-From e9c0fd87b6169baf5bd10293a85675d505086191 Mon Sep 17 00:00:00 2001
-From: Stefan Wahren <wahrenst@gmx.net>
-Date: Sat, 4 May 2019 17:06:15 +0200
-Subject: [PATCH] hwrng: iproc-rng200: Add BCM2838 support
-
-The HWRNG on the BCM2838 is compatible to iproc-rng200, so add the
-support to this driver instead of bcm2835-rng.
-
-Signed-off-by: Stefan Wahren <wahrenst@gmx.net>
----
- drivers/char/hw_random/Kconfig | 4 +-
- drivers/char/hw_random/iproc-rng200.c | 81 +++++++++++++++++++++++++--
- 2 files changed, 79 insertions(+), 6 deletions(-)
-
---- a/drivers/char/hw_random/Kconfig
-+++ b/drivers/char/hw_random/Kconfig
-@@ -89,11 +89,11 @@ config HW_RANDOM_BCM2835
-
- config HW_RANDOM_IPROC_RNG200
- tristate "Broadcom iProc/STB RNG200 support"
-- depends on ARCH_BCM_IPROC || ARCH_BRCMSTB
-+ depends on ARCH_BCM_IPROC || ARCH_BCM2835 || ARCH_BRCMSTB
- default HW_RANDOM
- ---help---
- This driver provides kernel-side support for the RNG200
-- hardware found on the Broadcom iProc and STB SoCs.
-+ hardware found on the Broadcom iProc, BCM2838 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
-@@ -29,6 +29,7 @@
- #define RNG_CTRL_RNG_RBGEN_MASK 0x00001FFF
- #define RNG_CTRL_RNG_RBGEN_ENABLE 0x00000001
- #define RNG_CTRL_RNG_RBGEN_DISABLE 0x00000000
-+#define RNG_CTRL_RNG_DIV_CTRL_SHIFT 13
-
- #define RNG_SOFT_RESET_OFFSET 0x04
- #define RNG_SOFT_RESET 0x00000001
-@@ -36,16 +37,23 @@
- #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;
-@@ -166,6 +174,64 @@ static int iproc_rng200_init(struct hwrn
- return 0;
- }
-
-+static int bcm2838_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 bcm2838_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);
-@@ -202,10 +268,16 @@ static int iproc_rng200_probe(struct pla
- return PTR_ERR(priv->base);
- }
-
-- priv->rng.name = "iproc-rng200",
-- priv->rng.read = iproc_rng200_read,
-- priv->rng.init = iproc_rng200_init,
-- priv->rng.cleanup = iproc_rng200_cleanup,
-+ priv->rng.name = pdev->name;
-+ priv->rng.cleanup = iproc_rng200_cleanup;
-+
-+ if (of_device_is_compatible(dev->of_node, "brcm,bcm2838-rng200")) {
-+ priv->rng.init = bcm2838_rng200_init;
-+ priv->rng.read = bcm2838_rng200_read;
-+ } else {
-+ priv->rng.init = iproc_rng200_init;
-+ priv->rng.read = iproc_rng200_read;
-+ }
-
- /* Register driver */
- ret = devm_hwrng_register(dev, &priv->rng);
-@@ -222,6 +294,7 @@ static int iproc_rng200_probe(struct pla
- static const struct of_device_id iproc_rng200_of_match[] = {
- { .compatible = "brcm,bcm7278-rng200", },
- { .compatible = "brcm,iproc-rng200", },
-+ { .compatible = "brcm,bcm2838-rng200"},
- {},
- };
- MODULE_DEVICE_TABLE(of, iproc_rng200_of_match);
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