arch/mips/alchemy/devboards/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
  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 }