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hwrng: meson - add support for S4

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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@sberdevices.ru>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
This commit is contained in:
Alexey Romanov 2023-09-29 13:29:36 +03:00 committed by Herbert Xu
parent b42ab1c61a
commit a5de196d6d
1 changed files with 77 additions and 3 deletions
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80
drivers/char/hw_random/meson-rng.c
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@ -13,12 +13,23 @@
#include <linux/types.h> #include <linux/types.h>
#include <linux/of.h> #include <linux/of.h>
#include <linux/clk.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 { struct meson_rng_data {
void __iomem *base; void __iomem *base;
struct hwrng rng; struct hwrng rng;
struct device *dev;
}; };
static int meson_rng_read(struct hwrng *rng, void *buf, size_t max, bool wait) 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); 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) static int meson_rng_probe(struct platform_device *pdev)
{ {
struct device *dev = &pdev->dev; struct device *dev = &pdev->dev;
struct meson_rng_data *data; struct meson_rng_data *data;
struct clk *core_clk; struct clk *core_clk;
const struct meson_rng_priv *priv;
data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL); data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
if (!data) if (!data)
return -ENOMEM; return -ENOMEM;
priv = device_get_match_data(&pdev->dev);
if (!priv)
return -ENODEV;
data->base = devm_platform_ioremap_resource(pdev, 0); data->base = devm_platform_ioremap_resource(pdev, 0);
if (IS_ERR(data->base)) if (IS_ERR(data->base))
return PTR_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"); "Failed to get core clock\n");
data->rng.name = pdev->name; 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); 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[] = { 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); MODULE_DEVICE_TABLE(of, meson_rng_of_match);