Linux 2.6.20.9

[linux/fpc-iii.git] / arch / x86_64 / kernel / pci-calgary.c

/*
 * Derived from arch/powerpc/kernel/iommu.c
 *
 * Copyright (C) IBM Corporation, 2006
 * Copyright (C) 2006  Jon Mason <jdmason@kudzu.us>
 *
 * Author: Jon Mason <jdmason@kudzu.us>
 * Author: Muli Ben-Yehuda <muli@il.ibm.com>

 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
 */

#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/types.h>
#include <linux/slab.h>
#include <linux/mm.h>
#include <linux/spinlock.h>
#include <linux/string.h>
#include <linux/dma-mapping.h>
#include <linux/init.h>
#include <linux/bitops.h>
#include <linux/pci_ids.h>
#include <linux/pci.h>
#include <linux/delay.h>
#include <asm/proto.h>
#include <asm/calgary.h>
#include <asm/tce.h>
#include <asm/pci-direct.h>
#include <asm/system.h>
#include <asm/dma.h>
#include <asm/rio.h>

#ifdef CONFIG_CALGARY_IOMMU_ENABLED_BY_DEFAULT
int use_calgary __read_mostly = 1;
#else
int use_calgary __read_mostly = 0;
#endif /* CONFIG_CALGARY_DEFAULT_ENABLED */

#define PCI_DEVICE_ID_IBM_CALGARY 0x02a1
#define PCI_VENDOR_DEVICE_ID_CALGARY \
        (PCI_VENDOR_ID_IBM | PCI_DEVICE_ID_IBM_CALGARY << 16)

/* we need these for register space address calculation */
#define START_ADDRESS           0xfe000000
#define CHASSIS_BASE            0
#define ONE_BASED_CHASSIS_NUM   1

/* register offsets inside the host bridge space */
#define CALGARY_CONFIG_REG      0x0108
#define PHB_CSR_OFFSET          0x0110 /* Channel Status */
#define PHB_PLSSR_OFFSET        0x0120
#define PHB_CONFIG_RW_OFFSET    0x0160
#define PHB_IOBASE_BAR_LOW      0x0170
#define PHB_IOBASE_BAR_HIGH     0x0180
#define PHB_MEM_1_LOW           0x0190
#define PHB_MEM_1_HIGH          0x01A0
#define PHB_IO_ADDR_SIZE        0x01B0
#define PHB_MEM_1_SIZE          0x01C0
#define PHB_MEM_ST_OFFSET       0x01D0
#define PHB_AER_OFFSET          0x0200
#define PHB_CONFIG_0_HIGH       0x0220
#define PHB_CONFIG_0_LOW        0x0230
#define PHB_CONFIG_0_END        0x0240
#define PHB_MEM_2_LOW           0x02B0
#define PHB_MEM_2_HIGH          0x02C0
#define PHB_MEM_2_SIZE_HIGH     0x02D0
#define PHB_MEM_2_SIZE_LOW      0x02E0
#define PHB_DOSHOLE_OFFSET      0x08E0

/* PHB_CONFIG_RW */
#define PHB_TCE_ENABLE          0x20000000
#define PHB_SLOT_DISABLE        0x1C000000
#define PHB_DAC_DISABLE         0x01000000
#define PHB_MEM2_ENABLE         0x00400000
#define PHB_MCSR_ENABLE         0x00100000
/* TAR (Table Address Register) */
#define TAR_SW_BITS             0x0000ffffffff800fUL
#define TAR_VALID               0x0000000000000008UL
/* CSR (Channel/DMA Status Register) */
#define CSR_AGENT_MASK          0xffe0ffff
/* CCR (Calgary Configuration Register) */
#define CCR_2SEC_TIMEOUT        0x000000000000000EUL

#define MAX_NUM_OF_PHBS         8 /* how many PHBs in total? */
#define MAX_NUM_CHASSIS         8 /* max number of chassis */
/* MAX_PHB_BUS_NUM is the maximal possible dev->bus->number */
#define MAX_PHB_BUS_NUM         (MAX_NUM_OF_PHBS * MAX_NUM_CHASSIS * 2)
#define PHBS_PER_CALGARY        4

/* register offsets in Calgary's internal register space */
static const unsigned long tar_offsets[] = {
        0x0580 /* TAR0 */,
        0x0588 /* TAR1 */,
        0x0590 /* TAR2 */,
        0x0598 /* TAR3 */
};

static const unsigned long split_queue_offsets[] = {
        0x4870 /* SPLIT QUEUE 0 */,
        0x5870 /* SPLIT QUEUE 1 */,
        0x6870 /* SPLIT QUEUE 2 */,
        0x7870 /* SPLIT QUEUE 3 */
};

static const unsigned long phb_offsets[] = {
        0x8000 /* PHB0 */,
        0x9000 /* PHB1 */,
        0xA000 /* PHB2 */,
        0xB000 /* PHB3 */
};

/* PHB debug registers */

static const unsigned long phb_debug_offsets[] = {
        0x4000  /* PHB 0 DEBUG */,
        0x5000  /* PHB 1 DEBUG */,
        0x6000  /* PHB 2 DEBUG */,
        0x7000  /* PHB 3 DEBUG */
};

