| Message ID | 1454366511-10640-2-git-send-email-joshua.henderson@microchip.com (mailing list archive) |
|---|---|
| State | Changes Requested |
| Delegated to: | Herbert Xu |
| Headers | show |
On 01/02/16 22:41, Joshua Henderson wrote: > Add support for the hardware pseudo and 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> > --- > drivers/char/hw_random/Kconfig | 13 +++ > drivers/char/hw_random/Makefile | 1 + > drivers/char/hw_random/pic32-rng.c | 152 ++++++++++++++++++++++++++++++++++++ > 3 files changed, 166 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..d2f32c4 > --- /dev/null > +++ b/drivers/char/hw_random/pic32-rng.c > @@ -0,0 +1,152 @@ > +/* > + * 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/kernel.h> > +#include <linux/module.h> > +#include <linux/delay.h> > +#include <linux/slab.h> > +#include <linux/err.h> > +#include <linux/io.h> > +#include <linux/hw_random.h> > +#include <linux/platform_device.h> > +#include <linux/of.h> > +#include <linux/of_device.h> > +#include <linux/clk.h> > +#include <linux/clkdev.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; > +}; > + > +static int pic32_rng_read(struct hwrng *rng, void *buf, size_t max, > + bool wait) > +{ > + struct pic32_rng *prng = container_of(rng, struct pic32_rng, rng); > + u64 *data = buf; > + > + *data = ((u64)readl(prng->base + RNGNUMGEN2) << 32) + > + readl(prng->base + RNGNUMGEN1); > + return 4; > +} I have a number of questions at this point (although #3 is by far the most important). 1. If the random number of 42-bit shouldn't this be return 5; ? 2. If you really do mean return 4; then why mess about with all the shifting. You can just read and discard the upper 32-bits. 3. Why are you using the PRNG at all? The PRNG is a simple LSFR and I don't think it ever gets reseeded at any point (meaning we get almost no useful entropy from it at all). Far better to read directly from the TRNG. > + > +static int pic32_rng_probe(struct platform_device *pdev) > +{ > + struct pic32_rng *prng; > + struct resource *res; > + u32 v, t; > + int ret; > + > + prng = devm_kzalloc(&pdev->dev, sizeof(*prng), GFP_KERNEL); > + if (!prng) > + return -ENOMEM; > + > + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); > + prng->base = devm_ioremap_resource(&pdev->dev, res); > + if (IS_ERR(prng->base)) > + return PTR_ERR(prng->base); > + > + prng->clk = devm_clk_get(&pdev->dev, NULL); > + if (IS_ERR(prng->clk)) > + return PTR_ERR(prng->clk); > + > + clk_prepare_enable(prng->clk); > + > + /* enable TRNG in enhanced mode */ > + v = readl(prng->base + RNGCON); > + v &= ~(TRNGEN | PRNGEN | 0xff); > + v |= TRNGMOD; > + writel(v | TRNGEN, prng->base + RNGCON); > + > + /* wait for valid seed */ > + usleep_range(100, 200); > + t = readl(prng->base + RNGRCNT) & RCNT_MASK; > + if (t < 0x2A) > + dev_warn(&pdev->dev, "seed not generated.\n"); > + > + /* load initial seed */ > + writel(v | SEEDLOAD, prng->base + RNGCON); > + > + /* load initial polynomial: 42bit poly */ > + writel(0x00c00003, prng->base + RNGPOLY1); > + writel(0x00000000, prng->base + RNGPOLY2); > + > + /* start PRNG to generate 42bit random */ > + v |= 0x2A | PRNGCONT | PRNGEN; > + writel(v, prng->base + RNGCON); > + > + prng->rng.name = pdev->name; > + prng->rng.read = pic32_rng_read; > + > + ret = hwrng_register(&prng->rng); > + if (ret) > + goto err_register; > + > + platform_set_drvdata(pdev, prng); > + > + return 0; > + > +err_register: > + return ret; Looks like we leak clock references on this error path. > + > +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"); > -- To unsubscribe from this list: send the line "unsubscribe linux-crypto" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Daniel, On 02/03/2016 04:22 AM, Daniel Thompson wrote: > On 01/02/16 22:41, Joshua Henderson wrote: >> Add support for the hardware pseudo and 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> >> --- >> drivers/char/hw_random/Kconfig | 13 +++ >> drivers/char/hw_random/Makefile | 1 + >> drivers/char/hw_random/pic32-rng.c | 152 ++++++++++++++++++++++++++++++++++++ >> 3 files changed, 166 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..d2f32c4 >> --- /dev/null >> +++ b/drivers/char/hw_random/pic32-rng.c >> @@ -0,0 +1,152 @@ >> +/* >> + * 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/kernel.h> >> +#include <linux/module.h> >> +#include <linux/delay.h> >> +#include <linux/slab.h> >> +#include <linux/err.h> >> +#include <linux/io.h> >> +#include <linux/hw_random.h> >> +#include <linux/platform_device.h> >> +#include <linux/of.h> >> +#include <linux/of_device.h> >> +#include <linux/clk.h> >> +#include <linux/clkdev.