openloongarch-linux-6.12/drivers/mfd/loongson-timers.c

// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (C) STMicroelectronics 2016
 * Author: Benjamin Gaignard <benjamin.gaignard@st.com>
 *
 * Copyright (C) 2025 Ilikara <3435193369@qq.com>
 * Modified by: Ilikara <3435193369@qq.com>
 */

#include <linux/bitfield.h>
#include <linux/module.h>
#include <linux/of_platform.h>
#include <linux/platform_device.h>
#include <linux/reset.h>

#include <linux/mfd/loongson-timers.h>

#define LS_TIMERS_MAX_REGISTERS	0x3fc

/* DIER register DMA enable bits */
static const u32 loongson_timers_dier_dmaen[LS_TIMERS_MAX_DMAS] = {
	TIM_DIER_CC1DE,
	TIM_DIER_CC2DE,
	TIM_DIER_CC3DE,
	TIM_DIER_CC4DE,
	TIM_DIER_UIE,
	TIM_DIER_TDE,
	TIM_DIER_COMDE
};

static void loongson_timers_dma_done(void *p)
{
	struct loongson_timers_dma *dma = p;
	struct dma_tx_state state;
	enum dma_status status;

	status = dmaengine_tx_status(dma->chan, dma->chan->cookie, &state);
	if (status == DMA_COMPLETE)
		complete(&dma->completion);
}

/**
 * loongson_timers_dma_burst_read - Read from timers registers using DMA.
 *
 * Read from Loongson timers registers using DMA on a single event.
 * @dev: reference to loongson_timers MFD device
 * @buf: DMA'able destination buffer
 * @id: loongson_timers_dmas event identifier (ch[1..4], up, trig or com)
 * @reg: registers start offset for DMA to read from (like CCRx for capture)
 * @num_reg: number of registers to read upon each DMA request, starting @reg.
 * @bursts: number of bursts to read (e.g. like two for pwm period capture)
 * @tmo_ms: timeout (milliseconds)
 */
int loongson_timers_dma_burst_read(struct device *dev, u32 *buf,
				enum loongson_timers_dmas id, u32 reg,
				unsigned int num_reg, unsigned int bursts,
				unsigned long tmo_ms)
{
	struct loongson_timers *ddata = dev_get_drvdata(dev);
	unsigned long timeout = msecs_to_jiffies(tmo_ms);
	struct regmap *regmap = ddata->regmap;
	struct loongson_timers_dma *dma = &ddata->dma;
	size_t len = num_reg * bursts * sizeof(u32);
	struct dma_async_tx_descriptor *desc;
	struct dma_slave_config config;
	dma_cookie_t cookie;
	dma_addr_t dma_buf;
	long err;
	int ret;

	/* Sanity check */
	if (id < LS_TIMERS_DMA_CH1 || id >= LS_TIMERS_MAX_DMAS)
		return -EINVAL;

	if (!num_reg || !bursts || reg > LS_TIMERS_MAX_REGISTERS ||
	    (reg + num_reg * sizeof(u32)) > LS_TIMERS_MAX_REGISTERS)
		return -EINVAL;

	if (!dma->chans[id])
		return -ENODEV;
	mutex_lock(&dma->lock);

	/* Select DMA channel in use */
	dma->chan = dma->chans[id];
	dma_buf = dma_map_single(dev, buf, len, DMA_FROM_DEVICE);
	if (dma_mapping_error(dev, dma_buf)) {
		ret = -ENOMEM;
		goto unlock;
	}

	/* Prepare DMA read from timer registers, using DMA burst mode */
	memset(&config, 0, sizeof(config));
	config.src_addr = (dma_addr_t)dma->phys_base + reg;
	config.src_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
	ret = dmaengine_slave_config(dma->chan, &config);
	if (ret)
		goto unmap;

	desc = dmaengine_prep_dma_cyclic(dma->chan, dma_buf, len, bursts,
					 DMA_DEV_TO_MEM, DMA_PREP_INTERRUPT);
	if (!desc) {
		ret = -EBUSY;
		goto unmap;
	}

	desc->callback = loongson_timers_dma_done;
	desc->callback_param = dma;
	cookie = dmaengine_submit(desc);
	ret = dma_submit_error(cookie);
	if (ret)
		goto dma_term;

	reinit_completion(&dma->completion);
	dma_async_issue_pending(dma->chan);

	/* Clear pending flags before enabling DMA request */
	ret = regmap_write(regmap, TIM_SR, 0);
	if (ret)
		goto dma_term;

	ret = regmap_update_bits(regmap, TIM_DIER, loongson_timers_dier_dmaen[id],
				 loongson_timers_dier_dmaen[id]);
	if (ret)
		goto dma_term;
	print_hex_dump(KERN_DEBUG, "DMA dump: ", DUMP_PREFIX_ADDRESS, 4, 1, ioremap(0x1612c030, 0x10), 0x10, false);
	print_hex_dump(KERN_DEBUG, "GTIM dump: ", DUMP_PREFIX_ADDRESS, 4, 1, ioremap(0x16119000, 0x50), 0x50, false);

	err = wait_for_completion_interruptible_timeout(&dma->completion,
							timeout);
	if (err == 0)
		ret = -ETIMEDOUT;
	else if (err < 0)
		ret = err;

	regmap_update_bits(regmap, TIM_DIER, loongson_timers_dier_dmaen[id], 0);
	regmap_write(regmap, TIM_SR, 0);
dma_term:
	dmaengine_terminate_all(dma->chan);
unmap:
	dma_unmap_single(dev, dma_buf, len, DMA_FROM_DEVICE);
unlock:
	dma->chan = NULL;
	mutex_unlock(&dma->lock);

	return ret;
}
EXPORT_SYMBOL_GPL(loongson_timers_dma_burst_read);

static const struct regmap_config loongson_timers_regmap_cfg = {
	.reg_bits = 32,
	.val_bits = 32,
	.reg_stride = sizeof(u32),
	.max_register = LS_TIMERS_MAX_REGISTERS,
};

static void loongson_timers_get_arr_size(struct loongson_timers *ddata)
{
	u32 arr;

