LXR linux/arch/mips/pci/msi-octeon.c

   1/*
   2 * This file is subject to the terms and conditions of the GNU General Public
   3 * License.  See the file "COPYING" in the main directory of this archive
   4 * for more details.
   5 *
   6 * Copyright (C) 2005-2009, 2010 Cavium Networks
   7 */
   8#include <linux/kernel.h>
   9#include <linux/init.h>
  10#include <linux/msi.h>
  11#include <linux/spinlock.h>
  12#include <linux/interrupt.h>
  13
  14#include <asm/octeon/octeon.h>
  15#include <asm/octeon/cvmx-npi-defs.h>
  16#include <asm/octeon/cvmx-pci-defs.h>
  17#include <asm/octeon/cvmx-npei-defs.h>
  18#include <asm/octeon/cvmx-pexp-defs.h>
  19#include <asm/octeon/pci-octeon.h>
  20
  21/*
  22 * Each bit in msi_free_irq_bitmask represents a MSI interrupt that is
  23 * in use.
  24 */
  25static u64 msi_free_irq_bitmask[4];
  26
  27/*
  28 * Each bit in msi_multiple_irq_bitmask tells that the device using
  29 * this bit in msi_free_irq_bitmask is also using the next bit. This
  30 * is used so we can disable all of the MSI interrupts when a device
  31 * uses multiple.
  32 */
  33static u64 msi_multiple_irq_bitmask[4];
  34
  35/*
  36 * This lock controls updates to msi_free_irq_bitmask and
  37 * msi_multiple_irq_bitmask.
  38 */
  39static DEFINE_SPINLOCK(msi_free_irq_bitmask_lock);
  40
  41/*
  42 * Number of MSI IRQs used. This variable is set up in
  43 * the module init time.
  44 */
  45static int msi_irq_size;
  46
  47/**
  48 * Called when a driver request MSI interrupts instead of the
  49 * legacy INT A-D. This routine will allocate multiple interrupts
  50 * for MSI devices that support them. A device can override this by
  51 * programming the MSI control bits [6:4] before calling
  52 * pci_enable_msi().
  53 *
  54 * @dev:    Device requesting MSI interrupts
  55 * @desc:   MSI descriptor
  56 *
  57 * Returns 0 on success.
  58 */
  59int arch_setup_msi_irq(struct pci_dev *dev, struct msi_desc *desc)
  60{
  61        struct msi_msg msg;
  62        u16 control;
  63        int configured_private_bits;
  64        int request_private_bits;
  65        int irq = 0;
  66        int irq_step;
  67        u64 search_mask;
  68        int index;
  69
  70        /*
  71         * Read the MSI config to figure out how many IRQs this device
  72         * wants.  Most devices only want 1, which will give
  73         * configured_private_bits and request_private_bits equal 0.
  74         */
  75        pci_read_config_word(dev, desc->msi_attrib.pos + PCI_MSI_FLAGS,
  76                             &control);
  77
  78        /*
  79         * If the number of private bits has been configured then use
  80         * that value instead of the requested number. This gives the
  81         * driver the chance to override the number of interrupts
  82         * before calling pci_enable_msi().
  83         */
  84        configured_private_bits = (control & PCI_MSI_FLAGS_QSIZE) >> 4;
  85        if (configured_private_bits == 0) {
  86                /* Nothing is configured, so use the hardware requested size */
  87                request_private_bits = (control & PCI_MSI_FLAGS_QMASK) >> 1;
  88        } else {
  89                /*
  90                 * Use the number of configured bits, assuming the
  91                 * driver wanted to override the hardware request
  92                 * value.
  93                 */
  94                request_private_bits = configured_private_bits;
  95        }
  96
  97        /*
  98         * The PCI 2.3 spec mandates that there are at most 32
  99         * interrupts. If this device asks for more, only give it one.
 100         */
 101        if (request_private_bits > 5)
 102                request_private_bits = 0;
 103
 104try_only_one:
 105        /*
 106         * The IRQs have to be aligned on a power of two based on the
 107         * number being requested.
