hwrng: add data_mode to support rand data with post process

driver inclusion
category: Feature
bugzilla: NA
CVE: NA

In this patch, provide data_mode para to support rand data with post
process, such as sm3 and poker test.
Signed-off-by: NYu'an Wang <wangyuan46@huawei.com>
Reviewed-by: NWeili Qian <qianweili@huawei.com>
Signed-off-by: NYang Yingliang <yangyingliang@huawei.com>

drivers/char/hw_random/hisi-trng-v2.c

@@ -10,18 +10,79 @@
 #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_REG		0x00F0
 #define HISI_TRNG_BYTES		4
 #define HISI_TRNG_QUALITY	512
 #define SLEEP_US		10
 #define TIMEOUT_US		10000
+#define RAND_DATA_NORMAL	0
+#define RAND_DATA_POSTPRO	1
 
 struct hisi_trng {
 	void __iomem *base;
 	struct hwrng rng;
+	void *va;
+	phys_addr_t pa;
 };
 
+static int data_mode_set(const char *val, const struct kernel_param *kp)
+{
+	u32 n;
+	int ret;
+
+	if (!val)
+		return -EINVAL;
+
+	ret = kstrtou32(val, 10, &n);
+	if (ret < 0 || (n != RAND_DATA_NORMAL && n != RAND_DATA_POSTPRO))
+		return -EINVAL;
+
+	return param_set_int(val, kp);
+}
+
+static const struct kernel_param_ops data_mode_ops = {
+	.set = data_mode_set,
+	.get = param_get_int,
+};
+
+static int data_mode = RAND_DATA_NORMAL;
+module_param_cb(data_mode, &data_mode_ops, &data_mode, 0444);
+MODULE_PARM_DESC(data_mode, "Rand data with post process or not, 0(default), 1");
+
+static int hisi_trng_read_v2(struct hwrng *rng, void *buf, size_t max,
+				   bool wait)
+{
+	struct arm_smccc_res res = {0};
+	struct hisi_trng *trng;
+	int currsize = 0;
+
+	trng = container_of(rng, struct hisi_trng, rng);
+
+	do {
+		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_trng_read(struct hwrng *rng, void *buf, size_t max, bool wait)
 {
 	struct hisi_trng *trng;
@@ -69,9 +130,19 @@ static int hisi_trng_probe(struct platform_device *pdev)
 		return PTR_ERR(trng->base);
 
 	trng->rng.name = pdev->name;
-	trng->rng.read = hisi_trng_read;
 	trng->rng.quality = HISI_TRNG_QUALITY;
 
+	if (data_mode) {
+		trng->rng.read = hisi_trng_read_v2;
+		trng->va = devm_kzalloc(&pdev->dev, HISI_TRNG_SMC_BYTES,
+					GFP_KERNEL);
+		if (!trng->va)
+			return -ENOMEM;
+
+		trng->pa = virt_to_phys(trng->va);
+	} else
+		trng->rng.read = hisi_trng_read;
+
 	ret = devm_hwrng_register(&pdev->dev, &trng->rng);
 	if (ret)
 		dev_err(&pdev->dev, "failed to register hwrng!\n");