summaryrefslogtreecommitdiffstats
path: root/drivers/char/hw_random/omap-rng.c
diff options
context:
space:
mode:
Diffstat (limited to 'drivers/char/hw_random/omap-rng.c')
-rw-r--r--drivers/char/hw_random/omap-rng.c571
1 files changed, 571 insertions, 0 deletions
diff --git a/drivers/char/hw_random/omap-rng.c b/drivers/char/hw_random/omap-rng.c
new file mode 100644
index 000000000..00ff96703
--- /dev/null
+++ b/drivers/char/hw_random/omap-rng.c
@@ -0,0 +1,571 @@
+/*
+ * omap-rng.c - RNG driver for TI OMAP CPU family
+ *
+ * Author: Deepak Saxena <dsaxena@plexity.net>
+ *
+ * Copyright 2005 (c) MontaVista Software, Inc.
+ *
+ * Mostly based on original driver:
+ *
+ * Copyright (C) 2005 Nokia Corporation
+ * Author: Juha Yrjölä <juha.yrjola@nokia.com>
+ *
+ * This file is licensed under the terms of the GNU General Public
+ * License version 2. This program is licensed "as is" without any
+ * warranty of any kind, whether express or implied.
+ */
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/random.h>
+#include <linux/err.h>
+#include <linux/platform_device.h>
+#include <linux/hw_random.h>
+#include <linux/delay.h>
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/pm_runtime.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/of_address.h>
+#include <linux/interrupt.h>
+#include <linux/clk.h>
+#include <linux/io.h>
+
+#define RNG_REG_STATUS_RDY (1 << 0)
+
+#define RNG_REG_INTACK_RDY_MASK (1 << 0)
+#define RNG_REG_INTACK_SHUTDOWN_OFLO_MASK (1 << 1)
+#define RNG_SHUTDOWN_OFLO_MASK (1 << 1)
+
+#define RNG_CONTROL_STARTUP_CYCLES_SHIFT 16
+#define RNG_CONTROL_STARTUP_CYCLES_MASK (0xffff << 16)
+#define RNG_CONTROL_ENABLE_TRNG_SHIFT 10
+#define RNG_CONTROL_ENABLE_TRNG_MASK (1 << 10)
+
+#define RNG_CONFIG_MAX_REFIL_CYCLES_SHIFT 16
+#define RNG_CONFIG_MAX_REFIL_CYCLES_MASK (0xffff << 16)
+#define RNG_CONFIG_MIN_REFIL_CYCLES_SHIFT 0
+#define RNG_CONFIG_MIN_REFIL_CYCLES_MASK (0xff << 0)
+
+#define RNG_CONTROL_STARTUP_CYCLES 0xff
+#define RNG_CONFIG_MIN_REFIL_CYCLES 0x21
+#define RNG_CONFIG_MAX_REFIL_CYCLES 0x22
+
+#define RNG_ALARMCNT_ALARM_TH_SHIFT 0x0
+#define RNG_ALARMCNT_ALARM_TH_MASK (0xff << 0)
+#define RNG_ALARMCNT_SHUTDOWN_TH_SHIFT 16
+#define RNG_ALARMCNT_SHUTDOWN_TH_MASK (0x1f << 16)
+#define RNG_ALARM_THRESHOLD 0xff
+#define RNG_SHUTDOWN_THRESHOLD 0x4
+
+#define RNG_REG_FROENABLE_MASK 0xffffff
+#define RNG_REG_FRODETUNE_MASK 0xffffff
+
+#define OMAP2_RNG_OUTPUT_SIZE 0x4
+#define OMAP4_RNG_OUTPUT_SIZE 0x8
+#define EIP76_RNG_OUTPUT_SIZE 0x10
+
+/*
+ * EIP76 RNG takes approx. 700us to produce 16 bytes of output data
+ * as per testing results. And to account for the lack of udelay()'s
+ * reliability, we keep the timeout as 1000us.
