1226b0b0aSThomas Gleixner // SPDX-License-Identifier: GPL-2.0-or-later
2c6a97c42SDaniel Thompson /*
3c6a97c42SDaniel Thompson * Copyright (c) 2015, Daniel Thompson
4c6a97c42SDaniel Thompson */
5c6a97c42SDaniel Thompson
6c6a97c42SDaniel Thompson #include <linux/clk.h>
7c6a97c42SDaniel Thompson #include <linux/delay.h>
8c6a97c42SDaniel Thompson #include <linux/hw_random.h>
9c6a97c42SDaniel Thompson #include <linux/io.h>
10279f4f8fSlionel.debieve@st.com #include <linux/iopoll.h>
11c6a97c42SDaniel Thompson #include <linux/kernel.h>
12c6a97c42SDaniel Thompson #include <linux/module.h>
13*0788257aSRob Herring #include <linux/of.h>
14c6a97c42SDaniel Thompson #include <linux/of_address.h>
15*0788257aSRob Herring #include <linux/platform_device.h>
16c6a97c42SDaniel Thompson #include <linux/pm_runtime.h>
17326ed382Slionel.debieve@st.com #include <linux/reset.h>
18c6a97c42SDaniel Thompson #include <linux/slab.h>
19c6a97c42SDaniel Thompson
20c6a97c42SDaniel Thompson #define RNG_CR 0x00
21c6a97c42SDaniel Thompson #define RNG_CR_RNGEN BIT(2)
22529571edSlionel.debieve@st.com #define RNG_CR_CED BIT(5)
23c6a97c42SDaniel Thompson
24c6a97c42SDaniel Thompson #define RNG_SR 0x04
25c6a97c42SDaniel Thompson #define RNG_SR_SEIS BIT(6)
26c6a97c42SDaniel Thompson #define RNG_SR_CEIS BIT(5)
27c6a97c42SDaniel Thompson #define RNG_SR_DRDY BIT(0)
28c6a97c42SDaniel Thompson
29c6a97c42SDaniel Thompson #define RNG_DR 0x08
30c6a97c42SDaniel Thompson
31c6a97c42SDaniel Thompson struct stm32_rng_private {
32c6a97c42SDaniel Thompson struct hwrng rng;
33c6a97c42SDaniel Thompson void __iomem *base;
34c6a97c42SDaniel Thompson struct clk *clk;
35326ed382Slionel.debieve@st.com struct reset_control *rst;
36529571edSlionel.debieve@st.com bool ced;
37c6a97c42SDaniel Thompson };
38c6a97c42SDaniel Thompson
stm32_rng_read(struct hwrng * rng,void * data,size_t max,bool wait)39c6a97c42SDaniel Thompson static int stm32_rng_read(struct hwrng *rng, void *data, size_t max, bool wait)
40c6a97c42SDaniel Thompson {
41c6a97c42SDaniel Thompson struct stm32_rng_private *priv =
42c6a97c42SDaniel Thompson container_of(rng, struct stm32_rng_private, rng);
43c6a97c42SDaniel Thompson u32 sr;
44c6a97c42SDaniel Thompson int retval = 0;
45c6a97c42SDaniel Thompson
46c6a97c42SDaniel Thompson pm_runtime_get_sync((struct device *) priv->rng.priv);
47c6a97c42SDaniel Thompson
48e64f57e8STomas Marek while (max >= sizeof(u32)) {
49c6a97c42SDaniel Thompson sr = readl_relaxed(priv->base + RNG_SR);
50279f4f8fSlionel.debieve@st.com /* Manage timeout which is based on timer and take */
51279f4f8fSlionel.debieve@st.com /* care of initial delay time when enabling rng */
52c6a97c42SDaniel Thompson if (!sr && wait) {
537cdc5e6bSTomas Marek int err;
547e11a4fcSTomas Marek
557cdc5e6bSTomas Marek err = readl_relaxed_poll_timeout_atomic(priv->base
56279f4f8fSlionel.debieve@st.com + RNG_SR,