 108         */
 109        irq_step = 1 << request_private_bits;
 110
 111        /* Mask with one bit for each IRQ */
 112        search_mask = (1 << irq_step) - 1;
 113
 114        /*
 115         * We're going to search msi_free_irq_bitmask_lock for zero
 116         * bits. This represents an MSI interrupt number that isn't in
 117         * use.
 118         */
 119        spin_lock(&msi_free_irq_bitmask_lock);
 120        for (index = 0; index < msi_irq_size/64; index++) {
 121                for (irq = 0; irq < 64; irq += irq_step) {
 122                        if ((msi_free_irq_bitmask[index] & (search_mask << irq)) == 0) {
 123                                msi_free_irq_bitmask[index] |= search_mask << irq;
 124                                msi_multiple_irq_bitmask[index] |= (search_mask >> 1) << irq;
 125                                goto msi_irq_allocated;
 126                        }
 127                }
 128        }
 129msi_irq_allocated:
 130        spin_unlock(&msi_free_irq_bitmask_lock);
 131
 132        /* Make sure the search for available interrupts didn't fail */
 133        if (irq >= 64) {
 134                if (request_private_bits) {
 135                        pr_err("arch_setup_msi_irq: Unable to find %d free interrupts, trying just one",
 136                               1 << request_private_bits);
 137                        request_private_bits = 0;
 138                        goto try_only_one;
 139                } else
 140                        panic("arch_setup_msi_irq: Unable to find a free MSI interrupt");
 141        }
 142
 143        /* MSI interrupts start at logical IRQ OCTEON_IRQ_MSI_BIT0 */
 144        irq += index*64;
 145        irq += OCTEON_IRQ_MSI_BIT0;
 146
 147        switch (octeon_dma_bar_type) {
 148        case OCTEON_DMA_BAR_TYPE_SMALL:
 149                /* When not using big bar, Bar 0 is based at 128MB */
 150                msg.address_lo =
 151                        ((128ul << 20) + CVMX_PCI_MSI_RCV) & 0xffffffff;
 152                msg.address_hi = ((128ul << 20) + CVMX_PCI_MSI_RCV) >> 32;
 153        case OCTEON_DMA_BAR_TYPE_BIG:
 154                /* When using big bar, Bar 0 is based at 0 */
 155                msg.address_lo = (0 + CVMX_PCI_MSI_RCV) & 0xffffffff;
 156                msg.address_hi = (0 + CVMX_PCI_MSI_RCV) >> 32;
 157                break;
 158        case OCTEON_DMA_BAR_TYPE_PCIE:
 159                /* When using PCIe, Bar 0 is based at 0 */
 160                /* FIXME CVMX_NPEI_MSI_RCV* other than 0? */
 161                msg.address_lo = (0 + CVMX_NPEI_PCIE_MSI_RCV) & 0xffffffff;
 162                msg.address_hi = (0 + CVMX_NPEI_PCIE_MSI_RCV) >> 32;
 163                break;
 164        default:
 165                panic("arch_setup_msi_irq: Invalid octeon_dma_bar_type");
 166        }
 167        msg.data = irq - OCTEON_IRQ_MSI_BIT0;
 168
 169        /* Update the number of IRQs the device has available to it */
 170        control &= ~PCI_MSI_FLAGS_QSIZE;
 171        control |= request_private_bits << 4;
 172        pci_write_config_word(dev, desc->msi_attrib.pos + PCI_MSI_FLAGS,
 173                              control);
 174
 175        irq_set_msi_desc(irq, desc);
 176        write_msi_msg(irq, &msg);
 177        return 0;
 178}
 179
 180int arch_setup_msi_irqs(struct pci_dev *dev, int nvec, int type)
 181{
 182        struct msi_desc *entry;
 183        int ret;
 184
 185        /*
 186         * MSI-X is not supported.
