Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
soc: apple: Add hardware tunable support
Various hardware, like the Type-C PHY or the Thunderbolt/USB4 NHI,
present on Apple SoCs need machine-specific tunables passed from our
bootloader m1n1 to the device tree. Add generic helpers so that we
don't have to duplicate this across multiple drivers.
Reviewed-by: Alyssa Rosenzweig <alyssa@rosenzweig.io>
Reviewed-by: Neal Gompa <neal@gompa.dev>
Reviewed-by: Janne Grunau <j@jannau.net>
Signed-off-by: Sven Peter <sven@kernel.org>
Link: https://patch.msgid.link/20251214-b4-atcphy-v3-1-ba82b20e9459@kernel.org
Signed-off-by: Vinod Koul <vkoul@kernel.org>
authored by
Sven Peter
and committed by
Vinod Koul
a722de30
81791c45
+149
+4
drivers/soc/apple/Kconfig
+4
drivers/soc/apple/Kconfig
+3
drivers/soc/apple/Makefile
+3
drivers/soc/apple/Makefile
+80
drivers/soc/apple/tunable.c
+80
drivers/soc/apple/tunable.c
···
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// SPDX-License-Identifier: GPL-2.0-only OR MIT
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/*
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* Apple Silicon hardware tunable support
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*
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* Each tunable is a list with each entry containing a offset into the MMIO
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* region, a mask of bits to be cleared and a set of bits to be set. These
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* tunables are passed along by the previous boot stages and vary from device
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* to device such that they cannot be hardcoded in the individual drivers.
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*
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* Copyright (C) The Asahi Linux Contributors
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*/
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#include <linux/io.h>
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#include <linux/module.h>
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#include <linux/of.h>
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#include <linux/overflow.h>
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#include <linux/soc/apple/tunable.h>
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struct apple_tunable *devm_apple_tunable_parse(struct device *dev,
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struct device_node *np,
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const char *name,
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struct resource *res)
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{
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struct apple_tunable *tunable;
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struct property *prop;
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const __be32 *p;
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size_t sz;
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int i;
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if (resource_size(res) < 4)
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return ERR_PTR(-EINVAL);
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prop = of_find_property(np, name, NULL);
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if (!prop)
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return ERR_PTR(-ENOENT);
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if (prop->length % (3 * sizeof(u32)))
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return ERR_PTR(-EINVAL);
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sz = prop->length / (3 * sizeof(u32));
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tunable = devm_kzalloc(dev, struct_size(tunable, values, sz), GFP_KERNEL);
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if (!tunable)
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return ERR_PTR(-ENOMEM);
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tunable->sz = sz;
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+
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for (i = 0, p = NULL; i < tunable->sz; ++i) {
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p = of_prop_next_u32(prop, p, &tunable->values[i].offset);
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p = of_prop_next_u32(prop, p, &tunable->values[i].mask);
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p = of_prop_next_u32(prop, p, &tunable->values[i].value);
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/* Sanity checks to catch bugs in our bootloader */
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if (tunable->values[i].offset % 4)
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return ERR_PTR(-EINVAL);
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if (tunable->values[i].offset > (resource_size(res) - 4))
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return ERR_PTR(-EINVAL);
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}
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return tunable;
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}
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EXPORT_SYMBOL(devm_apple_tunable_parse);
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void apple_tunable_apply(void __iomem *regs, struct apple_tunable *tunable)
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{
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size_t i;
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for (i = 0; i < tunable->sz; ++i) {
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u32 val, old_val;
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old_val = readl(regs + tunable->values[i].offset);
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val = old_val & ~tunable->values[i].mask;
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val |= tunable->values[i].value;
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if (val != old_val)
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writel(val, regs + tunable->values[i].offset);
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}
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}
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EXPORT_SYMBOL(apple_tunable_apply);
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MODULE_LICENSE("Dual MIT/GPL");
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MODULE_AUTHOR("Sven Peter <sven@kernel.org>");
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MODULE_DESCRIPTION("Apple Silicon hardware tunable support");
+62
include/linux/soc/apple/tunable.h
+62
include/linux/soc/apple/tunable.h
···
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/* SPDX-License-Identifier: GPL-2.0-only OR MIT */
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/*
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* Apple Silicon hardware tunable support
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+
*
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+
* Each tunable is a list with each entry containing a offset into the MMIO
6
+
* region, a mask of bits to be cleared and a set of bits to be set. These
7
+
* tunables are passed along by the previous boot stages and vary from device
8
+
* to device such that they cannot be hardcoded in the individual drivers.
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*
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* Copyright (C) The Asahi Linux Contributors
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*/
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#ifndef _LINUX_SOC_APPLE_TUNABLE_H_
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#define _LINUX_SOC_APPLE_TUNABLE_H_
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#include <linux/device.h>
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#include <linux/types.h>
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/**
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* Struct to store an Apple Silicon hardware tunable.
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*
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* Each tunable is a list with each entry containing a offset into the MMIO
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* region, a mask of bits to be cleared and a set of bits to be set. These
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* tunables are passed along by the previous boot stages and vary from device
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* to device such that they cannot be hardcoded in the individual drivers.
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*
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* @param sz Number of [offset, mask, value] tuples stored in values.
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* @param values [offset, mask, value] array.
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*/
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struct apple_tunable {
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size_t sz;
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struct {
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u32 offset;
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u32 mask;
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u32 value;
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} values[] __counted_by(sz);
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};
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/**
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* Parse an array of hardware tunables from the device tree.
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*
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* @dev: Device node used for devm_kzalloc internally.
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* @np: Device node which contains the tunable array.
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* @name: Name of the device tree property which contains the tunables.
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* @res: Resource to which the tunables will be applied, used for bound checking
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*
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* @return: devres allocated struct on success or PTR_ERR on failure.
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*/
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struct apple_tunable *devm_apple_tunable_parse(struct device *dev,
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struct device_node *np,
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const char *name,
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struct resource *res);
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/**
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* Apply a previously loaded hardware tunable.
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*
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* @param regs: MMIO to which the tunable will be applied.
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* @param tunable: Pointer to the tunable.
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*/
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void apple_tunable_apply(void __iomem *regs, struct apple_tunable *tunable);
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#endif