From 7b11cccd6733b2d19289ed58b3f87c26a8e50cd3 Mon Sep 17 00:00:00 2001
From: Fede2782 <78815152+Fede2782@users.noreply.github.com>
Date: Sun, 12 May 2024 11:29:35 +0200
Subject: [PATCH] hwrng: exysdw-rng: Update from P615XXS7FWK1

---
 drivers/char/hw_random/exyswd-rng.c | 85 ++++++++++++++---------------
 1 file changed, 41 insertions(+), 44 deletions(-)

diff --git a/drivers/char/hw_random/exyswd-rng.c b/drivers/char/hw_random/exyswd-rng.c
index fb116a2a9c0c..64e209f24de9 100644
--- a/drivers/char/hw_random/exyswd-rng.c
+++ b/drivers/char/hw_random/exyswd-rng.c
@@ -43,6 +43,12 @@ static int hwrng_disabled;
 #endif
 static int start_up_test;
 
+atomic_t hwrng_suspend_flag;
+atomic_t hwrng_running_flag;
+
+/* Protects exyswd read functions */
+static DEFINE_SPINLOCK(rng_running_lock);
+
 #ifdef CONFIG_EXYRNG_DEBUG
 #define exyrng_debug(args...)	printk(KERN_INFO args)
 #else
@@ -165,6 +171,7 @@ static int exynos_swd_read(struct hwrng *rng, void *data, size_t max, bool wait)
 	uint32_t *read_buf = data;
 	uint32_t read_size = max;
 	unsigned long flag;
+	unsigned long running_flag;
 	uint32_t retry_cnt;
 	int ret = HWRNG_RET_OK;
 
@@ -172,6 +179,17 @@ static int exynos_swd_read(struct hwrng *rng, void *data, size_t max, bool wait)
 	if (hwrng_disabled)
 		return -EPERM;
 #endif
+	spin_lock_irqsave(&rng_running_lock, running_flag);
+	if (atomic_read(&hwrng_suspend_flag) == 1) {
+		atomic_set(&hwrng_running_flag, 0);
+		spin_unlock_irqrestore(&rng_running_lock, running_flag);
+		printk("[ExyRNG] exynos_swd_read is failed because of suspend flag\n");
+		return -EFAULT;
+	}
+
+	atomic_set(&hwrng_running_flag, 1);
+	spin_unlock_irqrestore(&rng_running_lock, running_flag);
+
 	retry_cnt = 0;
 	do {
 		spin_lock_irqsave(&hwrandom_lock, flag);
@@ -204,7 +222,8 @@ static int exynos_swd_read(struct hwrng *rng, void *data, size_t max, bool wait)
 	} while (ret == HWRNG_RET_RETRY_ERROR);
 	if (ret != HWRNG_RET_OK) {
 		msleep(1);
-		return -EFAULT;
+		ret = -EFAULT;
+		goto err;
 	}
 
 	if (start_up_test) {
@@ -283,6 +302,11 @@ static int exynos_swd_read(struct hwrng *rng, void *data, size_t max, bool wait)
 		usleep_range(50, 100);
 	} while(1);
 
+err:
+	spin_lock_irqsave(&rng_running_lock, running_flag);
+	atomic_set(&hwrng_running_flag, 0);
+	spin_unlock_irqrestore(&rng_running_lock, running_flag);
+
 	return ret;
 }
 
@@ -299,6 +323,9 @@ static int exyswd_rng_probe(struct platform_device *pdev)
 	start_up_test = 1;
 #endif
 
+	atomic_set(&hwrng_suspend_flag, 0);
+	atomic_set(&hwrng_running_flag, 0);
+
 	ret = hwrng_register(&rng);
 	if (ret)
 		return ret;
@@ -318,62 +345,32 @@ static int exyswd_rng_remove(struct platform_device *pdev)
 #if defined(CONFIG_PM_SLEEP) || defined(CONFIG_PM_RUNTIME)
 static int exyswd_rng_suspend(struct device *dev)
 {
-	uint64_t reg0;
-	uint64_t reg1;
-	uint64_t reg2;
-	uint64_t reg3;
 	unsigned long flag;
 	int ret = HWRNG_RET_OK;
 
-	spin_lock_irqsave(&hwrandom_lock, flag);
-	if (hwrng_read_flag) {
-		reg0 = SMC_CMD_RANDOM;
-		reg1 = HWRNG_EXIT;
-		reg2 = 0;
-		reg3 = 0;
-
-		ret = exynos_cm_smc(&reg0, &reg1, &reg2, &reg3);
-		if (ret != HWRNG_RET_OK)
-			printk("[ExyRNG] failed to enter suspend with %d\n", ret);
+	spin_lock_irqsave(&rng_running_lock, flag);
+	if (atomic_read(&hwrng_running_flag) == 1) {
+		printk("[ExyRNG] exyswd_rng_suspend: hwrng_running_flag is 1.\n");
+		ret = -EFAULT;
+		goto out;
 	}
-	spin_unlock_irqrestore(&hwrandom_lock, flag);
+
+	atomic_set(&hwrng_suspend_flag, 1);
+out:
+	spin_unlock_irqrestore(&rng_running_lock, flag);
 
 	return ret;
 }
 
 static int exyswd_rng_resume(struct device *dev)
 {
-	uint64_t reg0;
-	uint64_t reg1;
-	uint64_t reg2;
-	uint64_t reg3;
 	unsigned long flag;
-	int ret = HWRNG_RET_OK;
-
-	spin_lock_irqsave(&hwrandom_lock, flag);
-#if defined(CONFIG_EXYRNG_FIPS_COMPLIANCE)
-	reg0 = SMC_CMD_RANDOM;
-	reg1 = HWRNG_RESUME;
-	reg2 = 0;
-	reg3 = 0;
-
-	ret = exynos_cm_smc(&reg0, &reg1, &reg2, &reg3);
-	if (ret != HWRNG_RET_OK)
-		printk("[ExyRNG] failed to resume with %d\n", ret);
-#endif
-	if (hwrng_read_flag) {
-		reg0 = SMC_CMD_RANDOM;
-		reg1 = HWRNG_INIT;
-		reg2 = 0;
-		reg3 = 0;
 
-		ret = exynos_cm_smc(&reg0, &reg1, &reg2, &reg3);
-		if (ret != HWRNG_RET_OK)
-			printk("[ExyRNG] failed to resume with %d\n", ret);
-	}
-	spin_unlock_irqrestore(&hwrandom_lock, flag);
+	spin_lock_irqsave(&rng_running_lock, flag);
+	atomic_set(&hwrng_suspend_flag, 0);
+	spin_unlock_irqrestore(&rng_running_lock, flag);
 
-	return ret;
+	return HWRNG_RET_OK;
 }
 #endif