/*
 * STUFF register for each debug PHB,
 * byte 1 = start bus number, byte 2 = end bus number
 */

#define PHB_DEBUG_STUFF_OFFSET  0x0020

unsigned int specified_table_size = TCE_TABLE_SIZE_UNSPECIFIED;
static int translate_empty_slots __read_mostly = 0;
static int calgary_detected __read_mostly = 0;

static struct rio_table_hdr     *rio_table_hdr __initdata;
static struct scal_detail       *scal_devs[MAX_NUMNODES] __initdata;
static struct rio_detail        *rio_devs[MAX_NUMNODES * 4] __initdata;

struct calgary_bus_info {
        void *tce_space;
        unsigned char translation_disabled;
        signed char phbid;
        void __iomem *bbar;
};

static struct calgary_bus_info bus_info[MAX_PHB_BUS_NUM] = { { NULL, 0, 0 }, };

static void tce_cache_blast(struct iommu_table *tbl);

/* enable this to stress test the chip's TCE cache */
#ifdef CONFIG_IOMMU_DEBUG
int debugging __read_mostly = 1;

static inline unsigned long verify_bit_range(unsigned long* bitmap,
        int expected, unsigned long start, unsigned long end)
{
        unsigned long idx = start;

        BUG_ON(start >= end);

        while (idx < end) {
                if (!!test_bit(idx, bitmap) != expected)
                        return idx;
                ++idx;
        }

        /* all bits have the expected value */
        return ~0UL;
}
#else /* debugging is disabled */
int debugging __read_mostly = 0;

static inline unsigned long verify_bit_range(unsigned long* bitmap,
        int expected, unsigned long start, unsigned long end)
{
        return ~0UL;
}
#endif /* CONFIG_IOMMU_DEBUG */

static inline unsigned int num_dma_pages(unsigned long dma, unsigned int dmalen)
{
        unsigned int npages;

        npages = PAGE_ALIGN(dma + dmalen) - (dma & PAGE_MASK);
        npages >>= PAGE_SHIFT;

        return npages;
}

static inline int translate_phb(struct pci_dev* dev)
{
        int disabled = bus_info[dev->bus->number].translation_disabled;
        return !disabled;
}

static void iommu_range_reserve(struct iommu_table *tbl,
        unsigned long start_addr, unsigned int npages)
{
        unsigned long index;
        unsigned long end;
        unsigned long badbit;

        index = start_addr >> PAGE_SHIFT;

        /* bail out if we're asked to reserve a region we don't cover */
        if (index >= tbl->it_size)
                return;

        end = index + npages;
        if (end > tbl->it_size) /* don't go off the table */
                end = tbl->it_size;

        badbit = verify_bit_range(tbl->it_map, 0, index, end);
        if (badbit != ~0UL) {
                if (printk_ratelimit())
                        printk(KERN_ERR "Calgary: entry already allocated at "
                               "0x%lx tbl %p dma 0x%lx npages %u\n",
                               badbit, tbl, start_addr, npages);
        }

        set_bit_string(tbl->it_map, index, npages);
}

static unsigned long iommu_range_alloc(struct iommu_table *tbl,
        unsigned int npages)
{
        unsigned long offset;

        BUG_ON(npages == 0);

        offset = find_next_zero_string(tbl->it_map, tbl->it_hint,
                                       tbl->it_size, npages);
        if (offset == ~0UL) {
                tce_cache_blast(tbl);
                offset = find_next_zero_string(tbl->it_map, 0,
                                               tbl->it_size, npages);
                if (offset == ~0UL) {
                        printk(KERN_WARNING "Calgary: IOMMU full.\n");
                        if (panic_on_overflow)
                                panic("Calgary: fix the allocator.\n");
                        else
                                return bad_dma_address;
                }
        }

        set_bit_string(tbl->it_map, offset, npages);
        tbl->it_hint = offset + npages;
        BUG_ON(tbl->it_hint > tbl->it_size);

        return offset;
}

static dma_addr_t iommu_alloc(struct iommu_table *tbl, void *vaddr,
        unsigned int npages, int direction)
{
        unsigned long entry, flags;
        dma_addr_t ret = bad_dma_address;

        spin_lock_irqsave(&tbl->it_lock, flags);

        entry = iommu_range_alloc(tbl, npages);

        if (unlikely(entry == bad_dma_address))
                goto error;

        /* set the return dma address */
        ret = (entry << PAGE_SHIFT) | ((unsigned long)vaddr & ~PAGE_MASK);

        /* put the TCEs in the HW table */
        tce_build(tbl, entry, npages, (unsigned long)vaddr & PAGE_MASK,
                  direction);

        spin_unlock_irqrestore(&tbl->it_lock, flags);

        return ret;

error:
        spin_unlock_irqrestore(&tbl->it_lock, flags);
        printk(KERN_WARNING "Calgary: failed to allocate %u pages in "
               "iommu %p\n", npages, tbl);
        return bad_dma_address;
}

static void __iommu_free(struct iommu_table *tbl, dma_addr_t dma_addr,
        unsigned int npages)
{
        unsigned long entry;
        unsigned long badbit;

        entry = dma_addr >> PAGE_SHIFT;

