^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2) * RNG driver for TX4939 Random Number Generators (RNG)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 4) * Copyright (C) 2009 Atsushi Nemoto <anemo@mba.ocn.ne.jp>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 5) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 6) * This file is subject to the terms and conditions of the GNU General Public
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 7) * License. See the file "COPYING" in the main directory of this archive
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 8) * for more details.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 9) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 10) #include <linux/err.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 11) #include <linux/module.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 12) #include <linux/kernel.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 13) #include <linux/init.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 14) #include <linux/delay.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 15) #include <linux/io.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 16) #include <linux/platform_device.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 17) #include <linux/hw_random.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 18) #include <linux/gfp.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 19)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 20) #define TX4939_RNG_RCSR 0x00000000
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 21) #define TX4939_RNG_ROR(n) (0x00000018 + (n) * 8)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 22)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 23) #define TX4939_RNG_RCSR_INTE 0x00000008
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 24) #define TX4939_RNG_RCSR_RST 0x00000004
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 25) #define TX4939_RNG_RCSR_FIN 0x00000002
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 26) #define TX4939_RNG_RCSR_ST 0x00000001
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 27)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 28) struct tx4939_rng {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 29) struct hwrng rng;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 30) void __iomem *base;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 31) u64 databuf[3];
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 32) unsigned int data_avail;
^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) static void rng_io_start(void)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 36) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 37) #ifndef CONFIG_64BIT
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 38) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 39) * readq is reading a 64-bit register using a 64-bit load. On
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 40) * a 32-bit kernel however interrupts or any other processor
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 41) * exception would clobber the upper 32-bit of the processor
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 42) * register so interrupts need to be disabled.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 43) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 44) local_irq_disable();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 45) #endif
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 46) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 47)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 48) static void rng_io_end(void)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 49) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 50) #ifndef CONFIG_64BIT
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 51) local_irq_enable();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 52) #endif
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 53) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 54)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 55) static u64 read_rng(void __iomem *base, unsigned int offset)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 56) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 57) return ____raw_readq(base + offset);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 58) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 59)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 60) static void write_rng(u64 val, void __iomem *base, unsigned int offset)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 61) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 62) return ____raw_writeq(val, base + offset);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 63) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 64)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 65) static int tx4939_rng_data_present(struct hwrng *rng, int wait)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 66) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 67) struct tx4939_rng *rngdev = container_of(rng, struct tx4939_rng, rng);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 68) int i;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 69)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 70) if (rngdev->data_avail)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 71) return rngdev->data_avail;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 72) for (i = 0; i < 20; i++) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 73) rng_io_start();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 74) if (!(read_rng(rngdev->base, TX4939_RNG_RCSR)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 75) & TX4939_RNG_RCSR_ST)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 76) rngdev->databuf[0] =
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 77) read_rng(rngdev->base, TX4939_RNG_ROR(0));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 78) rngdev->databuf[1] =
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 79) read_rng(rngdev->base, TX4939_RNG_ROR(1));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 80) rngdev->databuf[2] =
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 81) read_rng(rngdev->base, TX4939_RNG_ROR(2));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 82) rngdev->data_avail =
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 83) sizeof(rngdev->databuf) / sizeof(u32);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 84) /* Start RNG */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 85) write_rng(TX4939_RNG_RCSR_ST,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 86) rngdev->base, TX4939_RNG_RCSR);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 87) wait = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 88) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 89) rng_io_end();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 90) if (!wait)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 91) break;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 92) /* 90 bus clock cycles by default for generation */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 93) ndelay(90 * 5);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 94) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 95) return rngdev->data_avail;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 96) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 97)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 98) static int tx4939_rng_data_read(struct hwrng *rng, u32 *buffer)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 99) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 100) struct tx4939_rng *rngdev = container_of(rng, struct tx4939_rng, rng);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 101)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 102) rngdev->data_avail--;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 103) *buffer = *((u32 *)&rngdev->databuf + rngdev->data_avail);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 104) return sizeof(u32);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 105) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 106)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 107) static int __init tx4939_rng_probe(struct platform_device *dev)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 108) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 109) struct tx4939_rng *rngdev;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 110) int i;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 111)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 112) rngdev = devm_kzalloc(&dev->dev, sizeof(*rngdev), GFP_KERNEL);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 113) if (!rngdev)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 114) return -ENOMEM;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 115) rngdev->base = devm_platform_ioremap_resource(dev, 0);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 116) if (IS_ERR(rngdev->base))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 117) return PTR_ERR(rngdev->base);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 118)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 119) rngdev->rng.name = dev_name(&dev->dev);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 120) rngdev->rng.data_present = tx4939_rng_data_present;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 121) rngdev->rng.data_read = tx4939_rng_data_read;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 122)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 123) rng_io_start();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 124) /* Reset RNG */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 125) write_rng(TX4939_RNG_RCSR_RST, rngdev->base, TX4939_RNG_RCSR);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 126) write_rng(0, rngdev->base, TX4939_RNG_RCSR);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 127) /* Start RNG */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 128) write_rng(TX4939_RNG_RCSR_ST, rngdev->base, TX4939_RNG_RCSR);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 129) rng_io_end();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 130) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 131) * Drop first two results. From the datasheet:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 132) * The quality of the random numbers generated immediately
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 133) * after reset can be insufficient. Therefore, do not use
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 134) * random numbers obtained from the first and second
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 135) * generations; use the ones from the third or subsequent
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 136) * generation.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 137) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 138) for (i = 0; i < 2; i++) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 139) rngdev->data_avail = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 140) if (!tx4939_rng_data_present(&rngdev->rng, 1))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 141) return -EIO;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 142) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 143)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 144) platform_set_drvdata(dev, rngdev);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 145) return devm_hwrng_register(&dev->dev, &rngdev->rng);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 146) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 147)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 148) static struct platform_driver tx4939_rng_driver = {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 149) .driver = {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 150) .name = "tx4939-rng",
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 151) },
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 152) };
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 153)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 154) module_platform_driver_probe(tx4939_rng_driver, tx4939_rng_probe);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 155)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 156) MODULE_DESCRIPTION("H/W Random Number Generator (RNG) driver for TX4939");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 157) MODULE_LICENSE("GPL");
Orange Pi5 kernel
Deprecated Linux kernel 5.10.110 for OrangePi 5/5B/5+ boards
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