57279f4f8fSlionel.debieve@st.com sr, sr,
58279f4f8fSlionel.debieve@st.com 10, 50000);
597cdc5e6bSTomas Marek if (err)
60279f4f8fSlionel.debieve@st.com dev_err((struct device *)priv->rng.priv,
61279f4f8fSlionel.debieve@st.com "%s: timeout %x!\n", __func__, sr);
62c6a97c42SDaniel Thompson }
63c6a97c42SDaniel Thompson
64c6a97c42SDaniel Thompson /* If error detected or data not ready... */
651ff69adfSMaxime Coquelin if (sr != RNG_SR_DRDY) {
661ff69adfSMaxime Coquelin if (WARN_ONCE(sr & (RNG_SR_SEIS | RNG_SR_CEIS),
671ff69adfSMaxime Coquelin "bad RNG status - %x\n", sr))
681ff69adfSMaxime Coquelin writel_relaxed(0, priv->base + RNG_SR);
69c6a97c42SDaniel Thompson break;
701ff69adfSMaxime Coquelin }
71c6a97c42SDaniel Thompson
72c6a97c42SDaniel Thompson *(u32 *)data = readl_relaxed(priv->base + RNG_DR);
73c6a97c42SDaniel Thompson
74c6a97c42SDaniel Thompson retval += sizeof(u32);
75c6a97c42SDaniel Thompson data += sizeof(u32);
76c6a97c42SDaniel Thompson max -= sizeof(u32);
77c6a97c42SDaniel Thompson }
78c6a97c42SDaniel Thompson
79c6a97c42SDaniel Thompson pm_runtime_mark_last_busy((struct device *) priv->rng.priv);
80c6a97c42SDaniel Thompson pm_runtime_put_sync_autosuspend((struct device *) priv->rng.priv);
81c6a97c42SDaniel Thompson
82c6a97c42SDaniel Thompson return retval || !wait ? retval : -EIO;
83c6a97c42SDaniel Thompson }
84c6a97c42SDaniel Thompson
stm32_rng_init(struct hwrng * rng)85c6a97c42SDaniel Thompson static int stm32_rng_init(struct hwrng *rng)
86c6a97c42SDaniel Thompson {
87c6a97c42SDaniel Thompson struct stm32_rng_private *priv =
88c6a97c42SDaniel Thompson container_of(rng, struct stm32_rng_private, rng);
89c6a97c42SDaniel Thompson int err;
90c6a97c42SDaniel Thompson
91c6a97c42SDaniel Thompson err = clk_prepare_enable(priv->clk);
92c6a97c42SDaniel Thompson if (err)
93c6a97c42SDaniel Thompson return err;
94c6a97c42SDaniel Thompson
95529571edSlionel.debieve@st.com if (priv->ced)
96c6a97c42SDaniel Thompson writel_relaxed(RNG_CR_RNGEN, priv->base + RNG_CR);
97529571edSlionel.debieve@st.com else
98529571edSlionel.debieve@st.com writel_relaxed(RNG_CR_RNGEN | RNG_CR_CED,
99529571edSlionel.debieve@st.com priv->base + RNG_CR);
100c6a97c42SDaniel Thompson
101c6a97c42SDaniel Thompson /* clear error indicators */
102c6a97c42SDaniel Thompson writel_relaxed(0, priv->base + RNG_SR);
103c6a97c42SDaniel Thompson
104c6a97c42SDaniel Thompson return 0;
105c6a97c42SDaniel Thompson }
106c6a97c42SDaniel Thompson
stm32_rng_cleanup(struct hwrng * rng)107c6a97c42SDaniel Thompson static void stm32_rng_cleanup(struct hwrng *rng)
108c6a97c42SDaniel Thompson {
109c6a97c42SDaniel Thompson struct stm32_rng_private *priv =
110c6a97c42SDaniel Thompson container_of(rng, struct stm32_rng_private, rng);
111c6a97c42SDaniel Thompson
112c6a97c42SDaniel Thompson writel_relaxed(0, priv->base + RNG_CR);
113c6a97c42SDaniel Thompson clk_disable_unprepare(priv->clk);
