| Message ID | 1492067108-14748-3-git-send-email-sean.wang@mediatek.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
Hi Sean, Mostly looks good, have few minor comments. On 13 April 2017 at 12:35, <sean.wang@mediatek.com> wrote: > +static bool mtk_rng_wait_ready(struct hwrng *rng, bool wait) > +{ > + struct mtk_rng *priv = to_mtk_rng(rng); > + int ready; > + > + ready = readl(priv->base + RNG_CTRL) & RNG_READY; > + if (!ready && wait) > + readl_poll_timeout_atomic(priv->base + RNG_CTRL, ready, > + ready & RNG_READY, USEC_POLL, > + TIMEOUT_POLL); > + return !!ready; > +} Use readl_poll_timeout_atomic's return value or -EIO instead of !!ready. This will simplify mtk_rng_read. > +static int mtk_rng_read(struct hwrng *rng, void *buf, size_t max, bool wait) > +{ > + struct mtk_rng *priv = to_mtk_rng(rng); > + int retval = 0; > + > + while (max >= sizeof(u32)) { > + if (!mtk_rng_wait_ready(rng, wait)) > + break; > + > + *(u32 *)buf = readl(priv->base + RNG_DATA); > + retval += sizeof(u32); > + buf += sizeof(u32); > + max -= sizeof(u32); > + } > + > + if (unlikely(wait && max)) > + dev_warn(priv->dev, "timeout might be not properly set\n"); Is this really necessary? Better to choose proper timeout than providing this warning message. In rare cases if the timeout could occur due to some reason (may be a hardware fault) print appropriate warning message. > + return retval || !wait ? retval : -EIO; > +} Set retavl to mtk_rng_wait_ready and return retval. Regards, Prasanna
Hello I have some minor comment below: On Thu, Apr 13, 2017 at 03:05:08PM +0800, sean.wang@mediatek.com wrote: > From: Sean Wang <sean.wang@mediatek.com> > > This patch adds support for hardware random generator on MT7623 SoC > and should also work on other similar Mediatek SoCs. Currently, > the driver is already tested successfully with rng-tools. > > Signed-off-by: Sean Wang <sean.wang@mediatek.com> > --- > drivers/char/hw_random/Kconfig | 16 +++- > drivers/char/hw_random/Makefile | 2 +- > drivers/char/hw_random/mtk-rng.c | 174 +++++++++++++++++++++++++++++++++++++++ > 3 files changed, 190 insertions(+), 2 deletions(-) > create mode 100644 drivers/char/hw_random/mtk-rng.c > > diff --git a/drivers/char/hw_random/Kconfig b/drivers/char/hw_random/Kconfig > index 0cafe08..af782ce 100644 > --- a/drivers/char/hw_random/Kconfig > +++ b/drivers/char/hw_random/Kconfig > @@ -419,10 +419,24 @@ config HW_RANDOM_CAVIUM > Generator hardware found on Cavium SoCs. > > To compile this driver as a module, choose M here: the > - module will be called cavium_rng. > + module will be called mtk-rng. Unwanted change > > If unsure, say Y. > > +config HW_RANDOM_MTK > + tristate "Mediatek Random Number Generator support" > + depends on HW_RANDOM > + depends on ARCH_MEDIATEK || COMPILE_TEST > + default y > + ---help--- > + This driver provides kernel-side support for the Random Number > + Generator hardware found on Mediatek SoCs. > + > + To compile this driver as a module, choose M here. the > + module will be called mtk-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 5f52b1e..68be716 100644 > --- a/drivers/char/hw_random/Makefile > +++ b/drivers/char/hw_random/Makefile > @@ -1,7 +1,6 @@ > # > # Makefile for HW Random Number Generator (RNG) device drivers. > # > - Another unwanted change > obj-$(CONFIG_HW_RANDOM) += rng-core.o > rng-core-y := core.o > obj-$(CONFIG_HW_RANDOM_TIMERIOMEM) += timeriomem-rng.o > @@ -36,3 +35,4 @@ obj-$(CONFIG_HW_RANDOM_STM32) += stm32-rng.o > obj-$(CONFIG_HW_RANDOM_PIC32) += pic32-rng.o > obj-$(CONFIG_HW_RANDOM_MESON) += meson-rng.o > obj-$(CONFIG_HW_RANDOM_CAVIUM) += cavium-rng.o cavium-rng-vf.o > +obj-$(CONFIG_HW_RANDOM_MTK) += mtk-rng.o > diff --git a/drivers/char/hw_random/mtk-rng.c b/drivers/char/hw_random/mtk-rng.c > new file mode 100644 > index 0000000..6561ee0 > --- /dev/null > +++ b/drivers/char/hw_random/mtk-rng.c > @@ -0,0 +1,174 @@ > +/* > + * Driver for Mediatek Hardware Random Number Generator > + * > + * Copyright (C) 2017 Sean Wang <sean.wang@mediatek.com> > + * > + * This program is free software; you can redistribute it and/or > + * modify it under the terms of the GNU General Public License as > + * published by the Free Software Foundation; either version 2 of > + * the License, or (at your option) any later version. > + * > + * This program is distributed in the hope that 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. > + */ > +#define MTK_RNG_DEV KBUILD_MODNAME > + > +#include <linux/clk.h> > +#include <linux/delay.h> > +#include <linux/err.h> > +#include <linux/hw_random.h> > +#include <linux/io.h> > +#include <linux/iopoll.h> > +#include <linux/kernel.h> > +#include <linux/module.h> > +#include <linux/of.h> > +#include <linux/platform_device.h> > + > +#define USEC_POLL 2 > +#define TIMEOUT_POLL 20 > + > +#define RNG_CTRL 0x00 > +#define RNG_EN BIT(0) > +#define RNG_READY BIT(31) Keep only one space between define and name > + > +#define RNG_DATA 0x08 > + > +#define to_mtk_rng(p) container_of(p, struct mtk_rng, rng) > + > +struct mtk_rng { > + struct device *dev; > + void __iomem *base; > + struct clk *clk; > + struct hwrng rng; > +}; > + > +static int mtk_rng_init(struct hwrng *rng) > +{ > + struct mtk_rng *priv = to_mtk_rng(rng); > + u32 val; > + int err; > + > + err = clk_prepare_enable(priv->clk); > + if (err) > + return err; > + > + val = readl(priv->base + RNG_CTRL); > + val |= RNG_EN; > + writel(val, priv->base + RNG_CTRL); > + > + return 0; > +} > + > +static void mtk_rng_cleanup(struct hwrng *rng) > +{ > + struct mtk_rng *priv = to_mtk_rng(rng); > + u32 val; > + > + val = readl(priv->base + RNG_CTRL); > + val &= ~RNG_EN; > + writel(val, priv->base + RNG_CTRL); > + > + clk_disable_unprepare(priv->clk); > +} > + > +static bool mtk_rng_wait_ready(struct hwrng *rng, bool wait) > +{ > + struct mtk_rng *priv = to_mtk_rng(rng); > + int ready; > + > + ready = readl(priv->base + RNG_CTRL) & RNG_READY; > + if (!ready && wait) > + readl_poll_timeout_atomic(priv->base + RNG_CTRL, ready, > + ready & RNG_READY, USEC_POLL, > + TIMEOUT_POLL); > + return !!ready; > +} > + > +static int mtk_rng_read(struct hwrng *rng, void *buf, size_t max, bool wait) > +{ > + struct mtk_rng *priv = to_mtk_rng(rng); > + int retval = 0; > + > + while (max >= sizeof(u32)) { > + if (!mtk_rng_wait_ready(rng, wait)) > + break; > + > + *(u32 *)buf = readl(priv->base + RNG_DATA); > + retval += sizeof(u32); > + buf += sizeof(u32); > + max -= sizeof(u32); > + } > + > + if (unlikely(wait && max)) > + dev_warn(priv->dev, "timeout might be not properly set\n"); > + > + return retval || !wait ? retval : -EIO; > +} > + > +static int mtk_rng_probe(struct platform_device *pdev) > +{ > + struct resource *res; > + int ret; > + struct mtk_rng *priv; > + > + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); > + if (!res) { > + dev_err(&pdev->dev, "no