--- /dev/null
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * AMD Versal True Random Number Generator driver
+ * Copyright (c) 2024 - 2025 Advanced Micro Devices, Inc.
+ */
+
+#include <linux/bitfield.h>
+#include <linux/clk.h>
+#include <linux/crypto.h>
+#include <linux/delay.h>
+#include <linux/errno.h>
+#include <linux/firmware/xlnx-zynqmp.h>
+#include <linux/hw_random.h>
+#include <linux/io.h>
+#include <linux/iopoll.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/mod_devicetable.h>
+#include <linux/platform_device.h>
+#include <linux/string.h>
+#include <crypto/internal/cipher.h>
+#include <crypto/internal/rng.h>
+#include <crypto/aes.h>
+
+/* TRNG Registers Offsets */
+#define TRNG_STATUS_OFFSET 0x4U
+#define TRNG_CTRL_OFFSET 0x8U
+#define TRNG_EXT_SEED_OFFSET 0x40U
+#define TRNG_PER_STRNG_OFFSET 0x80U
+#define TRNG_CORE_OUTPUT_OFFSET 0xC0U
+#define TRNG_RESET_OFFSET 0xD0U
+#define TRNG_OSC_EN_OFFSET 0xD4U
+
+/* Mask values */
+#define TRNG_RESET_VAL_MASK BIT(0)
+#define TRNG_OSC_EN_VAL_MASK BIT(0)
+#define TRNG_CTRL_PRNGSRST_MASK BIT(0)
+#define TRNG_CTRL_EUMODE_MASK BIT(8)
+#define TRNG_CTRL_TRSSEN_MASK BIT(2)
+#define TRNG_CTRL_PRNGSTART_MASK BIT(5)
+#define TRNG_CTRL_PRNGXS_MASK BIT(3)
+#define TRNG_CTRL_PRNGMODE_MASK BIT(7)
+#define TRNG_STATUS_DONE_MASK BIT(0)
+#define TRNG_STATUS_QCNT_MASK GENMASK(11, 9)
+#define TRNG_STATUS_QCNT_16_BYTES 0x800
+
+/* Sizes in bytes */
+#define TRNG_SEED_LEN_BYTES 48U
+#define TRNG_ENTROPY_SEED_LEN_BYTES 64U
+#define TRNG_SEC_STRENGTH_SHIFT 5U
+#define TRNG_SEC_STRENGTH_BYTES BIT(TRNG_SEC_STRENGTH_SHIFT)
+#define TRNG_BYTES_PER_REG 4U
+#define TRNG_RESET_DELAY 10
+#define TRNG_NUM_INIT_REGS 12U
+#define TRNG_READ_4_WORD 4
+#define TRNG_DATA_READ_DELAY 8000
+
+struct xilinx_rng {
+ void __iomem *rng_base;
+ struct device *dev;
+ struct mutex lock; /* Protect access to TRNG device */
+ struct hwrng trng;
+};
+
+struct xilinx_rng_ctx {
+ struct xilinx_rng *rng;
+};
+
+static struct xilinx_rng *xilinx_rng_dev;
+
+static void xtrng_readwrite32(void __iomem *addr, u32 mask, u8 value)
+{
+ u32 val;
+
+ val = ioread32(addr);
+ val = (val & (~mask)) | (mask & value);
+ iowrite32(val, addr);
+}
+
+static void xtrng_trng_reset(void __iomem *addr)
+{
+ xtrng_readwrite32(addr + TRNG_RESET_OFFSET, TRNG_RESET_VAL_MASK, TRNG_RESET_VAL_MASK);
+ udelay(TRNG_RESET_DELAY);
+ xtrng_readwrite32(addr + TRNG_RESET_OFFSET, TRNG_RESET_VAL_MASK, 0);
+}
+
+static void xtrng_hold_reset(void __iomem *addr)
+{
+ xtrng_readwrite32(addr + TRNG_CTRL_OFFSET, TRNG_CTRL_PRNGSRST_MASK,
+ TRNG_CTRL_PRNGSRST_MASK);
+ iowrite32(TRNG_RESET_VAL_MASK, addr + TRNG_RESET_OFFSET);
+ udelay(TRNG_RESET_DELAY);
+}
+
+static void xtrng_softreset(struct xilinx_rng *rng)
+{
+ xtrng_readwrite32(rng->rng_base + TRNG_CTRL_OFFSET, TRNG_CTRL_PRNGSRST_MASK,
+ TRNG_CTRL_PRNGSRST_MASK);
+ udelay(TRNG_RESET_DELAY);
+ xtrng_readwrite32(rng->rng_base + TRNG_CTRL_OFFSET, TRNG_CTRL_PRNGSRST_MASK, 0);
+}
+
+/* Return no. of bytes read */
