arch/powerpc/platforms/85xx/socrates_fpga_pic.c

   1 /*
   2  *  Copyright (C) 2008 Ilya Yanok, Emcraft Systems
   3  *
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License version 2 as
   7  * published by the Free Software Foundation.
   8  *
   9  */
  10
  11 #include <linux/irq.h>
  12 #include <linux/of_platform.h>
  13 #include <linux/io.h>
  14
  15 /*
  16  * The FPGA supports 9 interrupt sources, which can be routed to 3
  17  * interrupt request lines of the MPIC. The line to be used can be
  18  * specified through the third cell of FDT property  "interrupts".
  19  */
  20
  21 #define SOCRATES_FPGA_NUM_IRQS  9
  22
  23 #define FPGA_PIC_IRQCFG         (0x0)
  24 #define FPGA_PIC_IRQMASK(n)     (0x4 + 0x4 * (n))
  25
  26 #define SOCRATES_FPGA_IRQ_MASK  ((1 << SOCRATES_FPGA_NUM_IRQS) - 1)
  27
  28 struct socrates_fpga_irq_info {
  29         unsigned int irq_line;
  30         int type;
  31 };
  32
  33 /*
  34  * Interrupt routing and type table
  35  *
  36  * IRQ_TYPE_NONE means the interrupt type is configurable,
  37  * otherwise it's fixed to the specified value.
  38  */
  39 static struct socrates_fpga_irq_info fpga_irqs[SOCRATES_FPGA_NUM_IRQS] = {
  40         [0] = {0, IRQ_TYPE_NONE},
  41         [1] = {0, IRQ_TYPE_LEVEL_HIGH},
  42         [2] = {0, IRQ_TYPE_LEVEL_LOW},
  43         [3] = {0, IRQ_TYPE_NONE},
  44         [4] = {0, IRQ_TYPE_NONE},
  45         [5] = {0, IRQ_TYPE_NONE},
  46         [6] = {0, IRQ_TYPE_NONE},
  47         [7] = {0, IRQ_TYPE_NONE},
  48         [8] = {0, IRQ_TYPE_LEVEL_HIGH},
  49 };
  50
  51 static DEFINE_RAW_SPINLOCK(socrates_fpga_pic_lock);
  52
  53 static void __iomem *socrates_fpga_pic_iobase;
  54 static struct irq_domain *socrates_fpga_pic_irq_host;
  55 static unsigned int socrates_fpga_irqs[3];
  56
  57 static inline uint32_t socrates_fpga_pic_read(int reg)
  58 {
  59         return in_be32(socrates_fpga_pic_iobase + reg);
  60 }
  61
  62 static inline void socrates_fpga_pic_write(int reg, uint32_t val)
  63 {
  64         out_be32(socrates_fpga_pic_iobase + reg, val);
  65 }
  66
  67 static inline unsigned int socrates_fpga_pic_get_irq(unsigned int irq)
  68 {
  69         uint32_t cause;
  70         unsigned long flags;
  71         int i;
  72
  73         /* Check irq line routed to the MPIC */
  74         for (i = 0; i < 3; i++) {
  75                 if (irq == socrates_fpga_irqs[i])
  76                         break;
  77         }
  78         if (i == 3)
  79                 return NO_IRQ;
  80
  81         raw_spin_lock_irqsave(&socrates_fpga_pic_lock, flags);
  82         cause = socrates_fpga_pic_read(FPGA_PIC_IRQMASK(i));
  83         raw_spin_unlock_irqrestore(&socrates_fpga_pic_lock, flags);
  84         for (i = SOCRATES_FPGA_NUM_IRQS - 1; i >= 0; i--) {
  85                 if (cause >> (i + 16))
  86                         break;
  87         }
  88         return irq_linear_revmap(socrates_fpga_pic_irq_host,
  89                         (irq_hw_number_t)i);
  90 }
  91
  92 void socrates_fpga_pic_cascade(unsigned int irq, struct irq_desc *desc)
  93 {
  94         struct irq_chip *chip = irq_desc_get_chip(desc);
  95         unsigned int cascade_irq;
  96
  97         /*
  98          * See if we actually have an interrupt, call generic handling code if
  99          * we do.
