summaryrefslogtreecommitdiffstats
path: root/arch/arm/plat-samsung/irq-uart.c
blob: 4d4e571af5530dfd8ff5d72ef74be8d25b8a9b55 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
/* arch/arm/plat-samsung/irq-uart.c
 *	originally part of arch/arm/plat-s3c64xx/irq.c
 *
 * Copyright 2008 Openmoko, Inc.
 * Copyright 2008 Simtec Electronics
 *      Ben Dooks <ben@simtec.co.uk>
 *      http://armlinux.simtec.co.uk/
 *
 * Samsung- UART Interrupt handling
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#include <linux/kernel.h>
#include <linux/interrupt.h>
#include <linux/serial_core.h>
#include <linux/irq.h>
#include <linux/io.h>

#include <mach/map.h>
#include <plat/irq-uart.h>
#include <plat/regs-serial.h>
#include <plat/cpu.h>

/* Note, we make use of the fact that the parent IRQs, IRQ_UART[0..3]
 * are consecutive when looking up the interrupt in the demux routines.
 */

static inline void __iomem *s3c_irq_uart_base(struct irq_data *data)
{
	struct s3c_uart_irq *uirq = irq_data_get_irq_chip_data(data);
	return uirq->regs;
}

static inline unsigned int s3c_irq_uart_bit(unsigned int irq)
{
	return irq & 3;
}

static void s3c_irq_uart_mask(struct irq_data *data)
{
	void __iomem *regs = s3c_irq_uart_base(data);
	unsigned int bit = s3c_irq_uart_bit(data->irq);
	u32 reg;

	reg = __raw_readl(regs + S3C64XX_UINTM);
	reg |= (1 << bit);
	__raw_writel(reg, regs + S3C64XX_UINTM);
}

static void s3c_irq_uart_maskack(struct irq_data *data)
{
	void __iomem *regs = s3c_irq_uart_base(data);
	unsigned int bit = s3c_irq_uart_bit(data->irq);
	u32 reg;

	reg = __raw_readl(regs + S3C64XX_UINTM);
	reg |= (1 << bit);
	__raw_writel(reg, regs + S3C64XX_UINTM);
	__raw_writel(1 << bit, regs + S3C64XX_UINTP);
}

static void s3c_irq_uart_unmask(struct irq_data *data)
{
	void __iomem *regs = s3c_irq_uart_base(data);
	unsigned int bit = s3c_irq_uart_bit(data->irq);
	u32 reg;

	reg = __raw_readl(regs + S3C64XX_UINTM);
	reg &= ~(1 << bit);
	__raw_writel(reg, regs + S3C64XX_UINTM);
}

static void s3c_irq_uart_ack(struct irq_data *data)
{
	void __iomem *regs = s3c_irq_uart_base(data);
	unsigned int bit = s3c_irq_uart_bit(data->irq);

	__raw_writel(1 << bit, regs + S3C64XX_UINTP);
}

static void s3c_irq_demux_uart(unsigned int irq, struct irq_desc *desc)
{
	struct s3c_uart_irq *uirq = desc->irq_data.handler_data;
	u32 pend = __raw_readl(uirq->regs + S3C64XX_UINTP);
	int base = uirq->base_irq;

	if (pend & (1 << 0))
		generic_handle_irq(base);
	if (pend & (1 << 1))
		generic_handle_irq(base + 1);
	if (pend & (1 << 2))
		generic_handle_irq(base + 2);
	if (pend & (1 << 3))
		generic_handle_irq(base + 3);
}

static struct irq_chip s3c_irq_uart = {
	.name		= "s3c-uart",
	.irq_mask	= s3c_irq_uart_mask,
	.irq_unmask	= s3c_irq_uart_unmask,
	.irq_mask_ack	= s3c_irq_uart_maskack,
	.irq_ack	= s3c_irq_uart_ack,
};

static void __init s3c_init_uart_irq(struct s3c_uart_irq *uirq)
{
	void __iomem *reg_base = uirq->regs;
	unsigned int irq;
	int offs;

	/* mask all interrupts at the start. */
	__raw_writel(0xf, reg_base + S3C64XX_UINTM);

	for (offs = 0; offs < 3; offs++) {
		irq = uirq->base_irq + offs;

		irq_set_chip_and_handler(irq, &s3c_irq_uart, handle_level_irq);
		irq_set_chip_data(irq, uirq);
		set_irq_flags(irq, IRQF_VALID);
	}

	irq_set_handler_data(uirq->parent_irq, uirq);
	irq_set_chained_handler(uirq->parent_irq, s3c_irq_demux_uart);
}

/**
 * s3c_init_uart_irqs() - initialise UART IRQs and the necessary demuxing
 * @irq: The interrupt data for registering
 * @nr_irqs: The number of interrupt descriptions in @irq.
 *
 * Register the UART interrupts specified by @irq including the demuxing
 * routines. This supports the S3C6400 and newer style of devices.
 */
void __init s3c_init_uart_irqs(struct s3c_uart_irq *irq, unsigned int nr_irqs)
{
	for (; nr_irqs > 0; nr_irqs--, irq++)
		s3c_init_uart_irq(irq);
}