114c6a97c42SDaniel Thompson }
115c6a97c42SDaniel Thompson
stm32_rng_probe(struct platform_device * ofdev)116c6a97c42SDaniel Thompson static int stm32_rng_probe(struct platform_device *ofdev)
117c6a97c42SDaniel Thompson {
118c6a97c42SDaniel Thompson struct device *dev = &ofdev->dev;
119c6a97c42SDaniel Thompson struct device_node *np = ofdev->dev.of_node;
120c6a97c42SDaniel Thompson struct stm32_rng_private *priv;
121c6a97c42SDaniel Thompson struct resource res;
122c6a97c42SDaniel Thompson int err;
123c6a97c42SDaniel Thompson
124c6a97c42SDaniel Thompson priv = devm_kzalloc(dev, sizeof(struct stm32_rng_private), GFP_KERNEL);
125c6a97c42SDaniel Thompson if (!priv)
126c6a97c42SDaniel Thompson return -ENOMEM;
127c6a97c42SDaniel Thompson
128c6a97c42SDaniel Thompson err = of_address_to_resource(np, 0, &res);
129c6a97c42SDaniel Thompson if (err)
130c6a97c42SDaniel Thompson return err;
131c6a97c42SDaniel Thompson
132c6a97c42SDaniel Thompson priv->base = devm_ioremap_resource(dev, &res);
133c6a97c42SDaniel Thompson if (IS_ERR(priv->base))
134c6a97c42SDaniel Thompson return PTR_ERR(priv->base);
135c6a97c42SDaniel Thompson
136c6a97c42SDaniel Thompson priv->clk = devm_clk_get(&ofdev->dev, NULL);
137c6a97c42SDaniel Thompson if (IS_ERR(priv->clk))
138c6a97c42SDaniel Thompson return PTR_ERR(priv->clk);
139c6a97c42SDaniel Thompson
140326ed382Slionel.debieve@st.com priv->rst = devm_reset_control_get(&ofdev->dev, NULL);
141326ed382Slionel.debieve@st.com if (!IS_ERR(priv->rst)) {
142326ed382Slionel.debieve@st.com reset_control_assert(priv->rst);
143326ed382Slionel.debieve@st.com udelay(2);
144326ed382Slionel.debieve@st.com reset_control_deassert(priv->rst);
145326ed382Slionel.debieve@st.com }
146326ed382Slionel.debieve@st.com
147529571edSlionel.debieve@st.com priv->ced = of_property_read_bool(np, "clock-error-detect");
148529571edSlionel.debieve@st.com
149c6a97c42SDaniel Thompson dev_set_drvdata(dev, priv);
150c6a97c42SDaniel Thompson
151436cdcdeSJulia Lawall priv->rng.name = dev_driver_string(dev);
152c6a97c42SDaniel Thompson #ifndef CONFIG_PM
153436cdcdeSJulia Lawall priv->rng.init = stm32_rng_init;
154436cdcdeSJulia Lawall priv->rng.cleanup = stm32_rng_cleanup;
155c6a97c42SDaniel Thompson #endif
156436cdcdeSJulia Lawall priv->rng.read = stm32_rng_read;
157c6a97c42SDaniel Thompson priv->rng.priv = (unsigned long) dev;
15838a1965fSLionel Debieve priv->rng.quality = 900;
159c6a97c42SDaniel Thompson
160c6a97c42SDaniel Thompson pm_runtime_set_autosuspend_delay(dev, 100);
161c6a97c42SDaniel Thompson pm_runtime_use_autosuspend(dev);
162c6a97c42SDaniel Thompson pm_runtime_enable(dev);
163c6a97c42SDaniel Thompson
164c6a97c42SDaniel Thompson return devm_hwrng_register(dev, &priv->rng);
165c6a97c42SDaniel Thompson }
166c6a97c42SDaniel Thompson
stm32_rng_remove(struct platform_device * ofdev)167af0d4442SLionel Debieve static int stm32_rng_remove(struct platform_device *ofdev)
