1// SPDX-License-Identifier: GPL-2.0
  2/*
  3 * Loongson LPC Interrupt Controller support
  4 *
  5 * Copyright (C) 2020-2022 Loongson Technology Corporation Limited
  6 */
  7
  8#define pr_fmt(fmt) "lpc: " fmt
  9
 10#include <linux/interrupt.h>
 11#include <linux/irq.h>
 12#include <linux/irqchip.h>
 13#include <linux/irqchip/chained_irq.h>
 14#include <linux/irqdomain.h>
 15#include <linux/kernel.h>
 16#include <linux/syscore_ops.h>
 17
 18#include "irq-loongson.h"
 19
 20/* Registers */
 21#define LPC_INT_CTL		0x00
 22#define LPC_INT_ENA		0x04
 23#define LPC_INT_STS		0x08
 24#define LPC_INT_CLR		0x0c
 25#define LPC_INT_POL		0x10
 26#define LPC_COUNT		16
 27
 28/* LPC_INT_CTL */
 29#define LPC_INT_CTL_EN		BIT(31)
 30
 31struct pch_lpc {
 32	void __iomem		*base;
 33	struct irq_domain	*lpc_domain;
 34	raw_spinlock_t		lpc_lock;
 35	u32			saved_reg_ctl;
 36	u32			saved_reg_ena;
 37	u32			saved_reg_pol;
 38};
 39
 40static struct pch_lpc *pch_lpc_priv;
 41struct fwnode_handle *pch_lpc_handle;
 42
 43static void lpc_irq_ack(struct irq_data *d)
 44{
 45	unsigned long flags;
 46	struct pch_lpc *priv = d->domain->host_data;
 47
 48	raw_spin_lock_irqsave(&priv->lpc_lock, flags);
 49	writel(0x1 << d->hwirq, priv->base + LPC_INT_CLR);
 50	raw_spin_unlock_irqrestore(&priv->lpc_lock, flags);
 51}
 52
 53static void lpc_irq_mask(struct irq_data *d)
 54{
 55	unsigned long flags;
 56	struct pch_lpc *priv = d->domain->host_data;
 57
 58	raw_spin_lock_irqsave(&priv->lpc_lock, flags);
 59	writel(readl(priv->base + LPC_INT_ENA) & (~(0x1 << (d->hwirq))),
 60			priv->base + LPC_INT_ENA);
 61	raw_spin_unlock_irqrestore(&priv->lpc_lock, flags);
 62}
 63
 64static void lpc_irq_unmask(struct irq_data *d)
 65{
 66	unsigned long flags;
 67	struct pch_lpc *priv = d->domain->host_data;
 68
 69	raw_spin_lock_irqsave(&priv->lpc_lock, flags);
 70	writel(readl(priv->base + LPC_INT_ENA) | (0x1 << (d->hwirq)),
 71			priv->base + LPC_INT_ENA);
 72	raw_spin_unlock_irqrestore(&priv->lpc_lock, flags);
 73}
 74
 75static int lpc_irq_set_type(struct irq_data *d, unsigned int type)
 76{
 77	u32 val;
 78	u32 mask = 0x1 << (d->hwirq);
 79	struct pch_lpc *priv = d->domain->host_data;
 80
 81	if (!(type & IRQ_TYPE_LEVEL_MASK))
 82		return 0;
 83
 84	val = readl(priv->base + LPC_INT_POL);
 85
 86	if (type == IRQ_TYPE_LEVEL_HIGH)
 87		val |= mask;
 88	else
 89		val &= ~mask;
 90
 91	writel(val, priv->base + LPC_INT_POL);
 92
 93	return 0;
 94}
 95
 96static const struct irq_chip pch_lpc_irq_chip = {
 97	.name			= "PCH LPC",
 98	.irq_mask		= lpc_irq_mask,
 99	.irq_unmask		= lpc_irq_unmask,
100	.irq_ack		= lpc_irq_ack,
101	.irq_set_type		= lpc_irq_set_type,
102	.flags			= IRQCHIP_SKIP_SET_WAKE,
103};
104
105static void lpc_irq_dispatch(struct irq_desc *desc)
106{
107	u32 pending, bit;
108	struct irq_chip *chip = irq_desc_get_chip(desc);
109	struct pch_lpc *priv = irq_desc_get_handler_data(desc);
110
111	chained_irq_enter(chip, desc);
112
113	pending = readl(priv->base + LPC_INT_ENA);
114	pending &= readl(priv->base + LPC_INT_STS);
115	if (!pending)
116		spurious_interrupt();
117
118	while (pending) {
119		bit = __ffs(pending);
120
121		generic_handle_domain_irq(priv->lpc_domain, bit);
