[PATCH 1/2] rng: Add iProc RNG200 driver
matthias.bgg at kernel.org
matthias.bgg at kernel.org
Mon Dec 14 17:24:00 CET 2020
From: Matthias Brugger <mbrugger at suse.com>
Add support for random number generator RNG200.
This is for example found on RPi4.
Signed-off-by: Matthias Brugger <mbrugger at suse.com>
---
drivers/rng/Kconfig | 6 ++
drivers/rng/Makefile | 1 +
drivers/rng/iproc_rng200.c | 186 +++++++++++++++++++++++++++++++++++++
3 files changed, 193 insertions(+)
create mode 100644 drivers/rng/iproc_rng200.c
diff --git a/drivers/rng/Kconfig b/drivers/rng/Kconfig
index 11001c8ae7..94915d45b3 100644
--- a/drivers/rng/Kconfig
+++ b/drivers/rng/Kconfig
@@ -46,4 +46,10 @@ config RNG_ROCKCHIP
Enable random number generator for rockchip.This driver is
support rng module of crypto v1 and crypto v2.
+config RNG_IPROC200
+ bool "Broadcom iProc RNG200 random number generator"
+ depends on DM_RNG
+ default n
+ help
+ Enable random number generator for RPI4.
endif
diff --git a/drivers/rng/Makefile b/drivers/rng/Makefile
index 8953406882..39f7ee3f03 100644
--- a/drivers/rng/Makefile
+++ b/drivers/rng/Makefile
@@ -9,3 +9,4 @@ obj-$(CONFIG_RNG_SANDBOX) += sandbox_rng.o
obj-$(CONFIG_RNG_MSM) += msm_rng.o
obj-$(CONFIG_RNG_STM32MP1) += stm32mp1_rng.o
obj-$(CONFIG_RNG_ROCKCHIP) += rockchip_rng.o
+obj-$(CONFIG_RNG_IPROC200) += iproc_rng200.o
diff --git a/drivers/rng/iproc_rng200.c b/drivers/rng/iproc_rng200.c
new file mode 100644
index 0000000000..1063f43953
--- /dev/null
+++ b/drivers/rng/iproc_rng200.c
@@ -0,0 +1,186 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright 2020, Matthias Brugger <mbrugger at suse.com>
+ *
+ * Driver for Raspberry Pi hardware random number generator
+ */
+
+#include <common.h>
+#include <dm.h>
+#include <linux/delay.h>
+#include <rng.h>
+#include <asm/io.h>
+
+#define usleep_range(a, b) udelay((b))
+
+#define RNG_CTRL_OFFSET 0x00
+#define RNG_CTRL_RNG_RBGEN_MASK 0x00001FFF
+#define RNG_CTRL_RNG_RBGEN_ENABLE 0x00000001
+#define RNG_CTRL_RNG_RBGEN_DISABLE 0x00000000
+
+#define RNG_SOFT_RESET_OFFSET 0x04
+#define RNG_SOFT_RESET 0x00000001
+
+#define RBG_SOFT_RESET_OFFSET 0x08
+#define RBG_SOFT_RESET 0x00000001
+
+#define RNG_INT_STATUS_OFFSET 0x18
+#define RNG_INT_STATUS_MASTER_FAIL_LOCKOUT_IRQ_MASK 0x80000000
+#define RNG_INT_STATUS_NIST_FAIL_IRQ_MASK 0x00000020
+
+#define RNG_FIFO_DATA_OFFSET 0x20
+
+#define RNG_FIFO_COUNT_OFFSET 0x24
+#define RNG_FIFO_COUNT_RNG_FIFO_COUNT_MASK 0x000000FF
+
+struct iproc_rng200_platdata {
+ fdt_addr_t base;
+};
+
+static void iproc_rng200_enable(struct iproc_rng200_platdata *pdata, bool enable)
+{
+ fdt_addr_t rng_base = pdata->base;
+ u32 val;
+
+ val = readl(rng_base + RNG_CTRL_OFFSET);
+ val &= ~RNG_CTRL_RNG_RBGEN_MASK;
+ if (enable)
+ val |= RNG_CTRL_RNG_RBGEN_ENABLE;
+ else
+ val &= ~RNG_CTRL_RNG_RBGEN_ENABLE;
+
+ writel(val, rng_base + RNG_CTRL_OFFSET);
+
+}
+
+static void iproc_rng200_restart(struct iproc_rng200_platdata *pdata)
+{
+ fdt_addr_t rng_base = pdata->base;
+ u32 val;
+
+ iproc_rng200_enable(pdata, false);
+
+ /* Clear all interrupt status */
+ writel(0xFFFFFFFFUL, rng_base + RNG_INT_STATUS_OFFSET);
