diff options
Diffstat (limited to 'drivers/char/hw_random/tx4939-rng.c')
| -rw-r--r-- | drivers/char/hw_random/tx4939-rng.c | 157 |
1 files changed, 0 insertions, 157 deletions
diff --git a/drivers/char/hw_random/tx4939-rng.c b/drivers/char/hw_random/tx4939-rng.c deleted file mode 100644 index c8bd34e740fd..000000000000 --- a/drivers/char/hw_random/tx4939-rng.c +++ /dev/null @@ -1,157 +0,0 @@ -/* - * RNG driver for TX4939 Random Number Generators (RNG) - * - * Copyright (C) 2009 Atsushi Nemoto <anemo@mba.ocn.ne.jp> - * - * This file is subject to the terms and conditions of the GNU General Public - * License. See the file "COPYING" in the main directory of this archive - * for more details. - */ -#include <linux/err.h> -#include <linux/module.h> -#include <linux/kernel.h> -#include <linux/init.h> -#include <linux/delay.h> -#include <linux/io.h> -#include <linux/platform_device.h> -#include <linux/hw_random.h> -#include <linux/gfp.h> - -#define TX4939_RNG_RCSR 0x00000000 -#define TX4939_RNG_ROR(n) (0x00000018 + (n) * 8) - -#define TX4939_RNG_RCSR_INTE 0x00000008 -#define TX4939_RNG_RCSR_RST 0x00000004 -#define TX4939_RNG_RCSR_FIN 0x00000002 -#define TX4939_RNG_RCSR_ST 0x00000001 - -struct tx4939_rng { - struct hwrng rng; - void __iomem *base; - u64 databuf[3]; - unsigned int data_avail; -}; - -static void rng_io_start(void) -{ -#ifndef CONFIG_64BIT - /* - * readq is reading a 64-bit register using a 64-bit load. On - * a 32-bit kernel however interrupts or any other processor - * exception would clobber the upper 32-bit of the processor - * register so interrupts need to be disabled. - */ - local_irq_disable(); -#endif -} - -static void rng_io_end(void) -{ -#ifndef CONFIG_64BIT - local_irq_enable(); -#endif -} - -static u64 read_rng(void __iomem *base, unsigned int offset) -{ - return ____raw_readq(base + offset); -} - -static void write_rng(u64 val, void __iomem *base, unsigned int offset) -{ - return ____raw_writeq(val, base + offset); -} - -static int tx4939_rng_data_present(struct hwrng *rng, int wait) -{ - struct tx4939_rng *rngdev = container_of(rng, struct tx4939_rng, rng); - int i; - - if (rngdev->data_avail) - return rngdev->data_avail; - for (i = 0; i < 20; i++) { - rng_io_start(); - if (!(read_rng(rngdev->base, TX4939_RNG_RCSR) - & TX4939_RNG_RCSR_ST)) { - rngdev->databuf[0] = - read_rng(rngdev->base, TX4939_RNG_ROR(0)); - rngdev->databuf[1] = - read_rng(rngdev->base, TX4939_RNG_ROR(1)); - rngdev->databuf[2] = - read_rng(rngdev->base, TX4939_RNG_ROR(2)); - rngdev->data_avail = - sizeof(rngdev->databuf) / sizeof(u32); - /* Start RNG */ - write_rng(TX4939_RNG_RCSR_ST, - rngdev->base, TX4939_RNG_RCSR); - wait = 0; - } - rng_io_end(); - if (!wait) - break; - /* 90 bus clock cycles by default for generation */ - ndelay(90 * 5); - } - return rngdev->data_avail; -} - -static int tx4939_rng_data_read(struct hwrng *rng, u32 *buffer) -{ - struct tx4939_rng *rngdev = container_of(rng, struct tx4939_rng, rng); - - rngdev->data_avail--; - *buffer = *((u32 *)&rngdev->databuf + rngdev->data_avail); - return sizeof(u32); -} - -static int __init tx4939_rng_probe(struct platform_device *dev) -{ - struct tx4939_rng *rngdev; - int i; - - rngdev = devm_kzalloc(&dev->dev, sizeof(*rngdev), GFP_KERNEL); - if (!rngdev) - return -ENOMEM; - rngdev->base = devm_platform_ioremap_resource(dev, 0); - if (IS_ERR(rngdev->base)) - return PTR_ERR(rngdev->base); - - rngdev->rng.name = dev_name(&dev->dev); - rngdev->rng.data_present = tx4939_rng_data_present; - rngdev->rng.data_read = tx4939_rng_data_read; - - rng_io_start(); - /* Reset RNG */ - write_rng(TX4939_RNG_RCSR_RST, rngdev->base, TX4939_RNG_RCSR); - write_rng(0, rngdev->base, TX4939_RNG_RCSR); - /* Start RNG */ - write_rng(TX4939_RNG_RCSR_ST, rngdev->base, TX4939_RNG_RCSR); - rng_io_end(); - /* - * Drop first two results. From the datasheet: - * The quality of the random numbers generated immediately - * after reset can be insufficient. Therefore, do not use - * random numbers obtained from the first and second - * generations; use the ones from the third or subsequent - * generation. - */ - for (i = 0; i < 2; i++) { - rngdev->data_avail = 0; - if (!tx4939_rng_data_present(&rngdev->rng, 1)) - return -EIO; - } - - platform_set_drvdata(dev, rngdev); - return devm_hwrng_register(&dev->dev, &rngdev->rng); -} - -static struct platform_driver tx4939_rng_driver = { - .driver = { - .name = "tx4939-rng", - }, -}; - -module_platform_driver_probe(tx4939_rng_driver, tx4939_rng_probe); - -MODULE_DESCRIPTION("H/W Random Number Generator (RNG) driver for TX4939"); -MODULE_LICENSE("GPL"); |