^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1) // SPDX-License-Identifier: GPL-2.0-only
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3) * ST Random Number Generator Driver ST's Platforms
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 4) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 5) * Author: Pankaj Dev: <pankaj.dev@st.com>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 6) * Lee Jones <lee.jones@linaro.org>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 7) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 8) * Copyright (C) 2015 STMicroelectronics (R&D) Limited
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 9) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 10)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 11) #include <linux/clk.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 12) #include <linux/delay.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 13) #include <linux/hw_random.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 14) #include <linux/io.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 15) #include <linux/kernel.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 16) #include <linux/module.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 17) #include <linux/of.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 18) #include <linux/platform_device.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 19) #include <linux/slab.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 20)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 21) /* Registers */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 22) #define ST_RNG_STATUS_REG 0x20
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 23) #define ST_RNG_DATA_REG 0x24
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 24)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 25) /* Registers fields */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 26) #define ST_RNG_STATUS_BAD_SEQUENCE BIT(0)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 27) #define ST_RNG_STATUS_BAD_ALTERNANCE BIT(1)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 28) #define ST_RNG_STATUS_FIFO_FULL BIT(5)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 29)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 30) #define ST_RNG_SAMPLE_SIZE 2 /* 2 Byte (16bit) samples */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 31) #define ST_RNG_FIFO_DEPTH 4
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 32) #define ST_RNG_FIFO_SIZE (ST_RNG_FIFO_DEPTH * ST_RNG_SAMPLE_SIZE)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 33)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 34) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 35) * Samples are documented to be available every 0.667us, so in theory
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 36) * the 4 sample deep FIFO should take 2.668us to fill. However, during
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 37) * thorough testing, it became apparent that filling the FIFO actually
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 38) * takes closer to 12us. We then multiply by 2 in order to account for
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 39) * the lack of udelay()'s reliability, suggested by Russell King.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 40) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 41) #define ST_RNG_FILL_FIFO_TIMEOUT (12 * 2)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 42)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 43) struct st_rng_data {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 44) void __iomem *base;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 45) struct clk *clk;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 46) struct hwrng ops;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 47) };
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 48)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 49) static int st_rng_read(struct hwrng *rng, void *data, size_t max, bool wait)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 50) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 51) struct st_rng_data *ddata = (struct st_rng_data *)rng->priv;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 52) u32 status;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 53) int i;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 54)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 55) /* Wait until FIFO is full - max 4uS*/
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 56) for (i = 0; i < ST_RNG_FILL_FIFO_TIMEOUT; i++) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 57) status = readl_relaxed(ddata->base + ST_RNG_STATUS_REG);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 58) if (status & ST_RNG_STATUS_FIFO_FULL)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 59) break;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 60) udelay(1);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 61) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 62)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 63) if (i == ST_RNG_FILL_FIFO_TIMEOUT)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 64) return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 65)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 66) for (i = 0; i < ST_RNG_FIFO_SIZE && i < max; i += 2)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 67) *(u16 *)(data + i) =
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 68) readl_relaxed(ddata->base + ST_RNG_DATA_REG);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 69)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 70) return i; /* No of bytes read */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 71) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 72)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 73) static int st_rng_probe(struct platform_device *pdev)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 74) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 75) struct st_rng_data *ddata;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 76) struct clk *clk;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 77) void __iomem *base;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 78) int ret;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 79)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 80) ddata = devm_kzalloc(&pdev->dev, sizeof(*ddata), GFP_KERNEL);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 81) if (!ddata)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 82) return -ENOMEM;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 83)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 84) base = devm_platform_ioremap_resource(pdev, 0);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 85) if (IS_ERR(base))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 86) return PTR_ERR(base);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 87)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 88) clk = devm_clk_get(&pdev->dev, NULL);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 89) if (IS_ERR(clk))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 90) return PTR_ERR(clk);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 91)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 92) ret = clk_prepare_enable(clk);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 93) if (ret)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 94) return ret;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 95)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 96) ddata->ops.priv = (unsigned long)ddata;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 97) ddata->ops.read = st_rng_read;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 98) ddata->ops.name = pdev->name;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 99) ddata->base = base;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 100) ddata->clk = clk;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 101)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 102) dev_set_drvdata(&pdev->dev, ddata);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 103)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 104) ret = devm_hwrng_register(&pdev->dev, &ddata->ops);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 105) if (ret) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 106) dev_err(&pdev->dev, "Failed to register HW RNG\n");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 107) clk_disable_unprepare(clk);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 108) return ret;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 109) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 110)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 111) dev_info(&pdev->dev, "Successfully registered HW RNG\n");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 112)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 113) return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 114) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 115)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 116) static int st_rng_remove(struct platform_device *pdev)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 117) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 118) struct st_rng_data *ddata = dev_get_drvdata(&pdev->dev);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 119)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 120) clk_disable_unprepare(ddata->clk);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 121)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 122) return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 123) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 124)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 125) static const struct of_device_id st_rng_match[] __maybe_unused = {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 126) { .compatible = "st,rng" },
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 127) {},
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 128) };
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 129) MODULE_DEVICE_TABLE(of, st_rng_match);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 130)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 131) static struct platform_driver st_rng_driver = {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 132) .driver = {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 133) .name = "st-hwrandom",
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 134) .of_match_table = of_match_ptr(st_rng_match),
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 135) },
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 136) .probe = st_rng_probe,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 137) .remove = st_rng_remove
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 138) };
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 139)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 140) module_platform_driver(st_rng_driver);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 141)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 142) MODULE_AUTHOR("Pankaj Dev <pankaj.dev@st.com>");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 143) MODULE_LICENSE("GPL v2");
Orange Pi5 kernel
Deprecated Linux kernel 5.10.110 for OrangePi 5/5B/5+ boards
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