416 строки
11 KiB
C
416 строки
11 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* APM X-Gene SoC RNG Driver
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*
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* Copyright (c) 2014, Applied Micro Circuits Corporation
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* Author: Rameshwar Prasad Sahu <rsahu@apm.com>
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* Shamal Winchurkar <swinchurkar@apm.com>
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* Feng Kan <fkan@apm.com>
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*/
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#include <linux/acpi.h>
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#include <linux/clk.h>
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#include <linux/delay.h>
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#include <linux/hw_random.h>
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#include <linux/init.h>
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#include <linux/interrupt.h>
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#include <linux/module.h>
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#include <linux/of_platform.h>
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#include <linux/of_irq.h>
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#include <linux/of_address.h>
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#include <linux/timer.h>
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#define RNG_MAX_DATUM 4
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#define MAX_TRY 100
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#define XGENE_RNG_RETRY_COUNT 20
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#define XGENE_RNG_RETRY_INTERVAL 10
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/* RNG Registers */
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#define RNG_INOUT_0 0x00
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#define RNG_INTR_STS_ACK 0x10
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#define RNG_CONTROL 0x14
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#define RNG_CONFIG 0x18
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#define RNG_ALARMCNT 0x1c
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#define RNG_FROENABLE 0x20
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#define RNG_FRODETUNE 0x24
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#define RNG_ALARMMASK 0x28
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#define RNG_ALARMSTOP 0x2c
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#define RNG_OPTIONS 0x78
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#define RNG_EIP_REV 0x7c
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#define MONOBIT_FAIL_MASK BIT(7)
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#define POKER_FAIL_MASK BIT(6)
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#define LONG_RUN_FAIL_MASK BIT(5)
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#define RUN_FAIL_MASK BIT(4)
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#define NOISE_FAIL_MASK BIT(3)
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#define STUCK_OUT_MASK BIT(2)
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#define SHUTDOWN_OFLO_MASK BIT(1)
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#define READY_MASK BIT(0)
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#define MAJOR_HW_REV_RD(src) (((src) & 0x0f000000) >> 24)
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#define MINOR_HW_REV_RD(src) (((src) & 0x00f00000) >> 20)
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#define HW_PATCH_LEVEL_RD(src) (((src) & 0x000f0000) >> 16)
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#define MAX_REFILL_CYCLES_SET(dst, src) \
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((dst & ~0xffff0000) | (((u32)src << 16) & 0xffff0000))
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#define MIN_REFILL_CYCLES_SET(dst, src) \
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((dst & ~0x000000ff) | (((u32)src) & 0x000000ff))
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#define ALARM_THRESHOLD_SET(dst, src) \
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((dst & ~0x000000ff) | (((u32)src) & 0x000000ff))
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#define ENABLE_RNG_SET(dst, src) \
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((dst & ~BIT(10)) | (((u32)src << 10) & BIT(10)))
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#define REGSPEC_TEST_MODE_SET(dst, src) \
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((dst & ~BIT(8)) | (((u32)src << 8) & BIT(8)))
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#define MONOBIT_FAIL_MASK_SET(dst, src) \
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((dst & ~BIT(7)) | (((u32)src << 7) & BIT(7)))
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#define POKER_FAIL_MASK_SET(dst, src) \
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((dst & ~BIT(6)) | (((u32)src << 6) & BIT(6)))
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#define LONG_RUN_FAIL_MASK_SET(dst, src) \
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((dst & ~BIT(5)) | (((u32)src << 5) & BIT(5)))
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#define RUN_FAIL_MASK_SET(dst, src) \
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((dst & ~BIT(4)) | (((u32)src << 4) & BIT(4)))
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#define NOISE_FAIL_MASK_SET(dst, src) \
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((dst & ~BIT(3)) | (((u32)src << 3) & BIT(3)))
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#define STUCK_OUT_MASK_SET(dst, src) \
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((dst & ~BIT(2)) | (((u32)src << 2) & BIT(2)))
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#define SHUTDOWN_OFLO_MASK_SET(dst, src) \
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((dst & ~BIT(1)) | (((u32)src << 1) & BIT(1)))
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struct xgene_rng_dev {
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u32 irq;
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void __iomem *csr_base;
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u32 revision;
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u32 datum_size;
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u32 failure_cnt; /* Failure count last minute */
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unsigned long failure_ts;/* First failure timestamp */
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struct timer_list failure_timer;
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struct device *dev;
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struct clk *clk;
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};
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static void xgene_rng_expired_timer(struct timer_list *t)
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{
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struct xgene_rng_dev *ctx = from_timer(ctx, t, failure_timer);
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/* Clear failure counter as timer expired */
