From: LABBE Corentin <clabbe.montjoie@xxxxxxxxx>
The Security System have a PRNG.
This patch add support for it as an hwrng.
Signed-off-by: Corentin Labbe <clabbe.montjoie@xxxxxxxxx>
---
Changes since v1:
- Replaced all spin_lock_bh by simple spin_lock
- Removed handling of size not modulo 4 which will never happen
- Added add_random_ready_callback()
drivers/crypto/Kconfig | 8 +++
drivers/crypto/sunxi-ss/Makefile | 1 +
drivers/crypto/sunxi-ss/sun4i-ss-core.c | 14 +++++
drivers/crypto/sunxi-ss/sun4i-ss-hwrng.c | 99 ++++++++++++++++++++++++++++++++
drivers/crypto/sunxi-ss/sun4i-ss.h | 9 +++
5 files changed, 131 insertions(+)
create mode 100644 drivers/crypto/sunxi-ss/sun4i-ss-hwrng.c
diff --git a/drivers/crypto/Kconfig b/drivers/crypto/Kconfig
index 4d2b81f..38f7aca 100644
--- a/drivers/crypto/Kconfig
+++ b/drivers/crypto/Kconfig
@@ -538,6 +538,14 @@ config CRYPTO_DEV_SUN4I_SS
To compile this driver as a module, choose M here: the module
will be called sun4i-ss.
+config CRYPTO_DEV_SUN4I_SS_PRNG
+ bool "Support for Allwinner Security System PRNG"
+ depends on CRYPTO_DEV_SUN4I_SS
+ select HW_RANDOM
+ help
+ This driver provides kernel-side support for the Pseudo-Random
+ Number Generator found in the Security System.
+
config CRYPTO_DEV_ROCKCHIP
tristate "Rockchip's Cryptographic Engine driver"
depends on OF && ARCH_ROCKCHIP
diff --git a/drivers/crypto/sunxi-ss/Makefile b/drivers/crypto/sunxi-ss/Makefile
index 8f4c7a2..ca049ee 100644
--- a/drivers/crypto/sunxi-ss/Makefile
+++ b/drivers/crypto/sunxi-ss/Makefile
@@ -1,2 +1,3 @@
obj-$(CONFIG_CRYPTO_DEV_SUN4I_SS) += sun4i-ss.o
sun4i-ss-y += sun4i-ss-core.o sun4i-ss-hash.o sun4i-ss-cipher.o
+sun4i-ss-$(CONFIG_CRYPTO_DEV_SUN4I_SS_PRNG) += sun4i-ss-hwrng.o
diff --git a/drivers/crypto/sunxi-ss/sun4i-ss-core.c b/drivers/crypto/sunxi-ss/sun4i-ss-core.c
index 3ac6c6c..fa739de 100644
--- a/drivers/crypto/sunxi-ss/sun4i-ss-core.c
+++ b/drivers/crypto/sunxi-ss/sun4i-ss-core.c
@@ -359,6 +359,16 @@ static int sun4i_ss_probe(struct platform_device *pdev)
}
}
platform_set_drvdata(pdev, ss);
+
+#ifdef CONFIG_CRYPTO_DEV_SUN4I_SS_PRNG
+ /* Voluntarily made the PRNG optional */
+ err = sun4i_ss_hwrng_register(&ss->hwrng);
+ if (!err)
+ dev_info(ss->dev, "sun4i-ss PRNG loaded");
+ else
+ dev_err(ss->dev, "sun4i-ss PRNG failed");
+#endif
+
return 0;
error_alg:
i--;
@@ -386,6 +396,10 @@ static int sun4i_ss_remove(struct platform_device *pdev)
int i;
struct sun4i_ss_ctx *ss = platform_get_drvdata(pdev);
+#ifdef CONFIG_CRYPTO_DEV_SUN4I_SS_PRNG
+ sun4i_ss_hwrng_remove(&ss->hwrng);
+#endif
+
for (i = 0; i < ARRAY_SIZE(ss_algs); i++) {
switch (ss_algs[i].type) {
case CRYPTO_ALG_TYPE_ABLKCIPHER:
diff --git a/drivers/crypto/sunxi-ss/sun4i-ss-hwrng.c b/drivers/crypto/sunxi-ss/sun4i-ss-hwrng.c
new file mode 100644
index 0000000..8319cae
--- /dev/null
+++ b/drivers/crypto/sunxi-ss/sun4i-ss-hwrng.c
@@ -0,0 +1,99 @@
+#include "sun4i-ss.h"
+
+static void sun4i_ss_seed(struct random_ready_callback *rdy)
+{
+ struct sun4i_ss_ctx *ss;
+
+ ss = container_of(rdy, struct sun4i_ss_ctx, random_ready);
+ get_random_bytes(ss->seed, SS_SEED_LEN);
+ ss->random_ready.func = NULL;
+}
+
+static int sun4i_ss_hwrng_init(struct hwrng *hwrng)
+{
+ struct sun4i_ss_ctx *ss;