+ */
+#define RNG_DATA_FILL_TIMEOUT 100
+
+enum {
+ RNG_OUTPUT_0_REG = 0,
+ RNG_OUTPUT_1_REG,
+ RNG_OUTPUT_2_REG,
+ RNG_OUTPUT_3_REG,
+ RNG_STATUS_REG,
+ RNG_INTMASK_REG,
+ RNG_INTACK_REG,
+ RNG_CONTROL_REG,
+ RNG_CONFIG_REG,
+ RNG_ALARMCNT_REG,
+ RNG_FROENABLE_REG,
+ RNG_FRODETUNE_REG,
+ RNG_ALARMMASK_REG,
+ RNG_ALARMSTOP_REG,
+ RNG_REV_REG,
+ RNG_SYSCONFIG_REG,
+};
+
+static const u16 reg_map_omap2[] = {
+ [RNG_OUTPUT_0_REG] = 0x0,
+ [RNG_STATUS_REG] = 0x4,
+ [RNG_CONFIG_REG] = 0x28,
+ [RNG_REV_REG] = 0x3c,
+ [RNG_SYSCONFIG_REG] = 0x40,
+};
+
+static const u16 reg_map_omap4[] = {
+ [RNG_OUTPUT_0_REG] = 0x0,
+ [RNG_OUTPUT_1_REG] = 0x4,
+ [RNG_STATUS_REG] = 0x8,
+ [RNG_INTMASK_REG] = 0xc,
+ [RNG_INTACK_REG] = 0x10,
+ [RNG_CONTROL_REG] = 0x14,
+ [RNG_CONFIG_REG] = 0x18,
+ [RNG_ALARMCNT_REG] = 0x1c,
+ [RNG_FROENABLE_REG] = 0x20,
+ [RNG_FRODETUNE_REG] = 0x24,
+ [RNG_ALARMMASK_REG] = 0x28,
+ [RNG_ALARMSTOP_REG] = 0x2c,
+ [RNG_REV_REG] = 0x1FE0,
+ [RNG_SYSCONFIG_REG] = 0x1FE4,
+};
+
+static const u16 reg_map_eip76[] = {
+ [RNG_OUTPUT_0_REG] = 0x0,
+ [RNG_OUTPUT_1_REG] = 0x4,
+ [RNG_OUTPUT_2_REG] = 0x8,
+ [RNG_OUTPUT_3_REG] = 0xc,
+ [RNG_STATUS_REG] = 0x10,
+ [RNG_INTACK_REG] = 0x10,
+ [RNG_CONTROL_REG] = 0x14,
+ [RNG_CONFIG_REG] = 0x18,
+ [RNG_ALARMCNT_REG] = 0x1c,
+ [RNG_FROENABLE_REG] = 0x20,
+ [RNG_FRODETUNE_REG] = 0x24,
+ [RNG_ALARMMASK_REG] = 0x28,
+ [RNG_ALARMSTOP_REG] = 0x2c,
+ [RNG_REV_REG] = 0x7c,
+};
+
+struct omap_rng_dev;
+/**
+ * struct omap_rng_pdata - RNG IP block-specific data
+ * @regs: Pointer to the register offsets structure.
+ * @data_size: No. of bytes in RNG output.
+ * @data_present: Callback to determine if data is available.
+ * @init: Callback for IP specific initialization sequence.
+ * @cleanup: Callback for IP specific cleanup sequence.