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disable_irq(ctx->irq);
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ctx->failure_cnt = 0;
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del_timer(&ctx->failure_timer);
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enable_irq(ctx->irq);
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}
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static void xgene_rng_start_timer(struct xgene_rng_dev *ctx)
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{
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ctx->failure_timer.expires = jiffies + 120 * HZ;
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add_timer(&ctx->failure_timer);
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}
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/*
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* Initialize or reinit free running oscillators (FROs)
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*/
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static void xgene_rng_init_fro(struct xgene_rng_dev *ctx, u32 fro_val)
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{
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writel(fro_val, ctx->csr_base + RNG_FRODETUNE);
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writel(0x00000000, ctx->csr_base + RNG_ALARMMASK);
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writel(0x00000000, ctx->csr_base + RNG_ALARMSTOP);
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writel(0xFFFFFFFF, ctx->csr_base + RNG_FROENABLE);
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}
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static void xgene_rng_chk_overflow(struct xgene_rng_dev *ctx)
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{
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u32 val;
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val = readl(ctx->csr_base + RNG_INTR_STS_ACK);
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if (val & MONOBIT_FAIL_MASK)
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/*
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* LFSR detected an out-of-bounds number of 1s after
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* checking 20,000 bits (test T1 as specified in the
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* AIS-31 standard)
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*/
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dev_err(ctx->dev, "test monobit failure error 0x%08X\n", val);
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if (val & POKER_FAIL_MASK)
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/*
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* LFSR detected an out-of-bounds value in at least one
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* of the 16 poker_count_X counters or an out of bounds sum
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* of squares value after checking 20,000 bits (test T2 as
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* specified in the AIS-31 standard)
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*/
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dev_err(ctx->dev, "test poker failure error 0x%08X\n", val);
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if (val & LONG_RUN_FAIL_MASK)
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/*
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* LFSR detected a sequence of 34 identical bits
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* (test T4 as specified in the AIS-31 standard)
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*/
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dev_err(ctx->dev, "test long run failure error 0x%08X\n", val);
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if (val & RUN_FAIL_MASK)
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/*
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* LFSR detected an outof-bounds value for at least one
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* of the running counters after checking 20,000 bits
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* (test T3 as specified in the AIS-31 standard)
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*/
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dev_err(ctx->dev, "test run failure error 0x%08X\n", val);
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if (val & NOISE_FAIL_MASK)
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/* LFSR detected a sequence of 48 identical bits */
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dev_err(ctx->dev, "noise failure error 0x%08X\n", val);
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if (val & STUCK_OUT_MASK)
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/*
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* Detected output data registers generated same value twice
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* in a row
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*/
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dev_err(ctx->dev, "stuck out failure error 0x%08X\n", val);
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if (val & SHUTDOWN_OFLO_MASK) {
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u32 frostopped;
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/* FROs shut down after a second error event. Try recover. */
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if (++ctx->failure_cnt == 1) {
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/* 1st time, just recover */
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ctx->failure_ts = jiffies;
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frostopped = readl(ctx->csr_base + RNG_ALARMSTOP);
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xgene_rng_init_fro(ctx, frostopped);
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/*
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* We must start a timer to clear out this error
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* in case the system timer wrap around
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*/
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xgene_rng_start_timer(ctx);
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} else {
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/* 2nd time failure in lesser than 1 minute? */
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if (time_after(ctx->failure_ts + 60 * HZ, jiffies)) {
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dev_err(ctx->dev,
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"FRO shutdown failure error 0x%08X\n",
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val);
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} else {
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/* 2nd time failure after 1 minutes, recover */
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ctx->failure_ts = jiffies;
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ctx->failure_cnt = 1;
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/*
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* We must start a timer to clear out this
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* error in case the system timer wrap
