1// SPDX-License-Identifier: GPL-2.0-or-later
  2/*
  3 * OpenFirmware helpers for memory drivers
  4 *
  5 * Copyright (C) 2012 Texas Instruments, Inc.
  6 */
  7
  8#include <linux/device.h>
  9#include <linux/platform_device.h>
 10#include <linux/list.h>
 11#include <linux/of.h>
 12#include <linux/gfp.h>
 13#include <linux/export.h>
 14
 15#include "jedec_ddr.h"
 16#include "of_memory.h"
 17
 18/**
 19 * of_get_min_tck() - extract min timing values for ddr
 20 * @np: pointer to ddr device tree node
 21 * @device: device requesting for min timing values
 22 *
 23 * Populates the lpddr2_min_tck structure by extracting data
 24 * from device tree node. Returns a pointer to the populated
 25 * structure. If any error in populating the structure, returns
 26 * default min timings provided by JEDEC.
 27 */
 28const struct lpddr2_min_tck *of_get_min_tck(struct device_node *np,
 29		struct device *dev)
 30{
 31	int			ret = 0;
 32	struct lpddr2_min_tck	*min;
 33
 34	min = devm_kzalloc(dev, sizeof(*min), GFP_KERNEL);
 35	if (!min)
 36		goto default_min_tck;
 37
 38	ret |= of_property_read_u32(np, "tRPab-min-tck", &min->tRPab);
 39	ret |= of_property_read_u32(np, "tRCD-min-tck", &min->tRCD);
 40	ret |= of_property_read_u32(np, "tWR-min-tck", &min->tWR);
 41	ret |= of_property_read_u32(np, "tRASmin-min-tck", &min->tRASmin);
 42	ret |= of_property_read_u32(np, "tRRD-min-tck", &min->tRRD);
 43	ret |= of_property_read_u32(np, "tWTR-min-tck", &min->tWTR);
 44	ret |= of_property_read_u32(np, "tXP-min-tck", &min->tXP);
 45	ret |= of_property_read_u32(np, "tRTP-min-tck", &min->tRTP);
 46	ret |= of_property_read_u32(np, "tCKE-min-tck", &min->tCKE);
 47	ret |= of_property_read_u32(np, "tCKESR-min-tck", &min->tCKESR);
 48	ret |= of_property_read_u32(np, "tFAW-min-tck", &min->tFAW);
 49
 50	if (ret) {
 51		devm_kfree(dev, min);
 52		goto default_min_tck;
 53	}
 54
 55	return min;
 56
 57default_min_tck:
 58	dev_warn(dev, "%s: using default min-tck values\n", __func__);
 59	return &lpddr2_jedec_min_tck;
 60}
 61EXPORT_SYMBOL(of_get_min_tck);
 62
 63static int of_do_get_timings(struct device_node *np,
 64		struct lpddr2_timings *tim)
 65{
 66	int ret;
 67
 68	ret = of_property_read_u32(np, "max-freq", &tim->max_freq);
 69	ret |= of_property_read_u32(np, "min-freq", &tim->min_freq);
 70	ret |= of_property_read_u32(np, "tRPab", &tim->tRPab);
 71	ret |= of_property_read_u32(np, "tRCD", &tim->tRCD);
 72	ret |= of_property_read_u32(np, "tWR", &tim->tWR);
 73	ret |= of_property_read_u32(np, "tRAS-min", &tim->tRAS_min);
 74	ret |= of_property_read_u32(np, "tRRD", &tim->tRRD);
 75	ret |= of_property_read_u32(np, "tWTR", &tim->tWTR);
 76	ret |= of_property_read_u32(np, "tXP", &tim->tXP);
 77	ret |= of_property_read_u32(np, "tRTP", &tim->tRTP);
 78	ret |= of_property_read_u32(np, "tCKESR", &tim->tCKESR);
 79	ret |= of_property_read_u32(np, "tDQSCK-max", &tim->tDQSCK_max);
 80	ret |= of_property_read_u32(np, "tFAW", &tim->tFAW);
 81	ret |= of_property_read_u32(np, "tZQCS", &tim->tZQCS);
 82	ret |= of_property_read_u32(np, "tZQCL", &tim->tZQCL);
 83	ret |= of_property_read_u32(np, "tZQinit", &tim->tZQinit);
 84	ret |= of_property_read_u32(np, "tRAS-max-ns", &tim->tRAS_max_ns);
 85	ret |= of_property_read_u32(np, "tDQSCK-max-derated",
 86		&tim->tDQSCK_max_derated);
 87
 88	return ret;
 89}
 90
 91/**
 92 * of_get_ddr_timings() - extracts the ddr timings and updates no of
 93 * frequencies available.
 94 * @np_ddr: Pointer to ddr device tree node
 95 * @dev: Device requesting for ddr timings
 96 * @device_type: Type of ddr(LPDDR2 S2/S4)
 97 * @nr_frequencies: No of frequencies available for ddr
 98 * (updated by this function)
 99 *
100 * Populates lpddr2_timings structure by extracting data from device
101 * tree node. Returns pointer to populated structure. If any error
102 * while populating, returns default timings provided by JEDEC.
103 */
104const struct lpddr2_timings *of_get_ddr_timings(struct device_node *np_ddr,
105		struct device *dev, u32 device_type, u32 *nr_frequencies)
106{
107	struct lpddr2_timings	*timings = NULL;
108	u32			arr_sz = 0, i = 0;
109	struct device_node	*np_tim;
110	char			*tim_compat = NULL;
111
112	switch (device_type) {
113	case DDR_TYPE_LPDDR2_S2:
114	case DDR_TYPE_LPDDR2_S4:
115		tim_compat = "jedec,lpddr2-timings";
116		break;
117	default:
118		dev_warn(dev, "%s: un-supported memory type\n", __func__);
119	}
120
121	for_each_child_of_node(np_ddr, np_tim)
122		if (of_device_is_compatible(np_tim, tim_compat))
123			arr_sz++;
124
125	if (arr_sz)
126		timings = devm_kcalloc(dev, arr_sz, sizeof(*timings),
127				       GFP_KERNEL);
128
129	if (!timings)
130		goto default_timings;
131
132	for_each_child_of_node(np_ddr, np_tim) {
133		if (of_device_is_compatible(np_tim, tim_compat)) {
134			if (of_do_get_timings(np_tim, &timings[i])) {
135				devm_kfree(dev, timings);
136				goto default_timings;
137			}
138			i++;
139		}
140	}
141
142	*nr_frequencies = arr_sz;
143
144	return timings;
145
146default_timings:
147	dev_warn(dev, "%s: using default timings\n", __func__);
148	*nr_frequencies = ARRAY_SIZE(lpddr2_jedec_timings);
149	return lpddr2_jedec_timings;
150}
151EXPORT_SYMBOL(of_get_ddr_timings);