[PATCH v3 3/6] crypto: Add Qcom prng driver

Vinod Koul
2018-07-03T06:04:31Z

This ports the Qcom prng from older hw_random driver.

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

Signed-off-by: Vinod Koul <vkoul@kernel.org>
---
drivers/crypto/Kconfig | 11 +++
drivers/crypto/Makefile | 1 +
drivers/crypto/qcom-rng.c | 208 ++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 220 insertions(+)
create mode 100644 drivers/crypto/qcom-rng.c

diff --git a/drivers/crypto/Kconfig b/drivers/crypto/Kconfig
index 43cccf6aff61..b8d9e71e550a 100644
--- 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 Randon 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 7ae87b4f6c8d..3602875c4f80 100644
--- 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
index 000000000000..e235a35359d3
--- /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_device.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 MAX_HW_FIFO_DEPTH 16
+#define MAX_HW_FIFO_SIZE (MAX_HW_FIFO_DEPTH * 4)
+#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, void *data, size_t max)
+{
+ size_t currsize = 0;
+ u32 *retdata = data;
+ 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;
+
+ *retdata++ = val;
+ currsize += WORD_SZ;
+
+ /* make sure we stay on 32bit boundary */
+ if ((max - currsize) < WORD_SZ)
+ 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");
--
2.14.4