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path: root/drivers/soc/apple/rtkit-helper.c
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// SPDX-License-Identifier: GPL-2.0-only OR MIT
/*
 * Apple Generic RTKit helper coprocessor
 * Copyright The Asahi Linux Contributors
 */

#include <linux/device.h>
#include <linux/dma-mapping.h>
#include <linux/io.h>
#include <linux/ioport.h>
#include <linux/of.h>
#include <linux/of_platform.h>
#include <linux/soc/apple/rtkit.h>

#define APPLE_ASC_CPU_CONTROL		0x44
#define APPLE_ASC_CPU_CONTROL_RUN	BIT(4)

struct apple_rtkit_helper {
	struct device *dev;
	struct apple_rtkit *rtk;

	void __iomem *asc_base;

	struct resource *sram;
	void __iomem *sram_base;
};

static int apple_rtkit_helper_shmem_setup(void *cookie, struct apple_rtkit_shmem *bfr)
{
	struct apple_rtkit_helper *helper = cookie;
	struct resource res = {
		.start = bfr->iova,
		.end = bfr->iova + bfr->size - 1,
		.name = "rtkit_map",
	};

	if (!bfr->iova) {
		bfr->buffer = dma_alloc_coherent(helper->dev, bfr->size,
						    &bfr->iova, GFP_KERNEL);
		if (!bfr->buffer)
			return -ENOMEM;
		return 0;
	}

	if (!helper->sram) {
		dev_err(helper->dev,
			"RTKit buffer request with no SRAM region: %pR", &res);
		return -EFAULT;
	}

	res.flags = helper->sram->flags;

	if (res.end < res.start || !resource_contains(helper->sram, &res)) {
		dev_err(helper->dev,
			"RTKit buffer request outside SRAM region: %pR", &res);
		return -EFAULT;
	}

	bfr->iomem = helper->sram_base + (res.start - helper->sram->start);
	bfr->is_mapped = true;

	return 0;
}

static void apple_rtkit_helper_shmem_destroy(void *cookie, struct apple_rtkit_shmem *bfr)
{
	// no-op
}

static const struct apple_rtkit_ops apple_rtkit_helper_ops = {
	.shmem_setup = apple_rtkit_helper_shmem_setup,
	.shmem_destroy = apple_rtkit_helper_shmem_destroy,
};

static int apple_rtkit_helper_probe(struct platform_device *pdev)
{
	struct device *dev = &pdev->dev;
	struct apple_rtkit_helper *helper;
	int ret;

	helper = devm_kzalloc(dev, sizeof(*helper), GFP_KERNEL);
	if (!helper)
		return -ENOMEM;

	helper->dev = dev;
	platform_set_drvdata(pdev, helper);

	helper->asc_base = devm_platform_ioremap_resource_byname(pdev, "asc");
	if (IS_ERR(helper->asc_base))
		return PTR_ERR(helper->asc_base);

	helper->sram = platform_get_resource_byname(pdev, IORESOURCE_MEM, "sram");
	if (helper->sram) {
		helper->sram_base = devm_ioremap_resource(dev, helper->sram);
		if (IS_ERR(helper->sram_base))
			return dev_err_probe(dev, PTR_ERR(helper->sram_base),
					"Failed to map SRAM region");
	}

	helper->rtk =
		devm_apple_rtkit_init(dev, helper, NULL, 0, &apple_rtkit_helper_ops);
	if (IS_ERR(helper->rtk))
		return dev_err_probe(dev, PTR_ERR(helper->rtk),
				     "Failed to intialize RTKit");

	writel_relaxed(APPLE_ASC_CPU_CONTROL_RUN,
		       helper->asc_base + APPLE_ASC_CPU_CONTROL);

	/* Works for both wake and boot */
	ret = apple_rtkit_wake(helper->rtk);
	if (ret != 0)
		return dev_err_probe(dev, ret, "Failed to wake up coprocessor");

	return 0;
}

static int apple_rtkit_helper_remove(struct platform_device *pdev)
{
	struct apple_rtkit_helper *helper = platform_get_drvdata(pdev);

	if (apple_rtkit_is_running(helper->rtk))
		apple_rtkit_quiesce(helper->rtk);

	writel_relaxed(0, helper->asc_base + APPLE_ASC_CPU_CONTROL);

	return 0;
}

static const struct of_device_id apple_rtkit_helper_of_match[] = {
	{ .compatible = "apple,rtk-helper-asc4" },
	{},
};
MODULE_DEVICE_TABLE(of, apple_rtkit_helper_of_match);

static struct platform_driver apple_rtkit_helper_driver = {
	.driver = {
		.name = "rtkit-helper",
		.of_match_table = apple_rtkit_helper_of_match,
	},
	.probe = apple_rtkit_helper_probe,
	.remove = apple_rtkit_helper_remove,
};
module_platform_driver(apple_rtkit_helper_driver);

MODULE_AUTHOR("Hector Martin <marcan@marcan.st>");
MODULE_LICENSE("Dual MIT/GPL");
MODULE_DESCRIPTION("Apple RTKit helper driver");