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* around
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*/
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xgene_rng_start_timer(ctx);
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}
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frostopped = readl(ctx->csr_base + RNG_ALARMSTOP);
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xgene_rng_init_fro(ctx, frostopped);
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}
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}
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/* Clear them all */
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writel(val, ctx->csr_base + RNG_INTR_STS_ACK);
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}
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static irqreturn_t xgene_rng_irq_handler(int irq, void *id)
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{
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struct xgene_rng_dev *ctx = (struct xgene_rng_dev *) id;
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/* RNG Alarm Counter overflow */
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xgene_rng_chk_overflow(ctx);
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return IRQ_HANDLED;
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}
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static int xgene_rng_data_present(struct hwrng *rng, int wait)
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{
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struct xgene_rng_dev *ctx = (struct xgene_rng_dev *) rng->priv;
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u32 i, val = 0;
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for (i = 0; i < XGENE_RNG_RETRY_COUNT; i++) {
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val = readl(ctx->csr_base + RNG_INTR_STS_ACK);
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if ((val & READY_MASK) || !wait)
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break;
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udelay(XGENE_RNG_RETRY_INTERVAL);
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}
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return (val & READY_MASK);
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}
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static int xgene_rng_data_read(struct hwrng *rng, u32 *data)
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{
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struct xgene_rng_dev *ctx = (struct xgene_rng_dev *) rng->priv;
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int i;
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for (i = 0; i < ctx->datum_size; i++)
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data[i] = readl(ctx->csr_base + RNG_INOUT_0 + i * 4);
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/* Clear ready bit to start next transaction */
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writel(READY_MASK, ctx->csr_base + RNG_INTR_STS_ACK);
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return ctx->datum_size << 2;
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}
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static void xgene_rng_init_internal(struct xgene_rng_dev *ctx)
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{
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u32 val;
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writel(0x00000000, ctx->csr_base + RNG_CONTROL);
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val = MAX_REFILL_CYCLES_SET(0, 10);
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val = MIN_REFILL_CYCLES_SET(val, 10);
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writel(val, ctx->csr_base + RNG_CONFIG);
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val = ALARM_THRESHOLD_SET(0, 0xFF);
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writel(val, ctx->csr_base + RNG_ALARMCNT);
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xgene_rng_init_fro(ctx, 0);
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writel(MONOBIT_FAIL_MASK |
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POKER_FAIL_MASK |
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LONG_RUN_FAIL_MASK |
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RUN_FAIL_MASK |
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NOISE_FAIL_MASK |
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STUCK_OUT_MASK |
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SHUTDOWN_OFLO_MASK |
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READY_MASK, ctx->csr_base + RNG_INTR_STS_ACK);
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val = ENABLE_RNG_SET(0, 1);
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val = MONOBIT_FAIL_MASK_SET(val, 1);
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val = POKER_FAIL_MASK_SET(val, 1);
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val = LONG_RUN_FAIL_MASK_SET(val, 1);
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val = RUN_FAIL_MASK_SET(val, 1);
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val = NOISE_FAIL_MASK_SET(val, 1);
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val = STUCK_OUT_MASK_SET(val, 1);
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val = SHUTDOWN_OFLO_MASK_SET(val, 1);
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writel(val, ctx->csr_base + RNG_CONTROL);
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}
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static int xgene_rng_init(struct hwrng *rng)
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{
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struct xgene_rng_dev *ctx = (struct xgene_rng_dev *) rng->priv;
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ctx->failure_cnt = 0;
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timer_setup(&ctx->failure_timer, xgene_rng_expired_timer, 0);
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ctx->revision = readl(ctx->csr_base + RNG_EIP_REV);
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dev_dbg(ctx->dev, "Rev %d.%d.%d\n",
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MAJOR_HW_REV_RD(ctx->revision),
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MINOR_HW_REV_RD(ctx->revision),
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HW_PATCH_LEVEL_RD(ctx->revision));
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dev_dbg(ctx->dev, "Options 0x%08X",
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readl(ctx->csr_base + RNG_OPTIONS));
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xgene_rng_init_internal(ctx);
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ctx->datum_size = RNG_MAX_DATUM;
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return 0;
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}
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#ifdef CONFIG_ACPI
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static const struct acpi_device_id xgene_rng_acpi_match[] = {
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{ "APMC0D18", },
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{ }
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};
