[PATCH 2/2] hw_random: add driver for Freescale RNGC
Sascha Hauer
s.hauer at pengutronix.de
Fri Feb 9 01:52:44 PST 2018
From: Steffen Trumtrar <s.trumtrar at pengutronix.de>
The driver is ported from Freescales Linux git and can be
found in the
vendor/freescale/imx_2.6.35_maintain
branch.
According to that code, the RNGC is found on Freescales i.MX3/5 SoCs.
The i.MX2x actually has an RNGB, which has no driver implementation
in Freescales kernel. However as it turns out, the driver for the RNGC
works fine on the (at least) i.MX25. So, they seem to be somewhat
compatible.
Signed-off-by: Steffen Trumtrar <s.trumtrar at pengutronix.de>
---
drivers/hw_random/Kconfig | 11 ++
drivers/hw_random/Makefile | 1 +
drivers/hw_random/mxc-rngc.c | 305 +++++++++++++++++++++++++++++++++++++++++++
3 files changed, 317 insertions(+)
create mode 100644 drivers/hw_random/mxc-rngc.c
diff --git a/drivers/hw_random/Kconfig b/drivers/hw_random/Kconfig
index 807fcadd31..d1297a48d0 100644
--- a/drivers/hw_random/Kconfig
+++ b/drivers/hw_random/Kconfig
@@ -4,3 +4,14 @@ menuconfig HWRNG
Support for HWRNG(Hardware Random Number Generator) devices.
If unsure, say no.
+
+if HWRNG
+
+config HWRNG_MXC_RNGC
+ tristate "Freescale i.MX RNGC Random Number Generator"
+ depends on ARCH_IMX25 || ARCH_IMX35 || ARCH_IMX53
+ help
+ This driver provides kernel-side support for the Random Number
+ Generator hardware found on some Freescale i.MX processors.
+
+endif
diff --git a/drivers/hw_random/Makefile b/drivers/hw_random/Makefile
index 15307b100f..79c238c48d 100644
--- a/drivers/hw_random/Makefile
+++ b/drivers/hw_random/Makefile
@@ -1 +1,2 @@
obj-$(CONFIG_HWRNG) += core.o
+obj-$(CONFIG_HWRNG_MXC_RNGC) += mxc-rngc.o
diff --git a/drivers/hw_random/mxc-rngc.c b/drivers/hw_random/mxc-rngc.c
new file mode 100644
index 0000000000..7b22901523
--- /dev/null
+++ b/drivers/hw_random/mxc-rngc.c
@@ -0,0 +1,305 @@
+/*
+ * RNG driver for Freescale RNGC
+ *
+ * Copyright (C) 2008-2012 Freescale Semiconductor, Inc.
+ */
+
+/*
+ * The code contained herein is licensed under the GNU General Public
+ * License. You may obtain a copy of the GNU General Public License
+ * Version 2 or later at the following locations:
+ *
+ * http://www.opensource.org/licenses/gpl-license.html
+ * http://www.gnu.org/copyleft/gpl.html
+ */
+
+/*
+ * Hardware driver for the Intel/AMD/VIA Random Number Generators (RNG)
+ * (c) Copyright 2003 Red Hat Inc <jgarzik at redhat.com>
+ *
+ * derived from
+ *
+ * Hardware driver for the AMD 768 Random Number Generator (RNG)
+ * (c) Copyright 2001 Red Hat Inc <alan at redhat.com>
+ *
+ * derived from
+ *
+ * Hardware driver for Intel i810 Random Number Generator (RNG)
+ * Copyright 2000,2001 Jeff Garzik <jgarzik at pobox.com>
+ * Copyright 2000,2001 Philipp Rumpf <prumpf at mandrakesoft.com>
+ *
+ * This file is licensed under the terms of the GNU General Public
+ * License version 2. This program is licensed "as is" without any
+ * warranty of any kind, whether express or implied.
