1// SPDX-License-Identifier: GPL-2.0
  2//
  3// Copyright (c) 2015 Samsung Electronics Co., Ltd.
  4//	      http://www.samsung.com/
  5//
  6// EXYNOS - SROM Controller support
  7// Author: Pankaj Dubey <pankaj.dubey@samsung.com>
  8
  9#include <linux/io.h>
 10#include <linux/init.h>
 11#include <linux/of.h>
 12#include <linux/of_address.h>
 13#include <linux/of_platform.h>
 14#include <linux/platform_device.h>
 15#include <linux/slab.h>
 16
 17#include "exynos-srom.h"
 18
 19static const unsigned long exynos_srom_offsets[] = {
 20	/* SROM side */
 21	EXYNOS_SROM_BW,
 22	EXYNOS_SROM_BC0,
 23	EXYNOS_SROM_BC1,
 24	EXYNOS_SROM_BC2,
 25	EXYNOS_SROM_BC3,
 26};
 27
 28/**
 29 * struct exynos_srom_reg_dump: register dump of SROM Controller registers.
 30 * @offset: srom register offset from the controller base address.
 31 * @value: the value of register under the offset.
 32 */
 33struct exynos_srom_reg_dump {
 34	u32     offset;
 35	u32     value;
 36};
 37
 38/**
 39 * struct exynos_srom: platform data for exynos srom controller driver.
 40 * @dev: platform device pointer
 41 * @reg_base: srom base address
 42 * @reg_offset: exynos_srom_reg_dump pointer to hold offset and its value.
 43 */
 44struct exynos_srom {
 45	struct device *dev;
 46	void __iomem *reg_base;
 47	struct exynos_srom_reg_dump *reg_offset;
 48};
 49
 50static struct exynos_srom_reg_dump *exynos_srom_alloc_reg_dump(
 51		const unsigned long *rdump,
 52		unsigned long nr_rdump)
 53{
 54	struct exynos_srom_reg_dump *rd;
 55	unsigned int i;
 56
 57	rd = kcalloc(nr_rdump, sizeof(*rd), GFP_KERNEL);
 58	if (!rd)
 59		return NULL;
 60
 61	for (i = 0; i < nr_rdump; ++i)
 62		rd[i].offset = rdump[i];
 63
 64	return rd;
 65}
 66
 67static int exynos_srom_configure_bank(struct exynos_srom *srom,
 68				      struct device_node *np)
 69{
 70	u32 bank, width, pmc = 0;
 71	u32 timing[6];
 72	u32 cs, bw;
 73
 74	if (of_property_read_u32(np, "reg", &bank))
 75		return -EINVAL;
 76	if (of_property_read_u32(np, "reg-io-width", &width))
 77		width = 1;
 78	if (of_property_read_bool(np, "samsung,srom-page-mode"))
 79		pmc = 1 << EXYNOS_SROM_BCX__PMC__SHIFT;
 80	if (of_property_read_u32_array(np, "samsung,srom-timing", timing,
 81				       ARRAY_SIZE(timing)))
 82		return -EINVAL;
 83
 84	bank *= 4; /* Convert bank into shift/offset */
 85
 86	cs = 1 << EXYNOS_SROM_BW__BYTEENABLE__SHIFT;
 87	if (width == 2)
 88		cs |= 1 << EXYNOS_SROM_BW__DATAWIDTH__SHIFT;
 89
 90	bw = readl_relaxed(srom->reg_base + EXYNOS_SROM_BW);
 91	bw = (bw & ~(EXYNOS_SROM_BW__CS_MASK << bank)) | (cs << bank);
 92	writel_relaxed(bw, srom->reg_base + EXYNOS_SROM_BW);
 93
 94	writel_relaxed(pmc | (timing[0] << EXYNOS_SROM_BCX__TACP__SHIFT) |
 95		       (timing[1] << EXYNOS_SROM_BCX__TCAH__SHIFT) |
 96		       (timing[2] << EXYNOS_SROM_BCX__TCOH__SHIFT) |
 97		       (timing[3] << EXYNOS_SROM_BCX__TACC__SHIFT) |
 98		       (timing[4] << EXYNOS_SROM_BCX__TCOS__SHIFT) |
 99		       (timing[5] << EXYNOS_SROM_BCX__TACS__SHIFT),
