* [PATCH v2 2/2] rng: pic32-rng: Add PIC32 RNG hardware driver
2016-02-08 21:17 [PATCH v2 1/2] dt/bindings: Add bindings for the PIC32 random number generator Joshua Henderson
@ 2016-02-08 21:17 ` Joshua Henderson
2016-02-08 21:34 ` Daniel Thompson
2016-02-16 20:21 ` [PATCH v2 1/2] dt/bindings: Add bindings for the PIC32 random number generator Herbert Xu
1 sibling, 1 reply; 5+ messages in thread
From: Joshua Henderson @ 2016-02-08 21:17 UTC (permalink / raw)
To: devicetree, linux-kernel
Cc: Joshua Henderson, Purna Chandra Mandal, Rob Herring, Pawel Moll,
Mark Rutland, Ian Campbell, Kumar Gala, Matt Mackall, Herbert Xu,
Kieran Bingham, Lee Jones, Pankaj Dev, Scott Branden,
Daniel Thompson, Ray Jui, linux-crypto
Add support for the hardware true random number generator
peripheral found on PIC32.
Signed-off-by: Joshua Henderson <joshua.henderson@microchip.com>
Signed-off-by: Purna Chandra Mandal <purna.mandal@microchip.com>
---
Changes since v1:
- Reorder includes to be alphabetic.
- Drop use of PRNG and only use TRNG.
- Fix dangling clock ref in error condition.
- Remove unecessary error handling and fix other cases.
---
drivers/char/hw_random/Kconfig | 13 +++
drivers/char/hw_random/Makefile | 1 +
drivers/char/hw_random/pic32-rng.c | 155 ++++++++++++++++++++++++++++++++++++
3 files changed, 169 insertions(+)
create mode 100644 drivers/char/hw_random/pic32-rng.c
diff --git a/drivers/char/hw_random/Kconfig b/drivers/char/hw_random/Kconfig
index dbf2271..3ab0c46 100644
--- a/drivers/char/hw_random/Kconfig
+++ b/drivers/char/hw_random/Kconfig
@@ -381,6 +381,19 @@ config HW_RANDOM_STM32
If unsure, say N.
+config HW_RANDOM_PIC32
+ tristate "Microchip PIC32 Random Number Generator support"
+ depends on HW_RANDOM && MACH_PIC32
+ default y
+ ---help---
+ This driver provides kernel-side support for the Random Number
+ Generator hardware found on a PIC32.
+
+ To compile this driver as a module, choose M here. the
+ module will be called pic32-rng.
+
+ If unsure, say Y.
+
endif # HW_RANDOM
config UML_RANDOM
diff --git a/drivers/char/hw_random/Makefile b/drivers/char/hw_random/Makefile
index 5ad3976..f5a6fa7 100644
--- a/drivers/char/hw_random/Makefile
+++ b/drivers/char/hw_random/Makefile
@@ -33,3 +33,4 @@ obj-$(CONFIG_HW_RANDOM_MSM) += msm-rng.o
obj-$(CONFIG_HW_RANDOM_ST) += st-rng.o
obj-$(CONFIG_HW_RANDOM_XGENE) += xgene-rng.o
obj-$(CONFIG_HW_RANDOM_STM32) += stm32-rng.o
+obj-$(CONFIG_HW_RANDOM_PIC32) += pic32-rng.o
diff --git a/drivers/char/hw_random/pic32-rng.c b/drivers/char/hw_random/pic32-rng.c
new file mode 100644
index 0000000..108897b
--- /dev/null
+++ b/drivers/char/hw_random/pic32-rng.c
@@ -0,0 +1,155 @@
+/*
+ * PIC32 RNG driver
+ *
+ * Joshua Henderson <joshua.henderson@microchip.com>
+ * Copyright (C) 2016 Microchip Technology Inc. All rights reserved.
+ *
+ * This program is free software; you can distribute it and/or modify it
+ * under the terms of the GNU General Public License (Version 2) as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
+ * for more details.
+ */
+
+#include <linux/clk.h>
+#include <linux/clkdev.h>
+#include <linux/err.h>
+#include <linux/hw_random.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+
+#define RNGCON 0x04
+#define TRNGEN BIT(8)
+#define PRNGEN BIT(9)
+#define PRNGCONT BIT(10)
+#define TRNGMOD BIT(11)
+#define SEEDLOAD BIT(12)
+#define RNGPOLY1 0x08
+#define RNGPOLY2 0x0C
+#define RNGNUMGEN1 0x10
+#define RNGNUMGEN2 0x14
+#define RNGSEED1 0x18
+#define RNGSEED2 0x1C
+#define RNGRCNT 0x20
+#define RCNT_MASK 0x7F
+
+struct pic32_rng {
+ void __iomem *base;
+ struct hwrng rng;
+ struct clk *clk;
+};
+
+/*
+ * The TRNG can generate up to 24Mbps. This is a timeout that should be safe
+ * enough given the instructions in the loop and that the TRNG may not always
+ * be at maximum rate.
