+++ /dev/null
-/*
- * exynos-rng.c - Random Number Generator driver for the exynos
- *
- * Copyright (C) 2012 Samsung Electronics
- * Jonghwa Lee <jonghwa3.lee@samsung.com>
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation;
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
- *
- */
-
-#include <linux/hw_random.h>
-#include <linux/kernel.h>
-#include <linux/module.h>
-#include <linux/io.h>
-#include <linux/platform_device.h>
-#include <linux/clk.h>
-#include <linux/pm_runtime.h>
-#include <linux/err.h>
-
-#define EXYNOS_PRNG_STATUS_OFFSET 0x10
-#define EXYNOS_PRNG_SEED_OFFSET 0x140
-#define EXYNOS_PRNG_OUT1_OFFSET 0x160
-#define SEED_SETTING_DONE BIT(1)
-#define PRNG_START 0x18
-#define PRNG_DONE BIT(5)
-#define EXYNOS_AUTOSUSPEND_DELAY 100
-
-struct exynos_rng {
- struct device *dev;
- struct hwrng rng;
- void __iomem *mem;
- struct clk *clk;
-};
-
-static u32 exynos_rng_readl(struct exynos_rng *rng, u32 offset)
-{
- return readl_relaxed(rng->mem + offset);
-}
-
-static void exynos_rng_writel(struct exynos_rng *rng, u32 val, u32 offset)
-{
- writel_relaxed(val, rng->mem + offset);
-}
-
-static int exynos_rng_configure(struct exynos_rng *exynos_rng)
-{
- int i;
- int ret = 0;
-
- for (i = 0 ; i < 5 ; i++)
- exynos_rng_writel(exynos_rng, jiffies,
- EXYNOS_PRNG_SEED_OFFSET + 4*i);
-
- if (!(exynos_rng_readl(exynos_rng, EXYNOS_PRNG_STATUS_OFFSET)
- & SEED_SETTING_DONE))
- ret = -EIO;
-
- return ret;
-}
-
-static int exynos_init(struct hwrng *rng)
-{
- struct exynos_rng *exynos_rng = container_of(rng,
- struct exynos_rng, rng);
- int ret = 0;
-
- pm_runtime_get_sync(exynos_rng->dev);
- ret = exynos_rng_configure(exynos_rng);
- pm_runtime_mark_last_busy(exynos_rng->dev);
- pm_runtime_put_autosuspend(exynos_rng->dev);
-
- return ret;
-}
-
-static int exynos_read(struct hwrng *rng, void *buf,
- size_t max, bool wait)
-{
- struct exynos_rng *exynos_rng = container_of(rng,
- struct exynos_rng, rng);
- u32 *data = buf;
- int retry = 100;
- int ret = 4;
-
- pm_runtime_get_sync(exynos_rng->dev);
-
- exynos_rng_writel(exynos_rng, PRNG_START, 0);
-
- while (!(exynos_rng_readl(exynos_rng,
- EXYNOS_PRNG_STATUS_OFFSET) & PRNG_DONE) && --retry)
- cpu_relax();
- if (!retry) {
- ret = -ETIMEDOUT;
- goto out;
- }
-
- exynos_rng_writel(exynos_rng, PRNG_DONE, EXYNOS_PRNG_STATUS_OFFSET);
-
- *data = exynos_rng_readl(exynos_rng, EXYNOS_PRNG_OUT1_OFFSET);
-
-out:
- pm_runtime_mark_last_busy(exynos_rng->dev);
- pm_runtime_put_sync_autosuspend(exynos_rng->dev);
-
- return ret;
-}
-
-static int exynos_rng_probe(struct platform_device *pdev)
-{
- struct exynos_rng *exynos_rng;
- struct resource *res;
- int ret;
-
- exynos_rng = devm_kzalloc(&pdev->dev, sizeof(struct exynos_rng),
- GFP_KERNEL);
- if (!exynos_rng)
- return -ENOMEM;
-
- exynos_rng->dev = &pdev->dev;
- exynos_rng->rng.name = "exynos";
- exynos_rng->rng.init = exynos_init;
- exynos_rng->rng.read = exynos_read;
- exynos_rng->clk = devm_clk_get(&pdev->dev, "secss");
- if (IS_ERR(exynos_rng->clk)) {
- dev_err(&pdev->dev, "Couldn't get clock.\n");
- return -ENOENT;
- }
-
- res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
- exynos_rng->mem = devm_ioremap_resource(&pdev->dev, res);
- if (IS_ERR(exynos_rng->mem))
- return PTR_ERR(exynos_rng->mem);
-
- platform_set_drvdata(pdev, exynos_rng);
-
- pm_runtime_set_autosuspend_delay(&pdev->dev, EXYNOS_AUTOSUSPEND_DELAY);
