--- /dev/null
+/*
+ * APM X-Gene SoC RNG Driver
+ *
+ * Copyright (c) 2014, Applied Micro Circuits Corporation
+ * Author: Rameshwar Prasad Sahu <rsahu@apm.com>
+ * Shamal Winchurkar <swinchurkar@apm.com>
+ * Feng Kan <fkan@apm.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.
+ *
+ * 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");
projects / karo-tx-linux.git / commitdiff