+static size_t xtrng_readblock32(void __iomem *rng_base, __be32 *buf, int blocks32, bool wait)
+{
+ int read = 0, ret;
+ int timeout = 1;
+ int i, idx;
+ u32 val;
+
+ if (wait)
+ timeout = TRNG_DATA_READ_DELAY;
+
+ for (i = 0; i < (blocks32 * 2); i++) {
+ /* TRNG core generate data in 16 bytes. Read twice to complete 32 bytes read */
+ ret = readl_poll_timeout(rng_base + TRNG_STATUS_OFFSET, val,
+ (val & TRNG_STATUS_QCNT_MASK) ==
+ TRNG_STATUS_QCNT_16_BYTES, !!wait, timeout);
+ if (ret)
+ break;
+
+ for (idx = 0; idx < TRNG_READ_4_WORD; idx++) {
+ *(buf + read) = cpu_to_be32(ioread32(rng_base + TRNG_CORE_OUTPUT_OFFSET));
+ read += 1;
+ }
+ }
+ return read * 4;
+}
+
+static int xtrng_collect_random_data(struct xilinx_rng *rng, u8 *rand_gen_buf,
+ int no_of_random_bytes, bool wait)
+{
+ u8 randbuf[TRNG_SEC_STRENGTH_BYTES];
+ int byteleft, blocks, count = 0;
+ int ret;
+
+ byteleft = no_of_random_bytes & (TRNG_SEC_STRENGTH_BYTES - 1);
+ blocks = no_of_random_bytes >> TRNG_SEC_STRENGTH_SHIFT;
+ xtrng_readwrite32(rng->rng_base + TRNG_CTRL_OFFSET, TRNG_CTRL_PRNGSTART_MASK,
+ TRNG_CTRL_PRNGSTART_MASK);
+ if (blocks) {
+ ret = xtrng_readblock32(rng->rng_base, (__be32 *)rand_gen_buf, blocks, wait);
+ if (!ret)
+ return 0;
+ count += ret;
+ }
+
+ if (byteleft) {
+ ret = xtrng_readblock32(rng->rng_base, (__be32 *)randbuf, 1, wait);
+ if (!ret)
+ return count;
+ memcpy(rand_gen_buf + (blocks * TRNG_SEC_STRENGTH_BYTES), randbuf, byteleft);
+ count += byteleft;
+ }
+
+ xtrng_readwrite32(rng->rng_base + TRNG_CTRL_OFFSET,
+ TRNG_CTRL_PRNGMODE_MASK | TRNG_CTRL_PRNGSTART_MASK, 0U);
+
+ return count;
+}
+
+static void xtrng_write_multiple_registers(void __iomem *base_addr, u32 *values, size_t n)
+{
+ void __iomem *reg_addr;
+ size_t i;
+
+ /* Write seed value into EXTERNAL_SEED Registers in big endian format */
+ for (i = 0; i < n; i++) {
+ reg_addr = (base_addr + ((n - 1 - i) * TRNG_BYTES_PER_REG));
+ iowrite32((u32 __force)(cpu_to_be32(values[i])), reg_addr);
+ }
+}
+
+static void xtrng_enable_entropy(struct xilinx_rng *rng)
+{
+ iowrite32(TRNG_OSC_EN_VAL_MASK, rng->rng_base + TRNG_OSC_EN_OFFSET);
+ xtrng_softreset(rng);
+ iowrite32(TRNG_CTRL_EUMODE_MASK | TRNG_CTRL_TRSSEN_MASK, rng->rng_base + TRNG_CTRL_OFFSET);
+}
+
+static int xtrng_reseed_internal(struct xilinx_rng *rng)
+{
+ u8 entropy[TRNG_ENTROPY_SEED_LEN_BYTES];
+ u32 val;
+ int ret;
+
+ memset(entropy, 0, sizeof(entropy));
+ xtrng_enable_entropy(rng);
+
+ /* collect random data to use it as entropy (input for DF) */
+ ret = xtrng_collect_random_data(rng, entropy, TRNG_SEED_LEN_BYTES, true);
+ if (ret != TRNG_SEED_LEN_BYTES)
+ return -EINVAL;
+
+ xtrng_write_multiple_registers(rng->rng_base + TRNG_EXT_SEED_OFFSET,
+ (u32 *)entropy, TRNG_NUM_INIT_REGS);
+ /* select reseed operation */
+ iowrite32(TRNG_CTRL_PRNGXS_MASK, rng->rng_base + TRNG_CTRL_OFFSET);
+
+ /* Start the reseed operation with above configuration and wait for STATUS.Done bit to be
+ * set. Monitor STATUS.CERTF bit, if set indicates SP800-90B entropy health test has failed.