- pm_runtime_use_autosuspend(&pdev->dev);
- pm_runtime_enable(&pdev->dev);
-
- ret = devm_hwrng_register(&pdev->dev, &exynos_rng->rng);
- if (ret) {
- pm_runtime_dont_use_autosuspend(&pdev->dev);
- pm_runtime_disable(&pdev->dev);
- }
-
- return ret;
-}
-
-static int exynos_rng_remove(struct platform_device *pdev)
-{
- pm_runtime_dont_use_autosuspend(&pdev->dev);
- pm_runtime_disable(&pdev->dev);
-
- return 0;
-}
-
-static int __maybe_unused exynos_rng_runtime_suspend(struct device *dev)
-{
- struct platform_device *pdev = to_platform_device(dev);
- struct exynos_rng *exynos_rng = platform_get_drvdata(pdev);
-
- clk_disable_unprepare(exynos_rng->clk);
-
- return 0;
-}
-
-static int __maybe_unused exynos_rng_runtime_resume(struct device *dev)
-{
- struct platform_device *pdev = to_platform_device(dev);
- struct exynos_rng *exynos_rng = platform_get_drvdata(pdev);
-
- return clk_prepare_enable(exynos_rng->clk);
-}
-
-static int __maybe_unused exynos_rng_suspend(struct device *dev)
-{
- return pm_runtime_force_suspend(dev);
-}
-
-static int __maybe_unused exynos_rng_resume(struct device *dev)
-{
- struct platform_device *pdev = to_platform_device(dev);
- struct exynos_rng *exynos_rng = platform_get_drvdata(pdev);
- int ret;
-
- ret = pm_runtime_force_resume(dev);
- if (ret)
- return ret;
-
- return exynos_rng_configure(exynos_rng);
-}
-
-static const struct dev_pm_ops exynos_rng_pm_ops = {
- SET_SYSTEM_SLEEP_PM_OPS(exynos_rng_suspend, exynos_rng_resume)
- SET_RUNTIME_PM_OPS(exynos_rng_runtime_suspend,
- exynos_rng_runtime_resume, NULL)
-};
-
-static const struct of_device_id exynos_rng_dt_match[] = {
- {
- .compatible = "samsung,exynos4-rng",
- },
- { },
-};
-MODULE_DEVICE_TABLE(of, exynos_rng_dt_match);
-
-static struct platform_driver exynos_rng_driver = {
- .driver = {
- .name = "exynos-rng",
- .pm = &exynos_rng_pm_ops,
- .of_match_table = exynos_rng_dt_match,
- },
- .probe = exynos_rng_probe,
- .remove = exynos_rng_remove,
-};
-
-module_platform_driver(exynos_rng_driver);
-
-MODULE_DESCRIPTION("EXYNOS 4 H/W Random Number Generator driver");
-MODULE_AUTHOR("Jonghwa Lee <jonghwa3.lee@samsung.com>");
-MODULE_LICENSE("GPL");
--- /dev/null
+/*
+ * exynos-rng.c - Random Number Generator driver for the Exynos
+ *
+ * Copyright (c) 2017 Krzysztof Kozlowski <krzk@kernel.org>
+ *
+ * Loosely based on old driver from drivers/char/hw_random/exynos-rng.c:
+ * Copyright (C) 2012 Samsung Electronics
+ * Jonghwa Lee <jonghwa3.lee@samsung.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation;
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/clk.h>
+#include <linux/crypto.h>
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+
+#include <crypto/internal/rng.h>
+
+#define EXYNOS_RNG_CONTROL 0x0
+#define EXYNOS_RNG_STATUS 0x10
+#define EXYNOS_RNG_SEED_BASE 0x140
+#define EXYNOS_RNG_SEED(n) (EXYNOS_RNG_SEED_BASE + (n * 0x4))
+#define EXYNOS_RNG_OUT_BASE 0x160
+#define EXYNOS_RNG_OUT(n) (EXYNOS_RNG_OUT_BASE + (n * 0x4))
+
+/* EXYNOS_RNG_CONTROL bit fields */
+#define EXYNOS_RNG_CONTROL_START 0x18
+/* EXYNOS_RNG_STATUS bit fields */
+#define EXYNOS_RNG_STATUS_SEED_SETTING_DONE BIT(1)
+#define EXYNOS_RNG_STATUS_RNG_DONE BIT(5)
+
+/* Five seed and output registers, each 4 bytes */
+#define EXYNOS_RNG_SEED_REGS 5
+#define EXYNOS_RNG_SEED_SIZE (EXYNOS_RNG_SEED_REGS * 4)
+
+/*
+ * Driver re-seeds itself with generated random numbers to increase
+ * the randomness.
