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author | Jia Jie Ho <jiajie.ho@starfivetech.com> | 2023-01-17 09:54:44 +0800 |
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committer | Herbert Xu <herbert@gondor.apana.org.au> | 2023-01-27 18:58:09 +0800 |
commit | c388f458bc34eb3a5728b67f6614f9375cd99087 (patch) | |
tree | 3143d10d455a954765dc57094c3d24c26cde6b52 | |
parent | a482b02d6ae0d82c3c616ec0fb2a7b3080707e48 (diff) | |
download | linux-c388f458bc34eb3a5728b67f6614f9375cd99087.tar.gz linux-c388f458bc34eb3a5728b67f6614f9375cd99087.tar.bz2 linux-c388f458bc34eb3a5728b67f6614f9375cd99087.zip |
hwrng: starfive - Add TRNG driver for StarFive SoC
This adds driver support for the hardware random number generator in
Starfive SoCs and adds StarFive TRNG entry to MAINTAINERS.
Co-developed-by: Jenny Zhang <jenny.zhang@starfivetech.com>
Signed-off-by: Jenny Zhang <jenny.zhang@starfivetech.com>
Signed-off-by: Jia Jie Ho <jiajie.ho@starfivetech.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
-rw-r--r-- | MAINTAINERS | 6 | ||||
-rw-r--r-- | drivers/char/hw_random/Kconfig | 11 | ||||
-rw-r--r-- | drivers/char/hw_random/Makefile | 1 | ||||
-rw-r--r-- | drivers/char/hw_random/jh7110-trng.c | 393 |
4 files changed, 411 insertions, 0 deletions
diff --git a/MAINTAINERS b/MAINTAINERS index c4b4b9283d18..4f59559597ab 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -19905,6 +19905,12 @@ F: Documentation/devicetree/bindings/reset/starfive,jh7100-reset.yaml F: drivers/reset/reset-starfive-jh7100.c F: include/dt-bindings/reset/starfive-jh7100.h +STARFIVE TRNG DRIVER +M: Jia Jie Ho <jiajie.ho@starfivetech.com> +S: Supported +F: Documentation/devicetree/bindings/rng/starfive* +F: drivers/char/hw_random/starfive-trng.c + STATIC BRANCH/CALL M: Peter Zijlstra <peterz@infradead.org> M: Josh Poimboeuf <jpoimboe@kernel.org> diff --git a/drivers/char/hw_random/Kconfig b/drivers/char/hw_random/Kconfig index 3da8e85f8aae..be202959efa6 100644 --- a/drivers/char/hw_random/Kconfig +++ b/drivers/char/hw_random/Kconfig @@ -549,6 +549,17 @@ config HW_RANDOM_CN10K To compile this driver as a module, choose M here. The module will be called cn10k_rng. If unsure, say Y. +config HW_RANDOM_JH7110 + tristate "StarFive JH7110 Random Number Generator support" + depends on SOC_STARFIVE + depends on HW_RANDOM + help + This driver provides support for the True Random Number + Generator in StarFive JH7110 SoCs. + + To compile this driver as a module, choose M here. + The module will be called jh7110-trng. + endif # HW_RANDOM config UML_RANDOM diff --git a/drivers/char/hw_random/Makefile b/drivers/char/hw_random/Makefile index 3e948cf04476..09bde4a0f971 100644 --- a/drivers/char/hw_random/Makefile +++ b/drivers/char/hw_random/Makefile @@ -47,3 +47,4 @@ obj-$(CONFIG_HW_RANDOM_XIPHERA) += xiphera-trng.o obj-$(CONFIG_HW_RANDOM_ARM_SMCCC_TRNG) += arm_smccc_trng.o obj-$(CONFIG_HW_RANDOM_CN10K) += cn10k-rng.o obj-$(CONFIG_HW_RANDOM_POLARFIRE_SOC) += mpfs-rng.o +obj-$(CONFIG_HW_RANDOM_JH7110) += jh7110-trng.o diff --git a/drivers/char/hw_random/jh7110-trng.c b/drivers/char/hw_random/jh7110-trng.c new file mode 100644 index 000000000000..38474d48a25e --- /dev/null +++ b/drivers/char/hw_random/jh7110-trng.c @@ -0,0 +1,393 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * TRNG driver for the StarFive JH7110 SoC + * + * Copyright (C) 2022 StarFive Technology Co. + */ + +#include <linux/clk.h> +#include <linux/completion.h> +#include <linux/delay.h> +#include <linux/err.h> +#include <linux/hw_random.h> +#include <linux/interrupt.