+ */
+ xtrng_readwrite32(rng->rng_base + TRNG_CTRL_OFFSET, TRNG_CTRL_PRNGSTART_MASK,
+ TRNG_CTRL_PRNGSTART_MASK);
+
+ ret = readl_poll_timeout(rng->rng_base + TRNG_STATUS_OFFSET, val,
+ (val & TRNG_STATUS_DONE_MASK) == TRNG_STATUS_DONE_MASK,
+ 1U, 15000U);
+ if (ret)
+ return ret;
+
+ xtrng_readwrite32(rng->rng_base + TRNG_CTRL_OFFSET, TRNG_CTRL_PRNGSTART_MASK, 0U);
+
+ return 0;
+}
+
+static int xtrng_random_bytes_generate(struct xilinx_rng *rng, u8 *rand_buf_ptr,
+ u32 rand_buf_size, int wait)
+{
+ int nbytes;
+ int ret;
+
+ xtrng_readwrite32(rng->rng_base + TRNG_CTRL_OFFSET,
+ TRNG_CTRL_PRNGMODE_MASK | TRNG_CTRL_PRNGXS_MASK,
+ TRNG_CTRL_PRNGMODE_MASK | TRNG_CTRL_PRNGXS_MASK);
+ nbytes = xtrng_collect_random_data(rng, rand_buf_ptr, rand_buf_size, wait);
+
+ ret = xtrng_reseed_internal(rng);
+ if (ret) {
+ dev_err(rng->dev, "Re-seed fail\n");
+ return ret;
+ }
+
+ return nbytes;
+}
+
+static int xtrng_trng_generate(struct crypto_rng *tfm, const u8 *src, u32 slen,
+ u8 *dst, u32 dlen)
+{
+ struct xilinx_rng_ctx *ctx = crypto_rng_ctx(tfm);
+ int ret;
+
+ mutex_lock(&ctx->rng->lock);
+ ret = xtrng_random_bytes_generate(ctx->rng, dst, dlen, true);
+ mutex_unlock(&ctx->rng->lock);
+
+ return ret < 0 ? ret : 0;
+}
+
+static int xtrng_trng_seed(struct crypto_rng *tfm, const u8 *seed, unsigned int slen)
+{
+ return 0;
+}
+
+static int xtrng_trng_init(struct crypto_tfm *rtfm)
+{
+ struct xilinx_rng_ctx *ctx = crypto_tfm_ctx(rtfm);
+
+ ctx->rng = xilinx_rng_dev;
+
+ return 0;
+}
+
+static struct rng_alg xtrng_trng_alg = {
+ .generate = xtrng_trng_generate,
+ .seed = xtrng_trng_seed,
+ .seedsize = 0,
+ .base = {
+ .cra_name = "stdrng",
+ .cra_driver_name = "xilinx-trng",
+ .cra_priority = 300,
+ .cra_ctxsize = sizeof(struct xilinx_rng_ctx),
+ .cra_module = THIS_MODULE,
+ .cra_init = xtrng_trng_init,
+ },
+};
+
+static int xtrng_hwrng_trng_read(struct hwrng *hwrng, void *data, size_t max, bool wait)
+{
+ u8 buf[TRNG_SEC_STRENGTH_BYTES];
+ struct xilinx_rng *rng;
+ int ret = -EINVAL, i = 0;
+
+ rng = container_of(hwrng, struct xilinx_rng, trng);
+ /* Return in case wait not set and lock not available. */
+ if (!mutex_trylock(&rng->lock) && !wait)
+ return 0;
+ else if (!mutex_is_locked(&rng->lock) && wait)
+ mutex_lock(&rng->lock);
+
+ while (i < max) {
+ ret = xtrng_random_bytes_generate(rng, buf, TRNG_SEC_STRENGTH_BYTES, wait);
+ if (ret < 0)
+ break;
+
+ memcpy(data + i, buf, min_t(int, ret, (max - i)));
+ i += min_t(int, ret, (max - i));
+ }
+ mutex_unlock(&rng->lock);
+
+ return ret;
+}
+
