[PATCH 3/3] hwrng: mxc-fsl - add support for Freescale RNGC
Steffen Trumtrar
s.trumtrar at pengutronix.de
Mon Feb 29 07:52:36 PST 2016
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/char/hw_random/Kconfig | 13 ++
drivers/char/hw_random/Makefile | 1 +
drivers/char/hw_random/mxc-rngc.c | 400 ++++++++++++++++++++++++++++++++++++++
3 files changed, 414 insertions(+)
create mode 100644 drivers/char/hw_random/mxc-rngc.c
diff --git a/drivers/char/hw_random/Kconfig b/drivers/char/hw_random/Kconfig
index dbf22719462f..9d6b5c42255b 100644
--- a/drivers/char/hw_random/Kconfig
+++ b/drivers/char/hw_random/Kconfig
@@ -255,6 +255,19 @@ config HW_RANDOM_MXC_RNGA
If unsure, say Y.
+config HW_RANDOM_MXC_RNGC
+ tristate "Freescale i.MX RNGC Random Number Generator"
+ depends on ARCH_MXC
+ default HW_RANDOM
+ ---help---
+ This driver provides kernel-side support for the Random Number
+ Generator hardware found on some Freescale i.MX processors.
+
+ To compile this driver as a module, choose M here: the
+ module will be called mxc-rngc.
+
+ If unsure, say Y.
+
config HW_RANDOM_NOMADIK
tristate "ST-Ericsson Nomadik Random Number Generator support"
depends on ARCH_NOMADIK
diff --git a/drivers/char/hw_random/Makefile b/drivers/char/hw_random/Makefile
index 5ad397635128..008463bcf662 100644
--- a/drivers/char/hw_random/Makefile
+++ b/drivers/char/hw_random/Makefile
@@ -20,6 +20,7 @@ obj-$(CONFIG_HW_RANDOM_PASEMI) += pasemi-rng.o
obj-$(CONFIG_HW_RANDOM_VIRTIO) += virtio-rng.o
obj-$(CONFIG_HW_RANDOM_TX4939) += tx4939-rng.o
obj-$(CONFIG_HW_RANDOM_MXC_RNGA) += mxc-rnga.o
+obj-$(CONFIG_HW_RANDOM_MXC_RNGC) += mxc-rngc.o
obj-$(CONFIG_HW_RANDOM_OCTEON) += octeon-rng.o
obj-$(CONFIG_HW_RANDOM_NOMADIK) += nomadik-rng.o
obj-$(CONFIG_HW_RANDOM_PPC4XX) += ppc4xx-rng.o
diff --git a/drivers/char/hw_random/mxc-rngc.c b/drivers/char/hw_random/mxc-rngc.c
new file mode 100644
index 000000000000..e31d306dcacd
--- /dev/null
+++ b/drivers/char/hw_random/mxc-rngc.c
@@ -0,0 +1,400 @@
+/*
+ * 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 <linux/module.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/clk.h>
+#include <linux/err.h>
+#include <linux/platform_device.h>
+#include <linux/interrupt.h>
+#include <linux/hw_random.h>
+#include <linux/completion.h>
+#include <linux/io.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 *dev;
+ struct clk *clk;
+ void __iomem *base;
+ unsigned int irq;
+ struct hwrng rng;
+ struct completion rng_self_testing;
+ struct completion rng_seed_done;
+};
+
+static int mxc_rngc_read(struct hwrng *rng, void *data, size_t max, bool wait)
+{
+ struct mxc_rngc *rngc = container_of(rng, struct mxc_rngc, rng);
+ unsigned int status;
+ unsigned int level;
+ int retval = 0;
+
+ while (max > sizeof(u32)) {
+ status = __raw_readl(rngc->base + RNGC_STATUS);
+ /* how many random numbers are in FIFO? [0-16] */
+ level = (status & RNGC_STATUS_FIFO_LEVEL_MASK) >>
+ RNGC_STATUS_FIFO_LEVEL_SHIFT;
+
+ /* is there some error while reading this random number? */
