From: Steffen Trumtrar <[email protected]>
Add binding documentation for the Freescale RNGC found on
some i.MX2/3 SoCs.
Signed-off-by: Steffen Trumtrar <[email protected]>
Signed-off-by: Martin Kaiser <[email protected]>
---
Changes in v3:
- add compatible string for imx35
- remove imx5 from the commit message,
I couldn't find an i.MX5 soc that has an RNGC
Changes in v2:
none
Documentation/devicetree/bindings/rng/mxc_rngc.txt | 16 ++++++++++++++++
1 file changed, 16 insertions(+)
create mode 100644 Documentation/devicetree/bindings/rng/mxc_rngc.txt
diff --git a/Documentation/devicetree/bindings/rng/mxc_rngc.txt b/Documentation/devicetree/bindings/rng/mxc_rngc.txt
new file mode 100644
index 0000000..5a12ada
--- /dev/null
+++ b/Documentation/devicetree/bindings/rng/mxc_rngc.txt
@@ -0,0 +1,16 @@
+Freescale RNGC (Random Number Generator Version C)
+
+Required properties:
+- compatible : Should be "fsl,imx25-rng" or "fsl,imx35-rng"
+- reg : Offset and length of the register set of this block
+- interrupts : the interrupt number for the RNG block
+- clocks: should contain the RNG clk source
+
+Example:
+
+rng@53fb0000 {
+ compatible = "fsl,imx25-rng";
+ reg = <0x53fb0000 0x4000>;
+ interrupts = <22>;
+ clocks = <&trng_clk>;
+};
--
2.1.4
From: Steffen Trumtrar <[email protected]>
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 <[email protected]>
Signed-off-by: Martin Kaiser <[email protected]>
---
Changes in v3:
- use pdev->dev to request the irq, rngc->dev is not yet initialized
- remove unused defines for registers and fields
- use module_platform_driver_probe()
- clean up the error handling in the probe function,
disable the clock if necessary
- self-test must succeed in the first run
- check for errors after seeding, exit for errors unrelated to
statistics
- set a timeout when waiting for a completion
Changes in v2:
- remove irq variable from private struct
- move devm_request_irq from mxc_rngc_init to probe
- return irq in case of error
- handle irq 0 as error
drivers/char/hw_random/Kconfig | 13 ++
drivers/char/hw_random/Makefile | 1 +
drivers/char/hw_random/mxc-rngc.c | 351 ++++++++++++++++++++++++++++++++++++++
3 files changed, 365 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 1b223c3..ef057b7 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 b085975..043b71d 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_PSERIES) += pseries-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 0000000..56175b1
--- /dev/null
+++ b/drivers/char/hw_random/mxc-rngc.c
@@ -0,0 +1,351 @@
+/*
+ * 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 <[email protected]>
+ *
+ * derived from
+ *
+ * Hardware driver for the AMD 768 Random Number Generator (RNG)
+ * (c) Copyright 2001 Red Hat Inc <[email protected]>
+ *
+ * derived from
+ *
+ * Hardware driver for Intel i810 Random Number Generator (RNG)
+ * Copyright 2000,2001 Jeff Garzik <[email protected]>
+ * Copyright 2000,2001 Philipp Rumpf <[email protected]>
+ *
+ * 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_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_CMD_CLR_ERR 0x00000020
+#define RNGC_CMD_CLR_INT 0x00000010
+#define RNGC_CMD_SEED 0x00000002
+#define RNGC_CMD_SELF_TEST 0x00000001
+
+#define RNGC_CTRL_MASK_ERROR 0x00000040
+
+#define RNGC_CTRL_MASK_DONE 0x00000020
+
+#define RNGC_STATUS_ERROR 0x00010000
+#define RNGC_STATUS_FIFO_LEVEL_MASK 0x00000f00
+#define RNGC_STATUS_FIFO_LEVEL_SHIFT 8
+#define RNGC_STATUS_SEED_DONE 0x00000020
+#define RNGC_STATUS_ST_DONE 0x00000010
+
+#define RNGC_ERROR_STATUS_BAD_KEY 0x00000040
+#define RNGC_ERROR_STATUS_STAT_ERR 0x00000008
+#define RNGC_ERROR_STATUS_OSC_ERR 0x00000002
+
+#define RNGC_TIMEOUT 3000 /* 3 sec */
+
+struct mxc_rngc {
+ struct device *dev;
+ struct clk *clk;
+ void __iomem *base;
+ 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, ctrl, osc, err_stat, err_reg;
+ int ret;
+
+ err_stat = __raw_readl(rngc->base + RNGC_STATUS) & RNGC_STATUS_ERROR;
+ if (err_stat) {
+ /* 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;
+ }
+
+ /* 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);
+
+ ret = wait_for_completion_timeout(&rngc->rng_self_testing,
+ RNGC_TIMEOUT);
+ if (!ret)
