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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 | // SPDX-License-Identifier: GPL-2.0-or-later /* * Copyright 2020, Heinrich Schuchardt <xypron.glpk@gmx.de> * * Driver for Amlogic hardware random number generator */ #include <clk.h> #include <dm.h> #include <rng.h> #include <asm/io.h> #include <linux/iopoll.h> #define RNG_DATA 0x00 #define RNG_S4_DATA 0x08 #define RNG_S4_CFG 0x00 #define RUN_BIT BIT(0) #define SEED_READY_STS_BIT BIT(31) struct meson_rng_priv { u32 (*read)(fdt_addr_t base); }; struct meson_rng_plat { fdt_addr_t base; struct clk clk; struct meson_rng_priv *priv; }; /** * meson_rng_read() - fill buffer with random bytes * * @buffer: buffer to receive data * @size: size of buffer * * Return: 0 */ static int meson_rng_read(struct udevice *dev, void *data, size_t len) { struct meson_rng_plat *pdata = dev_get_plat(dev); struct meson_rng_priv *priv = pdata->priv; char *buffer = (char *)data; while (len) { u32 rand = priv->read(pdata->base); size_t step; if (len >= 4) step = 4; else step = len; memcpy(buffer, &rand, step); buffer += step; len -= step; } return 0; } static int meson_rng_wait_status(void __iomem *cfg_addr, int bit) { u32 status = 0; int ret; ret = readl_relaxed_poll_timeout(cfg_addr, status, !(status & bit), 10000); if (ret) return -EBUSY; return 0; } static u32 meson_common_rng_read(fdt_addr_t base) { return readl(base); } static u32 meson_s4_rng_read(fdt_addr_t base) { void __iomem *cfg_addr = (void *)base + RNG_S4_CFG; int err; writel_relaxed(readl_relaxed(cfg_addr) | SEED_READY_STS_BIT, cfg_addr); err = meson_rng_wait_status(cfg_addr, SEED_READY_STS_BIT); if (err) { pr_err("Seed isn't ready, try again\n"); return err; } err = meson_rng_wait_status(cfg_addr, RUN_BIT); if (err) { pr_err("Can't get random number, try again\n"); return err; } return readl_relaxed(base + RNG_S4_DATA); } /** * meson_rng_probe() - probe rng device * * @dev: device * Return: 0 if ok */ static int meson_rng_probe(struct udevice *dev) { struct meson_rng_plat *pdata = dev_get_plat(dev); int err; err = clk_enable(&pdata->clk); if (err) return err; pdata->priv = (struct meson_rng_priv *)dev_get_driver_data(dev); return 0; } /** * meson_rng_remove() - deinitialize rng device * * @dev: device * Return: 0 if ok */ static int meson_rng_remove(struct udevice *dev) { struct meson_rng_plat *pdata = dev_get_plat(dev); return clk_disable(&pdata->clk); } /** * meson_rng_of_to_plat() - transfer device tree data to plaform data * * @dev: device * Return: 0 if ok */ static int meson_rng_of_to_plat(struct udevice *dev) { struct meson_rng_plat *pdata = dev_get_plat(dev); int err; pdata->base = dev_read_addr(dev); if (!pdata->base) return -ENODEV; /* Get optional "core" clock */ err = clk_get_by_name_optional(dev, "core", &pdata->clk); if (err) return err; return 0; } static const struct dm_rng_ops meson_rng_ops = { .read = meson_rng_read, }; static const struct meson_rng_priv meson_rng_priv = { .read = meson_common_rng_read, }; static const struct meson_rng_priv meson_rng_priv_s4 = { .read = meson_s4_rng_read, }; static const struct udevice_id meson_rng_match[] = { { .compatible = "amlogic,meson-rng", .data = (ulong)&meson_rng_priv, }, { .compatible = "amlogic,meson-s4-rng", .data = (ulong)&meson_rng_priv_s4, }, {}, }; U_BOOT_DRIVER(meson_rng) = { .name = "meson-rng", .id = UCLASS_RNG, .of_match = meson_rng_match, .ops = &meson_rng_ops, .probe = meson_rng_probe, .remove = meson_rng_remove, .plat_auto = sizeof(struct meson_rng_plat), .of_to_plat = meson_rng_of_to_plat, }; |