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MODULE_DEVICE_TABLE(acpi, xgene_rng_acpi_match);
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#endif
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static struct hwrng xgene_rng_func = {
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.name = "xgene-rng",
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.init = xgene_rng_init,
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.data_present = xgene_rng_data_present,
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.data_read = xgene_rng_data_read,
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};
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static int xgene_rng_probe(struct platform_device *pdev)
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{
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struct xgene_rng_dev *ctx;
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int rc = 0;
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ctx = devm_kzalloc(&pdev->dev, sizeof(*ctx), GFP_KERNEL);
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if (!ctx)
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return -ENOMEM;
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ctx->dev = &pdev->dev;
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platform_set_drvdata(pdev, ctx);
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ctx->csr_base = devm_platform_ioremap_resource(pdev, 0);
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if (IS_ERR(ctx->csr_base))
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return PTR_ERR(ctx->csr_base);
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rc = platform_get_irq(pdev, 0);
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if (rc < 0) {
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dev_err(&pdev->dev, "No IRQ resource\n");
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return rc;
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}
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ctx->irq = rc;
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dev_dbg(&pdev->dev, "APM X-Gene RNG BASE %p ALARM IRQ %d",
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ctx->csr_base, ctx->irq);
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rc = devm_request_irq(&pdev->dev, ctx->irq, xgene_rng_irq_handler, 0,
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dev_name(&pdev->dev), ctx);
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if (rc) {
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dev_err(&pdev->dev, "Could not request RNG alarm IRQ\n");
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return rc;
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}
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/* Enable IP clock */
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ctx->clk = devm_clk_get(&pdev->dev, NULL);
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if (IS_ERR(ctx->clk)) {
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dev_warn(&pdev->dev, "Couldn't get the clock for RNG\n");
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} else {
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rc = clk_prepare_enable(ctx->clk);
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if (rc) {
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dev_warn(&pdev->dev,
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"clock prepare enable failed for RNG");
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return rc;
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}
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}
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xgene_rng_func.priv = (unsigned long) ctx;
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rc = devm_hwrng_register(&pdev->dev, &xgene_rng_func);
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if (rc) {
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dev_err(&pdev->dev, "RNG registering failed error %d\n", rc);
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if (!IS_ERR(ctx->clk))
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clk_disable_unprepare(ctx->clk);
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return rc;
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}
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rc = device_init_wakeup(&pdev->dev, 1);
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if (rc) {
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dev_err(&pdev->dev, "RNG device_init_wakeup failed error %d\n",
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rc);
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if (!IS_ERR(ctx->clk))
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clk_disable_unprepare(ctx->clk);
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return rc;
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}
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return 0;
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}
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static int xgene_rng_remove(struct platform_device *pdev)
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{
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struct xgene_rng_dev *ctx = platform_get_drvdata(pdev);
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int rc;
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rc = device_init_wakeup(&pdev->dev, 0);
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if (rc)
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dev_err(&pdev->dev, "RNG init wakeup failed error %d\n", rc);
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if (!IS_ERR(ctx->clk))
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clk_disable_unprepare(ctx->clk);
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return rc;
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}
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static const struct of_device_id xgene_rng_of_match[] = {
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{ .compatible = "apm,xgene-rng" },
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{ }
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};
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MODULE_DEVICE_TABLE(of, xgene_rng_of_match);
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static struct platform_driver xgene_rng_driver = {
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.probe = xgene_rng_probe,
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.remove = xgene_rng_remove,
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.driver = {
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.name = "xgene-rng",
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.of_match_table = xgene_rng_of_match,
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.acpi_match_table = ACPI_PTR(xgene_rng_acpi_match),
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},
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};
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module_platform_driver(xgene_rng_driver);
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MODULE_DESCRIPTION("APM X-Gene RNG driver");
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MODULE_LICENSE("GPL");
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