arch/mips/alchemy/devboards/bcsr.c

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