// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Aspeed AST24XX, AST25XX, and AST26XX SCU Interrupt Controller
* Copyright 2019 IBM Corporation
*
* Eddie James <eajames@linux.ibm.com>
*/
#include <linux/bitops.h>
#include <linux/irq.h>
#include <linux/irqchip.h>
#include <linux/irqchip/chained_irq.h>
#include <linux/irqdomain.h>
#include <linux/mfd/syscon.h>
#include <linux/of_irq.h>
#include <linux/regmap.h>
#define ASPEED_SCU_IC_REG 0x018
#define ASPEED_SCU_IC_SHIFT 0
#define ASPEED_SCU_IC_ENABLE GENMASK(15, ASPEED_SCU_IC_SHIFT)
#define ASPEED_SCU_IC_NUM_IRQS 7
#define ASPEED_SCU_IC_STATUS GENMASK(28, 16)
#define ASPEED_SCU_IC_STATUS_SHIFT 16
#define ASPEED_AST2600_SCU_IC0_REG 0x560
#define ASPEED_AST2600_SCU_IC0_SHIFT 0
#define ASPEED_AST2600_SCU_IC0_ENABLE \
GENMASK(5, ASPEED_AST2600_SCU_IC0_SHIFT)
#define ASPEED_AST2600_SCU_IC0_NUM_IRQS 6
#define ASPEED_AST2600_SCU_IC1_REG 0x570
#define ASPEED_AST2600_SCU_IC1_SHIFT 4
#define ASPEED_AST2600_SCU_IC1_ENABLE \
GENMASK(5, ASPEED_AST2600_SCU_IC1_SHIFT)
#define ASPEED_AST2600_SCU_IC1_NUM_IRQS 2
struct aspeed_scu_ic {
unsigned long irq_enable;
unsigned long irq_shift;
unsigned int num_irqs;
unsigned int reg;
struct regmap *scu;
struct irq_domain *irq_domain;
};
static void aspeed_scu_ic_irq_handler(struct irq_desc *desc)
{
unsigned int sts;
unsigned long bit;
unsigned long enabled;
unsigned long max;
unsigned long status;
struct aspeed_scu_ic *scu_ic = irq_desc_get_handler_data(desc);
struct irq_chip *chip = irq_desc_get_chip(desc);
unsigned int mask = scu_ic->irq_enable << ASPEED_SCU_IC_STATUS_SHIFT;
chained_irq_enter(chip, desc);
/*
* The SCU IC has just one register to control its operation and read
* status. The interrupt enable bits occupy the lower 16 bits of the
* register, while the interrupt status bits occupy the upper 16 bits.
* The status bit for a given interrupt is always 16 bits shifted from
* the enable bit for the same interrupt.
* Therefore, perform the IRQ operations in the enable bit space by
* shifting the status down to get the mapping and then back up to
* clear the bit.
*/
regmap_read(scu_ic->scu, scu_ic->reg, &sts);
enabled = sts & scu_ic->irq_enable;
status = (sts >> ASPEED_SCU_IC_STATUS_SHIFT) & enabled;
bit = scu_ic->irq_shift;
max = scu_ic->num_irqs + bit;
for_each_set_bit_from(bit, &status, max) {
generic_handle_domain_irq(scu_ic->irq_domain,
bit - scu_ic->irq_shift);
regmap_write_bits(scu_ic->scu, scu_ic->reg, mask,
BIT(bit + ASPEED_SCU_IC_STATUS_SHIFT));
}
chained_irq_exit(chip, desc);
}
static void aspeed_scu_ic_irq_mask(struct irq_data *data)
{
struct aspeed_scu_ic *scu_ic = irq_data_get_irq_chip_data(data);
unsigned int mask = BIT(data->hwirq + scu_ic->irq_shift) |
(scu_ic->irq_enable << ASPEED_SCU_IC_STATUS_SHIFT);
/*
* Status bits are cleared by writing 1. In order to prevent the mask
* operation from clearing the status bits, they should be under the
* mask and written with 0.
*/
regmap_update_bits(scu_ic->scu, scu_ic->reg, mask, 0);
}
static void aspeed_scu_ic_irq_unmask(struct irq_data *data)
{
struct aspeed_scu_ic *scu_ic = irq_data_get_irq_chip_data(data);
unsigned int bit = BIT(data->hwirq + scu_ic->irq_shift);
unsigned int mask = bit |
(scu_ic->irq_enable << ASPEED_SCU_IC_STATUS_SHIFT);
/*
* Status bits are cleared by writing 1. In order to prevent the unmask
* operation from clearing the status bits, they should be under the
* mask and written with 0.
