1 // SPDX-License-Identifier: GPL-2.0-or-later
3  * Copyright (C) 2022-2024 Canaan Bright Sight Co., Ltd
4  * Copyright (C) 2024-2025 Junhui Liu <junhui.liu@pigmoral.tech>
6  * The reset management module in the K230 SoC provides reset time control
8  * during which reset is applied or removed while the clock is stopped can be
10  * up to 255 * 0.25 = 63.75 µs. For RST_TYPE_FLUSH, the reset bit is
13  * Although this driver does not configure the reset time registers, delays have
14  * been added to the assert, deassert, and reset operations to cover the maximum
15  * reset time. Some reset types include done bits whose toggle does not
16  * unambiguously signal whether hardware reset removal or clock-stop period
17  * expiration occurred first. Delays are therefore retained for types with done
21 …* https://kendryte-download.canaan-creative.com/developer/k230/HDK/K230%E7%A1%AC%E4%BB%B6%E6%96%87…
30 #include <linux/reset-controller.h>
33 #include <dt-bindings/reset/canaan,k230-rst.h>
36  * enum k230_rst_type - K230 reset types
37  * @RST_TYPE_CPU0: Reset type for CPU0
39  * @RST_TYPE_CPU1: Reset type for CPU1
41  * @RST_TYPE_FLUSH: Reset type for CPU L2 cache flush
43  * @RST_TYPE_HW_DONE: Reset type for hardware auto clear
45  * @RST_TYPE_SW_DONE: Reset type for software manual clear
61 	u32			reset;  member
67 	/* protect register read-modify-write */
165 	guard(spinlock_irqsave)(&rstc->lock);  in k230_rst_clear_done()
167 	reg = readl(rstc->base + rmap->offset);  in k230_rst_clear_done()
168 	reg |= rmap->done; /* write 1 to clear */  in k230_rst_clear_done()
170 		reg |= rmap->done << 16;  in k230_rst_clear_done()
171 	writel(reg, rstc->base + rmap->offset);  in k230_rst_clear_done()
181 	ret = readl_poll_timeout(rstc->base + rmap->offset, reg,  in k230_rst_wait_and_clear_done()
182 				 reg & rmap->done, 10, 1000);  in k230_rst_wait_and_clear_done()
184 		dev_err(rstc->rcdev.dev, "Wait for reset done timeout\n");  in k230_rst_wait_and_clear_done()
199 	guard(spinlock_irqsave)(&rstc->lock);  in k230_rst_update()
201 	reg = readl(rstc->base + rmap->offset);  in k230_rst_update()
203 		reg |= rmap->reset;  in k230_rst_update()
205 		reg &= ~rmap->reset;  in k230_rst_update()
207 		reg |= rmap->reset << 16;  in k230_rst_update()
208 	writel(reg, rstc->base + rmap->offset);  in k230_rst_update()
226 		return -EOPNOTSUPP;  in k230_rst_assert()
230 	 * The time period when reset is applied but the clock is stopped for  in k230_rst_assert()
231 	 * RST_TYPE_CPU1 and RST_TYPE_SW_DONE can be set up to 3.75us. Delay  in k230_rst_assert()
232 	 * 10us to ensure proper reset timing.  in k230_rst_assert()
257 		return -EOPNOTSUPP;  in k230_rst_deassert()
261 	 * The time period when reset is removed but the clock is stopped for  in k230_rst_deassert()
262 	 * RST_TYPE_CPU1 and RST_TYPE_SW_DONE can be set up to 3.75us. Delay  in k230_rst_deassert()
263 	 * 10us to ensure proper reset timing.  in k230_rst_deassert()
277 	switch (rmap->type) {  in k230_rst_reset()
284 		 * The time period when reset is applied and removed but the  in k230_rst_reset()
285 		 * clock is stopped for RST_TYPE_CPU0 can be set up to 7.5us.  in k230_rst_reset()
286 		 * Delay 10us to ensure proper reset timing.  in k230_rst_reset()
295 		ret = readl_poll_timeout(rstc->base + rmap->offset, reg,  in k230_rst_reset()
296 					!(reg & rmap->reset), 10, 1000);  in k230_rst_reset()
298 			dev_err(rcdev->dev, "Wait for flush done timeout\n");  in k230_rst_reset()
307 		 * The time period when reset is applied and removed but the  in k230_rst_reset()
309 		 * 127.5us. Delay 200us to ensure proper reset timing.  in k230_rst_reset()
325 	.reset		= k230_rst_reset,
332 	struct device *dev = &pdev->dev;  in k230_rst_probe()
337 		return -ENOMEM;  in k230_rst_probe()
339 	rstc->base = devm_platform_ioremap_resource(pdev, 0);  in k230_rst_probe()
340 	if (IS_ERR(rstc->base))  in k230_rst_probe()
341 		return PTR_ERR(rstc->base);  in k230_rst_probe()
343 	spin_lock_init(&rstc->lock);  in k230_rst_probe()
345 	rstc->rcdev.dev		= dev;  in k230_rst_probe()
346 	rstc->rcdev.owner	= THIS_MODULE;  in k230_rst_probe()
347 	rstc->rcdev.ops		= &k230_rst_ops;  in k230_rst_probe()
348 	rstc->rcdev.nr_resets	= ARRAY_SIZE(k230_resets);  in k230_rst_probe()
349 	rstc->rcdev.of_node	= dev->of_node;  in k230_rst_probe()
351 	return devm_reset_controller_register(dev, &rstc->rcdev);  in k230_rst_probe()
355 	{ .compatible = "canaan,k230-rst", },
363 		.name = "k230-rst",
370 MODULE_DESCRIPTION("Canaan K230 reset driver");