+ *
+ * Time for next re-seed in ms.
+ */
+#define EXYNOS_RNG_RESEED_TIME 100
+/*
+ * In polling mode, do not wait infinitely for the engine to finish the work.
+ */
+#define EXYNOS_RNG_WAIT_RETRIES 100
+
+/* Context for crypto */
+struct exynos_rng_ctx {
+ struct exynos_rng_dev *rng;
+};
+
+/* Device associated memory */
+struct exynos_rng_dev {
+ struct device *dev;
+ void __iomem *mem;
+ struct clk *clk;
+ /* Generated numbers stored for seeding during resume */
+ u8 seed_save[EXYNOS_RNG_SEED_SIZE];
+ unsigned int seed_save_len;
+ /* Time of last seeding in jiffies */
+ unsigned long last_seeding;
+};
+
+static struct exynos_rng_dev *exynos_rng_dev;
+
+static u32 exynos_rng_readl(struct exynos_rng_dev *rng, u32 offset)
+{
+ return readl_relaxed(rng->mem + offset);
+}
+
+static void exynos_rng_writel(struct exynos_rng_dev *rng, u32 val, u32 offset)
+{
+ writel_relaxed(val, rng->mem + offset);
+}
+
+static int exynos_rng_set_seed(struct exynos_rng_dev *rng,
+ const u8 *seed, unsigned int slen)
+{
+ u32 val;
+ int i;
+
+ /* Round seed length because loop iterates over full register size */
+ slen = ALIGN_DOWN(slen, 4);
+
+ if (slen < EXYNOS_RNG_SEED_SIZE)
+ return -EINVAL;
+
+ for (i = 0; i < slen ; i += 4) {
+ unsigned int seed_reg = (i / 4) % EXYNOS_RNG_SEED_REGS;
+
+ val = seed[i] << 24;
+ val |= seed[i + 1] << 16;
+ val |= seed[i + 2] << 8;
+ val |= seed[i + 3] << 0;
+
+ exynos_rng_writel(rng, val, EXYNOS_RNG_SEED(seed_reg));
+ }
+
+ val = exynos_rng_readl(rng, EXYNOS_RNG_STATUS);
+ if (!(val & EXYNOS_RNG_STATUS_SEED_SETTING_DONE)) {
+ dev_warn(rng->dev, "Seed setting not finished\n");
+ return -EIO;
+ }
+
+ rng->last_seeding = jiffies;
+
+ return 0;
+}
+
+/*
+ * Read from output registers and put the data under 'dst' array,
+ * up to dlen bytes.
+ *
+ * Returns number of bytes actually stored in 'dst' (dlen
+ * or EXYNOS_RNG_SEED_SIZE).
+ */
+static unsigned int exynos_rng_copy_random(struct exynos_rng_dev *rng,
+ u8 *dst, unsigned int dlen)
+{
+ unsigned int cnt = 0;
+ int i, j;
+ u32 val;
+
+ for (j = 0; j < EXYNOS_RNG_SEED_REGS; j++) {
+ val = exynos_rng_readl(rng, EXYNOS_RNG_OUT(j));
+
+ for (i = 0; i < 4; i++) {
+ dst[cnt] = val & 0xff;
+ val >>= 8;
+ if (++cnt >= dlen)
+ return cnt;
+ }
+ }
+
+ return cnt;
+}
+
+/*
+ * Start the engine and poll for finish. Then read from output registers
+ * filling the 'dst' buffer up to 'dlen' bytes or up to size of generated
+ * random data (EXYNOS_RNG_SEED_SIZE).