 100          */
 101         cascade_irq = socrates_fpga_pic_get_irq(irq);
 102
 103         if (cascade_irq != NO_IRQ)
 104                 generic_handle_irq(cascade_irq);
 105         chip->irq_eoi(&desc->irq_data);
 106 }
 107
 108 static void socrates_fpga_pic_ack(struct irq_data *d)
 109 {
 110         unsigned long flags;
 111         unsigned int irq_line, hwirq = irqd_to_hwirq(d);
 112         uint32_t mask;
 113
 114         irq_line = fpga_irqs[hwirq].irq_line;
 115         raw_spin_lock_irqsave(&socrates_fpga_pic_lock, flags);
 116         mask = socrates_fpga_pic_read(FPGA_PIC_IRQMASK(irq_line))
 117                 & SOCRATES_FPGA_IRQ_MASK;
 118         mask |= (1 << (hwirq + 16));
 119         socrates_fpga_pic_write(FPGA_PIC_IRQMASK(irq_line), mask);
 120         raw_spin_unlock_irqrestore(&socrates_fpga_pic_lock, flags);
 121 }
 122
 123 static void socrates_fpga_pic_mask(struct irq_data *d)
 124 {
 125         unsigned long flags;
 126         unsigned int hwirq = irqd_to_hwirq(d);
 127         int irq_line;
 128         u32 mask;
 129
 130         irq_line = fpga_irqs[hwirq].irq_line;
 131         raw_spin_lock_irqsave(&socrates_fpga_pic_lock, flags);
 132         mask = socrates_fpga_pic_read(FPGA_PIC_IRQMASK(irq_line))
 133                 & SOCRATES_FPGA_IRQ_MASK;
 134         mask &= ~(1 << hwirq);
 135         socrates_fpga_pic_write(FPGA_PIC_IRQMASK(irq_line), mask);
 136         raw_spin_unlock_irqrestore(&socrates_fpga_pic_lock, flags);
 137 }
 138
 139 static void socrates_fpga_pic_mask_ack(struct irq_data *d)
 140 {
 141         unsigned long flags;
 142         unsigned int hwirq = irqd_to_hwirq(d);
 143         int irq_line;
 144         u32 mask;
 145
 146         irq_line = fpga_irqs[hwirq].irq_line;
 147         raw_spin_lock_irqsave(&socrates_fpga_pic_lock, flags);
 148         mask = socrates_fpga_pic_read(FPGA_PIC_IRQMASK(irq_line))
 149                 & SOCRATES_FPGA_IRQ_MASK;
 150         mask &= ~(1 << hwirq);
 151         mask |= (1 << (hwirq + 16));
 152         socrates_fpga_pic_write(FPGA_PIC_IRQMASK(irq_line), mask);
 153         raw_spin_unlock_irqrestore(&socrates_fpga_pic_lock, flags);
 154 }
 155
 156 static void socrates_fpga_pic_unmask(struct irq_data *d)
 157 {
 158         unsigned long flags;
 159         unsigned int hwirq = irqd_to_hwirq(d);
 160         int irq_line;
 161         u32 mask;
 162
 163         irq_line = fpga_irqs[hwirq].irq_line;
 164         raw_spin_lock_irqsave(&socrates_fpga_pic_lock, flags);
 165         mask = socrates_fpga_pic_read(FPGA_PIC_IRQMASK(irq_line))
 166                 & SOCRATES_FPGA_IRQ_MASK;
 167         mask |= (1 << hwirq);
 168         socrates_fpga_pic_write(FPGA_PIC_IRQMASK(irq_line), mask);
 169         raw_spin_unlock_irqrestore(&socrates_fpga_pic_lock, flags);
 170 }
 171
 172 static void socrates_fpga_pic_eoi(struct irq_data *d)
 173 {
 174         unsigned long flags;
 175         unsigned int hwirq = irqd_to_hwirq(d);
 176         int irq_line;
 177         u32 mask;
 178
 179         irq_line = fpga_irqs[hwirq].irq_line;
 180         raw_spin_lock_irqsave(&socrates_fpga_pic_lock, flags);
 181         mask = socrates_fpga_pic_read(FPGA_PIC_IRQMASK(irq_line))
 182                 & SOCRATES_FPGA_IRQ_MASK;
 183         mask |= (1 << (hwirq + 16));
 184         socrates_fpga_pic_write(FPGA_PIC_IRQMASK(irq_line), mask);
 185         raw_spin_unlock_irqrestore(&socrates_fpga_pic_lock, flags);
 186 }
 187
 188 static int socrates_fpga_pic_set_type(struct irq_data *d,
 189                 unsigned int flow_type)
 190 {
 191         unsigned long flags;
 192         unsigned int hwirq = irqd_to_hwirq(d);
 193         int polarity;
 194         u32 mask;
 195
 196         if (fpga_irqs[hwirq].type != IRQ_TYPE_NONE)
 197                 return -EINVAL;
 198
 199         switch (flow_type & IRQ_TYPE_SENSE_MASK) {
 200         case IRQ_TYPE_LEVEL_HIGH:
 201                 polarity = 1;
 202                 break;
 203         case IRQ_TYPE_LEVEL_LOW:
 204                 polarity = 0;
 205                 break;
 206         default:
 207                 return -EINVAL;
 208         }
 209         raw_spin_lock_irqsave(&socrates_fpga_pic_lock, flags);
 210         mask = socrates_fpga_pic_read(FPGA_PIC_IRQCFG);