        BUG_ON(entry + npages > tbl->it_size);

        tce_free(tbl, entry, npages);

        badbit = verify_bit_range(tbl->it_map, 1, entry, entry + npages);
        if (badbit != ~0UL) {
                if (printk_ratelimit())
                        printk(KERN_ERR "Calgary: bit is off at 0x%lx "
                               "tbl %p dma 0x%Lx entry 0x%lx npages %u\n",
                               badbit, tbl, dma_addr, entry, npages);
        }

        __clear_bit_string(tbl->it_map, entry, npages);
}

static void iommu_free(struct iommu_table *tbl, dma_addr_t dma_addr,
        unsigned int npages)
{
        unsigned long flags;

        spin_lock_irqsave(&tbl->it_lock, flags);

        __iommu_free(tbl, dma_addr, npages);

        spin_unlock_irqrestore(&tbl->it_lock, flags);
}

static void __calgary_unmap_sg(struct iommu_table *tbl,
        struct scatterlist *sglist, int nelems, int direction)
{
        while (nelems--) {
                unsigned int npages;
                dma_addr_t dma = sglist->dma_address;
                unsigned int dmalen = sglist->dma_length;

                if (dmalen == 0)
                        break;

                npages = num_dma_pages(dma, dmalen);
                __iommu_free(tbl, dma, npages);
                sglist++;
        }
}

void calgary_unmap_sg(struct device *dev, struct scatterlist *sglist,
                      int nelems, int direction)
{
        unsigned long flags;
        struct iommu_table *tbl = to_pci_dev(dev)->bus->self->sysdata;

        if (!translate_phb(to_pci_dev(dev)))
                return;

        spin_lock_irqsave(&tbl->it_lock, flags);

        __calgary_unmap_sg(tbl, sglist, nelems, direction);

        spin_unlock_irqrestore(&tbl->it_lock, flags);
}

static int calgary_nontranslate_map_sg(struct device* dev,
        struct scatterlist *sg, int nelems, int direction)
{
        int i;

        for (i = 0; i < nelems; i++ ) {
                struct scatterlist *s = &sg[i];
                BUG_ON(!s->page);
                s->dma_address = virt_to_bus(page_address(s->page) +s->offset);
                s->dma_length = s->length;
        }
        return nelems;
}

int calgary_map_sg(struct device *dev, struct scatterlist *sg,
        int nelems, int direction)
{
        struct iommu_table *tbl = to_pci_dev(dev)->bus->self->sysdata;
        unsigned long flags;
        unsigned long vaddr;
        unsigned int npages;
        unsigned long entry;
        int i;

        if (!translate_phb(to_pci_dev(dev)))
                return calgary_nontranslate_map_sg(dev, sg, nelems, direction);

        spin_lock_irqsave(&tbl->it_lock, flags);

        for (i = 0; i < nelems; i++ ) {
                struct scatterlist *s = &sg[i];
                BUG_ON(!s->page);

                vaddr = (unsigned long)page_address(s->page) + s->offset;
                npages = num_dma_pages(vaddr, s->length);

                entry = iommu_range_alloc(tbl, npages);
                if (entry == bad_dma_address) {
                        /* makes sure unmap knows to stop */
                        s->dma_length = 0;
                        goto error;
                }

                s->dma_address = (entry << PAGE_SHIFT) | s->offset;

                /* insert into HW table */
                tce_build(tbl, entry, npages, vaddr & PAGE_MASK,
                          direction);

                s->dma_length = s->length;
        }

        spin_unlock_irqrestore(&tbl->it_lock, flags);

        return nelems;
error:
        __calgary_unmap_sg(tbl, sg, nelems, direction);
        for (i = 0; i < nelems; i++) {
                sg[i].dma_address = bad_dma_address;
                sg[i].dma_length = 0;
        }
        spin_unlock_irqrestore(&tbl->it_lock, flags);
        return 0;
}

dma_addr_t calgary_map_single(struct device *dev, void *vaddr,
        size_t size, int direction)
{
        dma_addr_t dma_handle = bad_dma_address;
        unsigned long uaddr;
        unsigned int npages;
        struct iommu_table *tbl = to_pci_dev(dev)->bus->self->sysdata;

        uaddr = (unsigned long)vaddr;
        npages = num_dma_pages(uaddr, size);

        if (translate_phb(to_pci_dev(dev)))
                dma_handle = iommu_alloc(tbl, vaddr, npages, direction);
        else
                dma_handle = virt_to_bus(vaddr);

        return dma_handle;
}

void calgary_unmap_single(struct device *dev, dma_addr_t dma_handle,
        size_t size, int direction)
{
        struct iommu_table *tbl = to_pci_dev(dev)->bus->self->sysdata;
        unsigned int npages;

        if (!translate_phb(to_pci_dev(dev)))
                return;

        npages = num_dma_pages(dma_handle, size);
        iommu_free(tbl, dma_handle, npages);
}

void* calgary_alloc_coherent(struct device *dev, size_t size,
        dma_addr_t *dma_handle, gfp_t flag)
{
        void *ret = NULL;
        dma_addr_t mapping;
        unsigned int npages, order;
        struct iommu_table *tbl;

        tbl = to_pci_dev(dev)->bus->self->sysdata;

        size = PAGE_ALIGN(size); /* size rounded up to full pages */
        npages = size >> PAGE_SHIFT;
        order = get_order(size);