+ return -ETIMEDOUT;
+
+ if (__raw_readl(rngc->base + RNGC_ERROR) != 0) {
+ dev_err(rngc->dev, "FSL RNGC self test failed.\n");
+ return -EIO;
+ }
+
+ /* 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);
+
+ ret = wait_for_completion_timeout(&rngc->rng_seed_done,
+ RNGC_TIMEOUT);
+ if (!ret)
+ return -ETIMEDOUT;
+
+ err_reg = __raw_readl(rngc->base + RNGC_ERROR);
+
+ /* exit if there's a "non-statistical" error or no error */
+ } while (err_reg == RNGC_ERROR_STATUS_STAT_ERR);
+
+ if (err_reg != 0) {
+ dev_err(rngc->dev, "FSL RNGC random seed creation failed.\n");
+ return -EIO;
+ }
+
+ return 0;
+}
+
+static int mxc_rngc_probe(struct platform_device *pdev)
+{
+ struct mxc_rngc *rngc;
+ struct resource *res;
+ int ret;
+ int irq;
+
+ 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);
+ }
+
+ irq = platform_get_irq(pdev, 0);
+ if (irq <= 0) {
+ dev_err(&pdev->dev, "Couldn't get irq %d\n", irq);
+ return irq;
+ }
+
+ ret = clk_prepare_enable(rngc->clk);
+ if (ret)
+ return ret;
+
+ ret = devm_request_irq(&pdev->dev, irq, rngc_irq, 0, pdev->name,
+ (void *)rngc);
+ if (ret) {
+ dev_err(rngc->dev, "Can't get interrupt working.\n");
+ goto err;
+ }
+
+ 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);
+ goto err;
+ }
+
+ dev_info(&pdev->dev, "Freescale RNGC Registered.\n");
+ return 0;
+
+err:
+ clk_disable_unprepare(rngc->clk);
+
+ return ret;
+}
+
+static int __exit 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 = {
+ .driver = {
+ .name = "mxc_rngc",
+#ifdef CONFIG_PM
+ .pm = &mxc_rngc_pm_ops,
+#endif
+ .of_match_table = mxc_rngc_dt_ids,
+ },
+ .remove = __exit_p(mxc_rngc_remove),
+};
+
+module_platform_driver_probe(mxc_rngc_driver, mxc_rngc_probe);
+
+MODULE_AUTHOR("Freescale Semiconductor, Inc.");
+MODULE_DESCRIPTION("H/W RNGC driver for i.MX");
+MODULE_LICENSE("GPL");
--
2.1.4
From: Steffen Trumtrar <[email protected]>
Add a devicetree entry for the Random Number Generator Version C (RNGC).
Signed-off-by: Steffen Trumtrar <[email protected]>
Signed-off-by: Martin Kaiser <[email protected]>
---
Changes in v3:
- remove clock-names from dtsi
Changes in v2:
- remove interrupt-names from dtsi
arch/arm/boot/dts/imx25.dtsi | 7 +++++++
1 file changed, 7 insertions(+)
diff --git a/arch/arm/boot/dts/imx25.dtsi b/arch/arm/boot/dts/imx25.dtsi
index dfcc8e0..0d2f3a1 100644
--- a/arch/arm/boot/dts/imx25.dtsi
+++ b/arch/arm/boot/dts/imx25.dtsi
@@ -451,6 +451,13 @@
interrupt-names = "scm", "smn";
};
+ rng: rng@53fb0000 {
+ compatible = "fsl,imx25-rng";
+ reg = <0x53fb0000 0x4000>;
+ clocks = <&clks 109>;
+ interrupts = <22>;
+ };
+
esdhc1: esdhc@53fb4000 {
compatible = "fsl,imx25-esdhc";
reg = <0x53fb4000 0x4000>;
--
2.1.4
Hi Martin,
On 18 July 2017 at 02:46, Martin Kaiser <[email protected]> wrote:
> From: Steffen Trumtrar <[email protected]>
>
> 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 <[email protected]>
> Signed-off-by: Martin Kaiser <[email protected]>
> ---
> Changes in v3:
> - use pdev->dev to request the irq, rngc->dev is not yet initialized
> - remove unused defines for registers and fields
> - use module_platform_driver_probe()
> - clean up the error handling in the probe function,
> disable the clock if necessary
> - self-test must succeed in the first run
> - check for errors after seeding, exit for errors unrelated to
> statistics
> - set a timeout when waiting for a completion
>
> Changes in v2:
> - remove irq variable from private struct
> - move devm_request_irq from mxc_rngc_init to probe
> - return irq in case of error
> - handle irq 0 as error
>
> drivers/char/hw_random/Kconfig | 13 ++
> drivers/char/hw_random/Makefile | 1 +
> drivers/char/hw_random/mxc-rngc.c | 351 ++++++++++++++++++++++++++++++++++++++
> 3 files changed, 365 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 1b223c3..ef057b7 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 b085975..043b71d 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_PSERIES) += pseries-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 0000000..56175b1
> --- /dev/null
> +++ b/drivers/char/hw_random/mxc-rngc.c
> @@ -0,0 +1,351 @@
> +/*
> + * 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
> + */
Please combine above 2 comments.
