crypto: qcom-rng - Add Qcom prng driver

This ports the Qcom prng from older hw_random driver.

No change of functionality and move from hw_random to crypto
APIs is done.

Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

diff --git a/drivers/crypto/Kconfig b/drivers/crypto/Kconfig
index 7c6ba11..2bf799b 100644 (file)
--- a/drivers/crypto/Kconfig
+++ b/drivers/crypto/Kconfig
@@ -585,6 +585,17 @@ config CRYPTO_DEV_QCE
          hardware. To compile this driver as a module, choose M here. The
          module will be called qcrypto.
 
+config CRYPTO_DEV_QCOM_RNG
+       tristate "Qualcomm Random Number Generator Driver"
+       depends on ARCH_QCOM || COMPILE_TEST
+       select CRYPTO_RNG
+       help
+         This driver provides support for the Random Number
+         Generator hardware found on Qualcomm SoCs.
+
+         To compile this driver as a module, choose M here. The
+          module will be called qcom-rng. If unsure, say N.
+
 config CRYPTO_DEV_VMX
        bool "Support for VMX cryptographic acceleration instructions"
        depends on PPC64 && VSX

diff --git a/drivers/crypto/Makefile b/drivers/crypto/Makefile
index 7ae87b4..3602875 100644 (file)
--- a/drivers/crypto/Makefile
+++ b/drivers/crypto/Makefile
@@ -33,6 +33,7 @@ obj-$(CONFIG_CRYPTO_DEV_PICOXCELL) += picoxcell_crypto.o
 obj-$(CONFIG_CRYPTO_DEV_PPC4XX) += amcc/
 obj-$(CONFIG_CRYPTO_DEV_QAT) += qat/
 obj-$(CONFIG_CRYPTO_DEV_QCE) += qce/
+obj-$(CONFIG_CRYPTO_DEV_QCOM_RNG) += qcom-rng.o
 obj-$(CONFIG_CRYPTO_DEV_ROCKCHIP) += rockchip/
 obj-$(CONFIG_CRYPTO_DEV_S5P) += s5p-sss.o
 obj-$(CONFIG_CRYPTO_DEV_SAHARA) += sahara.o

