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1// SPDX-License-Identifier: GPL-2.0-only2/*3 * Copyright (C) 2006-2007 PA Semi, Inc4 *5 * Maintained by: Olof Johansson <olof@lixom.net>6 *7 * Driver for the PWRficient onchip rng8 */9 10#include <linux/module.h>11#include <linux/kernel.h>12#include <linux/mod_devicetable.h>13#include <linux/platform_device.h>14#include <linux/hw_random.h>15#include <linux/delay.h>16#include <linux/io.h>17 18#define SDCRNG_CTL_REG 0x0019#define SDCRNG_CTL_FVLD_M 0x0000f00020#define SDCRNG_CTL_FVLD_S 1221#define SDCRNG_CTL_KSZ 0x0000080022#define SDCRNG_CTL_RSRC_CRG 0x0000001023#define SDCRNG_CTL_RSRC_RRG 0x0000000024#define SDCRNG_CTL_CE 0x0000000425#define SDCRNG_CTL_RE 0x0000000226#define SDCRNG_CTL_DR 0x0000000127#define SDCRNG_CTL_SELECT_RRG_RNG (SDCRNG_CTL_RE | SDCRNG_CTL_RSRC_RRG)28#define SDCRNG_CTL_SELECT_CRG_RNG (SDCRNG_CTL_CE | SDCRNG_CTL_RSRC_CRG)29#define SDCRNG_VAL_REG 0x2030 31#define MODULE_NAME "pasemi_rng"32 33static int pasemi_rng_data_present(struct hwrng *rng, int wait)34{35 void __iomem *rng_regs = (void __iomem *)rng->priv;36 int data, i;37 38 for (i = 0; i < 20; i++) {39 data = (in_le32(rng_regs + SDCRNG_CTL_REG)40 & SDCRNG_CTL_FVLD_M) ? 1 : 0;41 if (data || !wait)42 break;43 udelay(10);44 }45 return data;46}47 48static int pasemi_rng_data_read(struct hwrng *rng, u32 *data)49{50 void __iomem *rng_regs = (void __iomem *)rng->priv;51 *data = in_le32(rng_regs + SDCRNG_VAL_REG);52 return 4;53}54 55static int pasemi_rng_init(struct hwrng *rng)56{57 void __iomem *rng_regs = (void __iomem *)rng->priv;58 u32 ctl;59 60 ctl = SDCRNG_CTL_DR | SDCRNG_CTL_SELECT_RRG_RNG | SDCRNG_CTL_KSZ;61 out_le32(rng_regs + SDCRNG_CTL_REG, ctl);62 out_le32(rng_regs + SDCRNG_CTL_REG, ctl & ~SDCRNG_CTL_DR);63 64 return 0;65}66 67static void pasemi_rng_cleanup(struct hwrng *rng)68{69 void __iomem *rng_regs = (void __iomem *)rng->priv;70 u32 ctl;71 72 ctl = SDCRNG_CTL_RE | SDCRNG_CTL_CE;73 out_le32(rng_regs + SDCRNG_CTL_REG,74 in_le32(rng_regs + SDCRNG_CTL_REG) & ~ctl);75}76 77static struct hwrng pasemi_rng = {78 .name = MODULE_NAME,79 .init = pasemi_rng_init,80 .cleanup = pasemi_rng_cleanup,81 .data_present = pasemi_rng_data_present,82 .data_read = pasemi_rng_data_read,83};84 85static int rng_probe(struct platform_device *pdev)86{87 void __iomem *rng_regs;88 89 rng_regs = devm_platform_ioremap_resource(pdev, 0);90 if (IS_ERR(rng_regs))91 return PTR_ERR(rng_regs);92 93 pasemi_rng.priv = (unsigned long)rng_regs;94 95 pr_info("Registering PA Semi RNG\n");96 return devm_hwrng_register(&pdev->dev, &pasemi_rng);97}98 99static const struct of_device_id rng_match[] = {100 { .compatible = "1682m-rng", },101 { .compatible = "pasemi,pwrficient-rng", },102 { },103};104MODULE_DEVICE_TABLE(of, rng_match);105 106static struct platform_driver rng_driver = {107 .driver = {108 .name = "pasemi-rng",109 .of_match_table = rng_match,110 },111 .probe = rng_probe,112};113 114module_platform_driver(rng_driver);115 116MODULE_LICENSE("GPL");117MODULE_AUTHOR("Egor Martovetsky <egor@pasemi.com>");118MODULE_DESCRIPTION("H/W RNG driver for PA Semi processor");119