/*
 * This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file "COPYING" in the main directory of this archive
 * for more details.
 *
 * Copyright (C) 2000  Ani Joshi <ajoshi@unixbox.com>
 * Copyright (C) 2000, 2001  Ralf Baechle <ralf@gnu.org>
 * Copyright (C) 2005 Ilya A. Volynets-Evenbakh <ilya@total-knowledge.com>
 * swiped from i386, and cloned for MIPS by Geert, polished by Ralf.
 * IP32 changes by Ilya.
 * Cavium Networks: Create new dma setup for Cavium Networks Octeon based on
 * the kernels original.
 */
#include <linux/types.h>
#include <linux/mm.h>
#include <linux/module.h>
#include <linux/string.h>
#include <linux/dma-mapping.h>
#include <linux/platform_device.h>
#include <linux/scatterlist.h>

#include <linux/cache.h>
#include <linux/io.h>

#include <asm/octeon/octeon.h>
#include <asm/octeon/cvmx-npi-defs.h>
#include <asm/octeon/cvmx-pci-defs.h>

#include <dma-coherence.h>

#ifdef CONFIG_PCI
#include <asm/octeon/pci-octeon.h>
#endif

#define BAR2_PCI_ADDRESS 0x8000000000ul

struct bar1_index_state {
        int16_t ref_count;      /* Number of PCI mappings using this index */
        uint16_t address_bits;  /* Upper bits of physical address. This is
                                   shifted 22 bits */
};

#ifdef CONFIG_PCI
static DEFINE_SPINLOCK(bar1_lock);
static struct bar1_index_state bar1_state[32];
#endif

dma_addr_t octeon_map_dma_mem(struct device *dev, void *ptr, size_t size)
{
#ifndef CONFIG_PCI
        /* Without PCI/PCIe this function can be called for Octeon internal
           devices such as USB. These devices all support 64bit addressing */
        mb();
        return virt_to_phys(ptr);
#else
        unsigned long flags;
        uint64_t dma_mask;
        int64_t start_index;
        dma_addr_t result = -1;
        uint64_t physical = virt_to_phys(ptr);
        int64_t index;

        mb();
        /*
         * Use the DMA masks to determine the allowed memory
         * region. For us it doesn't limit the actual memory, just the
         * address visible over PCI.  Devices with limits need to use
         * lower indexed Bar1 entries.
         */
        if (dev) {
                dma_mask = dev->coherent_dma_mask;
                if (dev->dma_mask)
                        dma_mask = *dev->dma_mask;
        } else {
                dma_mask = 0xfffffffful;
        }

        /*
         * Platform devices, such as the internal USB, skip all
         * translation and use Octeon physical addresses directly.
         */
        if (!dev || dev->bus == &platform_bus_type)
                return physical;

        switch (octeon_dma_bar_type) {
        case OCTEON_DMA_BAR_TYPE_PCIE:
                if (unlikely(physical < (16ul << 10)))
                        panic("dma_map_single: Not allowed to map first 16KB."
                              " It interferes with BAR0 special area\n");
                else if ((physical + size >= (256ul << 20)) &&
                         (physical < (512ul << 20)))
                        panic("dma_map_single: Not allowed to map bootbus\n");
                else if ((physical + size >= 0x400000000ull) &&
                         physical < 0x410000000ull)
                        panic("dma_map_single: "
                              "Attempt to map illegal memory address 0x%llx\n",
                              physical);
                else if (physical >= 0x420000000ull)
                        panic("dma_map_single: "
                              "Attempt to map illegal memory address 0x%llx\n",
                              physical);
                else if ((physical + size >=
                          (4ull<<30) - (OCTEON_PCI_BAR1_HOLE_SIZE<<20))
                         && physical < (4ull<<30))
                        pr_warning("dma_map_single: Warning: "
                                   "Mapping memory address that might "
                                   "conflict with devices 0x%llx-0x%llx\n",
                                   physical, physical+size-1);
                /* The 2nd 256MB is mapped at 256<<20 instead of 0x410000000 */
                if ((physical >= 0x410000000ull) && physical < 0x420000000ull)
                        result = physical - 0x400000000ull;
                else
                        result = physical;
                if (((result+size-1) & dma_mask) != result+size-1)
                        panic("dma_map_single: Attempt to map address "
                              "0x%llx-0x%llx, which can't be accessed "
                              "according to the dma mask 0x%llx\n",
                              physical, physical+size-1, dma_mask);
                goto done;