+ *
+ * On success: return 0 and store number of read bytes under 'read' address.
+ * On error: return -ERRNO.
+ */
+static int exynos_rng_get_random(struct exynos_rng_dev *rng,
+ u8 *dst, unsigned int dlen,
+ unsigned int *read)
+{
+ int retry = EXYNOS_RNG_WAIT_RETRIES;
+
+ exynos_rng_writel(rng, EXYNOS_RNG_CONTROL_START,
+ EXYNOS_RNG_CONTROL);
+
+ while (!(exynos_rng_readl(rng,
+ EXYNOS_RNG_STATUS) & EXYNOS_RNG_STATUS_RNG_DONE) && --retry)
+ cpu_relax();
+
+ if (!retry)
+ return -ETIMEDOUT;
+
+ /* Clear status bit */
+ exynos_rng_writel(rng, EXYNOS_RNG_STATUS_RNG_DONE,
+ EXYNOS_RNG_STATUS);
+ *read = exynos_rng_copy_random(rng, dst, dlen);
+
+ return 0;
+}
+
+/* Re-seed itself from time to time */
+static void exynos_rng_reseed(struct exynos_rng_dev *rng)
+{
+ unsigned long next_seeding = rng->last_seeding + \
+ msecs_to_jiffies(EXYNOS_RNG_RESEED_TIME);
+ unsigned long now = jiffies;
+ unsigned int read = 0;
+ u8 seed[EXYNOS_RNG_SEED_SIZE];
+
+ if (time_before(now, next_seeding))
+ return;
+
+ if (exynos_rng_get_random(rng, seed, sizeof(seed), &read))
+ return;
+
+ exynos_rng_set_seed(rng, seed, read);
+}
+
+static int exynos_rng_generate(struct crypto_rng *tfm,
+ const u8 *src, unsigned int slen,
+ u8 *dst, unsigned int dlen)
+{
+ struct exynos_rng_ctx *ctx = crypto_rng_ctx(tfm);
+ struct exynos_rng_dev *rng = ctx->rng;
+ unsigned int read = 0;
+ int ret;
+
+ ret = clk_prepare_enable(rng->clk);
+ if (ret)
+ return ret;
+
+ do {
+ ret = exynos_rng_get_random(rng, dst, dlen, &read);
+ if (ret)
+ break;
+
+ dlen -= read;
+ dst += read;
+
+ exynos_rng_reseed(rng);
+ } while (dlen > 0);
+
+ clk_disable_unprepare(rng->clk);
+
+ return ret;
+}
+
+static int exynos_rng_seed(struct crypto_rng *tfm, const u8 *seed,
+ unsigned int slen)
+{
+ struct exynos_rng_ctx *ctx = crypto_rng_ctx(tfm);
+ struct exynos_rng_dev *rng = ctx->rng;
+ int ret;
+
+ ret = clk_prepare_enable(rng->clk);
+ if (ret)
+ return ret;
+
+ ret = exynos_rng_set_seed(ctx->rng, seed, slen);
+
+ clk_disable_unprepare(rng->clk);
+
+ return ret;
+}
+
+static int exynos_rng_kcapi_init(struct crypto_tfm *tfm)
+{
+ struct exynos_rng_ctx *ctx = crypto_tfm_ctx(tfm);
+
+ ctx->rng = exynos_rng_dev;
+
+ return 0;
+}
+
+static struct rng_alg exynos_rng_alg = {
+ .generate = exynos_rng_generate,
+ .seed = exynos_rng_seed,
+ .seedsize = EXYNOS_RNG_SEED_SIZE,
+ .base = {
+ .cra_name = "stdrng",
+ .cra_driver_name = "exynos_rng",
+ .cra_priority = 100,
+ .cra_ctxsize = sizeof(struct exynos_rng_ctx),
+ .cra_module = THIS_MODULE,
+ .cra_init = exynos_rng_kcapi_init,
+ }
+};
+
+static int exynos_rng_probe(struct platform_device *pdev)
+{
+ struct exynos_rng_dev *rng;
+ struct resource *res;
+ int ret;
+
+ if (exynos_rng_dev)
+ return -EEXIST;
+