*/
regmap_update_bits(scu_ic->scu, scu_ic->reg, mask, bit);
}
static int aspeed_scu_ic_irq_set_affinity(struct irq_data *data,
const struct cpumask *dest,
bool force)
{
return -EINVAL;
}
static struct irq_chip aspeed_scu_ic_chip = {
.name = "aspeed-scu-ic",
.irq_mask = aspeed_scu_ic_irq_mask,
.irq_unmask = aspeed_scu_ic_irq_unmask,
.irq_set_affinity = aspeed_scu_ic_irq_set_affinity,
};
static int aspeed_scu_ic_map(struct irq_domain *domain, unsigned int irq,
irq_hw_number_t hwirq)
{
irq_set_chip_and_handler(irq, &aspeed_scu_ic_chip, handle_level_irq);
irq_set_chip_data(irq, domain->host_data);
return 0;
}
static const struct irq_domain_ops aspeed_scu_ic_domain_ops = {
.map = aspeed_scu_ic_map,
};
static int aspeed_scu_ic_of_init_common(struct aspeed_scu_ic *scu_ic,
struct device_node *node)
{
int irq;
int rc = 0;
if (!node->parent) {
rc = -ENODEV;
goto err;
}
scu_ic->scu = syscon_node_to_regmap(node->parent);
if (IS_ERR(scu_ic->scu)) {
rc = PTR_ERR(scu_ic->scu);
goto err;
}
regmap_write_bits(scu_ic->scu, scu_ic->reg, ASPEED_SCU_IC_STATUS, ASPEED_SCU_IC_STATUS);
regmap_write_bits(scu_ic->scu, scu_ic->reg, ASPEED_SCU_IC_ENABLE, 0);
irq = irq_of_parse_and_map(node, 0);
if (!irq) {
rc = -EINVAL;
goto err;
}
scu_ic->irq_domain = irq_domain_add_linear(node, scu_ic->num_irqs,
&aspeed_scu_ic_domain_ops,
scu_ic);
if (!scu_ic->irq_domain) {
rc = -ENOMEM;
goto err;
}
irq_set_chained_handler_and_data(irq, aspeed_scu_ic_irq_handler,
scu_ic);
return 0;
err:
kfree(scu_ic);
return rc;
}
static int __init aspeed_scu_ic_of_init(struct device_node *node,
struct device_node *parent)
{
struct aspeed_scu_ic *scu_ic = kzalloc(sizeof(*scu_ic), GFP_KERNEL);
if (!scu_ic)
return -ENOMEM;
scu_ic->irq_enable = ASPEED_SCU_IC_ENABLE;
scu_ic->irq_shift = ASPEED_SCU_IC_SHIFT;
scu_ic->num_irqs = ASPEED_SCU_IC_NUM_IRQS;
scu_ic->reg = ASPEED_SCU_IC_REG;
return aspeed_scu_ic_of_init_common(scu_ic, node);
}
static int __init aspeed_ast2600_scu_ic0_of_init(struct device_node *node,
struct device_node *parent)
{
struct aspeed_scu_ic *scu_ic = kzalloc(sizeof(*scu_ic), GFP_KERNEL);
if (!scu_ic)
return -ENOMEM;
scu_ic->irq_enable = ASPEED_AST2600_SCU_IC0_ENABLE;
scu_ic->irq_shift = ASPEED_AST2600_SCU_IC0_SHIFT;
scu_ic->num_irqs = ASPEED_AST2600_SCU_IC0_NUM_IRQS;
scu_ic->reg = ASPEED_AST2600_SCU_IC0_REG;
return aspeed_scu_ic_of_init_common(scu_ic, node);
}
static int __init aspeed_ast2600_scu_ic1_of_init(struct device_node *node,
struct device_node *parent)
{
struct aspeed_scu_ic *scu_ic = kzalloc(sizeof(*scu_ic), GFP_KERNEL);
if (!scu_ic)
return -ENOMEM;
scu_ic->irq_enable = ASPEED_AST2600_SCU_IC1_ENABLE;
scu_ic->irq_shift = ASPEED_AST2600_SCU_IC1_SHIFT;
scu_ic->num_irqs = ASPEED_AST2600_SCU_IC1_NUM_IRQS;
scu_ic->reg = ASPEED_AST2600_SCU_IC1_REG;
return aspeed_scu_ic_of_init_common(scu_ic, node);
}
IRQCHIP_DECLARE(ast2400_scu_ic, "aspeed,ast2400-scu-ic", aspeed_scu_ic_of_init);
IRQCHIP_DECLARE(ast2500_scu_ic, "aspeed,ast2500-scu-ic", aspeed_scu_ic_of_init);
IRQCHIP_DECLARE(ast2600_scu_ic0, "aspeed,ast2600-scu-ic0",
aspeed_ast2600_scu_ic0_of_init);
IRQCHIP_DECLARE(ast2600_scu_ic1, "aspeed,ast2600-scu-ic1",
aspeed_ast2600_scu_ic1_of_init);