        case OCTEON_DMA_BAR_TYPE_BIG:
#ifdef CONFIG_64BIT
                /* If the device supports 64bit addressing, then use BAR2 */
                if (dma_mask > BAR2_PCI_ADDRESS) {
                        result = physical + BAR2_PCI_ADDRESS;
                        goto done;
                }
#endif
                if (unlikely(physical < (4ul << 10))) {
                        panic("dma_map_single: Not allowed to map first 4KB. "
                              "It interferes with BAR0 special area\n");
                } else if (physical < (256ul << 20)) {
                        if (unlikely(physical + size > (256ul << 20)))
                                panic("dma_map_single: Requested memory spans "
                                      "Bar0 0:256MB and bootbus\n");
                        result = physical;
                        goto done;
                } else if (unlikely(physical < (512ul << 20))) {
                        panic("dma_map_single: Not allowed to map bootbus\n");
                } else if (physical < (2ul << 30)) {
                        if (unlikely(physical + size > (2ul << 30)))
                                panic("dma_map_single: Requested memory spans "
                                      "Bar0 512MB:2GB and BAR1\n");
                        result = physical;
                        goto done;
                } else if (physical < (2ul << 30) + (128 << 20)) {
                        /* Fall through */
                } else if (physical <
                           (4ul << 30) - (OCTEON_PCI_BAR1_HOLE_SIZE << 20)) {
                        if (unlikely
                            (physical + size >
                             (4ul << 30) - (OCTEON_PCI_BAR1_HOLE_SIZE << 20)))
                                panic("dma_map_single: Requested memory "
                                      "extends past Bar1 (4GB-%luMB)\n",
                                      OCTEON_PCI_BAR1_HOLE_SIZE);
                        result = physical;
                        goto done;
                } else if ((physical >= 0x410000000ull) &&
                           (physical < 0x420000000ull)) {
                        if (unlikely(physical + size > 0x420000000ull))
                                panic("dma_map_single: Requested memory spans "
                                      "non existant memory\n");
                        /* BAR0 fixed mapping 256MB:512MB ->
                         * 16GB+256MB:16GB+512MB */
                        result = physical - 0x400000000ull;
                        goto done;
                } else {
                        /* Continued below switch statement */
                }
                break;

        case OCTEON_DMA_BAR_TYPE_SMALL:
#ifdef CONFIG_64BIT
                /* If the device supports 64bit addressing, then use BAR2 */
                if (dma_mask > BAR2_PCI_ADDRESS) {
                        result = physical + BAR2_PCI_ADDRESS;
                        goto done;
                }
#endif
                /* Continued below switch statement */
                break;

        default:
                panic("dma_map_single: Invalid octeon_dma_bar_type\n");
        }

        /* Don't allow mapping to span multiple Bar entries. The hardware guys
           won't guarantee that DMA across boards work */
        if (unlikely((physical >> 22) != ((physical + size - 1) >> 22)))
                panic("dma_map_single: "
                      "Requested memory spans more than one Bar1 entry\n");

        if (octeon_dma_bar_type == OCTEON_DMA_BAR_TYPE_BIG)
                start_index = 31;
        else if (unlikely(dma_mask < (1ul << 27)))
                start_index = (dma_mask >> 22);
        else
                start_index = 31;

        /* Only one processor can access the Bar register at once */
        spin_lock_irqsave(&bar1_lock, flags);

        /* Look through Bar1 for existing mapping that will work */
        for (index = start_index; index >= 0; index--) {
                if ((bar1_state[index].address_bits == physical >> 22) &&
                    (bar1_state[index].ref_count)) {
                        /* An existing mapping will work, use it */
                        bar1_state[index].ref_count++;
                        if (unlikely(bar1_state[index].ref_count < 0))
                                panic("dma_map_single: "
                                      "Bar1[%d] reference count overflowed\n",
                                      (int) index);
                        result = (index << 22) | (physical & ((1 << 22) - 1));
                        /* Large BAR1 is offset at 2GB */
                        if (octeon_dma_bar_type == OCTEON_DMA_BAR_TYPE_BIG)
                                result += 2ul << 30;
                        goto done_unlock;
                }
        }