+ */
+struct omap_rng_pdata {
+ u16 *regs;
+ u32 data_size;
+ u32 (*data_present)(struct omap_rng_dev *priv);
+ int (*init)(struct omap_rng_dev *priv);
+ void (*cleanup)(struct omap_rng_dev *priv);
+};
+
+struct omap_rng_dev {
+ void __iomem *base;
+ struct device *dev;
+ const struct omap_rng_pdata *pdata;
+ struct hwrng rng;
+ struct clk *clk;
+ struct clk *clk_reg;
+};
+
+static inline u32 omap_rng_read(struct omap_rng_dev *priv, u16 reg)
+{
+ return __raw_readl(priv->base + priv->pdata->regs[reg]);
+}
+
+static inline void omap_rng_write(struct omap_rng_dev *priv, u16 reg,
+ u32 val)
+{
+ __raw_writel(val, priv->base + priv->pdata->regs[reg]);
+}
+
+
+static int omap_rng_do_read(struct hwrng *rng, void *data, size_t max,
+ bool wait)
+{
+ struct omap_rng_dev *priv;
+ int i, present;
+
+ priv = (struct omap_rng_dev *)rng->priv;
+
+ if (max < priv->pdata->data_size)
+ return 0;
+
+ for (i = 0; i < RNG_DATA_FILL_TIMEOUT; i++) {
+ present = priv->pdata->data_present(priv);
+ if (present || !wait)
+ break;
+
+ udelay(10);
+ }
+ if (!present)
+ return 0;
+
+ memcpy_fromio(data, priv->base + priv->pdata->regs[RNG_OUTPUT_0_REG],
+ priv->pdata->data_size);
+
+ if (priv->pdata->regs[RNG_INTACK_REG])
+ omap_rng_write(priv, RNG_INTACK_REG, RNG_REG_INTACK_RDY_MASK);
+
+ return priv->pdata->data_size;
+}
+
+static int omap_rng_init(struct hwrng *rng)
+{
+ struct omap_rng_dev *priv;
+
+ priv = (struct omap_rng_dev *)rng->priv;
+ return priv->pdata->init(priv);
+}
+
+static void omap_rng_cleanup(struct hwrng *rng)
+{
+ struct omap_rng_dev *priv;
+
+ priv = (struct omap_rng_dev *)rng->priv;
+ priv->pdata->cleanup(priv);
+}
+
+
+static inline u32 omap2_rng_data_present(struct omap_rng_dev *priv)
+{
+ return omap_rng_read(priv, RNG_STATUS_REG) ? 0 : 1;
+}
+
+static int omap2_rng_init(struct omap_rng_dev *priv)
+{
+ omap_rng_write(priv, RNG_SYSCONFIG_REG, 0x1);
+ return 0;
+}
+
+static void omap2_rng_cleanup(struct omap_rng_dev *priv)
+{
+ omap_rng_write(priv, RNG_SYSCONFIG_REG, 0x0);
+}
+
+static struct omap_rng_pdata omap2_rng_pdata = {
+ .regs = (u16 *)reg_map_omap2,
+ .data_size = OMAP2_RNG_OUTPUT_SIZE,
+ .data_present = omap2_rng_data_present,
+ .init = omap2_rng_init,
+ .cleanup = omap2_rng_cleanup,
+};
+
+static inline u32 omap4_rng_data_present(struct omap_rng_dev *priv)
+{
+ return omap_rng_read(priv, RNG_STATUS_REG) & RNG_REG_STATUS_RDY;
+}
+
+static int eip76_rng_init(struct omap_rng_dev *priv)
+{
+ u32 val;
+
+ /* Return if RNG is already running. */
+ if (omap_rng_read(priv, RNG_CONTROL_REG) & RNG_CONTROL_ENABLE_TRNG_MASK)
+ return 0;
+
+ /* Number of 512 bit blocks of raw Noise Source output data that must
+ * be processed by either the Conditioning Function or the
+ * SP 800-90 DRBG ‘BC_DF’ functionality to yield a ‘full entropy’
+ * output value.
