This adds the APM X-Gene SoC RNG support. Signed-off-by: Feng Kan <fkan@xxxxxxx> --- drivers/char/hw_random/Kconfig | 13 ++ drivers/char/hw_random/Makefile | 1 + drivers/char/hw_random/xgene-rng.c | 423 +++++++++++++++++++++++++++++++++++++ 3 files changed, 437 insertions(+) create mode 100644 drivers/char/hw_random/xgene-rng.c diff --git a/drivers/char/hw_random/Kconfig b/drivers/char/hw_random/Kconfig index 836b061..91a04ae 100644 --- a/drivers/char/hw_random/Kconfig +++ b/drivers/char/hw_random/Kconfig @@ -333,6 +333,19 @@ config HW_RANDOM_MSM If unsure, say Y. +config HW_RANDOM_XGENE + tristate "APM X-Gene True Random Number Generator (TRNG) support" + depends on HW_RANDOM && ARCH_XGENE + default HW_RANDOM + ---help--- + This driver provides kernel-side support for the Random Number + Generator hardware found on APM X-Gene SoC. + + To compile this driver as a module, choose M here: the + module will be called xgene_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 199ed283..0b4cd57 100644 --- a/drivers/char/hw_random/Makefile +++ b/drivers/char/hw_random/Makefile @@ -29,3 +29,4 @@ obj-$(CONFIG_HW_RANDOM_EXYNOS) += exynos-rng.o obj-$(CONFIG_HW_RANDOM_TPM) += tpm-rng.o obj-$(CONFIG_HW_RANDOM_BCM2835) += bcm2835-rng.o obj-$(CONFIG_HW_RANDOM_MSM) += msm-rng.o +obj-$(CONFIG_HW_RANDOM_XGENE) += xgene-rng.o diff --git a/drivers/char/hw_random/xgene-rng.c b/drivers/char/hw_random/xgene-rng.c new file mode 100644 index 0000000..23caa05 --- /dev/null +++ b/drivers/char/hw_random/xgene-rng.c @@ -0,0 +1,423 @@ +/* + * APM X-Gene SoC RNG Driver + * + * Copyright (c) 2014, Applied Micro Circuits Corporation + * Author: Rameshwar Prasad Sahu <rsahu@xxxxxxx> + * Shamal Winchurkar <swinchurkar@xxxxxxx> + * Feng Kan <fkan@xxxxxxx> + * + * 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. + * + * You should have received a copy of the GNU General Public License + * along with this program. If not, see <http://www.gnu.org/licenses/>. + * + */ + +#include <linux/clk.h> +#include <linux/delay.h> +#include <linux/hw_random.h> +#include <linux/init.h> +#include <linux/interrupt.h> +#include <linux/module.h> +#include <linux/of_platform.h> +#include <linux/of_irq.h> +#include <linux/of_address.h> +#include <linux/timer.h> + +#define RNG_MAX_DATUM 4 +#define MAX_TRY 100 +#define XGENE_RNG_RETRY_COUNT 20 +#define XGENE_RNG_RETRY_INTERVAL 10 + +/* RNG Registers */ +#define RNG_INOUT_0 0x00 +#define RNG_INTR_STS_ACK 0x10 +#define RNG_CONTROL 0x14 +#define RNG_CONFIG 0x18 +#define RNG_ALARMCNT 0x1c +#define RNG_FROENABLE 0x20 +#define RNG_FRODETUNE 0x24 +#define RNG_ALARMMASK 0x28 +#define RNG_ALARMSTOP 0x2c +#define RNG_OPTIONS 0x78 +#define RNG_EIP_REV 0x7c + +#define MONOBIT_FAIL_MASK BIT(7) +#define POKER_FAIL_MASK BIT(6) +#define LONG_RUN_FAIL_MASK BIT(5) +#define RUN_FAIL_MASK BIT(4) +#define NOISE_FAIL_MASK BIT(3) +#define STUCK_OUT_MASK BIT(2) +#define SHUTDOWN_OFLO_MASK BIT(1) +#define READY_MASK BIT(0) + +#define MAJOR_HW_REV_RD(src) (((src) & 0x0f000000) >> 24) +#define MINOR_HW_REV_RD(src) (((src) & 0x00f00000) >> 20) +#define HW_PATCH_LEVEL_RD(src) (((src) & 0x000f0000) >> 16) +#define MAX_REFILL_CYCLES_SET(dst, src) \ + ((dst & ~0xffff0000) | (((u32)src << 16) & 0xffff0000)) +#define MIN_REFILL_CYCLES_SET(dst, src) \ + ((dst & ~0x000000ff) | (((u32)src) & 0x000000ff)) +#define ALARM_THRESHOLD_SET(dst, src) \ + ((dst & ~0x000000ff) | (((u32)src) & 0x000000ff)) +#define ENABLE_RNG_SET(dst, src) \ + ((dst & ~BIT(10)) | (((u32)src << 10) & BIT(10))) +#define REGSPEC_TEST_MODE_SET(dst, src) \ + ((dst & ~BIT(8)) | (((u32)src << 8) & BIT(8))) +#define MONOBIT_FAIL_MASK_SET(dst, src) \ + ((dst & ~BIT(7)) | (((u32)src << 7) & BIT(7))) +#define POKER_FAIL_MASK_SET(dst, src) \ + ((dst & ~BIT(6)) | (((u32)src << 6) & BIT(6))) +#define LONG_RUN_FAIL_MASK_SET(dst, src) \ + ((dst & ~BIT(5)) | (((u32)src << 5) & BIT(5))) +#define RUN_FAIL_MASK_SET(dst, src) \ + ((dst & ~BIT(4)) | (((u32)src << 4) & BIT(4))) +#define NOISE_FAIL_MASK_SET(dst, src) \ + ((dst & ~BIT(3)) | (((u32)src << 3) & BIT(3))) +#define STUCK_OUT_MASK_SET(dst, src) \ + ((dst & ~BIT(2)) | (((u32)src << 2) & BIT(2))) +#define SHUTDOWN_OFLO_MASK_SET(dst, src) \ + ((dst & ~BIT(1)) | (((u32)src << 1) & BIT(1))) + +struct xgene_rng_dev { + u32 irq; + void __iomem *csr_base; + u32 revision; + u32 datum_size; + u32 failure_cnt; /* Failure count last minute */ + unsigned long failure_ts;/* First failure timestamp */ + struct timer_list failure_timer; + struct device *dev; + struct clk *clk; +}; + +static void xgene_rng_expired_timer(unsigned long arg) +{ + struct xgene_rng_dev *ctx = (struct xgene_rng_dev *) arg; + + /* Clear failure counter as timer expired */ + disable_irq(ctx->irq); + ctx->failure_cnt = 0; + del_timer(&ctx->failure_timer); + enable_irq(ctx->irq); +} + +static void xgene_rng_start_timer(struct xgene_rng_dev *ctx) +{ + ctx->failure_timer.data = (unsigned long) ctx; + ctx->failure_timer.function = xgene_rng_expired_timer; + ctx->failure_timer.expires = jiffies + 120 * HZ; + add_timer(&ctx->failure_timer); +} + +/* + * Initialize or reinit free running oscillators (FROs) + */ +static void xgene_rng_init_fro(struct xgene_rng_dev *ctx, u32 fro_val) +{ + writel(fro_val, ctx->csr_base + RNG_FRODETUNE); + writel(0x00000000, ctx->csr_base + RNG_ALARMMASK); + writel(0x00000000, ctx->csr_base + RNG_ALARMSTOP); + writel(0xFFFFFFFF, ctx->csr_base + RNG_FROENABLE); +} + +static void xgene_rng_chk_overflow(struct xgene_rng_dev *ctx) +{ + u32 val; + + val = readl(ctx->csr_base + RNG_INTR_STS_ACK); + if (val & MONOBIT_FAIL_MASK) + /* + * LFSR detected an out-of-bounds number of 1s after + * checking 20,000 bits (test T1 as specified in the + * AIS-31 standard) + */ + dev_err(ctx->dev, "test monobit failure error 0x%08X\n", val); + if (val & POKER_FAIL_MASK) + /* + * LFSR detected an out-of-bounds value in at least one + * of the 16 poker_count_X counters or an out of bounds sum + * of squares value after checking 20,000 bits (test T2 as + * specified in the AIS-31 standard) + */ + dev_err(ctx->dev, "test poker failure error 0x%08X\n", val); + if (val & LONG_RUN_FAIL_MASK) + /* + * LFSR detected a sequence of 34 identical bits + * (test T4 as specified in the AIS-31 standard) + */ + dev_err(ctx->dev, "test long run failure error 0x%08X\n", val); + if (val & RUN_FAIL_MASK) + /* + * LFSR detected an outof-bounds value for at least one + * of the running counters after checking 20,000 bits + * (test T3 as specified in the AIS-31 standard) + */ + dev_err(ctx->dev, "test run failure error 0x%08X\n", val); + if (val & NOISE_FAIL_MASK) + /* LFSR detected a sequence of 48 identical bits */ + dev_err(ctx->dev, "noise failure error 0x%08X\n", val); + if (val & STUCK_OUT_MASK) + /* + * Detected output data registers generated same value twice + * in a row + */ + dev_err(ctx->dev, "stuck out failure error 0x%08X\n", val); + + if (val & SHUTDOWN_OFLO_MASK) { + u32 frostopped; + + /* FROs shut down after a second error event. Try recover. */ + if (++ctx->failure_cnt == 1) { + /* 1st time, just recover */ + ctx->failure_ts = jiffies; + frostopped = readl(ctx->csr_base + RNG_ALARMSTOP); + xgene_rng_init_fro(ctx, frostopped); + + /* + * We must start a timer to clear out this error + * in case the system timer wrap around + */ + xgene_rng_start_timer(ctx); + } else { + /* 2nd time failure in lesser than 1 minute? */ + if (time_after(ctx->failure_ts + 60 * HZ, jiffies)) { + dev_err(ctx->dev, + "FRO shutdown failure error 0x%08X\n", + val); + } else { + /* 2nd time failure after 1 minutes, recover */ + ctx->failure_ts = jiffies; + ctx->failure_cnt = 1; + /* + * We must start a timer to clear out this + * error in case the system timer wrap + * around + */ + xgene_rng_start_timer(ctx); + } + frostopped = readl(ctx->csr_base + RNG_ALARMSTOP); + xgene_rng_init_fro(ctx, frostopped); + } + } + /* Clear them all */ + writel(val, ctx->csr_base + RNG_INTR_STS_ACK); +} + +static irqreturn_t xgene_rng_irq_handler(int irq, void *id) +{ + struct xgene_rng_dev *ctx = (struct xgene_rng_dev *) id; + + /* RNG Alarm Counter overflow */ + xgene_rng_chk_overflow(ctx); + + return IRQ_HANDLED; +} + +static int xgene_rng_data_present(struct hwrng *rng, int wait) +{ + struct xgene_rng_dev *ctx = (struct xgene_rng_dev *) rng->priv; + u32 i, val = 0; + + for (i = 0; i < XGENE_RNG_RETRY_COUNT; i++) { + val = readl(ctx->csr_base + RNG_INTR_STS_ACK); + if ((val & READY_MASK) || !wait) + break; + udelay(XGENE_RNG_RETRY_INTERVAL); + } + + return (val & READY_MASK); +} + +static int xgene_rng_data_read(struct hwrng *rng, u32 *data) +{ + struct xgene_rng_dev *ctx = (struct xgene_rng_dev *) rng->priv; + int i; + + for (i = 0; i < ctx->datum_size; i++) + data[i] = readl(ctx->csr_base + RNG_INOUT_0 + i * 4); + + /* Clear ready bit to start next transaction */ + writel(READY_MASK, ctx->csr_base + RNG_INTR_STS_ACK); + + return ctx->datum_size << 2; +} + +static void xgene_rng_init_internal(struct xgene_rng_dev *ctx) +{ + u32 val; + + writel(0x00000000, ctx->csr_base + RNG_CONTROL); + + val = MAX_REFILL_CYCLES_SET(0, 10); + val = MIN_REFILL_CYCLES_SET(val, 10); + writel(val, ctx->csr_base + RNG_CONFIG); + + val = ALARM_THRESHOLD_SET(0, 0xFF); + writel(val, ctx->csr_base + RNG_ALARMCNT); + + xgene_rng_init_fro(ctx, 0); + + writel(MONOBIT_FAIL_MASK | + POKER_FAIL_MASK | + LONG_RUN_FAIL_MASK | + RUN_FAIL_MASK | + NOISE_FAIL_MASK | + STUCK_OUT_MASK | + SHUTDOWN_OFLO_MASK | + READY_MASK, ctx->csr_base + RNG_INTR_STS_ACK); + + val = ENABLE_RNG_SET(0, 1); + val = MONOBIT_FAIL_MASK_SET(val, 1); + val = POKER_FAIL_MASK_SET(val, 1); + val = LONG_RUN_FAIL_MASK_SET(val, 1); + val = RUN_FAIL_MASK_SET(val, 1); + val = NOISE_FAIL_MASK_SET(val, 1); + val = STUCK_OUT_MASK_SET(val, 1); + val = SHUTDOWN_OFLO_MASK_SET(val, 1); + writel(val, ctx->csr_base + RNG_CONTROL); +} + +static int xgene_rng_init(struct hwrng *rng) +{ + struct xgene_rng_dev *ctx = (struct xgene_rng_dev *) rng->priv; + + ctx->failure_cnt = 0; + init_timer(&ctx->failure_timer); + + ctx->revision = readl(ctx->csr_base + RNG_EIP_REV); + + dev_dbg(ctx->dev, "Rev %d.