168af0d4442SLionel Debieve {
169af0d4442SLionel Debieve pm_runtime_disable(&ofdev->dev);
170af0d4442SLionel Debieve
171af0d4442SLionel Debieve return 0;
172af0d4442SLionel Debieve }
173af0d4442SLionel Debieve
174c6a97c42SDaniel Thompson #ifdef CONFIG_PM
stm32_rng_runtime_suspend(struct device * dev)175c6a97c42SDaniel Thompson static int stm32_rng_runtime_suspend(struct device *dev)
176c6a97c42SDaniel Thompson {
177d6ba06b8SDaniel Thompson struct stm32_rng_private *priv = dev_get_drvdata(dev);
178c6a97c42SDaniel Thompson
179c6a97c42SDaniel Thompson stm32_rng_cleanup(&priv->rng);
180c6a97c42SDaniel Thompson
181c6a97c42SDaniel Thompson return 0;
182c6a97c42SDaniel Thompson }
183c6a97c42SDaniel Thompson
stm32_rng_runtime_resume(struct device * dev)184c6a97c42SDaniel Thompson static int stm32_rng_runtime_resume(struct device *dev)
185c6a97c42SDaniel Thompson {
186d6ba06b8SDaniel Thompson struct stm32_rng_private *priv = dev_get_drvdata(dev);
187c6a97c42SDaniel Thompson
188c6a97c42SDaniel Thompson return stm32_rng_init(&priv->rng);
189c6a97c42SDaniel Thompson }
190c6a97c42SDaniel Thompson #endif
191c6a97c42SDaniel Thompson
1929bae5494Slionel.debieve@st.com static const struct dev_pm_ops stm32_rng_pm_ops = {
1939bae5494Slionel.debieve@st.com SET_RUNTIME_PM_OPS(stm32_rng_runtime_suspend,
1949bae5494Slionel.debieve@st.com stm32_rng_runtime_resume, NULL)
1959bae5494Slionel.debieve@st.com SET_SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend,
1969bae5494Slionel.debieve@st.com pm_runtime_force_resume)
1979bae5494Slionel.debieve@st.com };
1989bae5494Slionel.debieve@st.com
199c6a97c42SDaniel Thompson
200c6a97c42SDaniel Thompson static const struct of_device_id stm32_rng_match[] = {
201c6a97c42SDaniel Thompson {
202c6a97c42SDaniel Thompson .compatible = "st,stm32-rng",
203c6a97c42SDaniel Thompson },
204c6a97c42SDaniel Thompson {},
205c6a97c42SDaniel Thompson };
206c6a97c42SDaniel Thompson MODULE_DEVICE_TABLE(of, stm32_rng_match);
207c6a97c42SDaniel Thompson
208c6a97c42SDaniel Thompson static struct platform_driver stm32_rng_driver = {
209c6a97c42SDaniel Thompson .driver = {
210c6a97c42SDaniel Thompson .name = "stm32-rng",
211c6a97c42SDaniel Thompson .pm = &stm32_rng_pm_ops,
212c6a97c42SDaniel Thompson .of_match_table = stm32_rng_match,
213c6a97c42SDaniel Thompson },
214c6a97c42SDaniel Thompson .probe = stm32_rng_probe,
215af0d4442SLionel Debieve .remove = stm32_rng_remove,
216c6a97c42SDaniel Thompson };
217c6a97c42SDaniel Thompson
218c6a97c42SDaniel Thompson module_platform_driver(stm32_rng_driver);
219c6a97c42SDaniel Thompson
220c6a97c42SDaniel Thompson MODULE_LICENSE("GPL");
221c6a97c42SDaniel Thompson MODULE_AUTHOR("Daniel Thompson <daniel.thompson@linaro.org>");
222c6a97c42SDaniel Thompson MODULE_DESCRIPTION("STMicroelectronics STM32 RNG device driver");
223