	/* Backup ARR to restore it after getting the maximum value */
	regmap_read(ddata->regmap, TIM_ARR, &arr);

	/*
	 * Only the available bits will be written so when readback
	 * we get the maximum value of auto reload register
	 */
	regmap_write(ddata->regmap, TIM_ARR, ~0L);
	regmap_read(ddata->regmap, TIM_ARR, &ddata->max_arr);
	regmap_write(ddata->regmap, TIM_ARR, arr);
}

static int loongson_timers_dma_probe(struct device *dev,
				   struct loongson_timers *ddata)
{
	int i;
	int ret = 0;
	char name[4];

	init_completion(&ddata->dma.completion);
	mutex_init(&ddata->dma.lock);

	/* Optional DMA support: get valid DMA channel(s) or NULL */
	for (i = LS_TIMERS_DMA_CH1; i <= LS_TIMERS_DMA_CH4; i++) {
		snprintf(name, ARRAY_SIZE(name), "ch%1d", i + 1);
		ddata->dma.chans[i] = dma_request_chan(dev, name);
	}
	ddata->dma.chans[LS_TIMERS_DMA_UP] = dma_request_chan(dev, "up");
	ddata->dma.chans[LS_TIMERS_DMA_TRIG] = dma_request_chan(dev, "trig");
	ddata->dma.chans[LS_TIMERS_DMA_COM] = dma_request_chan(dev, "com");

	for (i = LS_TIMERS_DMA_CH1; i < LS_TIMERS_MAX_DMAS; i++) {
		if (IS_ERR(ddata->dma.chans[i])) {
			/* Save the first error code to return */
			if (PTR_ERR(ddata->dma.chans[i]) != -ENODEV && !ret)
				ret = PTR_ERR(ddata->dma.chans[i]);

			ddata->dma.chans[i] = NULL;
		}
	}

	return ret;
}

static void loongson_timers_dma_remove(struct device *dev,
				    struct loongson_timers *ddata)
{
	int i;

	for (i = LS_TIMERS_DMA_CH1; i < LS_TIMERS_MAX_DMAS; i++)
		if (ddata->dma.chans[i])
			dma_release_channel(ddata->dma.chans[i]);
}

static int loongson_timers_irq_probe(struct platform_device *pdev,
				  struct loongson_timers *ddata)
{
	int ret;

	ret = platform_get_irq_byname_optional(pdev, "global");
	if (ret < 0 && ret != -ENXIO) {
		return ret;
	} else if (ret != -ENXIO) {
		ddata->irq[LS_TIMERS_IRQ_GLOBAL] = ret;
		ddata->nr_irqs = 1;
		return 0;
	}

	return 0;
}

static int loongson_timers_probe(struct platform_device *pdev)
{
	struct device *dev = &pdev->dev;
	struct loongson_timers *ddata;
	struct resource *res;
	void __iomem *mmio;
	int ret;

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

	mmio = devm_platform_get_and_ioremap_resource(pdev, 0, &res);
	if (IS_ERR(mmio))
		return PTR_ERR(mmio);

	/* Timer physical addr for DMA */
	ddata->dma.phys_base = res->start;

	ddata->regmap = devm_regmap_init_mmio_clk(dev, "int", mmio,
						  &loongson_timers_regmap_cfg);
	if (IS_ERR(ddata->regmap))
		return PTR_ERR(ddata->regmap);

	ddata->clk = devm_clk_get(dev, NULL);
	if (IS_ERR(ddata->clk))
		return PTR_ERR(ddata->clk);

	loongson_timers_get_arr_size(ddata);

	ret = loongson_timers_irq_probe(pdev, ddata);
	if (ret)
		return ret;

	ret = loongson_timers_dma_probe(dev, ddata);
	if (ret) {
		loongson_timers_dma_remove(dev, ddata);
		return ret;
	}

	platform_set_drvdata(pdev, ddata);

	ret = of_platform_populate(pdev->dev.of_node, NULL, NULL, &pdev->dev);
	if (ret)
		loongson_timers_dma_remove(dev, ddata);

	return ret;
}

static void loongson_timers_remove(struct platform_device *pdev)
{
	struct loongson_timers *ddata = platform_get_drvdata(pdev);

	/*
	 * Don't use devm_ here: enfore of_platform_depopulate() happens before
	 * DMA are released, to avoid race on DMA.
	 */
	of_platform_depopulate(&pdev->dev);
	loongson_timers_dma_remove(&pdev->dev, ddata);
}

static const struct of_device_id loongson_timers_of_match[] = {
	{ .compatible = "loongson,loongson-timers", },
	{ /* end node */ },
};
MODULE_DEVICE_TABLE(of, loongson_timers_of_match);

static struct platform_driver loongson_timers_driver = {
	.probe = loongson_timers_probe,
	.remove_new = loongson_timers_remove,
	.driver	= {
		.name = "loongson-timers",
		.of_match_table = loongson_timers_of_match,
	},
};
module_platform_driver(loongson_timers_driver);

MODULE_DESCRIPTION("Loongson Timers");
MODULE_LICENSE("GPL v2");