From: Alexey Romanov <avromanov@xxxxxxxxxxxxxx>
For some Amlogic SOC's, mechanism to obtain random number
has been changed. For example, S4 now uses status bit waiting algo.
Signed-off-by: Alexey Romanov <avromanov@xxxxxxxxxxxxxx>
---
drivers/char/hw_random/meson-rng.c | 80 ++++++++++++++++++++++++++++--
1 file changed, 77 insertions(+), 3 deletions(-)
diff --git a/drivers/char/hw_random/meson-rng.c b/drivers/char/hw_random/meson-rng.c
index a4eb8e35f13d..75225eb9fef6 100644
--- a/drivers/char/hw_random/meson-rng.c
+++ b/drivers/char/hw_random/meson-rng.c
@@ -13,12 +13,23 @@
#include <linux/types.h>
#include <linux/of.h>
#include <linux/clk.h>
+#include <linux/iopoll.h>
-#define RNG_DATA 0x00
+#define RNG_DATA 0x00
+#define RNG_S4_DATA 0x08
+#define RNG_S4_CFG 0x00
+
+#define RUN_BIT BIT(0)
+#define SEED_READY_STS_BIT BIT(31)
+
+struct meson_rng_priv {
+ int (*read)(struct hwrng *rng, void *buf, size_t max, bool wait);
+};
struct meson_rng_data {
void __iomem *base;
struct hwrng rng;
+ struct device *dev;
};
static int meson_rng_read(struct hwrng *rng, void *buf, size_t max, bool wait)
@@ -31,16 +42,62 @@ static int meson_rng_read(struct hwrng *rng, void *buf, size_t max, bool wait)
return sizeof(u32);
}
+static int meson_rng_wait_status(void __iomem *cfg_addr, int bit)
+{
+ u32 status = 0;
+ int ret;
+
+ ret = readl_relaxed_poll_timeout_atomic(cfg_addr,
+ status, !(status & bit),
+ 10, 10000);
+ if (ret)
+ return -EBUSY;
+
+ return 0;
+}
+
+static int meson_s4_rng_read(struct hwrng *rng, void *buf, size_t max, bool wait)
+{
+ struct meson_rng_data *data =
+ container_of(rng, struct meson_rng_data, rng);
+
+ void __iomem *cfg_addr = data->base + RNG_S4_CFG;
+ int err;
+
+ writel_relaxed(readl_relaxed(cfg_addr) | SEED_READY_STS_BIT, cfg_addr);
+
+ err = meson_rng_wait_status(cfg_addr, SEED_READY_STS_BIT);
+ if (err) {
+ dev_err(data->dev, "Seed isn't ready, try again\n");
+ return err;
+ }
+
+ err = meson_rng_wait_status(cfg_addr, RUN_BIT);
+ if (err) {
+ dev_err(data->dev, "Can't get random number, try again\n");
+ return err;
+ }
+
+ *(u32 *)buf = readl_relaxed(data->base + RNG_S4_DATA);
+
+ return sizeof(u32);
+}
+
static int meson_rng_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
struct meson_rng_data *data;
struct clk *core_clk;
+ const struct meson_rng_priv *priv;
data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
if (!data)
return -ENOMEM;
+ priv = device_get_match_data(&pdev->dev);
+ if (!priv)
+ return -ENODEV;
+
data->base = devm_platform_ioremap_resource(pdev, 0);
if (IS_ERR(data->base))
return PTR_ERR(data->base);
@@ -51,13 +108,30 @@ static int meson_rng_probe(struct platform_device *pdev)
"Failed to get core clock\n");
data->rng.name = pdev->name;
- data->rng.read = meson_rng_read;
+ data->rng.read = priv->read;
+
+ data->dev = &pdev->dev;
return devm_hwrng_register(dev, &data->rng);
}
+static const struct meson_rng_priv meson_rng_priv = {
+ .read = meson_rng_read,
+};
+
+static const struct meson_rng_priv meson_rng_priv_s4 = {
+ .read = meson_s4_rng_read,
+};
+
static const struct of_device_id meson_rng_of_match[] = {
- { .compatible = "amlogic,meson-rng", },
+ {
+ .compatible = "amlogic,meson-rng",
+ .data = (void *)&meson_rng_priv,
+ },
+ {
+ .compatible = "amlogic,meson-s4-rng",
+ .data = (void *)&meson_rng_priv_s4,
+ },
{},
};
MODULE_DEVICE_TABLE(of, meson_rng_of_match);
--
2.25.1