 187         */
 188        if (type == PCI_CAP_ID_MSIX)
 189                return -EINVAL;
 190
 191        /*
 192         * If an architecture wants to support multiple MSI, it needs to
 193         * override arch_setup_msi_irqs()
 194         */
 195        if (type == PCI_CAP_ID_MSI && nvec > 1)
 196                return 1;
 197
 198        list_for_each_entry(entry, &dev->msi_list, list) {
 199                ret = arch_setup_msi_irq(dev, entry);
 200                if (ret < 0)
 201                        return ret;
 202                if (ret > 0)
 203                        return -ENOSPC;
 204        }
 205
 206        return 0;
 207}
 208
 209/**
 210 * Called when a device no longer needs its MSI interrupts. All
 211 * MSI interrupts for the device are freed.
 212 *
 213 * @irq:    The devices first irq number. There may be multple in sequence.
 214 */
 215void arch_teardown_msi_irq(unsigned int irq)
 216{
 217        int number_irqs;
 218        u64 bitmask;
 219        int index = 0;
 220        int irq0;
 221
 222        if ((irq < OCTEON_IRQ_MSI_BIT0)
 223                || (irq > msi_irq_size + OCTEON_IRQ_MSI_BIT0))
 224                panic("arch_teardown_msi_irq: Attempted to teardown illegal "
 225                      "MSI interrupt (%d)", irq);
 226
 227        irq -= OCTEON_IRQ_MSI_BIT0;
 228        index = irq / 64;
 229        irq0 = irq % 64;
 230
 231        /*
 232         * Count the number of IRQs we need to free by looking at the
 233         * msi_multiple_irq_bitmask. Each bit set means that the next
 234         * IRQ is also owned by this device.
 235         */
 236        number_irqs = 0;
 237        while ((irq0 + number_irqs < 64) &&
 238               (msi_multiple_irq_bitmask[index]
 239                & (1ull << (irq0 + number_irqs))))
 240                number_irqs++;
 241        number_irqs++;
 242        /* Mask with one bit for each IRQ */
 243        bitmask = (1 << number_irqs) - 1;
 244        /* Shift the mask to the correct bit location */
 245        bitmask <<= irq0;
 246        if ((msi_free_irq_bitmask[index] & bitmask) != bitmask)
 247                panic("arch_teardown_msi_irq: Attempted to teardown MSI "
 248                      "interrupt (%d) not in use", irq);
 249
 250        /* Checks are done, update the in use bitmask */
 251        spin_lock(&msi_free_irq_bitmask_lock);
 252        msi_free_irq_bitmask[index] &= ~bitmask;
 253        msi_multiple_irq_bitmask[index] &= ~bitmask;
 254        spin_unlock(&msi_free_irq_bitmask_lock);
 255}
 256
 257static DEFINE_RAW_SPINLOCK(octeon_irq_msi_lock);
 258
 259static u64 msi_rcv_reg[4];
 260static u64 mis_ena_reg[4];
 261
 262static void octeon_irq_msi_enable_pcie(struct irq_data *data)
 263{
 264        u64 en;
 265        unsigned long flags;
 266        int msi_number = data->irq - OCTEON_IRQ_MSI_BIT0;
 267        int irq_index = msi_number >> 6;
 268        int irq_bit = msi_number & 0x3f;
 269
 270        raw_spin_lock_irqsave(&octeon_irq_msi_lock, flags);
 271        en = cvmx_read_csr(mis_ena_reg[irq_index]);
 272        en |= 1ull << irq_bit;
 273        cvmx_write_csr(mis_ena_reg[irq_index], en);
 274        cvmx_read_csr(mis_ena_reg[irq_index]);
 275        raw_spin_unlock_irqrestore(&octeon_irq_msi_lock, flags);