100		       srom->reg_base + EXYNOS_SROM_BC0 + bank);
101
102	return 0;
103}
104
105static int exynos_srom_probe(struct platform_device *pdev)
106{
107	struct device_node *np, *child;
108	struct exynos_srom *srom;
109	struct device *dev = &pdev->dev;
110	bool bad_bank_config = false;
111
112	np = dev->of_node;
113	if (!np) {
114		dev_err(&pdev->dev, "could not find device info\n");
115		return -EINVAL;
116	}
117
118	srom = devm_kzalloc(&pdev->dev,
119			sizeof(struct exynos_srom), GFP_KERNEL);
120	if (!srom)
121		return -ENOMEM;
122
123	srom->dev = dev;
124	srom->reg_base = of_iomap(np, 0);
125	if (!srom->reg_base) {
126		dev_err(&pdev->dev, "iomap of exynos srom controller failed\n");
127		return -ENOMEM;
128	}
129
130	platform_set_drvdata(pdev, srom);
131
132	srom->reg_offset = exynos_srom_alloc_reg_dump(exynos_srom_offsets,
133			ARRAY_SIZE(exynos_srom_offsets));
134	if (!srom->reg_offset) {
135		iounmap(srom->reg_base);
136		return -ENOMEM;
137	}
138
139	for_each_child_of_node(np, child) {
140		if (exynos_srom_configure_bank(srom, child)) {
141			dev_err(dev,
142				"Could not decode bank configuration for %s\n",
143				child->name);
144			bad_bank_config = true;
145		}
146	}
147
148	/*
149	 * If any bank failed to configure, we still provide suspend/resume,
150	 * but do not probe child devices
151	 */
152	if (bad_bank_config)
153		return 0;
154
155	return of_platform_populate(np, NULL, NULL, dev);
156}
157
158#ifdef CONFIG_PM_SLEEP
159static void exynos_srom_save(void __iomem *base,
160				    struct exynos_srom_reg_dump *rd,
161				    unsigned int num_regs)
162{
163	for (; num_regs > 0; --num_regs, ++rd)
164		rd->value = readl(base + rd->offset);
165}
166
167static void exynos_srom_restore(void __iomem *base,
168				      const struct exynos_srom_reg_dump *rd,
169				      unsigned int num_regs)
170{
171	for (; num_regs > 0; --num_regs, ++rd)
172		writel(rd->value, base + rd->offset);
173}
174
175static int exynos_srom_suspend(struct device *dev)
176{
177	struct exynos_srom *srom = dev_get_drvdata(dev);
178
179	exynos_srom_save(srom->reg_base, srom->reg_offset,
180				ARRAY_SIZE(exynos_srom_offsets));
181	return 0;
182}
183
184static int exynos_srom_resume(struct device *dev)
185{
186	struct exynos_srom *srom = dev_get_drvdata(dev);
187
188	exynos_srom_restore(srom->reg_base, srom->reg_offset,
189				ARRAY_SIZE(exynos_srom_offsets));
190	return 0;
191}
192#endif
193
194static const struct of_device_id of_exynos_srom_ids[] = {
195	{
196		.compatible	= "samsung,exynos4210-srom",
197	},
198	{},
199};
200
201static SIMPLE_DEV_PM_OPS(exynos_srom_pm_ops, exynos_srom_suspend, exynos_srom_resume);
202
203static struct platform_driver exynos_srom_driver = {
204	.probe = exynos_srom_probe,
205	.driver = {
206		.name = "exynos-srom",
207		.of_match_table = of_exynos_srom_ids,
208		.pm = &exynos_srom_pm_ops,
209		.suppress_bind_attrs = true,
210	},
211};
212builtin_platform_driver(exynos_srom_driver);