[v2] crypto: sun4i-ss: support the Security System PRNG

Message ID	1480934922-20732-1-git-send-email-clabbe.montjoie@gmail.com (mailing list archive)
State	New, archived
Headers	show Return-Path: <linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org> From: Corentin Labbe <clabbe.montjoie@gmail.com> To: herbert@gondor.apana.org.au, davem@davemloft.net, maxime.ripard@free-electrons.com, wens@csie.org Subject: [PATCH v2] crypto: sun4i-ss: support the Security System PRNG Date: Mon, 5 Dec 2016 11:48:42 +0100 Message-Id: <1480934922-20732-1-git-send-email-clabbe.montjoie@gmail.com> Precedence: list Cc: LABBE Corentin <clabbe.montjoie@gmail.com>, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-crypto@vger.kernel.org MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" <linux-arm-kernel-bounces@lists.infradead.org> Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org

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);

[v2] crypto: sun4i-ss: support the Security System PRNG

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