xref: /linux/arch/mips/alchemy/devboards/bcsr.c (revision c532de5a67a70f8533d495f8f2aaa9a0491c3ad0)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * bcsr.h -- Db1xxx/Pb1xxx Devboard CPLD registers ("BCSR") abstraction.
4  *
5  * All Alchemy development boards (except, of course, the weird PB1000)
6  * have a few registers in a CPLD with standardised layout; they mostly
7  * only differ in base address.
8  * All registers are 16bits wide with 32bit spacing.
9  */
10 
11 #include <linux/interrupt.h>
12 #include <linux/irqchip/chained_irq.h>
13 #include <linux/init.h>
14 #include <linux/export.h>
15 #include <linux/spinlock.h>
16 #include <linux/irq.h>
17 #include <asm/addrspace.h>
18 #include <asm/io.h>
19 #include <asm/mach-db1x00/bcsr.h>
20 
21 static struct bcsr_reg {
22 	void __iomem *raddr;
23 	spinlock_t lock;
24 } bcsr_regs[BCSR_CNT];
25 
26 static void __iomem *bcsr_virt; /* KSEG1 addr of BCSR base */
27 static int bcsr_csc_base;	/* linux-irq of first cascaded irq */
28 
29 void __init bcsr_init(unsigned long bcsr1_phys, unsigned long bcsr2_phys)
30 {
31 	int i;
32 
33 	bcsr1_phys = KSEG1ADDR(CPHYSADDR(bcsr1_phys));
34 	bcsr2_phys = KSEG1ADDR(CPHYSADDR(bcsr2_phys));
35 
36 	bcsr_virt = (void __iomem *)bcsr1_phys;
37 
38 	for (i = 0; i < BCSR_CNT; i++) {
39 		if (i >= BCSR_HEXLEDS)
40 			bcsr_regs[i].raddr = (void __iomem *)bcsr2_phys +
41 					(0x04 * (i - BCSR_HEXLEDS));
42 		else
43 			bcsr_regs[i].raddr = (void __iomem *)bcsr1_phys +
44 					(0x04 * i);
45 
46 		spin_lock_init(&bcsr_regs[i].lock);
47 	}
48 }
49 
50 unsigned short bcsr_read(enum bcsr_id reg)
51 {
52 	unsigned short r;
53 	unsigned long flags;
54 
55 	spin_lock_irqsave(&bcsr_regs[reg].lock, flags);
56 	r = __raw_readw(bcsr_regs[reg].raddr);
57 	spin_unlock_irqrestore(&bcsr_regs[reg].lock, flags);
58 	return r;
59 }
60 EXPORT_SYMBOL_GPL(bcsr_read);
61 
62 void bcsr_write(enum bcsr_id reg, unsigned short val)
63 {
64 	unsigned long flags;
65 
66 	spin_lock_irqsave(&bcsr_regs[reg].lock, flags);
67 	__raw_writew(val, bcsr_regs[reg].raddr);
68 	wmb();
69 	spin_unlock_irqrestore(&bcsr_regs[reg].lock, flags);
70 }
71 EXPORT_SYMBOL_GPL(bcsr_write);
72 
73 void bcsr_mod(enum bcsr_id reg, unsigned short clr, unsigned short set)
74 {
75 	unsigned short r;
76 	unsigned long flags;
77 
78 	spin_lock_irqsave(&bcsr_regs[reg].lock, flags);
79 	r = __raw_readw(bcsr_regs[reg].raddr);
80 	r &= ~clr;
81 	r |= set;
82 	__raw_writew(r, bcsr_regs[reg].raddr);
83 	wmb();
84 	spin_unlock_irqrestore(&bcsr_regs[reg].lock, flags);
85 }
86 EXPORT_SYMBOL_GPL(bcsr_mod);
87 
88 /*
89  * DB1200/PB1200 CPLD IRQ muxer
90  */
91 static void bcsr_csc_handler(struct irq_desc *d)
92 {
93 	unsigned short bisr = __raw_readw(bcsr_virt + BCSR_REG_INTSTAT);
94 	struct irq_chip *chip = irq_desc_get_chip(d);
95 
96 	chained_irq_enter(chip, d);
97 	generic_handle_irq(bcsr_csc_base + __ffs(bisr));
98 	chained_irq_exit(chip, d);
99 }
100 
101 static void bcsr_irq_mask(struct irq_data *d)
102 {
103 	unsigned short v = 1 << (d->irq - bcsr_csc_base);
104 	__raw_writew(v, bcsr_virt + BCSR_REG_MASKCLR);
105 	wmb();
106 }
107 
108 static void bcsr_irq_maskack(struct irq_data *d)
109 {
110 	unsigned short v = 1 << (d->irq - bcsr_csc_base);
111 	__raw_writew(v, bcsr_virt + BCSR_REG_MASKCLR);
112 	__raw_writew(v, bcsr_virt + BCSR_REG_INTSTAT);	/* ack */
113 	wmb();
114 }
115 
116 static void bcsr_irq_unmask(struct irq_data *d)
117 {
118 	unsigned short v = 1 << (d->irq - bcsr_csc_base);
119 	__raw_writew(v, bcsr_virt + BCSR_REG_MASKSET);
120 	wmb();
121 }
122 
123 static struct irq_chip bcsr_irq_type = {
124 	.name		= "CPLD",
125 	.irq_mask	= bcsr_irq_mask,
126 	.irq_mask_ack	= bcsr_irq_maskack,
127 	.irq_unmask	= bcsr_irq_unmask,
128 };
129 
130 void __init bcsr_init_irq(int csc_start, int csc_end, int hook_irq)
131 {
132 	unsigned int irq;
133 
134 	/* mask & enable & ack all */
135 	__raw_writew(0xffff, bcsr_virt + BCSR_REG_MASKCLR);
136 	__raw_writew(0xffff, bcsr_virt + BCSR_REG_INTSET);
137 	__raw_writew(0xffff, bcsr_virt + BCSR_REG_INTSTAT);
138 	wmb();
139 
140 	bcsr_csc_base = csc_start;
141 
142 	for (irq = csc_start; irq <= csc_end; irq++)
143 		irq_set_chip_and_handler_name(irq, &bcsr_irq_type,
144 					      handle_level_irq, "level");
145 
146 	irq_set_chained_handler(hook_irq, bcsr_csc_handler);
147 }
148