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> +#include <linux/pm_runtime.h> +#include <linux/random.h> +#include <linux/reset.h> + +/* trng register offset */ +#define STARFIVE_CTRL 0x00 +#define STARFIVE_STAT 0x04 +#define STARFIVE_MODE 0x08 +#define STARFIVE_SMODE 0x0C +#define STARFIVE_IE 0x10 +#define STARFIVE_ISTAT 0x14 +#define STARFIVE_RAND0 0x20 +#define STARFIVE_RAND1 0x24 +#define STARFIVE_RAND2 0x28 +#define STARFIVE_RAND3 0x2C +#define STARFIVE_RAND4 0x30 +#define STARFIVE_RAND5 0x34 +#define STARFIVE_RAND6 0x38 +#define STARFIVE_RAND7 0x3C +#define STARFIVE_AUTO_RQSTS 0x60 +#define STARFIVE_AUTO_AGE 0x64 + +/* CTRL CMD */ +#define STARFIVE_CTRL_EXEC_NOP 0x0 +#define STARFIVE_CTRL_GENE_RANDNUM 0x1 +#define STARFIVE_CTRL_EXEC_RANDRESEED 0x2 + +/* STAT */ +#define STARFIVE_STAT_NONCE_MODE BIT(2) +#define STARFIVE_STAT_R256 BIT(3) +#define STARFIVE_STAT_MISSION_MODE BIT(8) +#define STARFIVE_STAT_SEEDED BIT(9) +#define STARFIVE_STAT_LAST_RESEED(x) ((x) << 16) +#define STARFIVE_STAT_SRVC_RQST BIT(27) +#define STARFIVE_STAT_RAND_GENERATING BIT(30) +#define STARFIVE_STAT_RAND_SEEDING BIT(31) + +/* MODE */ +#define STARFIVE_MODE_R256 BIT(3) + +/* SMODE */ +#define STARFIVE_SMODE_NONCE_MODE BIT(2) +#define STARFIVE_SMODE_MISSION_MODE BIT(8) +#define STARFIVE_SMODE_MAX_REJECTS(x) ((x) << 16) + +/* IE */ +#define STARFIVE_IE_RAND_RDY_EN BIT(0) +#define STARFIVE_IE_SEED_DONE_EN BIT(1) +#define STARFIVE_IE_LFSR_LOCKUP_EN BIT(4) +#define STARFIVE_IE_GLBL_EN BIT(31) + +#define STARFIVE_IE_ALL (STARFIVE_IE_GLBL_EN | \ + STARFIVE_IE_RAND_RDY_EN | \ + STARFIVE_IE_SEED_DONE_EN | \ + STARFIVE_IE_LFSR_LOCKUP_EN) + +/* ISTAT */ +#define STARFIVE_ISTAT_RAND_RDY BIT(0) +#define STARFIVE_ISTAT_SEED_DONE BIT(1) +#define STARFIVE_ISTAT_LFSR_LOCKUP BIT(4) + +#define STARFIVE_RAND_LEN sizeof(u32) + +#define to_trng(p) container_of(p, struct starfive_trng, rng) + +enum reseed { + RANDOM_RESEED, + NONCE_RESEED, +}; + +enum mode { + PRNG_128BIT, + PRNG_256BIT, +}; + +struct starfive_trng { + struct device *dev; + void __iomem *base; + struct clk *hclk; + struct clk *ahb; + struct reset_control *rst; + struct hwrng rng; + struct completion random_done; + struct completion reseed_done; + u32 mode; + u32 mission; + u32 reseed; + /* protects against concurrent write to ctrl register */ + spinlock_t write_lock; +}; + +static u16 autoreq; +module_param(autoreq, ushort, 0); +MODULE_PARM_DESC(autoreq, "Auto-reseeding after random number requests by host reaches specified counter:\n" + " 0 - disable counter\n" + " other - reload value for internal counter"); + +static u16 autoage; +module_param(autoage, ushort, 0); +MODULE_PARM_DESC(autoage, "Auto-reseeding after specified timer countdowns to 0:\n" + " 0 - disable timer\n" + " other - reload value for internal timer"); + +static inline int starfive_trng_wait_idle(struct starfive_trng *trng) +{ + u32 stat; + + return readl_relaxed_poll_timeout(trng->base + STARFIVE_STAT, stat, + !