+ */
+ val = 0x5 << RNG_CONFIG_MIN_REFIL_CYCLES_SHIFT;
+
+ /* Number of FRO samples that are XOR-ed together into one bit to be
+ * shifted into the main shift register
+ */
+ val |= RNG_CONFIG_MAX_REFIL_CYCLES << RNG_CONFIG_MAX_REFIL_CYCLES_SHIFT;
+ omap_rng_write(priv, RNG_CONFIG_REG, val);
+
+ /* Enable all available FROs */
+ omap_rng_write(priv, RNG_FRODETUNE_REG, 0x0);
+ omap_rng_write(priv, RNG_FROENABLE_REG, RNG_REG_FROENABLE_MASK);
+
+ /* Enable TRNG */
+ val = RNG_CONTROL_ENABLE_TRNG_MASK;
+ omap_rng_write(priv, RNG_CONTROL_REG, val);
+
+ return 0;
+}
+
+static int omap4_rng_init(struct omap_rng_dev *priv)
+{
+ u32 val;
+
+ /* Return if RNG is already running. */
+ if (omap_rng_read(priv, RNG_CONTROL_REG) & RNG_CONTROL_ENABLE_TRNG_MASK)
+ return 0;
+
+ val = RNG_CONFIG_MIN_REFIL_CYCLES << RNG_CONFIG_MIN_REFIL_CYCLES_SHIFT;
+ val |= RNG_CONFIG_MAX_REFIL_CYCLES << RNG_CONFIG_MAX_REFIL_CYCLES_SHIFT;
+ omap_rng_write(priv, RNG_CONFIG_REG, val);
+
+ omap_rng_write(priv, RNG_FRODETUNE_REG, 0x0);
+ omap_rng_write(priv, RNG_FROENABLE_REG, RNG_REG_FROENABLE_MASK);
+ val = RNG_ALARM_THRESHOLD << RNG_ALARMCNT_ALARM_TH_SHIFT;
+ val |= RNG_SHUTDOWN_THRESHOLD << RNG_ALARMCNT_SHUTDOWN_TH_SHIFT;
+ omap_rng_write(priv, RNG_ALARMCNT_REG, val);
+
+ val = RNG_CONTROL_STARTUP_CYCLES << RNG_CONTROL_STARTUP_CYCLES_SHIFT;
+ val |= RNG_CONTROL_ENABLE_TRNG_MASK;
+ omap_rng_write(priv, RNG_CONTROL_REG, val);
+
+ return 0;
+}
+
+static void omap4_rng_cleanup(struct omap_rng_dev *priv)
+{
+ int val;
+
+ val = omap_rng_read(priv, RNG_CONTROL_REG);
+ val &= ~RNG_CONTROL_ENABLE_TRNG_MASK;
+ omap_rng_write(priv, RNG_CONTROL_REG, val);
+}
+
+static irqreturn_t omap4_rng_irq(int irq, void *dev_id)
+{
+ struct omap_rng_dev *priv = dev_id;
+ u32 fro_detune, fro_enable;
+
+ /*
+ * Interrupt raised by a fro shutdown threshold, do the following:
+ * 1. Clear the alarm events.
+ * 2. De tune the FROs which are shutdown.
+ * 3. Re enable the shutdown FROs.