%d.%d\n", + MAJOR_HW_REV_RD(ctx->revision), + MINOR_HW_REV_RD(ctx->revision), + HW_PATCH_LEVEL_RD(ctx->revision)); + + dev_dbg(ctx->dev, "Options 0x%08X", + readl(ctx->csr_base + RNG_OPTIONS)); + + xgene_rng_init_internal(ctx); + + ctx->datum_size = RNG_MAX_DATUM; + + return 0; +} + +static struct hwrng xgene_rng_func = { + .name = "xgene-rng", + .init = xgene_rng_init, + .data_present = xgene_rng_data_present, + .data_read = xgene_rng_data_read, +}; + +static int xgene_rng_probe(struct platform_device *pdev) +{ + struct resource *res; + struct xgene_rng_dev *ctx; + int rc = 0; + + ctx = devm_kzalloc(&pdev->dev, sizeof(*ctx), GFP_KERNEL); + if (!ctx) + return -ENOMEM; + + ctx->dev = &pdev->dev; + platform_set_drvdata(pdev, ctx); + + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); + ctx->csr_base = devm_ioremap_resource(&pdev->dev, res); + if (IS_ERR(ctx->csr_base)) + return PTR_ERR(ctx->csr_base); + + ctx->irq = platform_get_irq(pdev, 0); + if (ctx->irq < 0) { + dev_err(&pdev->dev, "No IRQ resource\n"); + return ctx->irq; + } + + dev_dbg(&pdev->dev, "APM X-Gene RNG BASE %p ALARM IRQ %d", + ctx->csr_base, ctx->irq); + + rc = devm_request_irq(&pdev->dev, ctx->irq, xgene_rng_irq_handler, 0, + dev_name(&pdev->dev), ctx); + if (rc) { + dev_err(&pdev->dev, "Could not request RNG alarm IRQ\n"); + return rc; + } + + /* Enable IP clock */ + ctx->clk = devm_clk_get(&pdev->dev, NULL); + if (IS_ERR(ctx->clk)) { + dev_warn(&pdev->dev, "Couldn't get the clock for RNG\n"); + } else { + rc = clk_prepare_enable(ctx->clk); + if (rc) { + dev_warn(&pdev->dev, + "clock prepare enable failed for RNG"); + return rc; + } + } + + xgene_rng_func.priv = (unsigned long) ctx; + + rc = hwrng_register(&xgene_rng_func); + if (rc) { + dev_err(&pdev->dev, "RNG registering failed error %d\n", rc); + if (!IS_ERR(ctx->clk)) + clk_disable_unprepare(ctx->clk); + return rc; + } + + rc = device_init_wakeup(&pdev->dev, 1); + if (rc) { + dev_err(&pdev->dev, "RNG device_init_wakeup failed error %d\n", + rc); + if (!IS_ERR(ctx->clk)) + clk_disable_unprepare(ctx->clk); + hwrng_unregister(&xgene_rng_func); + return rc; + } + + return 0; +} + +static int xgene_rng_remove(struct platform_device *pdev) +{ + struct xgene_rng_dev *ctx = platform_get_drvdata(pdev); + int rc; + + rc = device_init_wakeup(&pdev->dev, 0); + if (rc) + dev_err(&pdev->dev, "RNG init wakeup failed error %d\n", rc); + if (!IS_ERR(ctx->clk)) + clk_disable_unprepare(ctx->clk); + hwrng_unregister(&xgene_rng_func); + + return rc; +} + +static const struct of_device_id xgene_rng_of_match[] = { + { .compatible = "apm,xgene-rng" }, + { } +}; + +MODULE_DEVICE_TABLE(of, xgene_rng_of_match); + +static struct platform_driver xgene_rng_driver = { + .probe = xgene_rng_probe, + .remove = xgene_rng_remove, + .driver = { + .name = "xgene-rng", + .of_match_table = xgene_rng_of_match, + }, +}; + +module_platform_driver(xgene_rng_driver); +MODULE_DESCRIPTION("APM X-Gene RNG driver"); +MODULE_LICENSE("GPL"); -- 1.9.1 -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