(stat & (STARFIVE_STAT_RAND_GENERATING | + STARFIVE_STAT_RAND_SEEDING)), + 10, 100000); +} + +static inline void starfive_trng_irq_mask_clear(struct starfive_trng *trng) +{ + /* clear register: ISTAT */ + u32 data = readl(trng->base + STARFIVE_ISTAT); + + writel(data, trng->base + STARFIVE_ISTAT); +} + +static int starfive_trng_cmd(struct starfive_trng *trng, u32 cmd, bool wait) +{ + int wait_time = 1000; + + /* allow up to 40 us for wait == 0 */ + if (!wait) + wait_time = 40; + + switch (cmd) { + case STARFIVE_CTRL_GENE_RANDNUM: + reinit_completion(&trng->random_done); + spin_lock_irq(&trng->write_lock); + writel(cmd, trng->base + STARFIVE_CTRL); + spin_unlock_irq(&trng->write_lock); + if (!wait_for_completion_timeout(&trng->random_done, usecs_to_jiffies(wait_time))) + return -ETIMEDOUT; + break; + case STARFIVE_CTRL_EXEC_RANDRESEED: + reinit_completion(&trng->reseed_done); + spin_lock_irq(&trng->write_lock); + writel(cmd, trng->base + STARFIVE_CTRL); + spin_unlock_irq(&trng->write_lock); + if (!wait_for_completion_timeout(&trng->reseed_done, usecs_to_jiffies(wait_time))) + return -ETIMEDOUT; + break; + default: + return -EINVAL; + } + + return 0; +} + +static int starfive_trng_init(struct hwrng *rng) +{ + struct starfive_trng *trng = to_trng(rng); + u32 mode, intr = 0; + + /* setup Auto Request/Age register */ + writel(autoage, trng->base + STARFIVE_AUTO_AGE); + writel(autoreq, trng->base + STARFIVE_AUTO_RQSTS); + + /* clear register: ISTAT */ + starfive_trng_irq_mask_clear(trng); + + intr |= STARFIVE_IE_ALL; + writel(intr, trng->base + STARFIVE_IE); + + mode = readl(trng->base + STARFIVE_MODE); + + switch (trng->mode) { + case PRNG_128BIT: + mode &= ~STARFIVE_MODE_R256; + break; + case PRNG_256BIT: + mode |= STARFIVE_MODE_R256; + break; + default: + mode |= STARFIVE_MODE_R256; + break; + } + + writel(mode, trng->base + STARFIVE_MODE); + + return starfive_trng_cmd(trng, STARFIVE_CTRL_EXEC_RANDRESEED, 1); +} + +static irqreturn_t starfive_trng_irq(int irq, void *priv) +{ + u32 status; + struct starfive_trng *trng = (struct starfive_trng *)priv; + + status = readl(trng->base + STARFIVE_ISTAT); + if (status & STARFIVE_ISTAT_RAND_RDY) { + writel(STARFIVE_ISTAT_RAND_RDY, trng->base + STARFIVE_ISTAT); + complete(&trng->random_done); + } + + if (status & STARFIVE_ISTAT_SEED_DONE) { + writel(STARFIVE_ISTAT_SEED_DONE, trng->base + STARFIVE_ISTAT); + complete(&trng->reseed_done); + } + + if (status & STARFIVE_ISTAT_LFSR_LOCKUP) { + writel(STARFIVE_ISTAT_LFSR_LOCKUP, trng->base + STARFIVE_ISTAT); + /* SEU occurred, reseeding required*/ + spin_lock(&trng->write_lock); + writel(STARFIVE_CTRL_EXEC_RANDRESEED, trng->base + STARFIVE_CTRL); + spin_unlock(&trng->write_lock); + } + + return IRQ_HANDLED; +} + +static void starfive_trng_cleanup(struct hwrng *rng) +{ + struct starfive_trng *trng = to_trng(rng); + + writel(0, trng->base + STARFIVE_CTRL); + + reset_control_assert(trng->rst); + clk_disable_unprepare(trng->hclk); + clk_disable_unprepare(trng->ahb); +} + +static int starfive_trng_read(struct hwrng *rng, void *buf, size_t max, bool wait) +{ + struct starfive_trng *trng = to_trng(rng); + int ret; + + pm_runtime_get_sync(trng->dev); + + if (trng->mode == PRNG_256BIT) + max = min_t(size_t, max, (STARFIVE_RAND_LEN * 8)); + else + max = min_t(size_t, max, (STARFIVE_RAND_LEN * 4)); + + if (wait) { + ret = starfive_trng_wait_idle(trng); + if (ret) + return -ETIMEDOUT; + } + + ret = starfive_trng_cmd(trng, STARFIVE_CTRL_GENE_RANDNUM, wait); + if (ret) + return