This patch had support for the TRNG present in the CE.
Note that according to the algorithm ID, 2 version of the TRNG exists,
the first present in H3/H5/R40/A64 and the second present in H6.
This patch adds support for both, but only the second is working
reliabily according to rngtest.

Signed-off-by: Corentin Labbe <cla...@baylibre.com>
---
 drivers/crypto/allwinner/Kconfig              |   8 ++
 drivers/crypto/allwinner/sun8i-ce/Makefile    |   1 +
 .../crypto/allwinner/sun8i-ce/sun8i-ce-core.c |  18 +++
 .../crypto/allwinner/sun8i-ce/sun8i-ce-trng.c | 127 ++++++++++++++++++
 drivers/crypto/allwinner/sun8i-ce/sun8i-ce.h  |  18 +++
 5 files changed, 172 insertions(+)
 create mode 100644 drivers/crypto/allwinner/sun8i-ce/sun8i-ce-trng.c

diff --git a/drivers/crypto/allwinner/Kconfig b/drivers/crypto/allwinner/Kconfig
index bf4d2a6328dc..0e72543ad1f1 100644
--- a/drivers/crypto/allwinner/Kconfig
+++ b/drivers/crypto/allwinner/Kconfig
@@ -96,6 +96,14 @@ config CRYPTO_DEV_SUN8I_CE_PRNG
          Select this option if you want to provide kernel-side support for
          the Pseudo-Random Number Generator found in the Crypto Engine.
 
+config CRYPTO_DEV_SUN8I_CE_TRNG
+       bool "Support for Allwinner Crypto Engine TRNG"
+       depends on CRYPTO_DEV_SUN8I_CE
+       select HW_RANDOM
+       help
+         Select this option if you want to provide kernel-side support for
+         the True Random Number Generator found in the Crypto Engine.
+
 config CRYPTO_DEV_SUN8I_SS
        tristate "Support for Allwinner Security System cryptographic offloader"
        select CRYPTO_SKCIPHER
diff --git a/drivers/crypto/allwinner/sun8i-ce/Makefile 
b/drivers/crypto/allwinner/sun8i-ce/Makefile
index c0ea81da2c7d..0842eb2d9408 100644
--- a/drivers/crypto/allwinner/sun8i-ce/Makefile
+++ b/drivers/crypto/allwinner/sun8i-ce/Makefile
@@ -2,3 +2,4 @@ obj-$(CONFIG_CRYPTO_DEV_SUN8I_CE) += sun8i-ce.o
 sun8i-ce-y += sun8i-ce-core.o sun8i-ce-cipher.o
 sun8i-ce-$(CONFIG_CRYPTO_DEV_SUN8I_CE_HASH) += sun8i-ce-hash.o
 sun8i-ce-$(CONFIG_CRYPTO_DEV_SUN8I_CE_PRNG) += sun8i-ce-prng.o
+sun8i-ce-$(CONFIG_CRYPTO_DEV_SUN8I_CE_TRNG) += sun8i-ce-trng.o
diff --git a/drivers/crypto/allwinner/sun8i-ce/sun8i-ce-core.c 
b/drivers/crypto/allwinner/sun8i-ce/sun8i-ce-core.c
index 9b7f8fdc4992..116425e3d2b9 100644
--- a/drivers/crypto/allwinner/sun8i-ce/sun8i-ce-core.c
+++ b/drivers/crypto/allwinner/sun8i-ce/sun8i-ce-core.c
@@ -47,6 +47,7 @@ static const struct ce_variant ce_h3_variant = {
                },
        .esr = ESR_H3,
        .prng = CE_ALG_PRNG,
+       .trng = CE_ID_NOTSUPP,
 };
 
 static const struct ce_variant ce_h5_variant = {
@@ -63,6 +64,7 @@ static const struct ce_variant ce_h5_variant = {
                },
        .esr = ESR_H5,
        .prng = CE_ALG_PRNG,
+       .trng = CE_ID_NOTSUPP,
 };
 
 static const struct ce_variant ce_h6_variant = {
@@ -76,6 +78,7 @@ static const struct ce_variant ce_h6_variant = {
        .cipher_t_dlen_in_bytes = true,
        .hash_t_dlen_in_bits = true,
        .prng_t_dlen_in_bytes = true,
+       .trng_t_dlen_in_bytes = true,
        .ce_clks = {
                { "bus", 0, 200000000 },
                { "mod", 300000000, 0 },
@@ -83,6 +86,7 @@ static const struct ce_variant ce_h6_variant = {
                },
        .esr = ESR_H6,
        .prng = CE_ALG_PRNG_V2,
+       .trng = CE_ALG_TRNG_V2,
 };
 
 static const struct ce_variant ce_a64_variant = {
@@ -99,6 +103,7 @@ static const struct ce_variant ce_a64_variant = {
                },
        .esr = ESR_A64,
        .prng = CE_ALG_PRNG,
+       .trng = CE_ID_NOTSUPP,
 };
 
 static const struct ce_variant ce_r40_variant = {
@@ -115,6 +120,7 @@ static const struct ce_variant ce_r40_variant = {
                },
        .esr = ESR_R40,
        .prng = CE_ALG_PRNG,
+       .trng = CE_ID_NOTSUPP,
 };
 