+ */
+#define RNG_TIMEOUT 500
+
+static int pic32_rng_read(struct hwrng *rng, void *buf, size_t max,
+ bool wait)
+{
+ struct pic32_rng *priv = container_of(rng, struct pic32_rng, rng);
+ u64 *data = buf;
+ u32 t;
+ unsigned int timeout = RNG_TIMEOUT;
+
+ if (max < 8)
+ return 0;
+
+ do {
+ t = readl(priv->base + RNGRCNT) & RCNT_MASK;
+ if (t == 64) {
+ /* TRNG value comes through the seed registers */
+ *data = ((u64)readl(priv->base + RNGSEED2) << 32) +
+ readl(priv->base + RNGSEED1);
+ return 8;
+ }
+ } while (wait && --timeout);
+
+ return -EIO;
+}
+
+static int pic32_rng_probe(struct platform_device *pdev)
+{
+ struct pic32_rng *priv;
+ struct resource *res;
+ u32 v;
+ int ret;
+
+ priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
+ if (!priv)
+ return -ENOMEM;
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ priv->base = devm_ioremap_resource(&pdev->dev, res);
+ if (IS_ERR(priv->base))
+ return PTR_ERR(priv->base);
+
+ priv->clk = devm_clk_get(&pdev->dev, NULL);
+ if (IS_ERR(priv->clk))
+ return PTR_ERR(priv->clk);
+
+ ret = clk_prepare_enable(priv->clk);
+ if (ret)
+ return ret;
+
+ /* enable TRNG in enhanced mode */
+ v = TRNGEN | TRNGMOD;
+ writel(v, priv->base + RNGCON);
+
+ priv->rng.name = pdev->name;
+ priv->rng.read = pic32_rng_read;
+
+ ret = hwrng_register(&priv->rng);
+ if (ret)
+ goto err_register;
+
+ platform_set_drvdata(pdev, priv);
+
+ return 0;
+
+err_register:
+ clk_disable_unprepare(priv->clk);
+ return ret;
+}
+
+static int pic32_rng_remove(struct platform_device *pdev)
+{
+ struct pic32_rng *rng = platform_get_drvdata(pdev);
+
+ hwrng_unregister(&rng->rng);
+ writel(0, rng->base + RNGCON);
+ clk_disable_unprepare(rng->clk);
+ return 0;
+}
+
+static const struct of_device_id pic32_rng_of_match[] = {
+ { .compatible = "microchip,pic32mzda-rng", },
+ { /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, pic32_rng_of_match);
+
+static struct platform_driver pic32_rng_driver = {
+ .probe = pic32_rng_probe,
+ .remove = pic32_rng_remove,
+ .driver = {
+ .name = "pic32-rng",
+ .owner = THIS_MODULE,
+ .of_match_table = of_match_ptr(pic32_rng_of_match),
+ },
+};
+
+module_platform_driver(pic32_rng_driver);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Joshua Henderson <joshua.henderson@microchip.com>");
+MODULE_DESCRIPTION("Microchip PIC32 RNG Driver");
--
1.7.9.5
^ permalink raw reply related [flat|nested] 5+ messages in thread* Re: [PATCH v2 1/2] dt/bindings: Add bindings for the PIC32 random number generator
2016-02-08 21:17 [PATCH v2 1/2] dt/bindings: Add bindings for the PIC32 random number generator Joshua Henderson
2016-02-08 21:17 ` [PATCH v2 2/2] rng: pic32-rng: Add PIC32 RNG hardware driver Joshua Henderson
@ 2016-02-16 20:21 ` Herbert Xu
2016-02-19 17:23 ` Joshua Henderson
1 sibling, 1 reply; 5+ messages in thread
From: Herbert Xu @ 2016-02-16 20:21 UTC (permalink / raw)
To: Joshua Henderson
Cc: devicetree, linux-kernel, Rob Herring, Pawel Moll, Mark Rutland,
Ian Campbell, Kumar Gala, Matt Mackall, Kieran Bingham, Lee Jones,
Pankaj Dev, Scott Branden, Daniel Thompson, Purna Chandra Mandal,
Ray Jui, linux-crypto
On Mon, Feb 08, 2016 at 02:17:52PM -0700, Joshua Henderson wrote:
> Document the devicetree bindings for the random number generator found
> on Microchip PIC32 class devices.
>
> Signed-off-by: Joshua Henderson <joshua.henderson@microchip.com>
> Acked-by: Rob Herring <robh@kernel.org>
All applied.
--
Email: Herbert Xu <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt
^ permalink raw reply [flat|nested] 5+ messages in thread