iomem resource\n"); > + return -ENXIO; > + } > + > + priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL); > + if (!priv) > + return -ENOMEM; > + > + priv->dev = &pdev->dev; > + priv->rng.name = pdev->name; > + priv->rng.init = mtk_rng_init; > + priv->rng.cleanup = mtk_rng_cleanup; > + priv->rng.read = mtk_rng_read; > + > + priv->clk = devm_clk_get(&pdev->dev, "rng"); > + if (IS_ERR(priv->clk)) { > + ret = PTR_ERR(priv->clk); > + dev_err(&pdev->dev, "no clock for device: %d\n", ret); > + return ret; > + } > + > + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); You get that resource twice Regards Corentin Labbe
Hi Corentin, I all agree and appreciate your careful reviewing. They will be added into the next one. Sean On Thu, 2017-04-13 at 13:06 +0200, Corentin Labbe wrote: > Hello > > I have some minor comment below: > > On Thu, Apr 13, 2017 at 03:05:08PM +0800, sean.wang@mediatek.com wrote: > > From: Sean Wang <sean.wang@mediatek.com> > > > > This patch adds support for hardware random generator on MT7623 SoC > > and should also work on other similar Mediatek SoCs. Currently, > > the driver is already tested successfully with rng-tools. > > > > Signed-off-by: Sean Wang <sean.wang@mediatek.com> > > --- > > drivers/char/hw_random/Kconfig | 16 +++- > > drivers/char/hw_random/Makefile | 2 +- > > drivers/char/hw_random/mtk-rng.c | 174 +++++++++++++++++++++++++++++++++++++++ > > 3 files changed, 190 insertions(+), 2 deletions(-) > > create mode 100644 drivers/char/hw_random/mtk-rng.c > > > > diff --git a/drivers/char/hw_random/Kconfig b/drivers/char/hw_random/Kconfig > > index 0cafe08..af782ce 100644 > > --- a/drivers/char/hw_random/Kconfig > > +++ b/drivers/char/hw_random/Kconfig > > @@ -419,10 +419,24 @@ config HW_RANDOM_CAVIUM > > Generator hardware found on Cavium SoCs. > > > > To compile this driver as a module, choose M here: the > > - module will be called cavium_rng. > > + module will be called mtk-rng. > > Unwanted change > > > > > If unsure, say Y. > > > > +config HW_RANDOM_MTK > > + tristate "Mediatek Random Number Generator support" > > + depends on HW_RANDOM > > + depends on ARCH_MEDIATEK || COMPILE_TEST > > + default y > > + ---help--- > > + This driver provides kernel-side support for the Random Number > > + Generator hardware found on Mediatek SoCs. > > + > > + To compile this driver as a module, choose M here. the > > + module will be called mtk-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 5f52b1e..68be716 100644 > > --- a/drivers/char/hw_random/Makefile > > +++ b/drivers/char/hw_random/Makefile > > @@ -1,7 +1,6 @@ > > # > > # Makefile for HW Random Number Generator (RNG) device drivers. > > # > > - > > Another unwanted change > > > obj-$(CONFIG_HW_RANDOM) += rng-core.o > > rng-core-y := core.o > > obj-$(CONFIG_HW_RANDOM_TIMERIOMEM) += timeriomem-rng.o > > @@ -36,3 +35,4 @@ obj-$(CONFIG_HW_RANDOM_STM32) += stm32-rng.o > > obj-$(CONFIG_HW_RANDOM_PIC32) += pic32-rng.o > > obj-$(CONFIG_HW_RANDOM_MESON) += meson-rng.o > > obj-$(CONFIG_HW_RANDOM_CAVIUM) += cavium-rng.o cavium-rng-vf.o > > +obj-$(CONFIG_HW_RANDOM_MTK) += mtk-rng.o > > diff --git a/drivers/char/hw_random/mtk-rng.c b/drivers/char/hw_random/mtk-rng.c > > new file mode 100644 > > index 0000000..6561ee0 > > --- /dev/null > > +++ b/drivers/char/hw_random/mtk-rng.c > > @@ -0,0 +1,174 @@ > > +/* > > + * Driver for Mediatek Hardware Random Number Generator > > + * > > + * Copyright (C) 2017 Sean Wang <sean.wang@mediatek.com> > > + * > > + * This program is free software; you can redistribute it and/or > > + * modify it under the terms of the GNU General Public License as > > + * published by the Free Software Foundation; either version 2 of > > + * the License, or (at your option) any later version. > > + * > > + * This program is distributed in the hope that 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. > > + */ > > +#define MTK_RNG_DEV KBUILD_MODNAME > > + > > +#include <linux/clk.h> > > +#include <linux/delay.h> > > +#include <linux/err.h> > > +#include <linux/hw_random.h> > > +#include <linux/io.h> > > +#include <linux/iopoll.h> > > +#include <linux/kernel.h> > > +#include <linux/module.h> > > +#include <linux/of.h> > > +#include <linux/platform_device.h> > > + > > +#define USEC_POLL 2 > > +#define TIMEOUT_POLL 20 > > + > > +#define RNG_CTRL 0x00 > > +#define RNG_EN BIT(0) > > +#define RNG_READY BIT(31) > > Keep only one space between define and name > > > + > > +#define RNG_DATA 0x08 > > + > > +#define to_mtk_rng(p) container_of(p, struct mtk_rng, rng) > > + > > +struct mtk_rng { > > + struct device *dev; > > + void __iomem *base; > > + struct clk *clk; > > + struct hwrng rng; > > +}; > > + > > +static int mtk_rng_init(struct hwrng *rng) > > +{ > > + struct mtk_rng *priv = to_mtk_rng(rng); > > + u32 val; > > + int err; > > + > > + err = clk_prepare_enable(priv->clk); > > + if (err) > > + return err; > > + > > + val = readl(priv->base + RNG_CTRL); > > + val |= RNG_EN; > > + writel(val, priv->base + RNG_CTRL); > > + > > + return 0; > > +} > > + > > +static void mtk_rng_cleanup(struct hwrng *rng) > > +{ > > + struct mtk_rng *priv = to_mtk_rng(rng); > > + u32 val; > > + > > + val = readl(priv->base + RNG_CTRL); > > + val &= ~RNG_EN; > > + writel(val, priv->base + RNG_CTRL); > > + > > + clk_disable_unprepare(priv->clk); > > +} > > + > > +static bool mtk_rng_wait_ready(struct hwrng *rng, bool wait) > > +{ > > + struct mtk_rng *priv = to_mtk_rng(rng); > > + int ready; > > + > > + ready = readl(priv->base + RNG_CTRL) & RNG_READY; > > + if (!ready && wait) > > + readl_poll_timeout_atomic(priv->base + RNG_CTRL, ready, > > + ready & RNG_READY, USEC_POLL, > > + TIMEOUT_POLL); > > + return !!ready; > > +} > > + > > +static int mtk_rng_read(struct hwrng *rng, void *buf, size_t max, bool wait) > > +{ > > + struct mtk_rng *priv = to_mtk_rng(rng); > > + int retval = 0; > > + > > + while (max >= sizeof(u32)) { > > + if (!mtk_rng_wait_ready(rng, wait)) > > + break; > > + > > + *(u32 *)buf = readl(priv->base + RNG_DATA); > > + retval += sizeof(u32); > > + buf += sizeof(u32); > > + max -= sizeof(u32); > > + } > > + > > + if (unlikely(wait && max)) > > + dev_warn(priv->dev, "timeout might be not properly set\n"); > > + > > + return retval || !wait ? retval : -EIO; > > +} > > + > > +static int mtk_rng_probe(struct platform_device *pdev) > > +{ > > + struct resource *res; > > + int ret; > > + struct mtk_rng *priv; > > + > > + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); > > + if (!res) { > > + dev_err(&pdev->dev, "no iomem resource\n"); > > + return -ENXIO; > > + } > > + > > + priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL); > > + if (!priv) > > + return -ENOMEM; > > + > > + priv->dev = &pdev->dev; > > + priv->rng.name = pdev->name; > > + priv->rng.init = mtk_rng_init; > > + priv->rng.cleanup = mtk_rng_cleanup; > > + priv->rng.read = mtk_rng_read; > > + > > + priv->clk = devm_clk_get(&pdev->dev, "rng"); > > + if (IS_ERR(priv->clk)) { > > + ret = PTR_ERR(priv->clk); > > + dev_err(&pdev->dev, "no clock for device: %d\n", ret); > > + return ret; > > + } > > + > > + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); > > You get that resource twice > > Regards > Corentin Labbe