+ */
+ omap_rng_write(priv, RNG_ALARMMASK_REG, 0x0);
+ omap_rng_write(priv, RNG_ALARMSTOP_REG, 0x0);
+
+ fro_enable = omap_rng_read(priv, RNG_FROENABLE_REG);
+ fro_detune = ~fro_enable & RNG_REG_FRODETUNE_MASK;
+ fro_detune = fro_detune | omap_rng_read(priv, RNG_FRODETUNE_REG);
+ fro_enable = RNG_REG_FROENABLE_MASK;
+
+ omap_rng_write(priv, RNG_FRODETUNE_REG, fro_detune);
+ omap_rng_write(priv, RNG_FROENABLE_REG, fro_enable);
+
+ omap_rng_write(priv, RNG_INTACK_REG, RNG_REG_INTACK_SHUTDOWN_OFLO_MASK);
+
+ return IRQ_HANDLED;
+}
+
+static struct omap_rng_pdata omap4_rng_pdata = {
+ .regs = (u16 *)reg_map_omap4,
+ .data_size = OMAP4_RNG_OUTPUT_SIZE,
+ .data_present = omap4_rng_data_present,
+ .init = omap4_rng_init,
+ .cleanup = omap4_rng_cleanup,
+};
+
+static struct omap_rng_pdata eip76_rng_pdata = {
+ .regs = (u16 *)reg_map_eip76,
+ .data_size = EIP76_RNG_OUTPUT_SIZE,
+ .data_present = omap4_rng_data_present,
+ .init = eip76_rng_init,
+ .cleanup = omap4_rng_cleanup,
+};
+
+static const struct of_device_id omap_rng_of_match[] __maybe_unused = {
+ {
+ .compatible = "ti,omap2-rng",
+ .data = &omap2_rng_pdata,
+ },
+ {
+ .compatible = "ti,omap4-rng",
+ .data = &omap4_rng_pdata,
+ },
+ {
+ .compatible = "inside-secure,safexcel-eip76",
+ .data = &eip76_rng_pdata,
+ },
+ {},
+};
+MODULE_DEVICE_TABLE(of, omap_rng_of_match);
+
+static int of_get_omap_rng_device_details(struct omap_rng_dev *priv,
+ struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ int irq, err;
+
+ priv->pdata = of_device_get_match_data(dev);
+ if (!priv->pdata)
+ return -ENODEV;
+
+
+ if (of_device_is_compatible(dev->of_node, "ti,omap4-rng") ||
+ of_device_is_compatible(dev->of_node, "inside-secure,safexcel-eip76")) {
+ irq = platform_get_irq(pdev, 0);
+ if (irq < 0)
+ return irq;
+
+ err = devm_request_irq(dev, irq, omap4_rng_irq,
+ IRQF_TRIGGER_NONE, dev_name(dev), priv);
+ if (err) {
+ dev_err(dev, "unable to request irq %d, err = %d\n",
+ irq, err);
+ return err;
+ }
+
+ /*
+ * On OMAP4, enabling the shutdown_oflo interrupt is
+ * done in the interrupt mask register. There is no
+ * such register on EIP76, and it's enabled by the
+ * same bit in the control register
+ */
+ if (priv->pdata->regs[RNG_INTMASK_REG])
+ omap_rng_write(priv, RNG_INTMASK_REG,
+ RNG_SHUTDOWN_OFLO_MASK);
+ else
+ omap_rng_write(priv, RNG_CONTROL_REG,
+ RNG_SHUTDOWN_OFLO_MASK);
+ }
+ return 0;
+}
+
+static int get_omap_rng_device_details(struct omap_rng_dev *omap_rng)
+{
+ /* Only OMAP2/3 can be non-DT */
+ omap_rng->pdata = &omap2_rng_pdata;
+ return 0;
+}
+
+static int omap_rng_probe(struct platform_device *pdev)
+{
+ struct omap_rng_dev *priv;
+ struct device *dev = &pdev->dev;
+ int ret;
+
+ priv = devm_kzalloc(dev, sizeof(struct omap_rng_dev), GFP_KERNEL);
+ if (!priv)
+ return -ENOMEM;
+
+ priv->rng.read = omap_rng_do_read;
+ priv->rng.init = omap_rng_init;
+ priv->rng.cleanup = omap_rng_cleanup;
+ priv->rng.quality = 900;
+
+ priv->rng.priv = (unsigned long)priv;
+ platform_set_drvdata(pdev, priv);
+ priv->dev = dev;