diff --git a/drivers/crypto/qcom-rng.c b/drivers/crypto/qcom-rng.c
new file mode 100644 (file)
index 0000000..e921382
--- /dev/null
+++ b/drivers/crypto/qcom-rng.c
@@ -0,0 +1,208 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (c) 2017-18 Linaro Limited
+//
+// Based on msm-rng.c and downstream driver
+
+#include <crypto/internal/rng.h>
+#include <linux/clk.h>
+#include <linux/crypto.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+
+/* Device specific register offsets */
+#define PRNG_DATA_OUT          0x0000
+#define PRNG_STATUS            0x0004
+#define PRNG_LFSR_CFG          0x0100
+#define PRNG_CONFIG            0x0104
+
+/* Device specific register masks and config values */
+#define PRNG_LFSR_CFG_MASK     0x0000ffff
+#define PRNG_LFSR_CFG_CLOCKS   0x0000dddd
+#define PRNG_CONFIG_HW_ENABLE  BIT(1)
+#define PRNG_STATUS_DATA_AVAIL BIT(0)
+
+#define WORD_SZ                        4
+
+struct qcom_rng {
+       struct mutex lock;
+       void __iomem *base;
+       struct clk *clk;
+};
+
+struct qcom_rng_ctx {
+       struct qcom_rng *rng;
+};
+
+static struct qcom_rng *qcom_rng_dev;
+
+static int qcom_rng_read(struct qcom_rng *rng, u8 *data, unsigned int max)
+{
+       unsigned int currsize = 0;
+       u32 val;
+
+       /* read random data from hardware */
+       do {
+               val = readl_relaxed(rng->base + PRNG_STATUS);
+               if (!(val & PRNG_STATUS_DATA_AVAIL))
+                       break;
+
+               val = readl_relaxed(rng->base + PRNG_DATA_OUT);
+               if (!val)
+                       break;
+
+               if ((max - currsize) >= WORD_SZ) {
+                       memcpy(data, &val, WORD_SZ);
+                       data += WORD_SZ;
+                       currsize += WORD_SZ;
+               } else {
+                       /* copy only remaining bytes */
+                       memcpy(data, &val, max - currsize);
+                       break;
+               }
+       } while (currsize < max);
+
+       return currsize;
+}
+
+static int qcom_rng_generate(struct crypto_rng *tfm,
+                            const u8 *src, unsigned int slen,
+                            u8 *dstn, unsigned int dlen)
+{
+       struct qcom_rng_ctx *ctx = crypto_rng_ctx(tfm);
+       struct qcom_rng *rng = ctx->rng;
+       int ret;
+
+       ret = clk_prepare_enable(rng->clk);
+       if (ret)
+               return ret;
+
+       mutex_lock(&rng->lock);
+
+       ret = qcom_rng_read(rng, dstn, dlen);
+
+       mutex_unlock(&rng->lock);
+       clk_disable_unprepare(rng->clk);
+
+       return 0;
+}
+
+static int qcom_rng_seed(struct crypto_rng *tfm, const u8 *seed,
+                        unsigned int slen)
+{
+       return 0;
+}
+
+static int qcom_rng_enable(struct qcom_rng *rng)
+{
+       u32 val;
+       int ret;
+
+       ret = clk_prepare_enable(rng->clk);
+       if (ret)
+               return ret;
+
+       /* Enable PRNG only if it is not already enabled */
+       val = readl_relaxed(rng->base + PRNG_CONFIG);
+       if (val & PRNG_CONFIG_HW_ENABLE)
+               goto already_enabled;
+
+       val = readl_relaxed(rng->base + PRNG_LFSR_CFG);
+       val &= ~PRNG_LFSR_CFG_MASK;
+       val |= PRNG_LFSR_CFG_CLOCKS;
+       writel(val, rng->base + PRNG_LFSR_CFG);
+
+       val = readl_relaxed(rng->base + PRNG_CONFIG);
+       val |= PRNG_CONFIG_HW_ENABLE;
+       writel(val, rng->base + PRNG_CONFIG);
+
+already_enabled:
+       clk_disable_unprepare(rng->clk);
+
+       return 0;
+}
+
+static int qcom_rng_init(struct crypto_tfm *tfm)
+{
+       struct qcom_rng_ctx *ctx = crypto_tfm_ctx(tfm);
+
+       ctx->rng = qcom_rng_dev;
+
+       return qcom_rng_enable(ctx->rng);
+}
+
+static struct rng_alg qcom_rng_alg = {
+       .generate       = qcom_rng_generate,
+       .seed           = qcom_rng_seed,
+       .seedsize       = 0,
+       .base           = {
+               .cra_name               = "stdrng",
+               .cra_driver_name        = "qcom-rng",
+               .cra_flags              = CRYPTO_ALG_TYPE_RNG,
+               .cra_priority           = 300,
+               .cra_ctxsize            = sizeof(struct qcom_rng_ctx),
+               .cra_module             = THIS_MODULE,
+               .cra_init               = qcom_rng_init,
+       }
+};
+
+static int qcom_rng_probe(struct platform_device *pdev)
+{
+       struct resource *res;
+       struct qcom_rng *rng;
+       int ret;
+
+       rng = devm_kzalloc(&pdev->dev, sizeof(*rng), GFP_KERNEL);
+       if (!rng)
+               return -ENOMEM;
+
+       platform_set_drvdata(pdev, rng);
+       mutex_init(&rng->lock);
+
+       res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+       rng->base = devm_ioremap_resource(&pdev->dev, res);
+       if (IS_ERR(rng->base))
+               return PTR_ERR(rng->base);
+
+       rng->clk = devm_clk_get(&pdev->dev, "core");
+       if (IS_ERR(rng->clk))
+               return PTR_ERR(rng->clk);
+
+       qcom_rng_dev = rng;
+       ret = crypto_register_rng(&qcom_rng_alg);
+       if (ret) {
+               dev_err(&pdev->dev, "Register crypto rng failed: %d\n", ret);
+               qcom_rng_dev = NULL;
+       }
+
+       return ret;
+}
+
+static int qcom_rng_remove(struct platform_device *pdev)
+{
+       crypto_unregister_rng(&qcom_rng_alg);
+
+       qcom_rng_dev = NULL;
+
+       return 0;
+}
+
+static const struct of_device_id qcom_rng_of_match[] = {
+       { .compatible = "qcom,prng" },
+       {}
+};
+MODULE_DEVICE_TABLE(of, qcom_rng_of_match);
+
+static struct platform_driver qcom_rng_driver = {
+       .probe = qcom_rng_probe,
+       .remove =  qcom_rng_remove,
+       .driver = {
+               .name = KBUILD_MODNAME,
+               .of_match_table = of_match_ptr(qcom_rng_of_match),
+       }
+};
+module_platform_driver(qcom_rng_driver);
+
+MODULE_ALIAS("platform:" KBUILD_MODNAME);
+MODULE_DESCRIPTION("Qualcomm random number generator driver");
+MODULE_LICENSE("GPL v2");