+ if (status & RNGC_STATUS_ERROR)
+ break;
+
+ if (level) {
+ /* retrieve a random number from FIFO */
+ *(u32 *)data = __raw_readl(rngc->base + RNGC_FIFO);
+
+ retval += sizeof(u32);
+ data += sizeof(u32);
+ max -= sizeof(u32);
+ }
+ }
+
+ return retval ? retval : -EIO;
+}
+
+static irqreturn_t rngc_irq(int irq, void *priv)
+{
+ struct mxc_rngc *rngc = (struct mxc_rngc *)priv;
+ int handled = IRQ_NONE;
+
+ /* is the seed creation done? */
+ if (__raw_readl(rngc->base + RNGC_STATUS) & RNGC_STATUS_SEED_DONE) {
+ complete(&rngc->rng_seed_done);
+ __raw_writel(RNGC_CMD_CLR_INT | RNGC_CMD_CLR_ERR,
+ rngc->base + RNGC_COMMAND);
+ handled = IRQ_HANDLED;
+ }
+
+ /* is the self test done? */
+ if (__raw_readl(rngc->base + RNGC_STATUS) & RNGC_STATUS_ST_DONE) {
+ complete(&rngc->rng_self_testing);
+ __raw_writel(RNGC_CMD_CLR_INT | RNGC_CMD_CLR_ERR,
+ rngc->base + RNGC_COMMAND);
+ handled = IRQ_HANDLED;
+ }
+
+ /* is there any error? */
+ if (__raw_readl(rngc->base + RNGC_STATUS) & RNGC_STATUS_ERROR) {
+ /* clear interrupt */
+ __raw_writel(RNGC_CMD_CLR_INT | RNGC_CMD_CLR_ERR,
+ rngc->base + RNGC_COMMAND);
+ handled = IRQ_HANDLED;
+ }
+
+ return handled;
+}
+
+static int mxc_rngc_init(struct hwrng *rng)
+{
+ struct mxc_rngc *rngc = container_of(rng, struct mxc_rngc, rng);
+ u32 cmd;
+ u32 ctrl;
+ u32 osc;
+ int err;
+
+ err = __raw_readl(rngc->base + RNGC_STATUS) & RNGC_STATUS_ERROR;
+ if (err) {
+ /* is this a bad keys error ? */
+ if (__raw_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 = __raw_readl(rngc->base + RNGC_CONTROL);
+ __raw_writel(ctrl | RNGC_CTRL_MASK_DONE | RNGC_CTRL_MASK_ERROR,
+ rngc->base + RNGC_CONTROL);
+
+ /* verify if oscillator is working */
+ osc = __raw_readl(rngc->base + RNGC_ERROR);
+ if (osc & RNGC_ERROR_STATUS_OSC_ERR) {
+ dev_err(rngc->dev, "RNGC Oscillator is dead!\n");
+ return -EIO;
+ }
+
+ err = devm_request_irq(rngc->dev, rngc->irq, rngc_irq, 0, rng->name,
+ (void *)rngc);
+ if (err) {
+ dev_err(rngc->dev, "Can't get interrupt working.\n");
+ return -EIO;
+ }
+
+ /* do self test, repeat until get success */
+ do {
+ /* clear error */
+ cmd = __raw_readl(rngc->base + RNGC_COMMAND);
+ __raw_writel(cmd | RNGC_CMD_CLR_ERR, rngc->base + RNGC_COMMAND);
+
+ /* unmask all interrupt */
+ ctrl = __raw_readl(rngc->base + RNGC_CONTROL);
+ __raw_writel(ctrl & ~(RNGC_CTRL_MASK_DONE |
+ RNGC_CTRL_MASK_ERROR),
+ rngc->base + RNGC_CONTROL);
+
+ /* run self test */
+ cmd = __raw_readl(rngc->base + RNGC_COMMAND);
+ __raw_writel(cmd | RNGC_CMD_SELF_TEST,
+ rngc->base + RNGC_COMMAND);
+
+ wait_for_completion(&rngc->rng_self_testing);
+
+ } while (__raw_readl(rngc->base + RNGC_ERROR) &
+ RNGC_ERROR_STATUS_ST_ERR);
+
+ /* clear interrupt. Is it really necessary here? */
+ __raw_writel(RNGC_CMD_CLR_INT | RNGC_CMD_CLR_ERR,
+ rngc->base + RNGC_COMMAND);
+
+ /* create seed, repeat while there is some statistical error */
+ do {
+ /* clear error */
+ cmd = __raw_readl(rngc->base + RNGC_COMMAND);