        /* alloc enough pages (and possibly more) */
        ret = (void *)__get_free_pages(flag, order);
        if (!ret)
                goto error;
        memset(ret, 0, size);

        if (translate_phb(to_pci_dev(dev))) {
                /* set up tces to cover the allocated range */
                mapping = iommu_alloc(tbl, ret, npages, DMA_BIDIRECTIONAL);
                if (mapping == bad_dma_address)
                        goto free;

                *dma_handle = mapping;
        } else /* non translated slot */
                *dma_handle = virt_to_bus(ret);

        return ret;

free:
        free_pages((unsigned long)ret, get_order(size));
        ret = NULL;
error:
        return ret;
}

static struct dma_mapping_ops calgary_dma_ops = {
        .alloc_coherent = calgary_alloc_coherent,
        .map_single = calgary_map_single,
        .unmap_single = calgary_unmap_single,
        .map_sg = calgary_map_sg,
        .unmap_sg = calgary_unmap_sg,
};

static inline void __iomem * busno_to_bbar(unsigned char num)
{
        return bus_info[num].bbar;
}

static inline int busno_to_phbid(unsigned char num)
{
        return bus_info[num].phbid;
}

static inline unsigned long split_queue_offset(unsigned char num)
{
        size_t idx = busno_to_phbid(num);

        return split_queue_offsets[idx];
}

static inline unsigned long tar_offset(unsigned char num)
{
        size_t idx = busno_to_phbid(num);

        return tar_offsets[idx];
}

static inline unsigned long phb_offset(unsigned char num)
{
        size_t idx = busno_to_phbid(num);

        return phb_offsets[idx];
}

static inline void __iomem* calgary_reg(void __iomem *bar, unsigned long offset)
{
        unsigned long target = ((unsigned long)bar) | offset;
        return (void __iomem*)target;
}

static void tce_cache_blast(struct iommu_table *tbl)
{
        u64 val;
        u32 aer;
        int i = 0;
        void __iomem *bbar = tbl->bbar;
        void __iomem *target;

        /* disable arbitration on the bus */
        target = calgary_reg(bbar, phb_offset(tbl->it_busno) | PHB_AER_OFFSET);
        aer = readl(target);
        writel(0, target);

        /* read plssr to ensure it got there */
        target = calgary_reg(bbar, phb_offset(tbl->it_busno) | PHB_PLSSR_OFFSET);
        val = readl(target);

        /* poll split queues until all DMA activity is done */
        target = calgary_reg(bbar, split_queue_offset(tbl->it_busno));
        do {
                val = readq(target);
                i++;
        } while ((val & 0xff) != 0xff && i < 100);
        if (i == 100)
                printk(KERN_WARNING "Calgary: PCI bus not quiesced, "
                       "continuing anyway\n");

        /* invalidate TCE cache */
        target = calgary_reg(bbar, tar_offset(tbl->it_busno));
        writeq(tbl->tar_val, target);

        /* enable arbitration */
        target = calgary_reg(bbar, phb_offset(tbl->it_busno) | PHB_AER_OFFSET);
        writel(aer, target);
        (void)readl(target); /* flush */
}

static void __init calgary_reserve_mem_region(struct pci_dev *dev, u64 start,
        u64 limit)
{
        unsigned int numpages;

        limit = limit | 0xfffff;
        limit++;

        numpages = ((limit - start) >> PAGE_SHIFT);
        iommu_range_reserve(dev->sysdata, start, numpages);
}

static void __init calgary_reserve_peripheral_mem_1(struct pci_dev *dev)
{
        void __iomem *target;
        u64 low, high, sizelow;
        u64 start, limit;
        struct iommu_table *tbl = dev->sysdata;
        unsigned char busnum = dev->bus->number;
        void __iomem *bbar = tbl->bbar;

        /* peripheral MEM_1 region */
        target = calgary_reg(bbar, phb_offset(busnum) | PHB_MEM_1_LOW);
        low = be32_to_cpu(readl(target));
        target = calgary_reg(bbar, phb_offset(busnum) | PHB_MEM_1_HIGH);
        high = be32_to_cpu(readl(target));
        target = calgary_reg(bbar, phb_offset(busnum) | PHB_MEM_1_SIZE);
        sizelow = be32_to_cpu(readl(target));

        start = (high << 32) | low;
        limit = sizelow;

        calgary_reserve_mem_region(dev, start, limit);
}

static void __init calgary_reserve_peripheral_mem_2(struct pci_dev *dev)
{
        void __iomem *target;
        u32 val32;
        u64 low, high, sizelow, sizehigh;
        u64 start, limit;
        struct iommu_table *tbl = dev->sysdata;
        unsigned char busnum = dev->bus->number;
        void __iomem *bbar = tbl->bbar;

