diff options
Diffstat (limited to 'roms/u-boot/drivers/rng/stm32mp1_rng.c')
| -rw-r--r-- | roms/u-boot/drivers/rng/stm32mp1_rng.c | 165 |
1 files changed, 165 insertions, 0 deletions
diff --git a/roms/u-boot/drivers/rng/stm32mp1_rng.c b/roms/u-boot/drivers/rng/stm32mp1_rng.c new file mode 100644 index 000000000..8ea00e3e8 --- /dev/null +++ b/roms/u-boot/drivers/rng/stm32mp1_rng.c @@ -0,0 +1,165 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Copyright (c) 2019, Linaro Limited + */ + +#define LOG_CATEGORY UCLASS_RNG + +#include <common.h> +#include <clk.h> +#include <dm.h> +#include <log.h> +#include <reset.h> +#include <rng.h> +#include <linux/bitops.h> +#include <linux/delay.h> + +#include <asm/io.h> +#include <linux/iopoll.h> +#include <linux/kernel.h> + +#define RNG_CR 0x00 +#define RNG_CR_RNGEN BIT(2) +#define RNG_CR_CED BIT(5) + +#define RNG_SR 0x04 +#define RNG_SR_SEIS BIT(6) +#define RNG_SR_CEIS BIT(5) +#define RNG_SR_SECS BIT(2) +#define RNG_SR_DRDY BIT(0) + +#define RNG_DR 0x08 + +struct stm32_rng_plat { + fdt_addr_t base; + struct clk clk; + struct reset_ctl rst; +}; + +static int stm32_rng_read(struct udevice *dev, void *data, size_t len) +{ + int retval, i; + u32 sr, count, reg; + size_t increment; + struct stm32_rng_plat *pdata = dev_get_plat(dev); + + while (len > 0) { + retval = readl_poll_timeout(pdata->base + RNG_SR, sr, + sr & RNG_SR_DRDY, 10000); + if (retval) + return retval; + + if (sr & (RNG_SR_SEIS | RNG_SR_SECS)) { + /* As per SoC TRM */ + clrbits_le32(pdata->base + RNG_SR, RNG_SR_SEIS); + for (i = 0; i < 12; i++) + readl(pdata->base + RNG_DR); + if (readl(pdata->base + RNG_SR) & RNG_SR_SEIS) { + log_err("RNG Noise"); + return -EIO; + } + /* start again */ + continue; + } + + /* + * Once the DRDY bit is set, the RNG_DR register can + * be read four consecutive times. + */ + count = 4; + while (len && count) { + reg = readl(pdata->base + RNG_DR); + memcpy(data, ®, min(len, sizeof(u32))); + increment = min(len, sizeof(u32)); + data += increment; + len -= increment; + count--; + } + } + + return 0; +} + +static int stm32_rng_init(struct stm32_rng_plat *pdata) +{ + int err; + + err = clk_enable(&pdata->clk); + if (err) + return err; + + /* Disable CED */ + writel(RNG_CR_RNGEN | RNG_CR_CED, pdata->base + RNG_CR); + + /* clear error indicators */ + writel(0, pdata->base + RNG_SR); + + return 0; +} + +static int stm32_rng_cleanup(struct stm32_rng_plat *pdata) +{ + writel(0, pdata->base + RNG_CR); + + return clk_disable(&pdata->clk); +} + +static int stm32_rng_probe(struct udevice *dev) +{ + struct stm32_rng_plat *pdata = dev_get_plat(dev); + + reset_assert(&pdata->rst); + udelay(20); + reset_deassert(&pdata->rst); + + return stm32_rng_init(pdata); +} + +static int stm32_rng_remove(struct udevice *dev) +{ + struct stm32_rng_plat *pdata = dev_get_plat(dev); + + return stm32_rng_cleanup(pdata); +} + +static int stm32_rng_of_to_plat(struct udevice *dev) +{ + struct stm32_rng_plat *pdata = dev_get_plat(dev); + int err; + + pdata->base = dev_read_addr(dev); + if (!pdata->base) + return -ENOMEM; + + err = clk_get_by_index(dev, 0, &pdata->clk); + if (err) + return err; + + err = reset_get_by_index(dev, 0, &pdata->rst); + if (err) + return err; + + return 0; +} + +static const struct dm_rng_ops stm32_rng_ops = { + .read = stm32_rng_read, +}; + +static const struct udevice_id stm32_rng_match[] = { + { + .compatible = "st,stm32-rng", + }, + {}, +}; + +U_BOOT_DRIVER(stm32_rng) = { + .name = "stm32-rng", + .id = UCLASS_RNG, + .of_match = stm32_rng_match, + .ops = &stm32_rng_ops, + .probe = stm32_rng_probe, + .remove = stm32_rng_remove, + .plat_auto = sizeof(struct stm32_rng_plat), + .of_to_plat = stm32_rng_of_to_plat, +}; |