+ */
+
+#include <common.h>
+#include <clock.h>
+#include <driver.h>
+#include <init.h>
+#include <io.h>
+#include <linux/clk.h>
+#include <linux/hw_random.h>
+
+#define RNGC_VERSION_MAJOR3 3
+
+#define RNGC_VERSION_ID 0x0000
+#define RNGC_COMMAND 0x0004
+#define RNGC_CONTROL 0x0008
+#define RNGC_STATUS 0x000C
+#define RNGC_ERROR 0x0010
+#define RNGC_FIFO 0x0014
+#define RNGC_VERIF_CTRL 0x0020
+#define RNGC_OSC_CTRL_COUNT 0x0028
+#define RNGC_OSC_COUNT 0x002C
+#define RNGC_OSC_COUNT_STATUS 0x0030
+
+#define RNGC_VERID_ZEROS_MASK 0x0f000000
+#define RNGC_VERID_RNG_TYPE_MASK 0xf0000000
+#define RNGC_VERID_RNG_TYPE_SHIFT 28
+#define RNGC_VERID_CHIP_VERSION_MASK 0x00ff0000
+#define RNGC_VERID_CHIP_VERSION_SHIFT 16
+#define RNGC_VERID_VERSION_MAJOR_MASK 0x0000ff00
+#define RNGC_VERID_VERSION_MAJOR_SHIFT 8
+#define RNGC_VERID_VERSION_MINOR_MASK 0x000000ff
+#define RNGC_VERID_VERSION_MINOR_SHIFT 0
+
+#define RNGC_CMD_ZEROS_MASK 0xffffff8c
+#define RNGC_CMD_SW_RST 0x00000040
+#define RNGC_CMD_CLR_ERR 0x00000020
+#define RNGC_CMD_CLR_INT 0x00000010
+#define RNGC_CMD_SEED 0x00000002
+#define RNGC_CMD_SELF_TEST 0x00000001
+
+#define RNGC_CTRL_ZEROS_MASK 0xfffffc8c
+#define RNGC_CTRL_CTL_ACC 0x00000200
+#define RNGC_CTRL_VERIF_MODE 0x00000100
+#define RNGC_CTRL_MASK_ERROR 0x00000040
+
+#define RNGC_CTRL_MASK_DONE 0x00000020
+#define RNGC_CTRL_AUTO_SEED 0x00000010
+#define RNGC_CTRL_FIFO_UFLOW_MASK 0x00000003
+#define RNGC_CTRL_FIFO_UFLOW_SHIFT 0
+
+#define RNGC_CTRL_FIFO_UFLOW_ZEROS_ERROR 0
+#define RNGC_CTRL_FIFO_UFLOW_ZEROS_ERROR2 1
+#define RNGC_CTRL_FIFO_UFLOW_BUS_XFR 2
+#define RNGC_CTRL_FIFO_UFLOW_ZEROS_INTR 3
+
+#define RNGC_STATUS_ST_PF_MASK 0x00c00000
+#define RNGC_STATUS_ST_PF_SHIFT 22
+#define RNGC_STATUS_ST_PF_TRNG 0x00800000
+#define RNGC_STATUS_ST_PF_PRNG 0x00400000
+#define RNGC_STATUS_ERROR 0x00010000
+#define RNGC_STATUS_FIFO_SIZE_MASK 0x0000f000
+#define RNGC_STATUS_FIFO_SIZE_SHIFT 12
+#define RNGC_STATUS_FIFO_LEVEL_MASK 0x00000f00
+#define RNGC_STATUS_FIFO_LEVEL_SHIFT 8
+#define RNGC_STATUS_NEXT_SEED_DONE 0x00000040
+#define RNGC_STATUS_SEED_DONE 0x00000020
+#define RNGC_STATUS_ST_DONE 0x00000010
+#define RNGC_STATUS_RESEED 0x00000008
+#define RNGC_STATUS_SLEEP 0x00000004
+#define RNGC_STATUS_BUSY 0x00000002
+#define RNGC_STATUS_SEC_STATE 0x00000001
+
+#define RNGC_ERROR_STATUS_ZEROS_MASK 0xffffffc0
+#define RNGC_ERROR_STATUS_BAD_KEY 0x00000040
+#define RNGC_ERROR_STATUS_RAND_ERR 0x00000020
+#define RNGC_ERROR_STATUS_FIFO_ERR 0x00000010
+#define RNGC_ERROR_STATUS_STAT_ERR 0x00000008