+
+ /* Reset RNG and RBG */
+ val = readl(rng_base + RBG_SOFT_RESET_OFFSET);
+ val |= RBG_SOFT_RESET;
+ writel(val, rng_base + RBG_SOFT_RESET_OFFSET);
+
+ val = readl(rng_base + RNG_SOFT_RESET_OFFSET);
+ val |= RNG_SOFT_RESET;
+ writel(val, rng_base + RNG_SOFT_RESET_OFFSET);
+
+ val = readl(rng_base + RNG_SOFT_RESET_OFFSET);
+ val &= ~RNG_SOFT_RESET;
+ writel(val, rng_base + RNG_SOFT_RESET_OFFSET);
+
+ val = readl(rng_base + RBG_SOFT_RESET_OFFSET);
+ val &= ~RBG_SOFT_RESET;
+ writel(val, rng_base + RBG_SOFT_RESET_OFFSET);
+
+ iproc_rng200_enable(pdata, true);
+}
+
+static int iproc_rng200_read(struct udevice *dev, void *data, size_t len)
+{
+ struct iproc_rng200_platdata *priv = dev_get_platdata(dev);
+ char *buf = (char *)data;
+ u32 num_remaining = len;
+ u32 status;
+
+ #define MAX_RESETS_PER_READ 1
+ u32 num_resets = 0;
+
+ while (num_remaining > 0) {
+
+ /* Is RNG sane? If not, reset it. */
+ status = readl(priv->base + RNG_INT_STATUS_OFFSET);
+ if ((status & (RNG_INT_STATUS_MASTER_FAIL_LOCKOUT_IRQ_MASK |
+ RNG_INT_STATUS_NIST_FAIL_IRQ_MASK)) != 0) {
+
+ if (num_resets >= MAX_RESETS_PER_READ)
+ return len - num_remaining;
+
+ iproc_rng200_restart(priv);
+ num_resets++;
+ }
+
+ /* Are there any random numbers available? */
+ if ((readl(priv->base + RNG_FIFO_COUNT_OFFSET) &
+ RNG_FIFO_COUNT_RNG_FIFO_COUNT_MASK) > 0) {
+
+ if (num_remaining >= sizeof(u32)) {
+ /* Buffer has room to store entire word */
+ *(u32 *)buf = readl(priv->base +
+ RNG_FIFO_DATA_OFFSET);
+ buf += sizeof(u32);
+ num_remaining -= sizeof(u32);
+ } else {
+ /* Buffer can only store partial word */
+ u32 rnd_number = readl(priv->base +
+ RNG_FIFO_DATA_OFFSET);
+ memcpy(buf, &rnd_number, num_remaining);
+ buf += num_remaining;
+ num_remaining = 0;
+ }
+
+ } else {
+ /* Can wait, give others chance to run */
+ usleep_range(min(num_remaining * 10, 500U), 500);
+ }
+ }
+
+ return 0;
+}
+
+static int iproc_rng200_probe(struct udevice *dev)
+{
+ struct iproc_rng200_platdata *priv = dev_get_platdata(dev);
+
+ iproc_rng200_enable(priv, true);
+
+ return 0;
+}
+
+static int iproc_rng200_remove(struct udevice *dev)
+{
+ struct iproc_rng200_platdata *priv = dev_get_platdata(dev);
+
+ iproc_rng200_enable(priv, false);
+
+ return 0;
+}
+
+static int iproc_rng200_ofdata_to_platdata(struct udevice *dev)
+{
+ struct iproc_rng200_platdata *pdata = dev_get_platdata(dev);
+
+ pdata->base = dev_read_addr(dev);
+ if (!pdata->base)
+ return -ENODEV;
+
+ return 0;
+}
+
+static const struct dm_rng_ops iproc_rng200_ops = {
+ .read = iproc_rng200_read,
+};
+
+static const struct udevice_id iproc_rng200_rng_match[] = {
+ { .compatible = "brcm,bcm2711-rng200", },
+ { .compatible = "brcm,iproc-rng200", },
+ {},
+};
+
+U_BOOT_DRIVER(iproc_rng200_rng) = {
+ .name = "iproc_rng200-rng",
+ .id = UCLASS_RNG,
+ .of_match = iproc_rng200_rng_match,
+ .ops = &iproc_rng200_ops,
+ .probe = iproc_rng200_probe,
+ .remove = iproc_rng200_remove,
+ .platdata_auto_alloc_size = sizeof(struct iproc_rng200_platdata),
+ .ofdata_to_platdata = iproc_rng200_ofdata_to_platdata,
+};
--
2.29.2
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