From: Corentin Labbe Subject: [PATCH] crypto: sun4i-ss: support the Security System PRNG Date: Tue, 18 Oct 2016 14:34:27 +0200 Message-ID: <1476794067-28563-1-git-send-email-clabbe.montjoie@gmail.com> Cc: linux-kernel@vger.kernel.org, linux-crypto@vger.kernel.org, linux-arm-kernel@lists.infradead.org, LABBE Corentin To: herbert@gondor.apana.org.au, davem@davemloft.net, maxime.ripard@free-electrons.com, wens@csie.org Return-path: Received: from mail-qk0-f196.google.com ([209.85.220.196]:33949 "EHLO mail-qk0-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753329AbcJRMgk (ORCPT ); Tue, 18 Oct 2016 08:36:40 -0400 Sender: linux-crypto-owner@vger.kernel.org List-ID: From: LABBE Corentin The Security System have a PRNG. This patch add support for it as an hwrng. Signed-off-by: Corentin Labbe --- 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 | 70 ++++++++++++++++++++++++++++++++ drivers/crypto/sunxi-ss/sun4i-ss.h | 8 ++++ 5 files changed, 101 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..95fadb7 --- /dev/null +++ b/drivers/crypto/sunxi-ss/sun4i-ss-hwrng.c @@ -0,0 +1,70 @@ +#include "sun4i-ss.h" + +static int sun4i_ss_hwrng_init(struct hwrng *hwrng) +{ + struct sun4i_ss_ctx *ss; + + ss = container_of(hwrng, struct sun4i_ss_ctx, hwrng); + get_random_bytes(ss->seed, SS_SEED_LEN); + + return 0; +} + +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); + + spin_lock_bh(&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); + + if (len % 4 > 0) { + v = readl(ss->base + SS_TXFIFO); + memcpy(data + len / 4, &v, 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_bh(&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) +{ + hwrng_unregister(hwrng); +} diff --git a/drivers/crypto/sunxi-ss/sun4i-ss.h b/drivers/crypto/sunxi-ss/sun4i-ss.h index f04c0f8..1297510 100644 --- a/drivers/crypto/sunxi-ss/sun4i-ss.h +++ b/drivers/crypto/sunxi-ss/sun4i-ss.h @@ -23,6 +23,7 @@ #include #include #include +#include #include #include #include @@ -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 +138,8 @@ struct sun4i_ss_ctx { struct device *dev; struct resource *res; spinlock_t slock; /* control the use of the device */ + struct hwrng hwrng; + u32 seed[SS_SEED_LEN / 4]; }; struct sun4i_ss_alg_template { @@ -199,3 +205,5 @@ 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