+#define RNGC_ERROR_STATUS_ST_ERR 0x00000004
+#define RNGC_ERROR_STATUS_OSC_ERR 0x00000002
+#define RNGC_ERROR_STATUS_LFSR_ERR 0x00000001
+
+#define RNG_ADDR_RANGE 0x34
+
+struct mxc_rngc {
+ struct device_d *dev;
+ struct clk *clk;
+ void __iomem *base;
+ struct hwrng rng;
+};
+
+static int mxc_rngc_data_present(struct hwrng *rng)
+{
+ struct mxc_rngc *rngc = container_of(rng, struct mxc_rngc, rng);
+
+ /* how many random numbers are in FIFO? [0-16] */
+ return (readl(rngc->base + RNGC_STATUS) &
+ RNGC_STATUS_FIFO_LEVEL_MASK) >> RNGC_STATUS_FIFO_LEVEL_SHIFT;
+}
+
+static int mxc_rngc_read(struct hwrng *rng, void *buf, size_t max, bool wait)
+{
+ struct mxc_rngc *rngc = container_of(rng, struct mxc_rngc, rng);
+ unsigned int err;
+ int count = 0;
+ u32 *data = buf;
+
+ while (mxc_rngc_data_present(rng) && max) {
+ /* retrieve a random number from FIFO */
+ *(data+count) = readl(rngc->base + RNGC_FIFO);
+
+ /* is there some error while reading this random number? */
+ err = readl(rngc->base + RNGC_STATUS) & RNGC_STATUS_ERROR;
+ if (err)
+ break;
+
+ count += 1;
+ max -= 4;
+ }
+
+ /* if error happened doesn't return random number */
+ return err ? 0 : count * 4;
+}
+
+static int mxc_rngc_init(struct hwrng *rng)
+{
+ struct mxc_rngc *rngc = container_of(rng, struct mxc_rngc, rng);
+ unsigned int err;
+ uint64_t start;
+ u32 cmd;
+ u32 ctrl;
+ u32 osc;
+
+ err = readl(rngc->base + RNGC_STATUS) & RNGC_STATUS_ERROR;
+ if (err) {
+ /* is this a bad keys error ? */
+ if (readl(rngc->base + RNGC_ERROR) &
+ RNGC_ERROR_STATUS_BAD_KEY) {
+ dev_err(rngc->dev, "Can't start, Bad Keys.\n");
+ return -EIO;
+ }
+ }
+
+ /* mask all interrupts, will be unmasked soon */
+ ctrl = readl(rngc->base + RNGC_CONTROL);
+ writel(ctrl | RNGC_CTRL_MASK_DONE | RNGC_CTRL_MASK_ERROR,
+ rngc->base + RNGC_CONTROL);
+
+ /* verify if oscillator is working */
+ osc = readl(rngc->base + RNGC_ERROR);
+ if (osc & RNGC_ERROR_STATUS_OSC_ERR) {
+ dev_err(rngc->dev, "RNGC Oscillator is dead!\n");
+ return -EIO;
+ }
+
+ /* do self test, repeat until get success */
+ do {
+ /* clear error */
+ cmd = readl(rngc->base + RNGC_COMMAND);
+ writel(cmd | RNGC_CMD_CLR_ERR, rngc->base + RNGC_COMMAND);
+
+ /* unmask all interrupt */
+ ctrl = readl(rngc->base + RNGC_CONTROL);
+ writel(ctrl & ~(RNGC_CTRL_MASK_DONE | RNGC_CTRL_MASK_ERROR),
+ rngc->base + RNGC_CONTROL);
+
+ /* run self test */
+ cmd = readl(rngc->base + RNGC_COMMAND);
+ writel(cmd | RNGC_CMD_SELF_TEST, rngc->base + RNGC_COMMAND);
+
+ start = get_time_ns();
+ while (!(readl(rngc->base + RNGC_STATUS) &