Hi PrasannaKumar, Add my comments inline On Thu, 2017-04-13 at 14:09 +0530, PrasannaKumar Muralidharan wrote: > Hi Sean, > > Mostly looks good, have few minor comments. > > On 13 April 2017 at 12:35, <sean.wang@mediatek.com> wrote: > > +static bool mtk_rng_wait_ready(struct hwrng *rng, bool wait) > > +{ > > + struct mtk_rng *priv = to_mtk_rng(rng); > > + int ready; > > + > > + ready = readl(priv->base + RNG_CTRL) & RNG_READY; > > + if (!ready && wait) > > + readl_poll_timeout_atomic(priv->base + RNG_CTRL, ready, > > + ready & RNG_READY, USEC_POLL, > > + TIMEOUT_POLL); > > + return !!ready; > > +} > > Use readl_poll_timeout_atomic's return value or -EIO instead of > !!ready. This will simplify mtk_rng_read. > !!ready provided is in order to let blocking/non-blocking case could share same code path. And readl_poll_timeout_atomic only handles blocking case. > > +static int mtk_rng_read(struct hwrng *rng, void *buf, size_t max, bool wait) > > +{ > > + struct mtk_rng *priv = to_mtk_rng(rng); > > + int retval = 0; > > + > > + while (max >= sizeof(u32)) { > > + if (!mtk_rng_wait_ready(rng, wait)) > > + break; > > + > > + *(u32 *)buf = readl(priv->base + RNG_DATA); > > + retval += sizeof(u32); > > + buf += sizeof(u32); > > + max -= sizeof(u32); > > + } > > + > > + if (unlikely(wait && max)) > > + dev_warn(priv->dev, "timeout might be not properly set\n"); > > Is this really necessary? Better to choose proper timeout than > providing this warning message. In rare cases if the timeout could > occur due to some reason (may be a hardware fault) print appropriate > warning message. It is good, I will choose the proper timeout and remove the log in the next one. > > > + return retval || !wait ? retval : -EIO; > > +} > > Set retavl to mtk_rng_wait_ready and return retval. > Maybe i didn't get your points exactly. Adding some explanation about thoughts here. "return retval || !wait ? retval : -EIO;" I use can also help handling the both cases in one line which i think is elegant enough. And retval is accumulated with each round if some data's existing in hardware, so we don't return the value from mtk_rng_wait_ready(). > Regards, > Prasanna thanks for all your reviewing and suggestion Sean
On 14 April 2017 at 09:28, Sean Wang <sean.wang@mediatek.com> wrote: > > Hi PrasannaKumar, > > Add my comments inline > >> >> Use readl_poll_timeout_atomic's return value or -EIO instead of >> !!ready. This will simplify mtk_rng_read. >> > > !!ready provided is in order to let blocking/non-blocking case could > share same code path. And readl_poll_timeout_atomic only handles > blocking case. Missed this point. Makes sense. My previous comment about return value in mtk_rng_read is invalid as I based it on a wrong assumption. > >> > +static int mtk_rng_read(struct hwrng *rng, void *buf, size_t max, bool wait) >> > +{ >> > + struct mtk_rng *priv = to_mtk_rng(rng); >> > + int retval = 0; >> > + >> > + while (max >= sizeof(u32)) { >> > + if (!mtk_rng_wait_ready(rng, wait)) >> > + break; >> > + >> > + *(u32 *)buf = readl(priv->base + RNG_DATA); >> > + retval += sizeof(u32); >> > + buf += sizeof(u32); >> > + max -= sizeof(u32); >> > + } >> > + >> > + if (unlikely(wait && max)) >> > + dev_warn(priv->dev, "timeout might be not properly set\n"); >> >> Is this really necessary? Better to choose proper timeout than >> providing this warning message. In rare cases if the timeout could >> occur due to some reason (may be a hardware fault) print appropriate >> warning message. > > It is good, I will choose the proper timeout and remove the log in the > next one. > >> >> > + return retval || !wait ? retval : -EIO; >> > +} >> >> Set retavl to mtk_rng_wait_ready and return retval. >> > > Maybe i didn't get your points exactly. Adding some explanation about > thoughts here. > > "return retval || !wait ? retval : -EIO;" I use can also help handling > the both cases in one line which i think is elegant enough. > > And retval is accumulated with each round if some data's existing in > hardware, so we don't return the value from mtk_rng_wait_ready(). retval can be 0 only when mkt_rng_wait_ready fails, returning 0 when wait is true is confusing. Expected return value when 0 bytes is read from device and wait is true is not clearly documented. "return retval || !wait ? retval : -EIO;" is also fine. Overall the code looks good to me. You can add: Reviewed-by: PrasannaKumar Muralidharan <prasannatsmkumar@gmail.com>. Regards, PrasannaKumar
diff --git a/drivers/char/hw_random/Kconfig b/drivers/char/hw_random/Kconfig index 0cafe08..af782ce 100644 --- a/drivers/char/hw_random/Kconfig +++ b/drivers/char/hw_random/Kconfig @@ -419,10 +419,24 @@ config HW_RANDOM_CAVIUM Generator hardware found on Cavium SoCs. To compile this driver as a module, choose M here: the - module will be called cavium_rng. + module will be called mtk-rng. If unsure, say Y. +config HW_RANDOM_MTK + tristate "Mediatek Random Number Generator support" + depends on HW_RANDOM + depends on ARCH_MEDIATEK || COMPILE_TEST + default y + ---help--- + This driver provides kernel-side support for the Random Number + Generator hardware found on Mediatek SoCs. + + To compile this driver as a module, choose M here. the + module will be called mtk-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 5f52b1e..68be716 100644 --- a/drivers/char/hw_random/Makefile +++ b/drivers/char/hw_random/Makefile @@ -1,7 +1,6 @@ # # Makefile for HW Random Number Generator (RNG) device drivers. # - obj-$(CONFIG_HW_RANDOM) += rng-core.o rng-core-y := core.o obj-$(CONFIG_HW_RANDOM_TIMERIOMEM) += timeriomem-rng.o @@ -36,3 +35,4 @@ obj-$(CONFIG_HW_RANDOM_STM32) += stm32-rng.o obj-$(CONFIG_HW_RANDOM_PIC32) += pic32-rng.o obj-$(CONFIG_HW_RANDOM_MESON) += meson-rng.o obj-$(CONFIG_HW_RANDOM_CAVIUM) += cavium-rng.o cavium-rng-vf.o +obj-$(CONFIG_HW_RANDOM_MTK) += mtk-rng.o diff --git a/drivers/char/hw_random/mtk-rng.c b/drivers/char/hw_random/mtk-rng.c new file mode 100644 index 0000000..6561ee0 --- /dev/null +++ b/drivers/char/hw_random/mtk-rng.c @@ -0,0 +1,174 @@ +/* + * Driver for Mediatek Hardware Random Number Generator + * + * Copyright (C) 2017 Sean Wang <sean.wang@mediatek.com> + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License as + * published by the Free Software Foundation; either version 2 of + * the License, or (at your option) any later version. + * + * This program is distributed in the hope that 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. + */ +#define