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; >> +}; >> + >> +static int pic32_rng_read(struct hwrng *rng, void *buf, size_t max, >> + bool wait) >> +{ >> + struct pic32_rng *prng = container_of(rng, struct pic32_rng, rng); >> + u64 *data = buf; >> + >> + *data = ((u64)readl(prng->base + RNGNUMGEN2) << 32) + >> + readl(prng->base + RNGNUMGEN1); >> + return 4; >> +} > > I have a number of questions at this point (although #3 is by far the most important). > > 1. If the random number of 42-bit shouldn't this be return 5; ? You are right. However, this will essentially be changed to 8 in response to moving to just the TRNG in comments below. > > 2. If you really do mean return 4; then why mess about with all the > shifting. You can just read and discard the upper 32-bits. > > 3. Why are you using the PRNG at all? The PRNG is a simple LSFR and > I don't think it ever gets reseeded at any point (meaning we get > almost no useful entropy from it at all). > > Far better to read directly from the TRNG. Makes sense. Typically we just use the TRNG to seed the LSFR, but I suppose there is no real reason to do this if max speed is not a concern (above 24Mbps which is max TRNG speed). I'll convert the driver to just drop usage of the PRNG and only use the TRNG. > > >> + >> +static int pic32_rng_probe(struct platform_device *pdev) >> +{ >> + struct pic32_rng *prng; >> + struct resource *res; >> + u32 v, t; >> + int ret; >> + >> + prng = devm_kzalloc(&pdev->dev, sizeof(*prng), GFP_KERNEL); >> + if (!prng) >> + return -ENOMEM; >> + >> + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); >> + prng->base = devm_ioremap_resource(&pdev->dev, res); >> + if (IS_ERR(prng->base)) >> + return PTR_ERR(prng->base); >> + >> + prng->clk = devm_clk_get(&pdev->dev, NULL); >> + if (IS_ERR(prng->clk)) >> + return PTR_ERR(prng->clk); >> + >> + clk_prepare_enable(prng->clk); >> + >> + /* enable TRNG in enhanced mode */ >> + v = readl(prng->base + RNGCON); >> + v &= ~(TRNGEN | PRNGEN | 0xff); >> + v |= TRNGMOD; >> + writel(v | TRNGEN, prng->base + RNGCON); >> + >> + /* wait for valid seed */ >> + usleep_range(100, 200); >> + t = readl(prng->base + RNGRCNT) & RCNT_MASK; >> + if (t < 0x2A) >> + dev_warn(&pdev->dev, "seed not generated.\n"); >> + >> + /* load initial seed */ >> + writel(v | SEEDLOAD, prng->base + RNGCON); >> + >> + /* load initial polynomial: 42bit poly */ >> + writel(0x00c00003, prng->base + RNGPOLY1); >> + writel(0x00000000, prng->base + RNGPOLY2); >> + >> + /* start PRNG to generate 42bit random */ >> + v |= 0x2A | PRNGCONT | PRNGEN; >> + writel(v, prng->base + RNGCON); >> + >> + prng->rng.name = pdev->name; >> + prng->rng.read = pic32_rng_read; >> + >> + ret = hwrng_register(&prng->rng); >> + if (ret) >> + goto err_register; >> + >> + platform_set_drvdata(pdev, prng); >> + >> + return 0; >> + >> +err_register: >> + return ret; > > Looks like we leak clock references on this error path. Good catch. Will fix. > > >> + >> +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"); >> > After a bit of testing, converting the driver to be pure TRNG does give good results with rngtest. Good call. Will submit an update. Thanks, Josh -- To unsubscribe from this list: send the line "unsubscribe linux-crypto" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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..d2f32c4 --- /dev/null +++ b/drivers/char/hw_random/pic32-rng.c @@ -0,0 +1,152 @@ +/* + * 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/kernel.h> +#include <linux/module.h> +#include <linux/delay.h> +#include <linux/slab.h> +#include <linux/err.h> +#include <linux/io.h> +#include <linux/hw_random.h> +#include <linux/platform_device.h> +#include <linux/of.h> +#include <linux/of_device.h> +#include <linux/clk.h> +#include <linux/clkdev.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; +}; + +static int pic32_rng_read(struct hwrng *rng, void *buf, size_t max, + bool wait) +{ + struct pic32_rng *prng = container_of(rng, struct pic32_rng, rng); + u64 *data = buf; + + *data = ((u64)readl(prng->base + RNGNUMGEN2) << 32) + + readl(prng->base + RNGNUMGEN1); + return 4; +} + +static int pic32_rng_probe(struct platform_device *pdev) +{ + struct pic32_rng *prng; + struct resource *res; + u32 v, t; + int ret; + + prng = devm_kzalloc(&pdev->dev, sizeof(*prng), GFP_KERNEL); + if (!prng) + return -ENOMEM; + + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); + prng->base = devm_ioremap_resource(&pdev->dev, res); + if (IS_ERR(prng->base)) + return PTR_ERR(prng->base); + + prng->clk = devm_clk_get(&pdev->dev, NULL); + if (IS_ERR(prng->clk)) + return PTR_ERR(prng->clk); + + clk_prepare_enable(prng->clk); + + /* enable TRNG in enhanced mode */ + v = readl(prng->base + RNGCON); + v &= ~(TRNGEN | PRNGEN | 0xff); + v |= TRNGMOD; + writel(v | TRNGEN, prng->base + RNGCON); + + /* wait for valid seed */ + usleep_range(100, 200); + t = readl(prng->base + RNGRCNT) & RCNT_MASK; + if (t < 0x2A) + dev_warn(&pdev->dev, "seed not generated.\n"); + + /* load initial seed */ + writel(v | SEEDLOAD, prng->base + RNGCON); + + /* load initial polynomial: 42bit poly */ + writel(0x00c00003, prng->base + RNGPOLY1); + writel(0x00000000, prng->base + RNGPOLY2); + + /* start PRNG to generate 42bit random */ + v |= 0x2A | PRNGCONT | PRNGEN; + writel(v, prng->base + RNGCON); + + prng->rng.name = pdev->name; + prng->rng.read = pic32_rng_read; + + ret = hwrng_register(&prng->rng); + if (ret) + goto err_register; + + platform_set_drvdata(pdev, prng); + + return 0; + +err_register: + 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");