xref: /openbmc/linux/arch/mips/alchemy/devboards/bcsr.c (revision 0da85d1e)
1 /*
2  * bcsr.h -- Db1xxx/Pb1xxx Devboard CPLD registers ("BCSR") abstraction.
3  *
4  * All Alchemy development boards (except, of course, the weird PB1000)
5  * have a few registers in a CPLD with standardised layout; they mostly
6  * only differ in base address.
7  * All registers are 16bits wide with 32bit spacing.
8  */
9 
10 #include <linux/interrupt.h>
11 #include <linux/module.h>
12 #include <linux/spinlock.h>
13 #include <linux/irq.h>
14 #include <asm/addrspace.h>
15 #include <asm/io.h>
16 #include <asm/mach-db1x00/bcsr.h>
17 
18 static struct bcsr_reg {
19 	void __iomem *raddr;
20 	spinlock_t lock;
21 } bcsr_regs[BCSR_CNT];
22 
23 static void __iomem *bcsr_virt; /* KSEG1 addr of BCSR base */
24 static int bcsr_csc_base;	/* linux-irq of first cascaded irq */
25 
26 void __init bcsr_init(unsigned long bcsr1_phys, unsigned long bcsr2_phys)
27 {
28 	int i;
29 
30 	bcsr1_phys = KSEG1ADDR(CPHYSADDR(bcsr1_phys));
31 	bcsr2_phys = KSEG1ADDR(CPHYSADDR(bcsr2_phys));
32 
33 	bcsr_virt = (void __iomem *)bcsr1_phys;
34 
35 	for (i = 0; i < BCSR_CNT; i++) {
36 		if (i >= BCSR_HEXLEDS)
37 			bcsr_regs[i].raddr = (void __iomem *)bcsr2_phys +
38 					(0x04 * (i - BCSR_HEXLEDS));
39 		else
40 			bcsr_regs[i].raddr = (void __iomem *)bcsr1_phys +
41 					(0x04 * i);
42 
43 		spin_lock_init(&bcsr_regs[i].lock);
44 	}
45 }
46 
47 unsigned short bcsr_read(enum bcsr_id reg)
48 {
49 	unsigned short r;
50 	unsigned long flags;
51 
52 	spin_lock_irqsave(&bcsr_regs[reg].lock, flags);
53 	r = __raw_readw(bcsr_regs[reg].raddr);
54 	spin_unlock_irqrestore(&bcsr_regs[reg].lock, flags);
55 	return r;
56 }
57 EXPORT_SYMBOL_GPL(bcsr_read);
58 
59 void bcsr_write(enum bcsr_id reg, unsigned short val)
60 {
61 	unsigned long flags;
62 
63 	spin_lock_irqsave(&bcsr_regs[reg].lock, flags);
64 	__raw_writew(val, bcsr_regs[reg].raddr);
65 	wmb();
66 	spin_unlock_irqrestore(&bcsr_regs[reg].lock, flags);
67 }
68 EXPORT_SYMBOL_GPL(bcsr_write);
69 
70 void bcsr_mod(enum bcsr_id reg, unsigned short clr, unsigned short set)
71 {
72 	unsigned short r;
73 	unsigned long flags;
74 
75 	spin_lock_irqsave(&bcsr_regs[reg].lock, flags);
76 	r = __raw_readw(bcsr_regs[reg].raddr);
77 	r &= ~clr;
78 	r |= set;
79 	__raw_writew(r, bcsr_regs[reg].raddr);
80 	wmb();
81 	spin_unlock_irqrestore(&bcsr_regs[reg].lock, flags);
82 }
83 EXPORT_SYMBOL_GPL(bcsr_mod);
84 
85 /*
86  * DB1200/PB1200 CPLD IRQ muxer
87  */
88 static void bcsr_csc_handler(unsigned int irq, struct irq_desc *d)
89 {
90 	unsigned short bisr = __raw_readw(bcsr_virt + BCSR_REG_INTSTAT);
91 
92 	disable_irq_nosync(irq);
93 	generic_handle_irq(bcsr_csc_base + __ffs(bisr));
94 	enable_irq(irq);
95 }
96 
97 static void bcsr_irq_mask(struct irq_data *d)
98 {
99 	unsigned short v = 1 << (d->irq - bcsr_csc_base);
100 	__raw_writew(v, bcsr_virt + BCSR_REG_MASKCLR);
101 	wmb();
102 }
103 
104 static void bcsr_irq_maskack(struct irq_data *d)
105 {
106 	unsigned short v = 1 << (d->irq - bcsr_csc_base);
107 	__raw_writew(v, bcsr_virt + BCSR_REG_MASKCLR);
108 	__raw_writew(v, bcsr_virt + BCSR_REG_INTSTAT);	/* ack */
109 	wmb();
110 }
111 
112 static void bcsr_irq_unmask(struct irq_data *d)
113 {
114 	unsigned short v = 1 << (d->irq - bcsr_csc_base);
115 	__raw_writew(v, bcsr_virt + BCSR_REG_MASKSET);
116 	wmb();
117 }
118 
119 static struct irq_chip bcsr_irq_type = {
120 	.name		= "CPLD",
121 	.irq_mask	= bcsr_irq_mask,
122 	.irq_mask_ack	= bcsr_irq_maskack,
123 	.irq_unmask	= bcsr_irq_unmask,
124 };
125 
126 void __init bcsr_init_irq(int csc_start, int csc_end, int hook_irq)
127 {
128 	unsigned int irq;
129 
130 	/* mask & enable & ack all */
131 	__raw_writew(0xffff, bcsr_virt + BCSR_REG_MASKCLR);
132 	__raw_writew(0xffff, bcsr_virt + BCSR_REG_INTSET);
133 	__raw_writew(0xffff, bcsr_virt + BCSR_REG_INTSTAT);
134 	wmb();
135 
136 	bcsr_csc_base = csc_start;
137 
138 	for (irq = csc_start; irq <= csc_end; irq++)
139 		irq_set_chip_and_handler_name(irq, &bcsr_irq_type,
140 					      handle_level_irq, "level");
141 
142 	irq_set_chained_handler(hook_irq, bcsr_csc_handler);
143 }
144