> +
> +/*
> + * Hardware driver for the Intel/AMD/VIA Random Number Generators (RNG)
> + * (c) Copyright 2003 Red Hat Inc <[email protected]>
> + *
> + * derived from
> + *
> + * Hardware driver for the AMD 768 Random Number Generator (RNG)
> + * (c) Copyright 2001 Red Hat Inc <[email protected]>
> + *
> + * derived from
> + *
> + * Hardware driver for Intel i810 Random Number Generator (RNG)
> + * Copyright 2000,2001 Jeff Garzik <[email protected]>
> + * Copyright 2000,2001 Philipp Rumpf <[email protected]>
> + *
> + * 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.
> + */
I feel this comment is because of copy paste. If that's the case please remove.
> +
> +#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_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_CMD_CLR_ERR 0x00000020
> +#define RNGC_CMD_CLR_INT 0x00000010
> +#define RNGC_CMD_SEED 0x00000002
> +#define RNGC_CMD_SELF_TEST 0x00000001
> +
> +#define RNGC_CTRL_MASK_ERROR 0x00000040
> +
> +#define RNGC_CTRL_MASK_DONE 0x00000020
> +
> +#define RNGC_STATUS_ERROR 0x00010000
> +#define RNGC_STATUS_FIFO_LEVEL_MASK 0x00000f00
> +#define RNGC_STATUS_FIFO_LEVEL_SHIFT 8
> +#define RNGC_STATUS_SEED_DONE 0x00000020
> +#define RNGC_STATUS_ST_DONE 0x00000010
> +
> +#define RNGC_ERROR_STATUS_BAD_KEY 0x00000040
> +#define RNGC_ERROR_STATUS_STAT_ERR 0x00000008
> +#define RNGC_ERROR_STATUS_OSC_ERR 0x00000002
> +
> +#define RNGC_TIMEOUT 3000 /* 3 sec */
> +
> +struct mxc_rngc {
> + struct device *dev;
> + struct clk *clk;
> + void __iomem *base;
> + 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)) {
Should the condition be max >= sizeof(u32)?
> + status = __raw_readl(rngc->base + RNGC_STATUS);
Is there any specific reason for using __raw_readl? Why not just readl?
If there is no specific reason for using __raw_readl please use readl
in all the places.
> + /* 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;
Before calculating level error check can be done.
> +
> + 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, ctrl, osc, err_stat, err_reg;
> + int ret;
> +
> + err_stat = __raw_readl(rngc->base + RNGC_STATUS) & RNGC_STATUS_ERROR;
> + if (err_stat) {
> + /* 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;
> + }
> + }
What keys? What is the purpose of this check? At this point only clk
is enabled for RNGC so I am wondering why this check is required?
> +
> + /* 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;
> + }
Is this check useful? If clock is initialised properly I do not think
this case will happen. May be I am missing something. Please add a
comment if this check is valid.
> +
> + /* 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);
> +
> + ret = wait_for_completion_timeout(&rngc->rng_self_testing,
> + RNGC_TIMEOUT);
> + if (!ret)
> + return -ETIMEDOUT;
RNG core can call init every time this rng device is selected as
current random number provider. Is self test required on every RNG
init?
By default self test need not be run, a module parameter can be added
for enabling self test.