+ int ret;
+
+ ss = container_of(hwrng, struct sun4i_ss_ctx, hwrng);
+
+ ss->random_ready.owner = THIS_MODULE;
+ ss->random_ready.func = sun4i_ss_seed;
+
+ ret = add_random_ready_callback(&ss->random_ready);
+ switch (ret) {
+ case 0:
+ break;
+ case -EALREADY:
+ get_random_bytes(ss->seed, SS_SEED_LEN);
+ ss->random_ready.func = NULL;
+ ret = 0;
+ break;
+ default:
+ ss->random_ready.func = NULL;
+ }
+
+ return ret;
+}
+
+static int sun4i_ss_hwrng_read(struct hwrng *hwrng, void *buf,
+ size_t max, bool wait)
+{
+ int i;
+ u32 v;
+ u32 *data = buf;
+ const u32 mode = SS_OP_PRNG | SS_PRNG_CONTINUE | SS_ENABLED;
+ size_t len;
+ struct sun4i_ss_ctx *ss;
+
+ ss = container_of(hwrng, struct sun4i_ss_ctx, hwrng);
+ len = min_t(size_t, SS_DATA_LEN, max);
+
+ /* If the PRNG is not seeded */
+ if (ss->random_ready.func)
+ return -EAGAIN;
+
+ spin_lock(&ss->slock);
+
+ writel(mode, ss->base + SS_CTL);
+
+ /* write the seed */
+ for (i = 0; i < SS_SEED_LEN / 4; i++)
+ writel(ss->seed[i], ss->base + SS_KEY0 + i * 4);
+ writel(mode | SS_PRNG_START, ss->base + SS_CTL);
+
+ /* Read the random data */
+ readsl(ss->base + SS_TXFIFO, data, len / 4);
+
+ /* Update the seed */
+ for (i = 0; i < SS_SEED_LEN / 4; i++) {
+ v = readl(ss->base + SS_KEY0 + i * 4);
+ ss->seed[i] = v;
+ }
+
+ writel(0, ss->base + SS_CTL);
+ spin_unlock(&ss->slock);
+ return len;
+}
+
+int sun4i_ss_hwrng_register(struct hwrng *hwrng)
+{
+ hwrng->name = "sun4i Security System PRNG";
+ hwrng->init = sun4i_ss_hwrng_init;
+ hwrng->read = sun4i_ss_hwrng_read;
+ hwrng->quality = 1000;
+
+ /* Cannot use devm_hwrng_register() since we need to hwrng_unregister
+ * before stopping clocks/regulator
+ */
+ return hwrng_register(hwrng);
+}
+
+void sun4i_ss_hwrng_remove(struct hwrng *hwrng)
+{
+ struct sun4i_ss_ctx *ss;
+
+ ss = container_of(hwrng, struct sun4i_ss_ctx, hwrng);
+ if (ss->random_ready.func)
+ del_random_ready_callback(&ss->random_ready);
+ hwrng_unregister(hwrng);
+}
diff --git a/drivers/crypto/sunxi-ss/sun4i-ss.h b/drivers/crypto/sunxi-ss/sun4i-ss.h
index f04c0f8..85772d7 100644
--- a/drivers/crypto/sunxi-ss/sun4i-ss.h
+++ b/drivers/crypto/sunxi-ss/sun4i-ss.h
@@ -23,6 +23,7 @@
#include <linux/scatterlist.h>
#include <linux/interrupt.h>
#include <linux/delay.h>
+#include <linux/hw_random.h>
#include <crypto/md5.h>
#include <crypto/sha.h>
#include <crypto/hash.h>
@@ -125,6 +126,9 @@
#define SS_RXFIFO_EMP_INT_ENABLE (1 << 2)
#define SS_TXFIFO_AVA_INT_ENABLE (1 << 0)
+#define SS_SEED_LEN (192 / 8)
+#define SS_DATA_LEN (160 / 8)
+
struct sun4i_ss_ctx {
void __iomem *base;
int irq;
@@ -134,6 +138,9 @@ struct sun4i_ss_ctx {
struct device *dev;
struct resource *res;
spinlock_t slock; /* control the use of the device */
+ struct random_ready_callback random_ready;
+ struct hwrng hwrng;
+ u32 seed[SS_SEED_LEN / 4];
};
struct sun4i_ss_alg_template {
@@ -199,3 +206,5 @@ int sun4i_ss_des_setkey(struct crypto_ablkcipher *tfm, const u8 *key,
unsigned int keylen);
int sun4i_ss_des3_setkey(struct crypto_ablkcipher *tfm, const u8 *key,
unsigned int keylen);
+int sun4i_ss_hwrng_register(struct hwrng *hwrng);
+void sun4i_ss_hwrng_remove(struct hwrng *hwrng);
--
2.7.3
--
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