 /*
@@ -589,6 +595,10 @@ static int sun8i_ce_dbgfs_read(struct seq_file *seq, void 
*v)
                        break;
                }
        }
+#ifdef CONFIG_CRYPTO_DEV_SUN8I_CE_TRNG
+       seq_printf(seq, "HWRNG %lu %lu\n",
+                  ce->hwrng_stat_req, ce->hwrng_stat_bytes);
+#endif
        return 0;
 }
 
@@ -939,6 +949,10 @@ static int sun8i_ce_probe(struct platform_device *pdev)
        if (err < 0)
                goto error_alg;
 
+#ifdef CONFIG_CRYPTO_DEV_SUN8I_CE_TRNG
+       sun8i_ce_hwrng_register(ce);
+#endif
+
        v = readl(ce->base + CE_CTR);
        v >>= CE_DIE_ID_SHIFT;
        v &= CE_DIE_ID_MASK;
@@ -968,6 +982,10 @@ static int sun8i_ce_remove(struct platform_device *pdev)
 {
        struct sun8i_ce_dev *ce = platform_get_drvdata(pdev);
 
+#ifdef CONFIG_CRYPTO_DEV_SUN8I_CE_TRNG
+       sun8i_ce_hwrng_unregister(ce);
+#endif
+
        sun8i_ce_unregister_algs(ce);
 
 #ifdef CONFIG_CRYPTO_DEV_SUN8I_CE_DEBUG
diff --git a/drivers/crypto/allwinner/sun8i-ce/sun8i-ce-trng.c 
b/drivers/crypto/allwinner/sun8i-ce/sun8i-ce-trng.c
new file mode 100644
index 000000000000..af99730d8fd1
--- /dev/null
+++ b/drivers/crypto/allwinner/sun8i-ce/sun8i-ce-trng.c
@@ -0,0 +1,127 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * sun8i-ce-trng.c - hardware cryptographic offloader for
+ * Allwinner H3/A64/H5/H2+/H6/R40 SoC
+ *
+ * Copyright (C) 2015-2020 Corentin Labbe <cla...@baylibre.com>
+ *
+ * This file handle the TRNG
+ *
+ * You could find a link for the datasheet in Documentation/arm/sunxi/README
+ */
+#include "sun8i-ce.h"
+#include <linux/dma-mapping.h>
+#include <linux/pm_runtime.h>
+#include <linux/hw_random.h>
+/*
+ * Note that according to the algorithm ID, 2 versions of the TRNG exists,
+ * The first present in H3/H5/R40/A64 and the second present in H6.
+ * This file adds support for both, but only the second is working
+ * reliabily according to rngtest.
+ **/
+
+static int sun8i_ce_trng_read(struct hwrng *rng, void *data, size_t max, bool 
wait)
+{
+       struct sun8i_ce_dev *ce;
+       dma_addr_t dma_dst;
+       int err = 0;
+       int flow = 3;
+       unsigned int todo;
+       struct sun8i_ce_flow *chan;
+       struct ce_task *cet;
+       u32 common;
+       void *d;
+
+       ce = container_of(rng, struct sun8i_ce_dev, trng);
+
+       /* round the data length to a multiple of 32*/
+       todo = max + 32;
+       todo -= todo % 32;
+
+       d = kzalloc(todo, GFP_KERNEL | GFP_DMA);
+       if (!d)
+               return -ENOMEM;
+
+#ifdef CONFIG_CRYPTO_DEV_SUN8I_CE_DEBUG
+       ce->hwrng_stat_req++;
+       ce->hwrng_stat_bytes += todo;
+#endif
+
+       dma_dst = dma_map_single(ce->dev, d, todo, DMA_FROM_DEVICE);
+       if (dma_mapping_error(ce->dev, dma_dst)) {
+               dev_err(ce->dev, "Cannot DMA MAP DST\n");
+               err = -EFAULT;
+               goto err_dst;
+       }
+
+       err = pm_runtime_get_sync(ce->dev);
+       if (err < 0) {
+               pm_runtime_put_noidle(ce->dev);
+               goto err_pm;
+       }
+
+       mutex_lock(&ce->rnglock);
+       chan = &ce->chanlist[flow];
+
+       cet = &chan->tl[0];
+       memset(cet, 0, sizeof(struct ce_task));
+
+       cet->t_id = cpu_to_le32(flow);
+       common = ce->variant->trng | CE_COMM_INT;
+       cet->t_common_ctl = cpu_to_le32(common);
+
+       /* recent CE (H6) need length in bytes, in word otherwise */
+       if (ce->variant->trng_t_dlen_in_bytes)
+               cet->t_dlen = cpu_to_le32(todo);
+       else
+               cet->t_dlen = cpu_to_le32(todo / 4);
+
+       cet->t_sym_ctl = 0;
+       cet->t_asym_ctl = 0;
+
+       cet->t_dst[0].addr = cpu_to_le32(dma_dst);
+       cet->t_dst[0].len = cpu_to_le32(todo / 4);
+       ce->chanlist[flow].timeout = todo;
+
+       err = sun8i_ce_run_task(ce, 3, "TRNG");
+       mutex_unlock(&ce->rnglock);
+
+       pm_runtime_put(ce->dev);
+
+err_pm:
+       dma_unmap_single(ce->dev, dma_dst, todo, DMA_FROM_DEVICE);
+
+       if (!err) {
+               memcpy(data, d, max);
+               err = max;
+       }
+       memzero_explicit(d, todo);
+err_dst:
+       kfree(d);
+       return err;
+}
+
+int sun8i_ce_hwrng_register(struct sun8i_ce_dev *ce)
+{
+       int ret;
+
+       if (ce->variant->trng == CE_ID_NOTSUPP) {
+               dev_info(ce->dev, "TRNG not supported\n");
+               return 0;
+       }
+       ce->trng.name = "sun8i Crypto Engine TRNG";
+       ce->trng.read = sun8i_ce_trng_read;
+       ce->trng.quality = 1000;
+
+       ret = hwrng_register(&ce->trng);
+       if (ret)
+               dev_err(ce->dev, "Fail to register the TRNG\n");
+       return ret;
+}
+
+void sun8i_ce_hwrng_unregister(struct sun8i_ce_dev *ce)
+{
+       if (ce->variant->trng == CE_ID_NOTSUPP)
+               return;
+       hwrng_unregister(&ce->trng);
+}
diff --git a/drivers/crypto/allwinner/sun8i-ce/sun8i-ce.h 
b/drivers/crypto/allwinner/sun8i-ce/sun8i-ce.h
index 48d518539c29..5ab71e696860 100644
--- a/drivers/crypto/allwinner/sun8i-ce/sun8i-ce.h
+++ b/drivers/crypto/allwinner/sun8i-ce/sun8i-ce.h
@@ -12,6 +12,7 @@
 #include <linux/atomic.h>
 #include <linux/debugfs.h>
 #include <linux/crypto.h>
+#include <linux/hw_random.h>
 #include <crypto/internal/hash.h>
 #include <crypto/md5.h>
 #include <crypto/rng.h>
@@ -55,7 +56,9 @@
 #define CE_ALG_SHA256           19
 #define CE_ALG_SHA384           20
 #define CE_ALG_SHA512           21
+#define CE_ALG_TRNG            48
 #define CE_ALG_PRNG            49
+#define CE_ALG_TRNG_V2         0x1c
 #define CE_ALG_PRNG_V2         0x1d
 