MTK_RNG_DEV KBUILD_MODNAME + +#include <linux/clk.h> +#include <linux/delay.h> +#include <linux/err.h> +#include <linux/hw_random.h> +#include <linux/io.h> +#include <linux/iopoll.h> +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/of.h> +#include <linux/platform_device.h> + +#define USEC_POLL 2 +#define TIMEOUT_POLL 20 + +#define RNG_CTRL 0x00 +#define RNG_EN BIT(0) +#define RNG_READY BIT(31) + +#define RNG_DATA 0x08 + +#define to_mtk_rng(p) container_of(p, struct mtk_rng, rng) + +struct mtk_rng { + struct device *dev; + void __iomem *base; + struct clk *clk; + struct hwrng rng; +}; + +static int mtk_rng_init(struct hwrng *rng) +{ + struct mtk_rng *priv = to_mtk_rng(rng); + u32 val; + int err; + + err = clk_prepare_enable(priv->clk); + if (err) + return err; + + val = readl(priv->base + RNG_CTRL); + val |= RNG_EN; + writel(val, priv->base + RNG_CTRL); + + return 0; +} + +static void mtk_rng_cleanup(struct hwrng *rng) +{ + struct mtk_rng *priv = to_mtk_rng(rng); + u32 val; + + val = readl(priv->base + RNG_CTRL); + val &= ~RNG_EN; + writel(val, priv->base + RNG_CTRL); + + clk_disable_unprepare(priv->clk); +} + +static bool mtk_rng_wait_ready(struct hwrng *rng, bool wait) +{ + struct mtk_rng *priv = to_mtk_rng(rng); + int ready; + + ready = readl(priv->base + RNG_CTRL) & RNG_READY; + if (!ready && wait) + readl_poll_timeout_atomic(priv->base + RNG_CTRL, ready, + ready & RNG_READY, USEC_POLL, + TIMEOUT_POLL); + return !!ready; +} + +static int mtk_rng_read(struct hwrng *rng, void *buf, size_t max, bool wait) +{ + struct mtk_rng *priv = to_mtk_rng(rng); + int retval = 0; + + while (max >= sizeof(u32)) { + if (!mtk_rng_wait_ready(rng, wait)) + break; + + *(u32 *)buf = readl(priv->base + RNG_DATA); + retval += sizeof(u32); + buf += sizeof(u32); + max -= sizeof(u32); + } + + if (unlikely(wait && max)) + dev_warn(priv->dev, "timeout might be not properly set\n"); + + return retval || !wait ? retval : -EIO; +} + +static int mtk_rng_probe(struct platform_device *pdev) +{ + struct resource *res; + int ret; + struct mtk_rng *priv; + + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); + if (!res) { + dev_err(&pdev->dev, "no iomem resource\n"); + return -ENXIO; + } + + priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL); + if (!priv) + return -ENOMEM; + + priv->dev = &pdev->dev; + priv->rng.name = pdev->name; + priv->rng.init = mtk_rng_init; + priv->rng.cleanup = mtk_rng_cleanup; + priv->rng.read = mtk_rng_read; + + priv->clk = devm_clk_get(&pdev->dev, "rng"); + if (IS_ERR(priv->clk)) { + ret = PTR_ERR(priv->clk); + dev_err(&pdev->dev, "no clock for device: %d\n", ret); + return ret; + } + + 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); + + ret = devm_hwrng_register(&pdev->dev, &priv->rng); + if (ret) { + dev_err(&pdev->dev, "failed to register rng device: %d\n", + ret); + return ret; + } + + dev_info(&pdev->dev, "registered RNG driver\n"); + + return 0; +} + +static const struct of_device_id mtk_rng_match[] = { + { .compatible = "mediatek,mt7623-rng" }, + {}, +}; +MODULE_DEVICE_TABLE(of, mtk_rng_match); + +static struct platform_driver mtk_rng_driver = { + .probe = mtk_rng_probe, + .driver = { + .name = MTK_RNG_DEV, + .of_match_table = mtk_rng_match, + }, +}; + +module_platform_driver(mtk_rng_driver); + +MODULE_DESCRIPTION("Mediatek Random Number Generator Driver"); +MODULE_AUTHOR("Sean Wang <sean.wang@mediatek.com>"); +MODULE_LICENSE("GPL");