diff options
Diffstat (limited to 'drivers/char/hw_random/starfive-vic-rng.c')
| -rw-r--r-- | drivers/char/hw_random/starfive-vic-rng.c | 256 |
1 files changed, 256 insertions, 0 deletions
diff --git a/drivers/char/hw_random/starfive-vic-rng.c b/drivers/char/hw_random/starfive-vic-rng.c new file mode 100644 index 000000000000..1e003b755a52 --- /dev/null +++ b/drivers/char/hw_random/starfive-vic-rng.c @@ -0,0 +1,256 @@ +/* + ****************************************************************************** + * @file starfive-vic-rng.c + * @author StarFive Technology + * @version V1.0 + * @date 08/13/2020 + * @brief + ****************************************************************************** + * @copy + * + * THE PRESENT SOFTWARE WHICH IS FOR GUIDANCE ONLY AIMS AT PROVIDING CUSTOMERS + * WITH CODING INFORMATION REGARDING THEIR PRODUCTS IN ORDER FOR THEM TO SAVE + * TIME. AS A RESULT, STARFIVE SHALL NOT BE HELD LIABLE FOR ANY + * DIRECT, INDIRECT OR CONSEQUENTIAL DAMAGES WITH RESPECT TO ANY CLAIMS ARISING + * FROM THE CONTENT OF SUCH SOFTWARE AND/OR THE USE MADE BY CUSTOMERS OF THE + * CODING INFORMATION CONTAINED HEREIN IN CONNECTION WITH THEIR PRODUCTS. + * + * COPYRIGHT 2020 Shanghai StarFive Technology Co., Ltd. + */ +#include <linux/err.h> +#include <linux/kernel.h> +#include <linux/hw_random.h> +#include <linux/io.h> +#include <linux/module.h> +#include <linux/of.h> +#include <linux/platform_device.h> +#include <linux/interrupt.h> +#include <linux/random.h> + +#include "starfive-vic-rng.h" + +#define to_vic_rng(p) container_of(p, struct vic_rng, rng) + +struct vic_rng { + struct device *dev; + void __iomem *base; + struct hwrng rng; +}; + +static inline void vic_wait_till_idle(struct vic_rng *hrng) +{ + while(readl(hrng->base + VIC_STAT) & VIC_STAT_BUSY) + ; +} + +static inline void vic_rng_irq_mask_clear(struct vic_rng *hrng) +{ + // clear register: ISTAT + u32 data = readl(hrng->base + VIC_ISTAT); + writel(data, hrng->base + VIC_ISTAT); + writel(0, hrng->base + VIC_ALARM); +} + +static int vic_trng_cmd(struct vic_rng *hrng, u32 cmd) { + int res = 0; + // wait till idle + vic_wait_till_idle(hrng); + switch (cmd) { + case VIC_CTRL_CMD_NOP: + case VIC_CTRL_CMD_GEN_NOISE: + case VIC_CTRL_CMD_GEN_NONCE: + case VIC_CTRL_CMD_CREATE_STATE: + case VIC_CTRL_CMD_RENEW_STATE: + case VIC_CTRL_CMD_REFRESH_ADDIN: + case VIC_CTRL_CMD_GEN_RANDOM: + case VIC_CTRL_CMD_ADVANCE_STATE: + case VIC_CTRL_CMD_KAT: + case VIC_CTRL_CMD_ZEROIZE: + writel(cmd, hrng->base + VIC_CTRL); + break; + default: + res = -1; + break; + } + + return res; +} + +static int vic_rng_init(struct hwrng *rng) +{ + struct vic_rng *hrng = to_vic_rng(rng); + + // wait till idle + + // clear register: ISTAT + vic_rng_irq_mask_clear(hrng); + + // set mission mode + writel(VIC_SMODE_SECURE_EN(1), hrng->base + VIC_SMODE); + + vic_trng_cmd(hrng, VIC_CTRL_CMD_GEN_NOISE); + vic_wait_till_idle(hrng); + + // set interrupt + writel(VIC_IE_ALL, hrng->base + VIC_IE); + + // zeroize + vic_trng_cmd(hrng, VIC_CTRL_CMD_ZEROIZE); + + vic_wait_till_idle(hrng); + + return 0; +} + +static irqreturn_t vic_rng_irq(int irq, void *priv) +{ + u32 status, val; + struct vic_rng *hrng = (struct vic_rng *)priv; + + /* + * clearing the interrupt will also clear the error register + * read error and status before clearing + */ + status = readl(hrng->base + VIC_ISTAT); + + if (status & VIC_ISTAT_ALARMS) { + writel(VIC_ISTAT_ALARMS, hrng->base + VIC_ISTAT); + val = readl(hrng->base + VIC_ALARM); + if (val & VIC_ALARM_ILLEGAL_CMD_SEQ) { + writel(VIC_ALARM_ILLEGAL_CMD_SEQ, hrng->base + VIC_ALARM); + //dev_info(hrng->dev, "ILLEGAL CMD SEQ: LAST_CMD=0x%x\r\n", + //VIC_STAT_LAST_CMD(readl(hrng->base + VIC_STAT))); + } else { + dev_info(hrng->dev, "Failed test: %x\r\n", val); + } + } + + if (status & VIC_ISTAT_ZEROIZE) { + writel(VIC_ISTAT_ZEROIZE, hrng->base + VIC_ISTAT); + //dev_info(hrng->dev, "zeroized\r\n"); + } + + if (status & VIC_ISTAT_KAT_COMPLETE) { + writel(VIC_ISTAT_KAT_COMPLETE, hrng->base + VIC_ISTAT); + //dev_info(hrng->dev, "kat_completed\r\n"); + } + + if (status & VIC_ISTAT_NOISE_RDY) { + writel(VIC_ISTAT_NOISE_RDY, hrng->base + VIC_ISTAT); + //dev_info(hrng->dev, "noise_rdy\r\n"); + } + + if (status & VIC_ISTAT_DONE) { + writel(VIC_ISTAT_DONE, hrng->base + VIC_ISTAT); + //dev_info(hrng->dev, "done\r\n"); + /* + if (VIC_STAT_LAST_CMD(readl(hrng->base + VIC_STAT)) == + VIC_CTRL_CMD_GEN_RANDOM) { + dev_info(hrng->dev, "Need Update Buffer\r\n"); + } + */ + } + vic_rng_irq_mask_clear(hrng); + + return IRQ_HANDLED; +} + +static void vic_rng_cleanup(struct hwrng *rng) +{ + struct vic_rng *hrng = to_vic_rng(rng); + + writel(0, hrng->base + VIC_CTRL); +} + +static int vic_rng_read(struct hwrng *rng, void *buf, size_t max, bool wait) +{ + struct vic_rng *hrng = to_vic_rng(rng); + + vic_trng_cmd(hrng, VIC_CTRL_CMD_ZEROIZE); + vic_trng_cmd(hrng, VIC_CTRL_CMD_GEN_NOISE); + vic_trng_cmd(hrng, VIC_CTRL_CMD_CREATE_STATE); + + vic_wait_till_idle(hrng); + max = min_t(size_t, max, (VIC_RAND_LEN * 4)); + + writel(0x0, hrng->base + VIC_MODE); + vic_trng_cmd(hrng, VIC_CTRL_CMD_GEN_RANDOM); + + vic_wait_till_idle(hrng); + memcpy_fromio(buf, hrng->base + VIC_RAND0, max); + vic_trng_cmd(hrng, VIC_CTRL_CMD_ZEROIZE); + + vic_wait_till_idle(hrng); + return max; +} + +static int vic_rng_probe(struct platform_device *pdev) +{ + int ret; + int irq; + struct vic_rng *rng; + struct resource *res; + + rng = devm_kzalloc(&pdev->dev, sizeof(*rng), GFP_KERNEL); + if (!rng){ + return -ENOMEM; + } + + platform_set_drvdata(pdev, rng); + + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); + rng->base = devm_ioremap_resource(&pdev->dev, res); + if (IS_ERR(rng->base)){ + return PTR_ERR(rng->base); + } + + irq = platform_get_irq(pdev, 0); + if (irq <= 0) { + dev_err(&pdev->dev, "Couldn't get irq %d\n", irq); + return irq; + } + + ret = devm_request_irq(&pdev->dev, irq, vic_rng_irq, 0, pdev->name, + (void *)rng); + if (ret) { + dev_err(&pdev->dev, "Can't get interrupt working.\n"); + return ret; + } + + rng->rng.name = pdev->name; + rng->rng.init = vic_rng_init; + rng->rng.cleanup = vic_rng_cleanup; + rng->rng.read = vic_rng_read; + + rng->dev = &pdev->dev; + + ret = devm_hwrng_register(&pdev->dev, &rng->rng); + if (ret) { + dev_err(&pdev->dev, "failed to register hwrng\n"); + return ret; + } + + dev_info(&pdev->dev, "Initialized\n"); + + return 0; +} + +static const struct of_device_id vic_rng_dt_ids[] = { + { .compatible = "starfive,vic-rng" }, + { } +}; +MODULE_DEVICE_TABLE(of, vic_rng_dt_ids); + +static struct platform_driver vic_rng_driver = { + .probe = vic_rng_probe, + .driver = { + .name = "vic-rng", + .of_match_table = vic_rng_dt_ids, + }, +}; + +module_platform_driver(vic_rng_driver); + +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Huan Feng <huan.feng@starfivetech.com>"); +MODULE_DESCRIPTION("Starfive VIC random number generator driver"); |