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// SPDX-License-Identifier: GPL-2.0-only OR MIT
/*
* Apple Silicon hardware tunable support
*
* Each tunable is a list with each entry containing a offset into the MMIO
* region, a mask of bits to be cleared and a set of bits to be set. These
* tunables are passed along by the previous boot stages and vary from device
* to device such that they cannot be hardcoded in the individual drivers.
*
* Copyright (C) The Asahi Linux Contributors
*/
#include <linux/io.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/overflow.h>
#include <linux/soc/apple/tunable.h>
struct apple_tunable *devm_apple_tunable_parse(struct device *dev,
struct device_node *np,
const char *name,
struct resource *res)
{
struct apple_tunable *tunable;
struct property *prop;
const __be32 *p;
size_t sz;
int i;
if (resource_size(res) < 4)
return ERR_PTR(-EINVAL);
prop = of_find_property(np, name, NULL);
if (!prop)
return ERR_PTR(-ENOENT);
if (prop->length % (3 * sizeof(u32)))
return ERR_PTR(-EINVAL);
sz = prop->length / (3 * sizeof(u32));
tunable = devm_kzalloc(dev, struct_size(tunable, values, sz), GFP_KERNEL);
if (!tunable)
return ERR_PTR(-ENOMEM);
tunable->sz = sz;
for (i = 0, p = NULL; i < tunable->sz; ++i) {
p = of_prop_next_u32(prop, p, &tunable->values[i].offset);
p = of_prop_next_u32(prop, p, &tunable->values[i].mask);
p = of_prop_next_u32(prop, p, &tunable->values[i].value);
/* Sanity checks to catch bugs in our bootloader */
if (tunable->values[i].offset % 4)
return ERR_PTR(-EINVAL);
if (tunable->values[i].offset > (resource_size(res) - 4))
return ERR_PTR(-EINVAL);
}
return tunable;
}
EXPORT_SYMBOL(devm_apple_tunable_parse);
void apple_tunable_apply(void __iomem *regs, struct apple_tunable *tunable)
{
size_t i;
for (i = 0; i < tunable->sz; ++i) {
u32 val, old_val;
old_val = readl(regs + tunable->values[i].offset);
val = old_val & ~tunable->values[i].mask;
val |= tunable->values[i].value;
if (val != old_val)
writel(val, regs + tunable->values[i].offset);
}
}
EXPORT_SYMBOL(apple_tunable_apply);
MODULE_LICENSE("Dual MIT/GPL");
MODULE_AUTHOR("Sven Peter <sven@kernel.org>");
MODULE_DESCRIPTION("Apple Silicon hardware tunable support");
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