+ rng = devm_kzalloc(&pdev->dev, sizeof(*rng), GFP_KERNEL);
+ if (!rng)
+ return -ENOMEM;
+
+ rng->dev = &pdev->dev;
+ rng->clk = devm_clk_get(&pdev->dev, "secss");
+ if (IS_ERR(rng->clk)) {
+ dev_err(&pdev->dev, "Couldn't get clock.\n");
+ return PTR_ERR(rng->clk);
+ }
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ rng->mem = devm_ioremap_resource(&pdev->dev, res);
+ if (IS_ERR(rng->mem))
+ return PTR_ERR(rng->mem);
+
+ platform_set_drvdata(pdev, rng);
+
+ exynos_rng_dev = rng;
+
+ ret = crypto_register_rng(&exynos_rng_alg);
+ if (ret) {
+ dev_err(&pdev->dev,
+ "Couldn't register rng crypto alg: %d\n", ret);
+ exynos_rng_dev = NULL;
+ }
+
+ return ret;
+}
+
+static int exynos_rng_remove(struct platform_device *pdev)
+{
+ crypto_unregister_rng(&exynos_rng_alg);
+
+ exynos_rng_dev = NULL;
+
+ return 0;
+}
+
+static int __maybe_unused exynos_rng_suspend(struct device *dev)
+{
+ struct platform_device *pdev = to_platform_device(dev);
+ struct exynos_rng_dev *rng = platform_get_drvdata(pdev);
+ int ret;
+
+ /* If we were never seeded then after resume it will be the same */
+ if (!rng->last_seeding)
+ return 0;
+
+ rng->seed_save_len = 0;
+ ret = clk_prepare_enable(rng->clk);
+ if (ret)
+ return ret;
+
+ /* Get new random numbers and store them for seeding on resume. */
+ exynos_rng_get_random(rng, rng->seed_save, sizeof(rng->seed_save),
+ &(rng->seed_save_len));
+ dev_dbg(rng->dev, "Stored %u bytes for seeding on system resume\n",
+ rng->seed_save_len);
+
+ clk_disable_unprepare(rng->clk);
+
+ return 0;
+}
+
+static int __maybe_unused exynos_rng_resume(struct device *dev)
+{
+ struct platform_device *pdev = to_platform_device(dev);
+ struct exynos_rng_dev *rng = platform_get_drvdata(pdev);
+ int ret;
+
+ /* Never seeded so nothing to do */
+ if (!rng->last_seeding)
+ return 0;
+
+ ret = clk_prepare_enable(rng->clk);
+ if (ret)
+ return ret;
+
+ ret = exynos_rng_set_seed(rng, rng->seed_save, rng->seed_save_len);
+
+ clk_disable_unprepare(rng->clk);
+
+ return ret;
+}
+
+static SIMPLE_DEV_PM_OPS(exynos_rng_pm_ops, exynos_rng_suspend,
+ exynos_rng_resume);
+
+static const struct of_device_id exynos_rng_dt_match[] = {
+ {
+ .compatible = "samsung,exynos4-rng",
+ },
+ { },
+};
+MODULE_DEVICE_TABLE(of, exynos_rng_dt_match);
+
+static struct platform_driver exynos_rng_driver = {
+ .driver = {
+ .name = "exynos-rng",
+ .pm = &exynos_rng_pm_ops,
+ .of_match_table = exynos_rng_dt_match,
+ },
+ .probe = exynos_rng_probe,
+ .remove = exynos_rng_remove,
+};
+
+module_platform_driver(exynos_rng_driver);
+
+MODULE_DESCRIPTION("Exynos H/W Random Number Generator driver");
+MODULE_AUTHOR("Krzysztof Kozlowski <krzk@kernel.org>");
+MODULE_LICENSE("GPL");
projects / GitHub / LineageOS / android_kernel_motorola_exynos9610.git / commitdiff