1/*
  2 * OpenFirmware helpers for memory drivers
  3 *
  4 * Copyright (C) 2012 Texas Instruments, Inc.
  5 *
  6 * This program is free software; you can redistribute it and/or modify
  7 * it under the terms of the GNU General Public License as published by
  8 * the Free Software Foundation; either version 2 of the License, or
  9 * (at your option) any later version.
 10 */
 11
 12#include <linux/device.h>
 13#include <linux/platform_device.h>
 14#include <linux/list.h>
 15#include <linux/of.h>
 16#include <linux/gfp.h>
 17#include <memory/jedec_ddr.h>
 18#include <linux/export.h>
 19
 20/**
 21 * of_get_min_tck() - extract min timing values for ddr
 22 * @np: pointer to ddr device tree node
 23 * @device: device requesting for min timing values
 24 *
 25 * Populates the lpddr2_min_tck structure by extracting data
 26 * from device tree node. Returns a pointer to the populated
 27 * structure. If any error in populating the structure, returns
 28 * default min timings provided by JEDEC.
 29 */
 30const struct lpddr2_min_tck *of_get_min_tck(struct device_node *np,
 31		struct device *dev)
 32{
 33	int			ret = 0;
 34	struct lpddr2_min_tck	*min;
 35
 36	min = devm_kzalloc(dev, sizeof(*min), GFP_KERNEL);
 37	if (!min)
 38		goto default_min_tck;
 39
 40	ret |= of_property_read_u32(np, "tRPab-min-tck", &min->tRPab);
 41	ret |= of_property_read_u32(np, "tRCD-min-tck", &min->tRCD);
 42	ret |= of_property_read_u32(np, "tWR-min-tck", &min->tWR);
 43	ret |= of_property_read_u32(np, "tRASmin-min-tck", &min->tRASmin);
 44	ret |= of_property_read_u32(np, "tRRD-min-tck", &min->tRRD);
 45	ret |= of_property_read_u32(np, "tWTR-min-tck", &min->tWTR);
 46	ret |= of_property_read_u32(np, "tXP-min-tck", &min->tXP);
 47	ret |= of_property_read_u32(np, "tRTP-min-tck", &min->tRTP);
 48	ret |= of_property_read_u32(np, "tCKE-min-tck", &min->tCKE);
 49	ret |= of_property_read_u32(np, "tCKESR-min-tck", &min->tCKESR);
 50	ret |= of_property_read_u32(np, "tFAW-min-tck", &min->tFAW);
 51
 52	if (ret) {
 53		devm_kfree(dev, min);
 54		goto default_min_tck;
 55	}
 56
 57	return min;
 58
 59default_min_tck:
 60	dev_warn(dev, "%s: using default min-tck values\n", __func__);
 61	return &lpddr2_jedec_min_tck;
 62}
 63EXPORT_SYMBOL(of_get_min_tck);
 64
 65static int of_do_get_timings(struct device_node *np,
 66		struct lpddr2_timings *tim)
 67{
 68	int ret;
 69
 70	ret = of_property_read_u32(np, "max-freq", &tim->max_freq);
 71	ret |= of_property_read_u32(np, "min-freq", &tim->min_freq);
 72	ret |= of_property_read_u32(np, "tRPab", &tim->tRPab);
 73	ret |= of_property_read_u32(np, "tRCD", &tim->tRCD);
 74	ret |= of_property_read_u32(np, "tWR", &tim->tWR);
 75	ret |= of_property_read_u32(np, "tRAS-min", &tim->tRAS_min);
 76	ret |= of_property_read_u32(np, "tRRD", &tim->tRRD);
 77	ret |= of_property_read_u32(np, "tWTR", &tim->tWTR);
 78	ret |= of_property_read_u32(np, "tXP", &tim->tXP);
 79	ret |= of_property_read_u32(np, "tRTP", &tim->tRTP);
 80	ret |= of_property_read_u32(np, "tCKESR", &tim->tCKESR);
 81	ret |= of_property_read_u32(np, "tDQSCK-max", &tim->tDQSCK_max);
 82	ret |= of_property_read_u32(np, "tFAW", &tim->tFAW);
 83	ret |= of_property_read_u32(np, "tZQCS", &tim->tZQCS);
 84	ret |= of_property_read_u32(np, "tZQCL", &tim->tZQCL);
 85	ret |= of_property_read_u32(np, "tZQinit", &tim->tZQinit);
 86	ret |= of_property_read_u32(np, "tRAS-max-ns", &tim->tRAS_max_ns);
 87	ret |= of_property_read_u32(np, "tDQSCK-max-derated",
 88		&tim->tDQSCK_max_derated);
 89
 90	return ret;
 91}
 92
 93/**
 94 * of_get_ddr_timings() - extracts the ddr timings and updates no of
 95 * frequencies available.
 96 * @np_ddr: Pointer to ddr device tree node
 97 * @dev: Device requesting for ddr timings
 98 * @device_type: Type of ddr(LPDDR2 S2/S4)
 99 * @nr_frequencies: No of frequencies available for ddr
100 * (updated by this function)
101 *
102 * Populates lpddr2_timings structure by extracting data from device
103 * tree node. Returns pointer to populated structure. If any error
104 * while populating, returns default timings provided by JEDEC.
105 */
106const struct lpddr2_timings *of_get_ddr_timings(struct device_node *np_ddr,
107		struct device *dev, u32 device_type, u32 *nr_frequencies)
108{
109	struct lpddr2_timings	*timings = NULL;
110	u32			arr_sz = 0, i = 0;
111	struct device_node	*np_tim;
112	char			*tim_compat;
113
114	switch (device_type) {
115	case DDR_TYPE_LPDDR2_S2:
116	case DDR_TYPE_LPDDR2_S4:
117		tim_compat = "jedec,lpddr2-timings";
118		break;
119	default:
120		dev_warn(dev, "%s: un-supported memory type\n", __func__);
121	}
122
123	for_each_child_of_node(np_ddr, np_tim)
124		if (of_device_is_compatible(np_tim, tim_compat))
125			arr_sz++;
126
127	if (arr_sz)
128		timings = devm_kzalloc(dev, sizeof(*timings) * arr_sz,
129			GFP_KERNEL);
130
131	if (!timings)
132		goto default_timings;
133
134	for_each_child_of_node(np_ddr, np_tim) {
135		if (of_device_is_compatible(np_tim, tim_compat)) {
136			if (of_do_get_timings(np_tim, &timings[i])) {
137				devm_kfree(dev, timings);
138				goto default_timings;
139			}
140			i++;
141		}
142	}
143
144	*nr_frequencies = arr_sz;
145
146	return timings;
147
148default_timings:
149	dev_warn(dev, "%s: using default timings\n", __func__);
150	*nr_frequencies = ARRAY_SIZE(lpddr2_jedec_timings);
151	return lpddr2_jedec_timings;
152}
153EXPORT_SYMBOL(of_get_ddr_timings);