mirror of
https://github.com/torvalds/linux.git
synced 2024-11-10 14:11:52 +00:00
4b5bcd5a3c
Amba bus core already sets owner, so driver does not need to. Link: https://lore.kernel.org/r/20240326-module-owner-amba-v1-15-4517b091385b@linaro.org Acked-by: Suzuki K Poulose <suzuki.poulose@arm.com> Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org> Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
92 lines
2.1 KiB
C
92 lines
2.1 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
|
|
/*
|
|
* Nomadik RNG support
|
|
* Copyright 2009 Alessandro Rubini
|
|
*/
|
|
|
|
#include <linux/kernel.h>
|
|
#include <linux/module.h>
|
|
#include <linux/device.h>
|
|
#include <linux/amba/bus.h>
|
|
#include <linux/hw_random.h>
|
|
#include <linux/io.h>
|
|
#include <linux/clk.h>
|
|
#include <linux/err.h>
|
|
|
|
static int nmk_rng_read(struct hwrng *rng, void *data, size_t max, bool wait)
|
|
{
|
|
void __iomem *base = (void __iomem *)rng->priv;
|
|
|
|
/*
|
|
* The register is 32 bits and gives 16 random bits (low half).
|
|
* A subsequent read will delay the core for 400ns, so we just read
|
|
* once and accept the very unlikely very small delay, even if wait==0.
|
|
*/
|
|
*(u16 *)data = __raw_readl(base + 8) & 0xffff;
|
|
return 2;
|
|
}
|
|
|
|
/* we have at most one RNG per machine, granted */
|
|
static struct hwrng nmk_rng = {
|
|
.name = "nomadik",
|
|
.read = nmk_rng_read,
|
|
};
|
|
|
|
static int nmk_rng_probe(struct amba_device *dev, const struct amba_id *id)
|
|
{
|
|
struct clk *rng_clk;
|
|
void __iomem *base;
|
|
int ret;
|
|
|
|
rng_clk = devm_clk_get_enabled(&dev->dev, NULL);
|
|
if (IS_ERR(rng_clk))
|
|
return dev_err_probe(&dev->dev, PTR_ERR(rng_clk), "could not get rng clock\n");
|
|
|
|
ret = amba_request_regions(dev, dev->dev.init_name);
|
|
if (ret)
|
|
return ret;
|
|
ret = -ENOMEM;
|
|
base = devm_ioremap(&dev->dev, dev->res.start,
|
|
resource_size(&dev->res));
|
|
if (!base)
|
|
goto out_release;
|
|
nmk_rng.priv = (unsigned long)base;
|
|
ret = devm_hwrng_register(&dev->dev, &nmk_rng);
|
|
if (ret)
|
|
goto out_release;
|
|
return 0;
|
|
|
|
out_release:
|
|
amba_release_regions(dev);
|
|
return ret;
|
|
}
|
|
|
|
static void nmk_rng_remove(struct amba_device *dev)
|
|
{
|
|
amba_release_regions(dev);
|
|
}
|
|
|
|
static const struct amba_id nmk_rng_ids[] = {
|
|
{
|
|
.id = 0x000805e1,
|
|
.mask = 0x000fffff, /* top bits are rev and cfg: accept all */
|
|
},
|
|
{0, 0},
|
|
};
|
|
|
|
MODULE_DEVICE_TABLE(amba, nmk_rng_ids);
|
|
|
|
static struct amba_driver nmk_rng_driver = {
|
|
.drv = {
|
|
.name = "rng",
|
|
},
|
|
.probe = nmk_rng_probe,
|
|
.remove = nmk_rng_remove,
|
|
.id_table = nmk_rng_ids,
|
|
};
|
|
|
|
module_amba_driver(nmk_rng_driver);
|
|
|
|
MODULE_DESCRIPTION("ST-Ericsson Nomadik Random Number Generator");
|
|
MODULE_LICENSE("GPL");
|