+ __raw_writel(cmd | RNGC_CMD_CLR_ERR, rngc->base + RNGC_COMMAND);
+
+ /* seed creation */
+ cmd = __raw_readl(rngc->base + RNGC_COMMAND);
+ __raw_writel(cmd | RNGC_CMD_SEED, rngc->base + RNGC_COMMAND);
+
+ wait_for_completion(&rngc->rng_seed_done);
+
+ } while (__raw_readl(rngc->base + RNGC_ERROR) &
+ RNGC_ERROR_STATUS_STAT_ERR);
+
+ err = __raw_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 platform_device *pdev)
+{
+ struct mxc_rngc *rngc;
+ struct resource *res;
+ int ret;
+
+ rngc = devm_kzalloc(&pdev->dev, sizeof(*rngc), GFP_KERNEL);
+ if (!rngc)
+ return -ENOMEM;
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ rngc->base = devm_ioremap_resource(&pdev->dev, res);
+ if (IS_ERR(rngc->base))
+ return PTR_ERR(rngc->base);
+
+ rngc->clk = devm_clk_get(&pdev->dev, NULL);
+ if (IS_ERR(rngc->clk)) {
+ dev_err(&pdev->dev, "Can not get rng_clk\n");
+ return PTR_ERR(rngc->clk);
+ }
+
+ ret = clk_prepare_enable(rngc->clk);
+ if (ret)
+ return ret;
+
+ rngc->irq = platform_get_irq(pdev, 0);
+ if (!rngc->irq) {
+ dev_err(&pdev->dev, "FSL RNGC couldn't get irq\n");
+ clk_disable_unprepare(rngc->clk);
+
+ return ret;
+ }
+
+
+ init_completion(&rngc->rng_self_testing);
+ init_completion(&rngc->rng_seed_done);
+
+ rngc->rng.name = pdev->name;
+ rngc->rng.init = mxc_rngc_init;
+ rngc->rng.read = mxc_rngc_read;
+
+ rngc->dev = &pdev->dev;
+ platform_set_drvdata(pdev, rngc);
+
+ ret = hwrng_register(&rngc->rng);
+ if (ret) {
+ dev_err(&pdev->dev, "FSL RNGC registering failed (%d)\n", ret);
+ clk_disable_unprepare(rngc->clk);
+
+ return ret;
+ }
+
+ dev_info(&pdev->dev, "Freescale RNGC Registered.\n");
+
+ return 0;
+}
+
+static int mxc_rngc_remove(struct platform_device *pdev)
+{
+ struct mxc_rngc *rngc = platform_get_drvdata(pdev);
+
+ hwrng_unregister(&rngc->rng);
+
+ clk_disable_unprepare(rngc->clk);
+
+ return 0;
+}
+
+#ifdef CONFIG_PM
+static int mxc_rngc_suspend(struct device *dev)
+{
+ struct mxc_rngc *rngc = dev_get_drvdata(dev);
+
+ clk_disable_unprepare(rngc->clk);
+
+ return 0;
+}
+
+static int mxc_rngc_resume(struct device *dev)
+{
+ struct mxc_rngc *rngc = dev_get_drvdata(dev);
+
+ clk_prepare_enable(rngc->clk);
+
+ return 0;
+}
+
+static const struct dev_pm_ops mxc_rngc_pm_ops = {
+ .suspend = mxc_rngc_suspend,
+ .resume = mxc_rngc_resume,
+};
+#endif
+
+static const struct of_device_id mxc_rngc_dt_ids[] = {
+ { .compatible = "fsl,imx25-rng", .data = NULL, },
+ { /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, mxc_rngc_dt_ids);
+
+static struct platform_driver mxc_rngc_driver = {
+ .probe = mxc_rngc_probe,
+ .remove = mxc_rngc_remove,
+ .driver = {
+ .name = "mxc_rngc",
+#ifdef CONFIG_PM
+ .pm = &mxc_rngc_pm_ops,
+#endif
+ .of_match_table = mxc_rngc_dt_ids,
+ },
+};
+
+module_platform_driver(mxc_rngc_driver);
+MODULE_AUTHOR("Freescale Semiconductor, Inc.");
+MODULE_DESCRIPTION("H/W RNGC driver for i.MX");
+MODULE_LICENSE("GPL");
--
2.7.0
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