[PATCH 2/4] hwrng: bcm2835: Support Broadcom NSP SoC rng

Yendapally Reddy Dhananjaya Reddy
2016-05-23T16:20:49Z

This supports the random number generator available in NSP SoC.
Masks the rng interrupt for NSP.

Signed-off-by: Yendapally Reddy Dhananjaya Reddy <yendapally.reddy@broadcom.com>
---
drivers/char/hw_random/Kconfig | 2 +-
drivers/char/hw_random/bcm2835-rng.c | 34 ++++++++++++++++++++++++++++++----
2 files changed, 31 insertions(+), 5 deletions(-)

diff --git a/drivers/char/hw_random/Kconfig b/drivers/char/hw_random/Kconfig
index 67ee8b0..f8d1a2b 100644
--- a/drivers/char/hw_random/Kconfig
+++ b/drivers/char/hw_random/Kconfig
@@ -90,7 +90,7 @@ config HW_RANDOM_BCM63XX

config HW_RANDOM_BCM2835
tristate "Broadcom BCM2835 Random Number Generator support"
- depends on ARCH_BCM2835
+ depends on ARCH_BCM2835 || ARCH_BCM_NSP
default HW_RANDOM
---help---
This driver provides kernel-side support for the Random Number
diff --git a/drivers/char/hw_random/bcm2835-rng.c b/drivers/char/hw_random/bcm2835-rng.c
index 7192ec2..b1e8b78 100644
--- a/drivers/char/hw_random/bcm2835-rng.c
+++ b/drivers/char/hw_random/bcm2835-rng.c
@@ -19,6 +19,7 @@
#define RNG_CTRL 0x0
#define RNG_STATUS 0x4
#define RNG_DATA 0x8
+#define RNG_INT_MASK 0x10

/* enable rng */
#define RNG_RBGEN 0x1
@@ -26,6 +27,18 @@
/* the initial numbers generated are "less random" so will be discarded */
#define RNG_WARMUP_COUNT 0x40000

+#define RNG_INT_OFF 0x1
+
+static void __init nsp_rng_init(void __iomem *base)
+{
+ u32 val;
+
+ /* mask the interrupt */
+ val = readl(base + RNG_INT_MASK);
+ val |= RNG_INT_OFF;
+ writel(val, base + RNG_INT_MASK);
+}
+
static int bcm2835_rng_read(struct hwrng *rng, void *buf, size_t max,
bool wait)
{
@@ -46,10 +59,18 @@ static struct hwrng bcm2835_rng_ops = {
.read = bcm2835_rng_read,
};

+static const struct of_device_id bcm2835_rng_of_match[] = {
+ { .compatible = "brcm,bcm2835-rng"},
+ { .compatible = "brcm,bcm-nsp-rng", .data = nsp_rng_init},
+ {},
+};
+
static int bcm2835_rng_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
struct device_node *np = dev->of_node;
+ void (*rng_setup)(void __iomem *base);
+ const struct of_device_id *rng_id;
void __iomem *rng_base;
int err;

@@ -61,6 +82,15 @@ static int bcm2835_rng_probe(struct platform_device *pdev)
}
bcm2835_rng_ops.priv = (unsigned long)rng_base;

+ rng_id = of_match_node(bcm2835_rng_of_match, np);
+ if (!rng_id)
+ return -EINVAL;
+
+ /* Check for rng init function, execute it */
+ rng_setup = rng_id->data;
+ if (rng_setup)
+ rng_setup(rng_base);
+
/* set warm-up count & enable */
__raw_writel(RNG_WARMUP_COUNT, rng_base + RNG_STATUS);
__raw_writel(RNG_RBGEN, rng_base + RNG_CTRL);
@@ -90,10 +120,6 @@ static int bcm2835_rng_remove(struct platform_device *pdev)
return 0;
}

-static const struct of_device_id bcm2835_rng_of_match[] = {
- { .compatible = "brcm,bcm2835-rng", },
- {},
-};
MODULE_DEVICE_TABLE(of, bcm2835_rng_of_match);

static struct platform_driver bcm2835_rng_driver = {
--
2.1.0