        /* is it enabled? */
        target = calgary_reg(bbar, phb_offset(busnum) | PHB_CONFIG_RW_OFFSET);
        val32 = be32_to_cpu(readl(target));
        if (!(val32 & PHB_MEM2_ENABLE))
                return;

        target = calgary_reg(bbar, phb_offset(busnum) | PHB_MEM_2_LOW);
        low = be32_to_cpu(readl(target));
        target = calgary_reg(bbar, phb_offset(busnum) | PHB_MEM_2_HIGH);
        high = be32_to_cpu(readl(target));
        target = calgary_reg(bbar, phb_offset(busnum) | PHB_MEM_2_SIZE_LOW);
        sizelow = be32_to_cpu(readl(target));
        target = calgary_reg(bbar, phb_offset(busnum) | PHB_MEM_2_SIZE_HIGH);
        sizehigh = be32_to_cpu(readl(target));

        start = (high << 32) | low;
        limit = (sizehigh << 32) | sizelow;

        calgary_reserve_mem_region(dev, start, limit);
}

/*
 * some regions of the IO address space do not get translated, so we
 * must not give devices IO addresses in those regions. The regions
 * are the 640KB-1MB region and the two PCI peripheral memory holes.
 * Reserve all of them in the IOMMU bitmap to avoid giving them out
 * later.
 */
static void __init calgary_reserve_regions(struct pci_dev *dev)
{
        unsigned int npages;
        u64 start;
        struct iommu_table *tbl = dev->sysdata;

        /* reserve bad_dma_address in case it's a legal address */
        iommu_range_reserve(tbl, bad_dma_address, 1);

        /* avoid the BIOS/VGA first 640KB-1MB region */
        start = (640 * 1024);
        npages = ((1024 - 640) * 1024) >> PAGE_SHIFT;
        iommu_range_reserve(tbl, start, npages);

        /* reserve the two PCI peripheral memory regions in IO space */
        calgary_reserve_peripheral_mem_1(dev);
        calgary_reserve_peripheral_mem_2(dev);
}

static int __init calgary_setup_tar(struct pci_dev *dev, void __iomem *bbar)
{
        u64 val64;
        u64 table_phys;
        void __iomem *target;
        int ret;
        struct iommu_table *tbl;

        /* build TCE tables for each PHB */
        ret = build_tce_table(dev, bbar);
        if (ret)
                return ret;

        tbl = dev->sysdata;
        tbl->it_base = (unsigned long)bus_info[dev->bus->number].tce_space;
        tce_free(tbl, 0, tbl->it_size);

        calgary_reserve_regions(dev);

        /* set TARs for each PHB */
        target = calgary_reg(bbar, tar_offset(dev->bus->number));
        val64 = be64_to_cpu(readq(target));

        /* zero out all TAR bits under sw control */
        val64 &= ~TAR_SW_BITS;

        tbl = dev->sysdata;
        table_phys = (u64)__pa(tbl->it_base);
        val64 |= table_phys;

        BUG_ON(specified_table_size > TCE_TABLE_SIZE_8M);
        val64 |= (u64) specified_table_size;

        tbl->tar_val = cpu_to_be64(val64);
        writeq(tbl->tar_val, target);
        readq(target); /* flush */

        return 0;
}

static void __init calgary_free_bus(struct pci_dev *dev)
{
        u64 val64;
        struct iommu_table *tbl = dev->sysdata;
        void __iomem *target;
        unsigned int bitmapsz;

        target = calgary_reg(tbl->bbar, tar_offset(dev->bus->number));
        val64 = be64_to_cpu(readq(target));
        val64 &= ~TAR_SW_BITS;
        writeq(cpu_to_be64(val64), target);
        readq(target); /* flush */

        bitmapsz = tbl->it_size / BITS_PER_BYTE;
        free_pages((unsigned long)tbl->it_map, get_order(bitmapsz));
        tbl->it_map = NULL;

        kfree(tbl);
        dev->sysdata = NULL;

        /* Can't free bootmem allocated memory after system is up :-( */
        bus_info[dev->bus->number].tce_space = NULL;
}

static void calgary_watchdog(unsigned long data)
{
        struct pci_dev *dev = (struct pci_dev *)data;
        struct iommu_table *tbl = dev->sysdata;
        void __iomem *bbar = tbl->bbar;
        u32 val32;
        void __iomem *target;

        target = calgary_reg(bbar, phb_offset(tbl->it_busno) | PHB_CSR_OFFSET);
        val32 = be32_to_cpu(readl(target));

        /* If no error, the agent ID in the CSR is not valid */
        if (val32 & CSR_AGENT_MASK) {
                printk(KERN_EMERG "calgary_watchdog: DMA error on PHB %#x, "
                                  "CSR = %#x\n", dev->bus->number, val32);
                writel(0, target);