+ RNGC_STATUS_ST_DONE)) {
+ if (is_timeout(start, 100 * MSECOND)) {
+ dev_err(rng->dev, "Timedout while seeding\n");
+ return -ETIMEDOUT;
+ }
+ }
+ writel(RNGC_CMD_CLR_INT | RNGC_CMD_CLR_ERR,
+ rngc->base + RNGC_COMMAND);
+ } while (readl(rngc->base + RNGC_ERROR) & RNGC_ERROR_STATUS_ST_ERR);
+
+ /* clear interrupt. Is it really necessary here? */
+ writel(RNGC_CMD_CLR_INT | RNGC_CMD_CLR_ERR, rngc->base + RNGC_COMMAND);
+
+ start = get_time_ns();
+ /* create seed, repeat while there is some statistical error */
+ do {
+ /* clear error */
+ cmd = readl(rngc->base + RNGC_COMMAND);
+ writel(cmd | RNGC_CMD_CLR_ERR, rngc->base + RNGC_COMMAND);
+
+ /* seed creation */
+ cmd = readl(rngc->base + RNGC_COMMAND);
+ writel(cmd | RNGC_CMD_SEED, rngc->base + RNGC_COMMAND);
+
+ while (!(readl(rngc->base + RNGC_STATUS) &
+ RNGC_STATUS_SEED_DONE)) {
+ if (is_timeout(start, 100 * MSECOND)) {
+ dev_err(rng->dev, "Timedout while seeding\n");
+ return -ETIMEDOUT;
+ }
+ }
+ writel(RNGC_CMD_CLR_INT | RNGC_CMD_CLR_ERR,
+ rngc->base + RNGC_COMMAND);
+ } while (readl(rngc->base + RNGC_ERROR) &
+ RNGC_ERROR_STATUS_STAT_ERR);
+
+ err = readl(rngc->base + RNGC_ERROR) &
+ (RNGC_ERROR_STATUS_STAT_ERR |
+ RNGC_ERROR_STATUS_RAND_ERR |
+ RNGC_ERROR_STATUS_FIFO_ERR |
+ RNGC_ERROR_STATUS_ST_ERR |
+ RNGC_ERROR_STATUS_OSC_ERR |
+ RNGC_ERROR_STATUS_LFSR_ERR);
+
+ if (err) {
+ dev_err(rngc->dev, "FSL RNGC appears inoperable.\n");
+ return -EIO;
+ }
+
+ return 0;
+}
+
+static int mxc_rngc_probe(struct device_d *dev)
+{
+ struct mxc_rngc *rngc;
+ int ret;
+
+ rngc = xzalloc(sizeof(*rngc));
+
+ rngc->base = dev_request_mem_region(dev, 0);
+ if (IS_ERR(rngc->base))
+ return PTR_ERR(rngc->base);
+
+ rngc->clk = clk_get(dev, "ipg");
+ if (IS_ERR(rngc->clk)) {
+ dev_err(dev, "Can not get rng_clk\n");
+ return PTR_ERR(rngc->clk);
+ }
+
+ ret = clk_enable(rngc->clk);
+ if (ret)
+ return ret;
+
+ rngc->rng.name = dev->name;
+ rngc->rng.read = mxc_rngc_read;
+ rngc->rng.init = mxc_rngc_init;
+
+ ret = hwrng_register(dev, &rngc->rng);
+ if (ret) {
+ dev_err(dev, "FSL RNGC registering failed (%d)\n", ret);
+ clk_disable(rngc->clk);
+
+ return ret;
+ }
+
+ dev_info(dev, "Freescale RNGC Registered.\n");
+
+ return 0;
+}
+
+static const struct of_device_id mxc_rngc_dt_ids[] = {
+ { .compatible = "fsl,imx25-rngb" },
+ { /* sentinel */ }
+};
+
+static struct driver_d mxc_rngc_driver = {
+ .name = "mxc_rngc",
+ .probe = mxc_rngc_probe,
+ .of_compatible = mxc_rngc_dt_ids,
+};
+device_platform_driver(mxc_rngc_driver);
--
2.15.1
More information about the barebox
mailing list