 211         if (polarity)
 212                 mask |= (1 << hwirq);
 213         else
 214                 mask &= ~(1 << hwirq);
 215         socrates_fpga_pic_write(FPGA_PIC_IRQCFG, mask);
 216         raw_spin_unlock_irqrestore(&socrates_fpga_pic_lock, flags);
 217         return 0;
 218 }
 219
 220 static struct irq_chip socrates_fpga_pic_chip = {
 221         .name           = "FPGA-PIC",
 222         .irq_ack        = socrates_fpga_pic_ack,
 223         .irq_mask       = socrates_fpga_pic_mask,
 224         .irq_mask_ack   = socrates_fpga_pic_mask_ack,
 225         .irq_unmask     = socrates_fpga_pic_unmask,
 226         .irq_eoi        = socrates_fpga_pic_eoi,
 227         .irq_set_type   = socrates_fpga_pic_set_type,
 228 };
 229
 230 static int socrates_fpga_pic_host_map(struct irq_domain *h, unsigned int virq,
 231                 irq_hw_number_t hwirq)
 232 {
 233         /* All interrupts are LEVEL sensitive */
 234         irq_set_status_flags(virq, IRQ_LEVEL);
 235         irq_set_chip_and_handler(virq, &socrates_fpga_pic_chip,
 236                                  handle_fasteoi_irq);
 237
 238         return 0;
 239 }
 240
 241 static int socrates_fpga_pic_host_xlate(struct irq_domain *h,
 242                 struct device_node *ct, const u32 *intspec, unsigned int intsize,
 243                 irq_hw_number_t *out_hwirq, unsigned int *out_flags)
 244 {
 245         struct socrates_fpga_irq_info *fpga_irq = &fpga_irqs[intspec[0]];
 246
 247         *out_hwirq = intspec[0];
 248         if  (fpga_irq->type == IRQ_TYPE_NONE) {
 249                 /* type is configurable */
 250                 if (intspec[1] != IRQ_TYPE_LEVEL_LOW &&
 251                     intspec[1] != IRQ_TYPE_LEVEL_HIGH) {
 252                         pr_warning("FPGA PIC: invalid irq type, "
 253                                    "setting default active low\n");
 254                         *out_flags = IRQ_TYPE_LEVEL_LOW;
 255                 } else {
 256                         *out_flags = intspec[1];
 257                 }
 258         } else {
 259                 /* type is fixed */
 260                 *out_flags = fpga_irq->type;
 261         }
 262
 263         /* Use specified interrupt routing */
 264         if (intspec[2] <= 2)
 265                 fpga_irq->irq_line = intspec[2];
 266         else
 267                 pr_warning("FPGA PIC: invalid irq routing\n");
 268
 269         return 0;
 270 }
 271
 272 static const struct irq_domain_ops socrates_fpga_pic_host_ops = {
 273         .map    = socrates_fpga_pic_host_map,
 274         .xlate  = socrates_fpga_pic_host_xlate,
 275 };
 276
 277 void socrates_fpga_pic_init(struct device_node *pic)
 278 {
 279         unsigned long flags;
 280         int i;
 281
 282         /* Setup an irq_domain structure */
 283         socrates_fpga_pic_irq_host = irq_domain_add_linear(pic,
 284                     SOCRATES_FPGA_NUM_IRQS, &socrates_fpga_pic_host_ops, NULL);
 285         if (socrates_fpga_pic_irq_host == NULL) {
 286                 pr_err("FPGA PIC: Unable to allocate host\n");
 287                 return;
 288         }
 289
 290         for (i = 0; i < 3; i++) {
 291                 socrates_fpga_irqs[i] = irq_of_parse_and_map(pic, i);
 292                 if (socrates_fpga_irqs[i] == NO_IRQ) {
 293                         pr_warning("FPGA PIC: can't get irq%d.\n", i);
 294                         continue;
 295                 }
 296                 irq_set_chained_handler(socrates_fpga_irqs[i],
 297                                         socrates_fpga_pic_cascade);
 298         }
 299
 300         socrates_fpga_pic_iobase = of_iomap(pic, 0);
 301
 302         raw_spin_lock_irqsave(&socrates_fpga_pic_lock, flags);
 303         socrates_fpga_pic_write(FPGA_PIC_IRQMASK(0),
 304                         SOCRATES_FPGA_IRQ_MASK << 16);
 305         socrates_fpga_pic_write(FPGA_PIC_IRQMASK(1),
 306                         SOCRATES_FPGA_IRQ_MASK << 16);
 307         socrates_fpga_pic_write(FPGA_PIC_IRQMASK(2),
 308                         SOCRATES_FPGA_IRQ_MASK << 16);
 309         raw_spin_unlock_irqrestore(&socrates_fpga_pic_lock, flags);
 310
 311         pr_info("FPGA PIC: Setting up Socrates FPGA PIC\n");
 312 }