> +
> + if (__raw_readl(rngc->base + RNGC_ERROR) != 0) {
> + dev_err(rngc->dev, "FSL RNGC self test failed.\n");
> + return -EIO;
> + }
> +
> + /* 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);
> +
> + ret = wait_for_completion_timeout(&rngc->rng_seed_done,
> + RNGC_TIMEOUT);
> + if (!ret)
> + return -ETIMEDOUT;
> +
> + err_reg = __raw_readl(rngc->base + RNGC_ERROR);
> +
> + /* exit if there's a "non-statistical" error or no error */
> + } while (err_reg == RNGC_ERROR_STATUS_STAT_ERR);
> +
> + if (err_reg != 0) {
> + dev_err(rngc->dev, "FSL RNGC random seed creation failed.\n");
> + return -EIO;
> + }
> +
> + return 0;
> +}
> +
> +static int mxc_rngc_probe(struct platform_device *pdev)
> +{
> + struct mxc_rngc *rngc;
> + struct resource *res;
> + int ret;
> + int irq;
> +
> + 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);
> + }
> +
> + irq = platform_get_irq(pdev, 0);
> + if (irq <= 0) {
> + dev_err(&pdev->dev, "Couldn't get irq %d\n", irq);
> + return irq;
> + }
> +
> + ret = clk_prepare_enable(rngc->clk);
> + if (ret)
> + return ret;
> +
> + ret = devm_request_irq(&pdev->dev, irq, rngc_irq, 0, pdev->name,
> + (void *)rngc);
> + if (ret) {
> + dev_err(rngc->dev, "Can't get interrupt working.\n");
> + goto err;
> + }
> +
> + 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;
Assiging a quality would be great. That will help in deciding which
rng device to use if there are mulitple rng devices.
> +
> + 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);
> + goto err;
> + }
> +
> + dev_info(&pdev->dev, "Freescale RNGC Registered.\n");
> + return 0;
> +
> +err:
> + clk_disable_unprepare(rngc->clk);
> +
> + return ret;
> +}
> +
> +static int __exit 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 = {
> + .driver = {
> + .name = "mxc_rngc",
> +#ifdef CONFIG_PM
> + .pm = &mxc_rngc_pm_ops,
> +#endif
> + .of_match_table = mxc_rngc_dt_ids,
> + },
> + .remove = __exit_p(mxc_rngc_remove),
> +};
> +
> +module_platform_driver_probe(mxc_rngc_driver, mxc_rngc_probe);
> +
> +MODULE_AUTHOR("Freescale Semiconductor, Inc.");
> +MODULE_DESCRIPTION("H/W RNGC driver for i.MX");
> +MODULE_LICENSE("GPL");
> --
> 2.1.4
>
Regards,
PrasannaKumar
Hi PrasannaKumar,
thanks for taking the time to review my submission.
Thus wrote PrasannaKumar Muralidharan ([email protected]):
> Please combine above 2 comments.
ok, I'll do this.
> > +
> > +/*
> > + * Hardware driver for the Intel/AMD/VIA Random Number Generators (RNG)
> > [...]
> I feel this comment is because of copy paste. If that's the case please remove.
A couple of files in drivers/char/hw_random have the same copyright
statement. So it looks like copy&paste. I'll remove it.
> > +
> > + while (max > sizeof(u32)) {
> Should the condition be max >= sizeof(u32)?
You're right. I'll fix this.
> > + status = __raw_readl(rngc->base + RNGC_STATUS);
> Is there any specific reason for using __raw_readl? Why not just readl?
> If there is no specific reason for using __raw_readl please use readl
> in all the places.
That looks like mxc-rnga.c was taken as a starting point. I'll change
__raw_read() to readl and __raw_writel to writel.
> > + /* 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;
> Before calculating level error check can be done.
Ok, I'll move the check right after reading the status register.
> > + if (__raw_readl(rngc->base + RNGC_ERROR) &
> > + RNGC_ERROR_STATUS_BAD_KEY) {
> > + dev_err(rngc->dev, "Can't start, Bad Keys.\n");
> > + return -EIO;
> > + }
> > + }
> What keys? What is the purpose of this check? At this point only clk
> is enabled for RNGC so I am wondering why this check is required?
The "key" is probably the internal state of the PRNG, which uses the
mechanism described in FIPS 186-2.
No idea why Freescale added this check before the self test. I guess
that we can safely run the self test and check for errors afterwards.
I'll remove the check.
Interestingly, this "bad key" error status is one of the few differences
between RNGB and RNGC, both of which should work with this driver...
> > +
> > + /* 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;
> > + }
> Is this check useful? If clock is initialised properly I do not think
> this case will happen. May be I am missing something. Please add a
> comment if this check is valid.
Agreed. Switching the clock on should be sufficient to get the
oscillator to run. And if not, we should see an error after the self
test.
> RNG core can call init every time this rng device is selected as
> current random number provider. Is self test required on every RNG
> init?
I'd say the self test should be run once when the driver is loaded. I'll
try to move the self test to the probe function.
> By default self test need not be run, a module parameter can be added
> for enabling self test.
Ok.
> > + rngc->rng.name = pdev->name;
> > + rngc->rng.init = mxc_rngc_init;
> > + rngc->rng.read = mxc_rngc_read;
> Assiging a quality would be great. That will help in deciding which
> rng device to use if there are mulitple rng devices.
I doubt that I have enough info to set the quality. I'll see what I can
dig up.
I'll try to upload v4 as soon as possible.
Thanks,
Martin