122		pending &= ~BIT(bit);
123	}
124	chained_irq_exit(chip, desc);
125}
126
127static int pch_lpc_map(struct irq_domain *d, unsigned int irq,
128			irq_hw_number_t hw)
129{
130	irq_set_chip_and_handler(irq, &pch_lpc_irq_chip, handle_level_irq);
131	return 0;
132}
133
134static const struct irq_domain_ops pch_lpc_domain_ops = {
135	.map 		= pch_lpc_map,
136	.translate	= irq_domain_translate_twocell,
137};
138
139static void pch_lpc_reset(struct pch_lpc *priv)
140{
141	/* Enable the LPC interrupt, bit31: en  bit30: edge */
142	writel(LPC_INT_CTL_EN, priv->base + LPC_INT_CTL);
143	writel(0, priv->base + LPC_INT_ENA);
144	/* Clear all 18-bit interrpt bit */
145	writel(GENMASK(17, 0), priv->base + LPC_INT_CLR);
146}
147
148static int pch_lpc_disabled(struct pch_lpc *priv)
149{
150	return (readl(priv->base + LPC_INT_ENA) == 0xffffffff) &&
151			(readl(priv->base + LPC_INT_STS) == 0xffffffff);
152}
153
154static int pch_lpc_suspend(void)
155{
156	pch_lpc_priv->saved_reg_ctl = readl(pch_lpc_priv->base + LPC_INT_CTL);
157	pch_lpc_priv->saved_reg_ena = readl(pch_lpc_priv->base + LPC_INT_ENA);
158	pch_lpc_priv->saved_reg_pol = readl(pch_lpc_priv->base + LPC_INT_POL);
159	return 0;
160}
161
162static void pch_lpc_resume(void)
163{
164	writel(pch_lpc_priv->saved_reg_ctl, pch_lpc_priv->base + LPC_INT_CTL);
165	writel(pch_lpc_priv->saved_reg_ena, pch_lpc_priv->base + LPC_INT_ENA);
166	writel(pch_lpc_priv->saved_reg_pol, pch_lpc_priv->base + LPC_INT_POL);
167}
168
169static struct syscore_ops pch_lpc_syscore_ops = {
170	.suspend = pch_lpc_suspend,
171	.resume = pch_lpc_resume,
172};
173
174int __init pch_lpc_acpi_init(struct irq_domain *parent,
175					struct acpi_madt_lpc_pic *acpi_pchlpc)
176{
177	int parent_irq;
178	struct pch_lpc *priv;
179	struct irq_fwspec fwspec;
180	struct fwnode_handle *irq_handle;
181
182	priv = kzalloc(sizeof(*priv), GFP_KERNEL);
183	if (!priv)
184		return -ENOMEM;
185
186	raw_spin_lock_init(&priv->lpc_lock);
187
188	priv->base = ioremap(acpi_pchlpc->address, acpi_pchlpc->size);
189	if (!priv->base)
190		goto free_priv;
191
192	if (pch_lpc_disabled(priv)) {
193		pr_err("Failed to get LPC status\n");
194		goto iounmap_base;
195	}
196
197	irq_handle = irq_domain_alloc_named_fwnode("lpcintc");
198	if (!irq_handle) {
199		pr_err("Unable to allocate domain handle\n");
200		goto iounmap_base;
201	}
202
203	priv->lpc_domain = irq_domain_create_linear(irq_handle, LPC_COUNT,
204					&pch_lpc_domain_ops, priv);
205	if (!priv->lpc_domain) {
206		pr_err("Failed to create IRQ domain\n");
207		goto free_irq_handle;
208	}
209	pch_lpc_reset(priv);
210
211	fwspec.fwnode = parent->fwnode;
212	fwspec.param[0] = acpi_pchlpc->cascade + GSI_MIN_PCH_IRQ;
213	fwspec.param[1] = IRQ_TYPE_LEVEL_HIGH;
214	fwspec.param_count = 2;
215	parent_irq = irq_create_fwspec_mapping(&fwspec);
216	irq_set_chained_handler_and_data(parent_irq, lpc_irq_dispatch, priv);
217
218	pch_lpc_priv = priv;
219	pch_lpc_handle = irq_handle;
220	register_syscore_ops(&pch_lpc_syscore_ops);
221
222	return 0;
223
224free_irq_handle:
225	irq_domain_free_fwnode(irq_handle);
226iounmap_base:
227	iounmap(priv->base);
228free_priv:
229	kfree(priv);
230
231	return -ENOMEM;
232}