 276}
 277
 278static void octeon_irq_msi_disable_pcie(struct irq_data *data)
 279{
 280        u64 en;
 281        unsigned long flags;
 282        int msi_number = data->irq - OCTEON_IRQ_MSI_BIT0;
 283        int irq_index = msi_number >> 6;
 284        int irq_bit = msi_number & 0x3f;
 285
 286        raw_spin_lock_irqsave(&octeon_irq_msi_lock, flags);
 287        en = cvmx_read_csr(mis_ena_reg[irq_index]);
 288        en &= ~(1ull << irq_bit);
 289        cvmx_write_csr(mis_ena_reg[irq_index], en);
 290        cvmx_read_csr(mis_ena_reg[irq_index]);
 291        raw_spin_unlock_irqrestore(&octeon_irq_msi_lock, flags);
 292}
 293
 294static struct irq_chip octeon_irq_chip_msi_pcie = {
 295        .name = "MSI",
 296        .irq_enable = octeon_irq_msi_enable_pcie,
 297        .irq_disable = octeon_irq_msi_disable_pcie,
 298};
 299
 300static void octeon_irq_msi_enable_pci(struct irq_data *data)
 301{
 302        /*
 303         * Octeon PCI doesn't have the ability to mask/unmask MSI
 304         * interrupts individually. Instead of masking/unmasking them
 305         * in groups of 16, we simple assume MSI devices are well
 306         * behaved. MSI interrupts are always enable and the ACK is
 307         * assumed to be enough
 308         */
 309}
 310
 311static void octeon_irq_msi_disable_pci(struct irq_data *data)
 312{
 313        /* See comment in enable */
 314}
 315
 316static struct irq_chip octeon_irq_chip_msi_pci = {
 317        .name = "MSI",
 318        .irq_enable = octeon_irq_msi_enable_pci,
 319        .irq_disable = octeon_irq_msi_disable_pci,
 320};
 321
 322/*
 323 * Called by the interrupt handling code when an MSI interrupt
 324 * occurs.
 325 */
 326static irqreturn_t __octeon_msi_do_interrupt(int index, u64 msi_bits)
 327{
 328        int irq;
 329        int bit;
 330
 331        bit = fls64(msi_bits);
 332        if (bit) {
 333                bit--;
 334                /* Acknowledge it first. */
 335                cvmx_write_csr(msi_rcv_reg[index], 1ull << bit);
 336
 337                irq = bit + OCTEON_IRQ_MSI_BIT0 + 64 * index;
 338                do_IRQ(irq);
 339                return IRQ_HANDLED;
 340        }
 341        return IRQ_NONE;
 342}
 343
 344#define OCTEON_MSI_INT_HANDLER_X(x)                                     \
 345static irqreturn_t octeon_msi_interrupt##x(int cpl, void *dev_id)       \
 346{                                                                       \
 347        u64 msi_bits = cvmx_read_csr(msi_rcv_reg[(x)]);                 \
 348        return __octeon_msi_do_interrupt((x), msi_bits);                \
 349}
 350
 351/*
 352 * Create octeon_msi_interrupt{0-3} function body
 353 */
 354OCTEON_MSI_INT_HANDLER_X(0);
 355OCTEON_MSI_INT_HANDLER_X(1);
 356OCTEON_MSI_INT_HANDLER_X(2);
 357OCTEON_MSI_INT_HANDLER_X(3);
 358
 359/*
 360 * Initializes the MSI interrupt handling code
 361 */
 362int __init octeon_msi_initialize(void)
 363{
 364        int irq;
 365        struct irq_chip *msi;
 366
 367        if (octeon_dma_bar_type == OCTEON_DMA_BAR_TYPE_PCIE) {
 368                msi_rcv_reg[0] = CVMX_PEXP_NPEI_MSI_RCV0;
 369                msi_rcv_reg[1] = CVMX_PEXP_NPEI_MSI_RCV1;
 370                msi_rcv_reg[2] = CVMX_PEXP_NPEI_MSI_RCV2;
 371                msi_rcv_reg[3] = CVMX_PEXP_NPEI_MSI_RCV3;
