exynos-srom.c

  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 *
 51exynos_srom_alloc_reg_dump(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 = devm_platform_ioremap_resource(pdev, 0);
125	if (IS_ERR(srom->reg_base)) {
126		dev_err(&pdev->dev, "iomap of exynos srom controller failed\n");
127		return PTR_ERR(srom->reg_base);
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		return -ENOMEM;
136
137	for_each_child_of_node(np, child) {
138		if (exynos_srom_configure_bank(srom, child)) {
139			dev_err(dev,
140				"Could not decode bank configuration for %pOFn\n",
141				child);
142			bad_bank_config = true;
143		}
144	}
145
146	/*
147	 * If any bank failed to configure, we still provide suspend/resume,
148	 * but do not probe child devices
149	 */
150	if (bad_bank_config)
151		return 0;
152
153	return of_platform_populate(np, NULL, NULL, dev);
154}
155
156#ifdef CONFIG_PM_SLEEP
157static void exynos_srom_save(void __iomem *base,
158			     struct exynos_srom_reg_dump *rd,
159			     unsigned int num_regs)
160{
161	for (; num_regs > 0; --num_regs, ++rd)
162		rd->value = readl(base + rd->offset);
163}
164
165static void exynos_srom_restore(void __iomem *base,
166				const struct exynos_srom_reg_dump *rd,
167				unsigned int num_regs)
168{
169	for (; num_regs > 0; --num_regs, ++rd)
170		writel(rd->value, base + rd->offset);
171}
172
173static int exynos_srom_suspend(struct device *dev)
174{
175	struct exynos_srom *srom = dev_get_drvdata(dev);
176
177	exynos_srom_save(srom->reg_base, srom->reg_offset,
178			 ARRAY_SIZE(exynos_srom_offsets));
179	return 0;
180}
181
182static int exynos_srom_resume(struct device *dev)
183{
184	struct exynos_srom *srom = dev_get_drvdata(dev);
185
186	exynos_srom_restore(srom->reg_base, srom->reg_offset,
187			    ARRAY_SIZE(exynos_srom_offsets));
188	return 0;
189}
190#endif
191
192static const struct of_device_id of_exynos_srom_ids[] = {
193	{
194		.compatible	= "samsung,exynos4210-srom",
195	},
196	{},
197};
198
199static SIMPLE_DEV_PM_OPS(exynos_srom_pm_ops, exynos_srom_suspend, exynos_srom_resume);
200
201static struct platform_driver exynos_srom_driver = {
202	.probe = exynos_srom_probe,
203	.driver = {
204		.name = "exynos-srom",
205		.of_match_table = of_exynos_srom_ids,
206		.pm = &exynos_srom_pm_ops,
207		.suppress_bind_attrs = true,
208	},
209};
210builtin_platform_driver(exynos_srom_driver);