+static int xtrng_hwrng_register(struct hwrng *trng)
+{
+ int ret;
+
+ trng->name = "Xilinx Versal Crypto Engine TRNG";
+ trng->read = xtrng_hwrng_trng_read;
+
+ ret = hwrng_register(trng);
+ if (ret)
+ pr_err("Fail to register the TRNG\n");
+
+ return ret;
+}
+
+static void xtrng_hwrng_unregister(struct hwrng *trng)
+{
+ hwrng_unregister(trng);
+}
+
+static int xtrng_probe(struct platform_device *pdev)
+{
+ struct xilinx_rng *rng;
+ int ret;
+
+ rng = devm_kzalloc(&pdev->dev, sizeof(*rng), GFP_KERNEL);
+ if (!rng)
+ return -ENOMEM;
+
+ rng->dev = &pdev->dev;
+ rng->rng_base = devm_platform_ioremap_resource(pdev, 0);
+ if (IS_ERR(rng->rng_base)) {
+ dev_err(&pdev->dev, "Failed to map resource %ld\n", PTR_ERR(rng->rng_base));
+ return PTR_ERR(rng->rng_base);
+ }
+
+ xtrng_trng_reset(rng->rng_base);
+ ret = xtrng_reseed_internal(rng);
+ if (ret) {
+ dev_err(&pdev->dev, "TRNG Seed fail\n");
+ return ret;
+ }
+
+ xilinx_rng_dev = rng;
+ mutex_init(&rng->lock);
+ ret = crypto_register_rng(&xtrng_trng_alg);
+ if (ret) {
+ dev_err(&pdev->dev, "Crypto Random device registration failed: %d\n", ret);
+ return ret;
+ }
+ ret = xtrng_hwrng_register(&rng->trng);
+ if (ret) {
+ dev_err(&pdev->dev, "HWRNG device registration failed: %d\n", ret);
+ goto crypto_rng_free;
+ }
+ platform_set_drvdata(pdev, rng);
+
+ return 0;
+
+crypto_rng_free:
+ crypto_unregister_rng(&xtrng_trng_alg);
+
+ return ret;
+}
+
+static void xtrng_remove(struct platform_device *pdev)
+{
+ struct xilinx_rng *rng;
+ u32 zero[TRNG_NUM_INIT_REGS] = { };
+
+ rng = platform_get_drvdata(pdev);
+ xtrng_hwrng_unregister(&rng->trng);
+ crypto_unregister_rng(&xtrng_trng_alg);
+ xtrng_write_multiple_registers(rng->rng_base + TRNG_EXT_SEED_OFFSET, zero,
+ TRNG_NUM_INIT_REGS);
+ xtrng_write_multiple_registers(rng->rng_base + TRNG_PER_STRNG_OFFSET, zero,
+ TRNG_NUM_INIT_REGS);
+ xtrng_hold_reset(rng->rng_base);
+ xilinx_rng_dev = NULL;
+}
+
+static const struct of_device_id xtrng_of_match[] = {
+ { .compatible = "xlnx,versal-trng", },
+ {},
+};
+
+MODULE_DEVICE_TABLE(of, xtrng_of_match);
+
+static struct platform_driver xtrng_driver = {
+ .driver = {
+ .name = "xlnx,versal-trng",
+ .of_match_table = xtrng_of_match,
+ },
+ .probe = xtrng_probe,
+ .remove = xtrng_remove,
+};
+
+module_platform_driver(xtrng_driver);
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Harsh Jain <h.jain@amd.com>");
+MODULE_AUTHOR("Mounika Botcha <mounika.botcha@amd.com>");
+MODULE_DESCRIPTION("True Random Number Generator Driver");
projects / thirdparty / kernel / stable.git / commitdiff