ret; + + memcpy_fromio(buf, trng->base + STARFIVE_RAND0, max); + + pm_runtime_put_sync_autosuspend(trng->dev); + + return max; +} + +static int starfive_trng_probe(struct platform_device *pdev) +{ + int ret; + int irq; + struct starfive_trng *trng; + + trng = devm_kzalloc(&pdev->dev, sizeof(*trng), GFP_KERNEL); + if (!trng) + return -ENOMEM; + + platform_set_drvdata(pdev, trng); + trng->dev = &pdev->dev; + + trng->base = devm_platform_ioremap_resource(pdev, 0); + if (IS_ERR(trng->base)) + return dev_err_probe(&pdev->dev, PTR_ERR(trng->base), + "Error remapping memory for platform device.\n"); + + irq = platform_get_irq(pdev, 0); + if (irq < 0) + return irq; + + init_completion(&trng->random_done); + init_completion(&trng->reseed_done); + spin_lock_init(&trng->write_lock); + + ret = devm_request_irq(&pdev->dev, irq, starfive_trng_irq, 0, pdev->name, + (void *)trng); + if (ret) + return dev_err_probe(&pdev->dev, irq, + "Failed to register interrupt handler\n"); + + trng->hclk = devm_clk_get(&pdev->dev, "hclk"); + if (IS_ERR(trng->hclk)) + return dev_err_probe(&pdev->dev, PTR_ERR(trng->hclk), + "Error getting hardware reference clock\n"); + + trng->ahb = devm_clk_get(&pdev->dev, "ahb"); + if (IS_ERR(trng->ahb)) + return dev_err_probe(&pdev->dev, PTR_ERR(trng->ahb), + "Error getting ahb reference clock\n"); + + trng->rst = devm_reset_control_get_shared(&pdev->dev, NULL); + if (IS_ERR(trng->rst)) + return dev_err_probe(&pdev->dev, PTR_ERR(trng->rst), + "Error getting hardware reset line\n"); + + clk_prepare_enable(trng->hclk); + clk_prepare_enable(trng->ahb); + reset_control_deassert(trng->rst); + + trng->rng.name = dev_driver_string(&pdev->dev); + trng->rng.init = starfive_trng_init; + trng->rng.cleanup = starfive_trng_cleanup; + trng->rng.read = starfive_trng_read; + + trng->mode = PRNG_256BIT; + trng->mission = 1; + trng->reseed = RANDOM_RESEED; + + pm_runtime_use_autosuspend(&pdev->dev); + pm_runtime_set_autosuspend_delay(&pdev->dev, 100); + pm_runtime_enable(&pdev->dev); + + ret = devm_hwrng_register(&pdev->dev, &trng->rng); + if (ret) { + pm_runtime_disable(&pdev->dev); + + reset_control_assert(trng->rst); + clk_disable_unprepare(trng->ahb); + clk_disable_unprepare(trng->hclk); + + return dev_err_probe(&pdev->dev, ret, "Failed to register hwrng\n"); + } + + return 0; +} + +static int __maybe_unused starfive_trng_suspend(struct device *dev) +{ + struct starfive_trng *trng = dev_get_drvdata(dev); + + clk_disable_unprepare(trng->hclk); + clk_disable_unprepare(trng->ahb); + + return 0; +} + +static int __maybe_unused starfive_trng_resume(struct device *dev) +{ + struct starfive_trng *trng = dev_get_drvdata(dev); + + clk_prepare_enable(trng->hclk); + clk_prepare_enable(trng->ahb); + + return 0; +} + +static DEFINE_SIMPLE_DEV_PM_OPS(starfive_trng_pm_ops, starfive_trng_suspend, + starfive_trng_resume); + +static const struct of_device_id trng_dt_ids[] __maybe_unused = { + { .compatible = "starfive,jh7110-trng" }, + { } +}; +MODULE_DEVICE_TABLE(of, trng_dt_ids); + +static struct platform_driver starfive_trng_driver = { + .probe = starfive_trng_probe, + .driver = { + .name = "jh7110-trng", + .pm = &starfive_trng_pm_ops, + .of_match_table = of_match_ptr(trng_dt_ids), + }, +}; + +module_platform_driver(starfive_trng_driver); + +MODULE_LICENSE("GPL"); +MODULE_DESCRIPTION("StarFive True Random Number Generator"); |