hwrng: add hisilicon GM auth trng driver

driver inclusion
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I4FHUR

----------------------------------------------------------

Provide kernel-side GM authentication support for the True Random Number
Generator hardware found on HiSilicon KP920 SoC
Signed-off-by: NYu'an Wang <wangyuan46@huawei.com>
Reviewed-by: NWeili Qian <qianweili@huawei.com>
Reviewed-by: NLongfang Liu <liulongfang@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

drivers/char/hw_random/Kconfig

@@ -348,6 +348,19 @@ config HW_RANDOM_HISI
 
 	  If unsure, say Y.
 
+config HW_RANDOM_HISI_GM
+	tristate "HiSilicon GM auth True Random Number Generator support"
+	depends on HW_RANDOM && ARM64 && ACPI
+	default HW_RANDOM
+	help
+	  This driver provides kernel-side gm authentication upport for the
+	  True Random Number Generator hardware found on HiSilicon Hi1620 SoC.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called hisi-gm-trng.
+
+	  If unsure, say Y.
+
 config HW_RANDOM_ST
 	tristate "ST Microelectronics HW Random Number Generator support"
 	depends on HW_RANDOM && ARCH_STI

drivers/char/hw_random/Makefile

@@ -30,6 +30,7 @@ obj-$(CONFIG_HW_RANDOM_NOMADIK) += nomadik-rng.o
 obj-$(CONFIG_HW_RANDOM_PSERIES) += pseries-rng.o
 obj-$(CONFIG_HW_RANDOM_POWERNV) += powernv-rng.o
 obj-$(CONFIG_HW_RANDOM_HISI)	+= hisi-rng.o
+obj-$(CONFIG_HW_RANDOM_HISI_GM) += hisi-gm-trng.o
 obj-$(CONFIG_HW_RANDOM_BCM2835) += bcm2835-rng.o
 obj-$(CONFIG_HW_RANDOM_IPROC_RNG200) += iproc-rng200.o
 obj-$(CONFIG_HW_RANDOM_ST) += st-rng.o

drivers/char/hw_random/hisi-gm-trng.c

+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2019 HiSilicon Limited. */
+
+#include <linux/acpi.h>
+#include <linux/err.h>
+#include <linux/hw_random.h>
+#include <linux/io.h>
+#include <linux/iopoll.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/random.h>
+#include <linux/arm-smccc.h>
+
+#define HISI_TRNG_SMC_CMD	0x83000109
+#define HISI_TRNG_SMC_BYTES	32
+#define HISI_TRNG_QUALITY	513
+
+struct hisi_gm_trng {
+	struct hwrng rng;
+	void *va;
+	phys_addr_t pa;
+};
+
+static int hisi_gm_trng_read(struct hwrng *rng, void *buf, size_t max, bool wait)
+{
+	struct arm_smccc_res res = {0};
+	struct hisi_gm_trng *trng;
+	int currsize = 0;
+
+	trng = container_of(rng, struct hisi_gm_trng, rng);
+
+	do {
+		/* get gm true random number through bios */
+		arm_smccc_smc(HISI_TRNG_SMC_CMD, trng->pa, 0, 0, 0, 0, 0, 0,
+			      &res);
+		if (res.a0)
+			return currsize;
+
+		if (max - currsize >= HISI_TRNG_SMC_BYTES) {
+			memcpy(buf + currsize, trng->va, HISI_TRNG_SMC_BYTES);
+			currsize += HISI_TRNG_SMC_BYTES;
+			if (currsize == max)
+				return currsize;
+			continue;
+		}
+
+		memcpy(buf + currsize, trng->va, max - currsize);
+		currsize = max;
+	} while (currsize < max);
+
+	return currsize;
+}
+
+static int hisi_gm_trng_probe(struct platform_device *pdev)
+{
+	struct hisi_gm_trng *trng;
+	int ret;
+
+	trng = devm_kzalloc(&pdev->dev, sizeof(*trng), GFP_KERNEL);
+	if (!trng)
+		return -ENOMEM;
+
+	trng->rng.name = pdev->name;
+	trng->rng.quality = HISI_TRNG_QUALITY;
+	trng->rng.read = hisi_gm_trng_read;
+	trng->va = devm_kzalloc(&pdev->dev, HISI_TRNG_SMC_BYTES, GFP_KERNEL);
+	if (!trng->va)
+		return -ENOMEM;
+
+	trng->pa = virt_to_phys(trng->va);
+
+	ret = devm_hwrng_register(&pdev->dev, &trng->rng);
+	if (ret)
+		dev_err(&pdev->dev, "failed to register hwrng!\n");
+
+	return ret;
+}
+
+static const struct acpi_device_id hisi_gm_trng_acpi_tbl[] = {
+	{ "HISI02B4", 0 },
+	{ }
+};
+MODULE_DEVICE_TABLE(acpi, hisi_gm_trng_acpi_tbl);
+
+static struct platform_driver hisi_gm_trng_driver = {
+	.probe		= hisi_gm_trng_probe,
+	.driver		= {
+		.name	= "hisi-gm-trng",
+		.acpi_match_table = ACPI_PTR(hisi_gm_trng_acpi_tbl),
+	},
+};
+
+module_platform_driver(hisi_gm_trng_driver);
+
+MODULE_LICENSE("GPL v2");
+MODULE_AUTHOR("Yuan Wang <wangyuan46@huawei.com>");
+MODULE_DESCRIPTION("HiSilicon GM auth true random number generator driver");
+