 /* Used in ce_variant */
@@ -129,9 +132,12 @@ struct ce_clock {
  *                             bits or words
  * @prng_t_dlen_in_bytes:      Does the request size for PRNG is in
  *                             bytes or words
+ * @trng_t_dlen_in_bytes:      Does the request size for TRNG is in
+ *                             bytes or words
  * @ce_clks:   list of clocks needed by this variant
  * @esr:       The type of error register
  * @prng:      The CE_ALG_XXX value for the PRNG
+ * @trng:      The CE_ALG_XXX value for the TRNG
  */
 struct ce_variant {
        char alg_cipher[CE_ID_CIPHER_MAX];
@@ -140,9 +146,11 @@ struct ce_variant {
        bool cipher_t_dlen_in_bytes;
        bool hash_t_dlen_in_bits;
        bool prng_t_dlen_in_bytes;
+       bool trng_t_dlen_in_bytes;
        struct ce_clock ce_clks[CE_MAX_CLOCKS];
        int esr;
        unsigned char prng;
+       unsigned char trng;
 };
 
 struct sginfo {
@@ -218,6 +226,13 @@ struct sun8i_ce_dev {
        struct dentry *dbgfs_dir;
        struct dentry *dbgfs_stats;
 #endif
+#ifdef CONFIG_CRYPTO_DEV_SUN8I_CE_TRNG
+       struct hwrng trng;
+#ifdef CONFIG_CRYPTO_DEV_SUN8I_CE_DEBUG
+       unsigned long hwrng_stat_req;
+       unsigned long hwrng_stat_bytes;
+#endif
+#endif
 };
 
 /*
@@ -351,3 +366,6 @@ int sun8i_ce_prng_generate(struct crypto_rng *tfm, const u8 
*src,
 int sun8i_ce_prng_seed(struct crypto_rng *tfm, const u8 *seed, unsigned int 
slen);
 void sun8i_ce_prng_exit(struct crypto_tfm *tfm);
 int sun8i_ce_prng_init(struct crypto_tfm *tfm);
+
+int sun8i_ce_hwrng_register(struct sun8i_ce_dev *ce);
+void sun8i_ce_hwrng_unregister(struct sun8i_ce_dev *ce);
-- 
2.26.2

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