+
+ priv->base = devm_platform_ioremap_resource(pdev, 0);
+ if (IS_ERR(priv->base)) {
+ ret = PTR_ERR(priv->base);
+ goto err_ioremap;
+ }
+
+ priv->rng.name = devm_kstrdup(dev, dev_name(dev), GFP_KERNEL);
+ if (!priv->rng.name) {
+ ret = -ENOMEM;
+ goto err_ioremap;
+ }
+
+ pm_runtime_enable(&pdev->dev);
+ ret = pm_runtime_resume_and_get(&pdev->dev);
+ if (ret < 0) {
+ dev_err(&pdev->dev, "Failed to runtime_get device: %d\n", ret);
+ goto err_ioremap;
+ }
+
+ priv->clk = devm_clk_get(&pdev->dev, NULL);
+ if (PTR_ERR(priv->clk) == -EPROBE_DEFER)
+ return -EPROBE_DEFER;
+ if (!IS_ERR(priv->clk)) {
+ ret = clk_prepare_enable(priv->clk);
+ if (ret) {
+ dev_err(&pdev->dev,
+ "Unable to enable the clk: %d\n", ret);
+ goto err_register;
+ }
+ }
+
+ priv->clk_reg = devm_clk_get(&pdev->dev, "reg");
+ if (PTR_ERR(priv->clk_reg) == -EPROBE_DEFER)
+ return -EPROBE_DEFER;
+ if (!IS_ERR(priv->clk_reg)) {
+ ret = clk_prepare_enable(priv->clk_reg);
+ if (ret) {
+ dev_err(&pdev->dev,
+ "Unable to enable the register clk: %d\n",
+ ret);
+ goto err_register;
+ }
+ }
+
+ ret = (dev->of_node) ? of_get_omap_rng_device_details(priv, pdev) :
+ get_omap_rng_device_details(priv);
+ if (ret)
+ goto err_register;
+
+ ret = devm_hwrng_register(&pdev->dev, &priv->rng);
+ if (ret)
+ goto err_register;
+
+ dev_info(&pdev->dev, "Random Number Generator ver. %02x\n",
+ omap_rng_read(priv, RNG_REV_REG));
+
+ return 0;
+
+err_register:
+ priv->base = NULL;
+ pm_runtime_put_sync(&pdev->dev);
+ pm_runtime_disable(&pdev->dev);
+
+ clk_disable_unprepare(priv->clk_reg);
+ clk_disable_unprepare(priv->clk);
+err_ioremap:
+ dev_err(dev, "initialization failed.\n");
+ return ret;
+}
+
+static int omap_rng_remove(struct platform_device *pdev)
+{
+ struct omap_rng_dev *priv = platform_get_drvdata(pdev);
+
+
+ priv->pdata->cleanup(priv);
+
+ pm_runtime_put_sync(&pdev->dev);
+ pm_runtime_disable(&pdev->dev);
+
+ clk_disable_unprepare(priv->clk);
+ clk_disable_unprepare(priv->clk_reg);
+
+ return 0;
+}
+
+static int __maybe_unused omap_rng_suspend(struct device *dev)
+{
+ struct omap_rng_dev *priv = dev_get_drvdata(dev);
+
+ priv->pdata->cleanup(priv);
+ pm_runtime_put_sync(dev);
+
+ return 0;
+}
+
+static int __maybe_unused omap_rng_resume(struct device *dev)
+{
+ struct omap_rng_dev *priv = dev_get_drvdata(dev);
+ int ret;
+
+ ret = pm_runtime_resume_and_get(dev);
+ if (ret < 0) {
+ dev_err(dev, "Failed to runtime_get device: %d\n", ret);
+ return ret;
+ }
+
+ priv->pdata->init(priv);
+
+ return 0;
+}
+
+static SIMPLE_DEV_PM_OPS(omap_rng_pm, omap_rng_suspend, omap_rng_resume);
+
+static struct platform_driver omap_rng_driver = {
+ .driver = {
+ .name = "omap_rng",
+ .pm = &omap_rng_pm,
+ .of_match_table = of_match_ptr(omap_rng_of_match),
+ },
+ .probe = omap_rng_probe,
+ .remove = omap_rng_remove,
+};
+
+module_platform_driver(omap_rng_driver);
+MODULE_ALIAS("platform:omap_rng");
+MODULE_AUTHOR("Deepak Saxena (and others)");
+MODULE_LICENSE("GPL");
generated by cgit v1.2.3 (git 2.39.1) at 2024-07-28 06:24:41 +0000