                /* Disable bus that caused the error */
                target = calgary_reg(bbar, phb_offset(tbl->it_busno) |
                                           PHB_CONFIG_RW_OFFSET);
                val32 = be32_to_cpu(readl(target));
                val32 |= PHB_SLOT_DISABLE;
                writel(cpu_to_be32(val32), target);
                readl(target); /* flush */
        } else {
                /* Reset the timer */
                mod_timer(&tbl->watchdog_timer, jiffies + 2 * HZ);
        }
}

static void __init calgary_increase_split_completion_timeout(void __iomem *bbar,
        unsigned char busnum)
{
        u64 val64;
        void __iomem *target;
        unsigned int phb_shift = ~0; /* silence gcc */
        u64 mask;

        switch (busno_to_phbid(busnum)) {
        case 0: phb_shift = (63 - 19);
                break;
        case 1: phb_shift = (63 - 23);
                break;
        case 2: phb_shift = (63 - 27);
                break;
        case 3: phb_shift = (63 - 35);
                break;
        default:
                BUG_ON(busno_to_phbid(busnum));
        }

        target = calgary_reg(bbar, CALGARY_CONFIG_REG);
        val64 = be64_to_cpu(readq(target));

        /* zero out this PHB's timer bits */
        mask = ~(0xFUL << phb_shift);
        val64 &= mask;
        val64 |= (CCR_2SEC_TIMEOUT << phb_shift);
        writeq(cpu_to_be64(val64), target);
        readq(target); /* flush */
}

static void __init calgary_enable_translation(struct pci_dev *dev)
{
        u32 val32;
        unsigned char busnum;
        void __iomem *target;
        void __iomem *bbar;
        struct iommu_table *tbl;

        busnum = dev->bus->number;
        tbl = dev->sysdata;
        bbar = tbl->bbar;

        /* enable TCE in PHB Config Register */
        target = calgary_reg(bbar, phb_offset(busnum) | PHB_CONFIG_RW_OFFSET);
        val32 = be32_to_cpu(readl(target));
        val32 |= PHB_TCE_ENABLE | PHB_DAC_DISABLE | PHB_MCSR_ENABLE;

        printk(KERN_INFO "Calgary: enabling translation on PHB %#x\n", busnum);
        printk(KERN_INFO "Calgary: errant DMAs will now be prevented on this "
               "bus.\n");

        writel(cpu_to_be32(val32), target);
        readl(target); /* flush */

        /*
         * Give split completion a longer timeout on bus 1 for aic94xx
         * http://bugzilla.kernel.org/show_bug.cgi?id=7180
         */
        if (busnum == 1)
                calgary_increase_split_completion_timeout(bbar, busnum);

        init_timer(&tbl->watchdog_timer);
        tbl->watchdog_timer.function = &calgary_watchdog;
        tbl->watchdog_timer.data = (unsigned long)dev;
        mod_timer(&tbl->watchdog_timer, jiffies);
}

static void __init calgary_disable_translation(struct pci_dev *dev)
{
        u32 val32;
        unsigned char busnum;
        void __iomem *target;
        void __iomem *bbar;
        struct iommu_table *tbl;

        busnum = dev->bus->number;
        tbl = dev->sysdata;
        bbar = tbl->bbar;

        /* disable TCE in PHB Config Register */
        target = calgary_reg(bbar, phb_offset(busnum) | PHB_CONFIG_RW_OFFSET);
        val32 = be32_to_cpu(readl(target));
        val32 &= ~(PHB_TCE_ENABLE | PHB_DAC_DISABLE | PHB_MCSR_ENABLE);

        printk(KERN_INFO "Calgary: disabling translation on PHB %#x!\n", busnum);
        writel(cpu_to_be32(val32), target);
        readl(target); /* flush */

        del_timer_sync(&tbl->watchdog_timer);
}

static void __init calgary_init_one_nontraslated(struct pci_dev *dev)
{
        pci_dev_get(dev);
        dev->sysdata = NULL;
        dev->bus->self = dev;
}

static int __init calgary_init_one(struct pci_dev *dev)
{
        void __iomem *bbar;
        int ret;

        BUG_ON(dev->bus->number >= MAX_PHB_BUS_NUM);

        bbar = busno_to_bbar(dev->bus->number);
        ret = calgary_setup_tar(dev, bbar);
        if (ret)
                goto done;

        pci_dev_get(dev);
        dev->bus->self = dev;
        calgary_enable_translation(dev);

        return 0;

done:
        return ret;
}

static int __init calgary_locate_bbars(void)
{
        int ret;
        int rioidx, phb, bus;
        void __iomem *bbar;
        void __iomem *target;
        unsigned long offset;
        u8 start_bus, end_bus;
        u32 val;

        ret = -ENODATA;
        for (rioidx = 0; rioidx < rio_table_hdr->num_rio_dev; rioidx++) {
                struct rio_detail *rio = rio_devs[rioidx];

                if ((rio->type != COMPAT_CALGARY) && (rio->type != ALT_CALGARY))
                        continue;

                /* map entire 1MB of Calgary config space */
                bbar = ioremap_nocache(rio->BBAR, 1024 * 1024);
                if (!bbar)
                        goto error;

                for (phb = 0; phb < PHBS_PER_CALGARY; phb++) {
                        offset = phb_debug_offsets[phb] | PHB_DEBUG_STUFF_OFFSET;
                        target = calgary_reg(bbar, offset);