 372                mis_ena_reg[0] = CVMX_PEXP_NPEI_MSI_ENB0;
 373                mis_ena_reg[1] = CVMX_PEXP_NPEI_MSI_ENB1;
 374                mis_ena_reg[2] = CVMX_PEXP_NPEI_MSI_ENB2;
 375                mis_ena_reg[3] = CVMX_PEXP_NPEI_MSI_ENB3;
 376                msi = &octeon_irq_chip_msi_pcie;
 377        } else {
 378                msi_rcv_reg[0] = CVMX_NPI_NPI_MSI_RCV;
 379#define INVALID_GENERATE_ADE 0x8700000000000000ULL;
 380                msi_rcv_reg[1] = INVALID_GENERATE_ADE;
 381                msi_rcv_reg[2] = INVALID_GENERATE_ADE;
 382                msi_rcv_reg[3] = INVALID_GENERATE_ADE;
 383                mis_ena_reg[0] = INVALID_GENERATE_ADE;
 384                mis_ena_reg[1] = INVALID_GENERATE_ADE;
 385                mis_ena_reg[2] = INVALID_GENERATE_ADE;
 386                mis_ena_reg[3] = INVALID_GENERATE_ADE;
 387                msi = &octeon_irq_chip_msi_pci;
 388        }
 389
 390        for (irq = OCTEON_IRQ_MSI_BIT0; irq <= OCTEON_IRQ_MSI_LAST; irq++)
 391                irq_set_chip_and_handler(irq, msi, handle_simple_irq);
 392
 393        if (octeon_has_feature(OCTEON_FEATURE_PCIE)) {
 394                if (request_irq(OCTEON_IRQ_PCI_MSI0, octeon_msi_interrupt0,
 395                                0, "MSI[0:63]", octeon_msi_interrupt0))
 396                        panic("request_irq(OCTEON_IRQ_PCI_MSI0) failed");
 397
 398                if (request_irq(OCTEON_IRQ_PCI_MSI1, octeon_msi_interrupt1,
 399                                0, "MSI[64:127]", octeon_msi_interrupt1))
 400                        panic("request_irq(OCTEON_IRQ_PCI_MSI1) failed");
 401
 402                if (request_irq(OCTEON_IRQ_PCI_MSI2, octeon_msi_interrupt2,
 403                                0, "MSI[127:191]", octeon_msi_interrupt2))
 404                        panic("request_irq(OCTEON_IRQ_PCI_MSI2) failed");
 405
 406                if (request_irq(OCTEON_IRQ_PCI_MSI3, octeon_msi_interrupt3,
 407                                0, "MSI[192:255]", octeon_msi_interrupt3))
 408                        panic("request_irq(OCTEON_IRQ_PCI_MSI3) failed");
 409
 410                msi_irq_size = 256;
 411        } else if (octeon_is_pci_host()) {
 412                if (request_irq(OCTEON_IRQ_PCI_MSI0, octeon_msi_interrupt0,
 413                                0, "MSI[0:15]", octeon_msi_interrupt0))
 414                        panic("request_irq(OCTEON_IRQ_PCI_MSI0) failed");
 415
 416                if (request_irq(OCTEON_IRQ_PCI_MSI1, octeon_msi_interrupt0,
 417                                0, "MSI[16:31]", octeon_msi_interrupt0))
 418                        panic("request_irq(OCTEON_IRQ_PCI_MSI1) failed");
 419
 420                if (request_irq(OCTEON_IRQ_PCI_MSI2, octeon_msi_interrupt0,
 421                                0, "MSI[32:47]", octeon_msi_interrupt0))
 422                        panic("request_irq(OCTEON_IRQ_PCI_MSI2) failed");
 423
 424                if (request_irq(OCTEON_IRQ_PCI_MSI3, octeon_msi_interrupt0,
 425                                0, "MSI[48:63]", octeon_msi_interrupt0))
 426                        panic("request_irq(OCTEON_IRQ_PCI_MSI3) failed");
 427                msi_irq_size = 64;
 428        }
 429        return 0;
 430}
 431subsys_initcall(octeon_msi_initialize);
 432