From e9ef45e5f3a2f36cd98277c11a9aeb34b1ec7a70 Mon Sep 17 00:00:00 2001
From: Dom Cobley <popcornmix@gmail.com>
Date: Wed, 13 Sep 2023 17:48:36 +0100
Subject: [PATCH] Revert "hwrng: iproc-rng200: Add BCM2838 support"

This reverts commit 7a01051faa2cdd074fa54fc59610251c39aefdfc.
---
 drivers/char/hw_random/Kconfig        |  2 +-
 drivers/char/hw_random/iproc-rng200.c | 78 ++-------------------------
 2 files changed, 4 insertions(+), 76 deletions(-)

--- a/drivers/char/hw_random/Kconfig
+++ b/drivers/char/hw_random/Kconfig
@@ -104,7 +104,7 @@ config HW_RANDOM_IPROC_RNG200
 	default HW_RANDOM
 	help
 	  This driver provides kernel-side support for the RNG200
-	  hardware found on the Broadcom iProc, BCM2711 and STB SoCs.
+	  hardware found on the Broadcom iProc and STB SoCs.
 
 	  To compile this driver as a module, choose M here: the
 	  module will be called iproc-rng200
--- a/drivers/char/hw_random/iproc-rng200.c
+++ b/drivers/char/hw_random/iproc-rng200.c
@@ -21,7 +21,6 @@
 #define RNG_CTRL_OFFSET					0x00
 #define RNG_CTRL_RNG_RBGEN_MASK				0x00001FFF
 #define RNG_CTRL_RNG_RBGEN_ENABLE			0x00000001
-#define RNG_CTRL_RNG_DIV_CTRL_SHIFT			13
 
 #define RNG_SOFT_RESET_OFFSET				0x04
 #define RNG_SOFT_RESET					0x00000001
@@ -29,23 +28,16 @@
 #define RBG_SOFT_RESET_OFFSET				0x08
 #define RBG_SOFT_RESET					0x00000001
 
-#define RNG_TOTAL_BIT_COUNT_OFFSET			0x0C
-
-#define RNG_TOTAL_BIT_COUNT_THRESHOLD_OFFSET		0x10
-
 #define RNG_INT_STATUS_OFFSET				0x18
 #define RNG_INT_STATUS_MASTER_FAIL_LOCKOUT_IRQ_MASK	0x80000000
 #define RNG_INT_STATUS_STARTUP_TRANSITIONS_MET_IRQ_MASK	0x00020000
 #define RNG_INT_STATUS_NIST_FAIL_IRQ_MASK		0x00000020
 #define RNG_INT_STATUS_TOTAL_BITS_COUNT_IRQ_MASK	0x00000001
 
-#define RNG_INT_ENABLE_OFFSET				0x1C
-
 #define RNG_FIFO_DATA_OFFSET				0x20
 
 #define RNG_FIFO_COUNT_OFFSET				0x24
 #define RNG_FIFO_COUNT_RNG_FIFO_COUNT_MASK		0x000000FF
-#define RNG_FIFO_COUNT_RNG_FIFO_THRESHOLD_SHIFT		8
 
 struct iproc_rng200_dev {
 	struct hwrng rng;
@@ -166,64 +158,6 @@ static int iproc_rng200_init(struct hwrn
 	return 0;
 }
 
-static int bcm2711_rng200_read(struct hwrng *rng, void *buf, size_t max,
-			       bool wait)
-{
-	struct iproc_rng200_dev *priv = to_rng_priv(rng);
-	u32 max_words = max / sizeof(u32);
-	u32 num_words, count, val;
-
-	/* ensure warm up period has elapsed */
-	while (1) {
-		val = ioread32(priv->base + RNG_TOTAL_BIT_COUNT_OFFSET);
-		if (val > 16)
-			break;
-		cpu_relax();
-	}
-
-	/* ensure fifo is not empty */
-	while (1) {
-		num_words = ioread32(priv->base + RNG_FIFO_COUNT_OFFSET) &
-			    RNG_FIFO_COUNT_RNG_FIFO_COUNT_MASK;
-		if (num_words)
-			break;
-		if (!wait)
-			return 0;
-		cpu_relax();
-	}
-
-	if (num_words > max_words)
-		num_words = max_words;
-
-	for (count = 0; count < num_words; count++) {
-		((u32 *)buf)[count] = ioread32(priv->base +
-					       RNG_FIFO_DATA_OFFSET);
-	}
-
-	return num_words * sizeof(u32);
-}
-
-static int bcm2711_rng200_init(struct hwrng *rng)
-{
-	struct iproc_rng200_dev *priv = to_rng_priv(rng);
-	uint32_t val;
-
-	if (ioread32(priv->base + RNG_CTRL_OFFSET) & RNG_CTRL_RNG_RBGEN_MASK)
-		return 0;
-
-	/* initial numbers generated are "less random" so will be discarded */
-	val = 0x40000;
-	iowrite32(val, priv->base + RNG_TOTAL_BIT_COUNT_THRESHOLD_OFFSET);
-	/* min fifo count to generate full interrupt */
-	val = 2 << RNG_FIFO_COUNT_RNG_FIFO_THRESHOLD_SHIFT;
-	iowrite32(val, priv->base + RNG_FIFO_COUNT_OFFSET);
-	/* enable the rng - 1Mhz sample rate */
-	val = (0x3 << RNG_CTRL_RNG_DIV_CTRL_SHIFT) | RNG_CTRL_RNG_RBGEN_MASK;
-	iowrite32(val, priv->base + RNG_CTRL_OFFSET);
-
-	return 0;
-}
-
 static void iproc_rng200_cleanup(struct hwrng *rng)
 {
 	struct iproc_rng200_dev *priv = to_rng_priv(rng);
@@ -250,17 +184,11 @@ static int iproc_rng200_probe(struct pla
 
 	dev_set_drvdata(dev, priv);
 
-	priv->rng.name = pdev->name;
+	priv->rng.name = "iproc-rng200";
+	priv->rng.read = iproc_rng200_read;
+	priv->rng.init = iproc_rng200_init;
 	priv->rng.cleanup = iproc_rng200_cleanup;
 
-	if (of_device_is_compatible(dev->of_node, "brcm,bcm2711-rng200")) {
-		priv->rng.init = bcm2711_rng200_init;
-		priv->rng.read = bcm2711_rng200_read;
-	} else {
-		priv->rng.init = iproc_rng200_init;
-		priv->rng.read = iproc_rng200_read;
-	}
-
 	/* Register driver */
 	ret = devm_hwrng_register(dev, &priv->rng);
 	if (ret) {