                        val = be32_to_cpu(readl(target));
                        start_bus = (u8)((val & 0x00FF0000) >> 16);
                        end_bus = (u8)((val & 0x0000FF00) >> 8);
                        for (bus = start_bus; bus <= end_bus; bus++) {
                                bus_info[bus].bbar = bbar;
                                bus_info[bus].phbid = phb;
                        }
                }
        }

        return 0;

error:
        /* scan bus_info and iounmap any bbars we previously ioremap'd */
        for (bus = 0; bus < ARRAY_SIZE(bus_info); bus++)
                if (bus_info[bus].bbar)
                        iounmap(bus_info[bus].bbar);

        return ret;
}

static int __init calgary_init(void)
{
        int ret;
        struct pci_dev *dev = NULL;

        ret = calgary_locate_bbars();
        if (ret)
                return ret;

        do {
                dev = pci_get_device(PCI_VENDOR_ID_IBM,
                                     PCI_DEVICE_ID_IBM_CALGARY,
                                     dev);
                if (!dev)
                        break;
                if (!translate_phb(dev)) {
                        calgary_init_one_nontraslated(dev);
                        continue;
                }
                if (!bus_info[dev->bus->number].tce_space && !translate_empty_slots)
                        continue;

                ret = calgary_init_one(dev);
                if (ret)
                        goto error;
        } while (1);

        return ret;

error:
        do {
                dev = pci_get_device_reverse(PCI_VENDOR_ID_IBM,
                                              PCI_DEVICE_ID_IBM_CALGARY,
                                              dev);
                if (!dev)
                        break;
                if (!translate_phb(dev)) {
                        pci_dev_put(dev);
                        continue;
                }
                if (!bus_info[dev->bus->number].tce_space && !translate_empty_slots)
                        continue;

                calgary_disable_translation(dev);
                calgary_free_bus(dev);
                pci_dev_put(dev); /* Undo calgary_init_one()'s pci_dev_get() */
        } while (1);

        return ret;
}

static inline int __init determine_tce_table_size(u64 ram)
{
        int ret;

        if (specified_table_size != TCE_TABLE_SIZE_UNSPECIFIED)
                return specified_table_size;

        /*
         * Table sizes are from 0 to 7 (TCE_TABLE_SIZE_64K to
         * TCE_TABLE_SIZE_8M). Table size 0 has 8K entries and each
         * larger table size has twice as many entries, so shift the
         * max ram address by 13 to divide by 8K and then look at the
         * order of the result to choose between 0-7.
         */
        ret = get_order(ram >> 13);
        if (ret > TCE_TABLE_SIZE_8M)
                ret = TCE_TABLE_SIZE_8M;

        return ret;
}

static int __init build_detail_arrays(void)
{
        unsigned long ptr;
        int i, scal_detail_size, rio_detail_size;

        if (rio_table_hdr->num_scal_dev > MAX_NUMNODES){
                printk(KERN_WARNING
                        "Calgary: MAX_NUMNODES too low! Defined as %d, "
                        "but system has %d nodes.\n",
                        MAX_NUMNODES, rio_table_hdr->num_scal_dev);
                return -ENODEV;
        }

        switch (rio_table_hdr->version){
        case 2:
                scal_detail_size = 11;
                rio_detail_size = 13;
                break;
        case 3:
                scal_detail_size = 12;
                rio_detail_size = 15;
                break;
        default:
                printk(KERN_WARNING
                       "Calgary: Invalid Rio Grande Table Version: %d\n",
                       rio_table_hdr->version);
                return -EPROTO;
        }

        ptr = ((unsigned long)rio_table_hdr) + 3;
        for (i = 0; i < rio_table_hdr->num_scal_dev;
                    i++, ptr += scal_detail_size)
                scal_devs[i] = (struct scal_detail *)ptr;

        for (i = 0; i < rio_table_hdr->num_rio_dev;
                    i++, ptr += rio_detail_size)
                rio_devs[i] = (struct rio_detail *)ptr;

        return 0;
}

void __init detect_calgary(void)
{
        u32 val;
        int bus;
        void *tbl;
        int calgary_found = 0;
        unsigned long ptr;
        unsigned int offset, prev_offset;
        int ret;

