diff options
Diffstat (limited to 'drivers/char/hw_random/iproc-rng200.c')
| -rw-r--r-- | drivers/char/hw_random/iproc-rng200.c | 80 |
1 files changed, 76 insertions, 4 deletions
diff --git a/drivers/char/hw_random/iproc-rng200.c b/drivers/char/hw_random/iproc-rng200.c index 32d9fe61a225..2a92ea658096 100644 --- a/drivers/char/hw_random/iproc-rng200.c +++ b/drivers/char/hw_random/iproc-rng200.c @@ -29,6 +29,7 @@ #define RNG_CTRL_RNG_RBGEN_MASK 0x00001FFF #define RNG_CTRL_RNG_RBGEN_ENABLE 0x00000001 #define RNG_CTRL_RNG_RBGEN_DISABLE 0x00000000 +#define RNG_CTRL_RNG_DIV_CTRL_SHIFT 13 #define RNG_SOFT_RESET_OFFSET 0x04 #define RNG_SOFT_RESET 0x00000001 @@ -36,16 +37,23 @@ #define RBG_SOFT_RESET_OFFSET 0x08 #define RBG_SOFT_RESET 0x00000001 +#define RNG_TOTAL_BIT_COUNT_OFFSET 0x0C + +#define RNG_TOTAL_BIT_COUNT_THRESHOLD_OFFSET 0x10 + #define RNG_INT_STATUS_OFFSET 0x18 #define RNG_INT_STATUS_MASTER_FAIL_LOCKOUT_IRQ_MASK 0x80000000 #define RNG_INT_STATUS_STARTUP_TRANSITIONS_MET_IRQ_MASK 0x00020000 #define RNG_INT_STATUS_NIST_FAIL_IRQ_MASK 0x00000020 #define RNG_INT_STATUS_TOTAL_BITS_COUNT_IRQ_MASK 0x00000001 +#define RNG_INT_ENABLE_OFFSET 0x1C + #define RNG_FIFO_DATA_OFFSET 0x20 #define RNG_FIFO_COUNT_OFFSET 0x24 #define RNG_FIFO_COUNT_RNG_FIFO_COUNT_MASK 0x000000FF +#define RNG_FIFO_COUNT_RNG_FIFO_THRESHOLD_SHIFT 8 struct iproc_rng200_dev { struct hwrng rng; @@ -166,6 +174,64 @@ static int iproc_rng200_init(struct hwrng *rng) return 0; } +static int bcm2711_rng200_read(struct hwrng *rng, void *buf, size_t max, + bool wait) +{ + struct iproc_rng200_dev *priv = to_rng_priv(rng); + u32 max_words = max / sizeof(u32); + u32 num_words, count, val; + + /* ensure warm up period has elapsed */ + while (1) { + val = ioread32(priv->base + RNG_TOTAL_BIT_COUNT_OFFSET); + if (val > 16) + break; + cpu_relax(); + } + + /* ensure fifo is not empty */ + while (1) { + num_words = ioread32(priv->base + RNG_FIFO_COUNT_OFFSET) & + RNG_FIFO_COUNT_RNG_FIFO_COUNT_MASK; + if (num_words) + break; + if (!wait) + return 0; + cpu_relax(); + } + + if (num_words > max_words) + num_words = max_words; + + for (count = 0; count < num_words; count++) { + ((u32 *)buf)[count] = ioread32(priv->base + + RNG_FIFO_DATA_OFFSET); + } + + return num_words * sizeof(u32); +} + +static int bcm2711_rng200_init(struct hwrng *rng) +{ + struct iproc_rng200_dev *priv = to_rng_priv(rng); + uint32_t val; + + if (ioread32(priv->base + RNG_CTRL_OFFSET) & RNG_CTRL_RNG_RBGEN_MASK) + return 0; + + /* initial numbers generated are "less random" so will be discarded */ + val = 0x40000; + iowrite32(val, priv->base + RNG_TOTAL_BIT_COUNT_THRESHOLD_OFFSET); + /* min fifo count to generate full interrupt */ + val = 2 << RNG_FIFO_COUNT_RNG_FIFO_THRESHOLD_SHIFT; + iowrite32(val, priv->base + RNG_FIFO_COUNT_OFFSET); + /* enable the rng - 1Mhz sample rate */ + val = (0x3 << RNG_CTRL_RNG_DIV_CTRL_SHIFT) | RNG_CTRL_RNG_RBGEN_MASK; + iowrite32(val, priv->base + RNG_CTRL_OFFSET); + + return 0; +} + static void iproc_rng200_cleanup(struct hwrng *rng) { struct iproc_rng200_dev *priv = to_rng_priv(rng); @@ -195,10 +261,16 @@ static int iproc_rng200_probe(struct platform_device *pdev) return PTR_ERR(priv->base); } - priv->rng.name = "iproc-rng200", - priv->rng.read = iproc_rng200_read, - priv->rng.init = iproc_rng200_init, - priv->rng.cleanup = iproc_rng200_cleanup, + priv->rng.name = pdev->name; + priv->rng.cleanup = iproc_rng200_cleanup; + + if (of_device_is_compatible(dev->of_node, "brcm,bcm2711-rng200")) { + priv->rng.init = bcm2711_rng200_init; + priv->rng.read = bcm2711_rng200_read; + } else { + priv->rng.init = iproc_rng200_init; + priv->rng.read = iproc_rng200_read; + } /* Register driver */ ret = devm_hwrng_register(dev, &priv->rng); |