bcsr.c

  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
 21static struct bcsr_reg {
 22	void __iomem *raddr;
 23	spinlock_t lock;
 24} bcsr_regs[BCSR_CNT];
 25
 26static void __iomem *bcsr_virt; /* KSEG1 addr of BCSR base */
 27static int bcsr_csc_base;	/* linux-irq of first cascaded irq */
 28
 29void __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
 50unsigned 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}
 60EXPORT_SYMBOL_GPL(bcsr_read);
 61
 62void 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}
 71EXPORT_SYMBOL_GPL(bcsr_write);
 72
 73void 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}
 86EXPORT_SYMBOL_GPL(bcsr_mod);
 87
 88/*
 89 * DB1200/PB1200 CPLD IRQ muxer
 90 */
 91static 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
101static 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
108static 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
116static 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
123static 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
130void __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}