        /*
         * if the user specified iommu=off or iommu=soft or we found
         * another HW IOMMU already, bail out.
         */
        if (swiotlb || no_iommu || iommu_detected)
                return;

        if (!use_calgary)
                return;

        if (!early_pci_allowed())
                return;

        printk(KERN_DEBUG "Calgary: detecting Calgary via BIOS EBDA area\n");

        ptr = (unsigned long)phys_to_virt(get_bios_ebda());

        rio_table_hdr = NULL;
        prev_offset = 0;
        offset = 0x180;
        /*
         * The next offset is stored in the 1st word.
         * Only parse up until the offset increases:
         */
        while (offset > prev_offset) {
                /* The block id is stored in the 2nd word */
                if (*((unsigned short *)(ptr + offset + 2)) == 0x4752){
                        /* set the pointer past the offset & block id */
                        rio_table_hdr = (struct rio_table_hdr *)(ptr + offset + 4);
                        break;
                }
                prev_offset = offset;
                offset = *((unsigned short *)(ptr + offset));
        }
        if (!rio_table_hdr) {
                printk(KERN_DEBUG "Calgary: Unable to locate Rio Grande table "
                       "in EBDA - bailing!\n");
                return;
        }

        ret = build_detail_arrays();
        if (ret) {
                printk(KERN_DEBUG "Calgary: build_detail_arrays ret %d\n", ret);
                return;
        }

        specified_table_size = determine_tce_table_size(end_pfn * PAGE_SIZE);

        for (bus = 0; bus < MAX_PHB_BUS_NUM; bus++) {
                int dev;
                struct calgary_bus_info *info = &bus_info[bus];

                if (read_pci_config(bus, 0, 0, 0) != PCI_VENDOR_DEVICE_ID_CALGARY)
                        continue;

                if (info->translation_disabled)
                        continue;

                /*
                 * Scan the slots of the PCI bus to see if there is a device present.
                 * The parent bus will be the zero-ith device, so start at 1.
                 */
                for (dev = 1; dev < 8; dev++) {
                        val = read_pci_config(bus, dev, 0, 0);
                        if (val != 0xffffffff || translate_empty_slots) {
                                tbl = alloc_tce_table();
                                if (!tbl)
                                        goto cleanup;
                                info->tce_space = tbl;
                                calgary_found = 1;
                                break;
                        }
                }
        }

        printk(KERN_DEBUG "Calgary: finished detection, Calgary %s\n",
               calgary_found ? "found" : "not found");

        if (calgary_found) {
                iommu_detected = 1;
                calgary_detected = 1;
                printk(KERN_INFO "PCI-DMA: Calgary IOMMU detected.\n");
                printk(KERN_INFO "PCI-DMA: Calgary TCE table spec is %d, "
                       "CONFIG_IOMMU_DEBUG is %s.\n", specified_table_size,
                       debugging ? "enabled" : "disabled");
        }
        return;

cleanup:
        for (--bus; bus >= 0; --bus) {
                struct calgary_bus_info *info = &bus_info[bus];

                if (info->tce_space)
                        free_tce_table(info->tce_space);
        }
}

int __init calgary_iommu_init(void)
{
        int ret;

        if (no_iommu || swiotlb)
                return -ENODEV;

        if (!calgary_detected)
                return -ENODEV;

        /* ok, we're trying to use Calgary - let's roll */
        printk(KERN_INFO "PCI-DMA: Using Calgary IOMMU\n");

        ret = calgary_init();
        if (ret) {
                printk(KERN_ERR "PCI-DMA: Calgary init failed %d, "
                       "falling back to no_iommu\n", ret);
                if (end_pfn > MAX_DMA32_PFN)
                        printk(KERN_ERR "WARNING more than 4GB of memory, "
                                        "32bit PCI may malfunction.\n");
                return ret;
        }

        force_iommu = 1;
        dma_ops = &calgary_dma_ops;

        return 0;
}

static int __init calgary_parse_options(char *p)
{
        unsigned int bridge;
        size_t len;
        char* endp;

        while (*p) {
                if (!strncmp(p, "64k", 3))
                        specified_table_size = TCE_TABLE_SIZE_64K;
                else if (!strncmp(p, "128k", 4))
                        specified_table_size = TCE_TABLE_SIZE_128K;
                else if (!strncmp(p, "256k", 4))
                        specified_table_size = TCE_TABLE_SIZE_256K;
                else if (!strncmp(p, "512k", 4))
                        specified_table_size = TCE_TABLE_SIZE_512K;
                else if (!strncmp(p, "1M", 2))
                        specified_table_size = TCE_TABLE_SIZE_1M;
                else if (!strncmp(p, "2M", 2))
                        specified_table_size = TCE_TABLE_SIZE_2M;
                else if (!strncmp(p, "4M", 2))
                        specified_table_size = TCE_TABLE_SIZE_4M;
                else if (!strncmp(p, "8M", 2))
                        specified_table_size = TCE_TABLE_SIZE_8M;

                len = strlen("translate_empty_slots");
                if (!strncmp(p, "translate_empty_slots", len))
                        translate_empty_slots = 1;

                len = strlen("disable");
                if (!strncmp(p, "disable", len)) {
                        p += len;
                        if (*p == '=')
                                ++p;
                        if (*p == '\0')
                                break;
                        bridge = simple_strtol(p, &endp, 0);
                        if (p == endp)
                                break;

                        if (bridge < MAX_PHB_BUS_NUM) {
                                printk(KERN_INFO "Calgary: disabling "
                                       "translation for PHB %#x\n", bridge);
                                bus_info[bridge].translation_disabled = 1;
                        }
                }

                p = strpbrk(p, ",");
                if (!p)
                        break;

                p++; /* skip ',' */
        }
        return 1;
}
__setup("calgary=", calgary_parse_options);