_axis[i].latency_axis;
		   pct = div64_u64(elem * 100, num_elem);
		   bytes_written += scnprintf(buf + bytes_written,
			   8192 - bytes_written,
			   "\t< %6lluus\t%llu\t%d%%\t%llu\t%llu\t%llu\t%llu\t%llu\t%llu\t%llu\t\t%llu\n",
			   latency_x_axis_us[i],
			   elem, pct,
			   s->latency_y_axis[i].chunk_0_count,
			   s->latency_y_axis[i].chunk_4k_count,
			   s->latency_y_axis[i].chunk_8k_count,
			   s->latency_y_axis[i].chunk_8_32k_count,
			   s->latency_y_axis[i].chunk_32_64k_count,
			   s->latency_y_axis[i].chunk_64_128k_count,
			   s->latency_y_axis[i].chunk_128_256k_count,
			   s->latency_y_axis[i].chunk_above_256k_count
			   );
	   }
	   /* Last element in y-axis table is overflow */
      elem = s->latency_y_axis[i].latency_axis;
	   pct = div64_u64(elem * 100, num_elem);
	   bytes_written += scnprintf(buf + bytes_written,
			   8192 - bytes_written,
			   "\t>=%6lluus\t%llu\t%d%%\t%llu\t%llu\t%llu\t%llu\t%llu\t%llu\t%llu\t\t%llu\n",
			   latency_x_axis_us[i - 1],
			   elem, pct,
			   s->latency_y_axis[i].chunk_0_count,
			   s->latency_y_axis[i].chunk_4k_count,
			   s->latency_y_axis[i].chunk_8k_count,
			   s->latency_y_axis[i].chunk_8_32k_count,
			   s->latency_y_axis[i].chunk_32_64k_count,
			   s->latency_y_axis[i].chunk_64_128k_count,
			   s->latency_y_axis[i].chunk_128_256k_count,
			   s->latency_y_axis[i].chunk_above_256k_count
			   );
	}

	return bytes_written;
}