        /* No existing mappings, look for a free entry */
        for (index = start_index; index >= 0; index--) {
                if (unlikely(bar1_state[index].ref_count == 0)) {
                        union cvmx_pci_bar1_indexx bar1_index;
                        /* We have a free entry, use it */
                        bar1_state[index].ref_count = 1;
                        bar1_state[index].address_bits = physical >> 22;
                        bar1_index.u32 = 0;
                        /* Address bits[35:22] sent to L2C */
                        bar1_index.s.addr_idx = physical >> 22;
                        /* Don't put PCI accesses in L2. */
                        bar1_index.s.ca = 1;
                        /* Endian Swap Mode */
                        bar1_index.s.end_swp = 1;
                        /* Set '1' when the selected address range is valid. */
                        bar1_index.s.addr_v = 1;
                        octeon_npi_write32(CVMX_NPI_PCI_BAR1_INDEXX(index),
                                           bar1_index.u32);
                        /* An existing mapping will work, use it */
                        result = (index << 22) | (physical & ((1 << 22) - 1));
                        /* Large BAR1 is offset at 2GB */
                        if (octeon_dma_bar_type == OCTEON_DMA_BAR_TYPE_BIG)
                                result += 2ul << 30;
                        goto done_unlock;
                }
        }

        pr_err("dma_map_single: "
               "Can't find empty BAR1 index for physical mapping 0x%llx\n",
               (unsigned long long) physical);

done_unlock:
        spin_unlock_irqrestore(&bar1_lock, flags);
done:
        pr_debug("dma_map_single 0x%llx->0x%llx\n", physical, result);
        return result;
#endif
}

void octeon_unmap_dma_mem(struct device *dev, dma_addr_t dma_addr)
{
#ifndef CONFIG_PCI
        /*
         * Without PCI/PCIe this function can be called for Octeon internal
         * devices such as USB. These devices all support 64bit addressing.
         */
        return;
#else
        unsigned long flags;
        uint64_t index;

        /*
         * Platform devices, such as the internal USB, skip all
         * translation and use Octeon physical addresses directly.
         */
        if (dev->bus == &platform_bus_type)
                return;

        switch (octeon_dma_bar_type) {
        case OCTEON_DMA_BAR_TYPE_PCIE:
                /* Nothing to do, all mappings are static */
                goto done;

        case OCTEON_DMA_BAR_TYPE_BIG:
#ifdef CONFIG_64BIT
                /* Nothing to do for addresses using BAR2 */
                if (dma_addr >= BAR2_PCI_ADDRESS)
                        goto done;
#endif
                if (unlikely(dma_addr < (4ul << 10)))
                        panic("dma_unmap_single: Unexpect DMA address 0x%llx\n",
                              dma_addr);
                else if (dma_addr < (2ul << 30))
                        /* Nothing to do for addresses using BAR0 */
                        goto done;
                else if (dma_addr < (2ul << 30) + (128ul << 20))
                        /* Need to unmap, fall through */
                        index = (dma_addr - (2ul << 30)) >> 22;
                else if (dma_addr <
                         (4ul << 30) - (OCTEON_PCI_BAR1_HOLE_SIZE << 20))
                        goto done;      /* Nothing to do for the rest of BAR1 */
                else
                        panic("dma_unmap_single: Unexpect DMA address 0x%llx\n",
                              dma_addr);
                /* Continued below switch statement */
                break;

        case OCTEON_DMA_BAR_TYPE_SMALL:
#ifdef CONFIG_64BIT
                /* Nothing to do for addresses using BAR2 */
                if (dma_addr >= BAR2_PCI_ADDRESS)
                        goto done;
#endif
                index = dma_addr >> 22;
                /* Continued below switch statement */
                break;

        default:
                panic("dma_unmap_single: Invalid octeon_dma_bar_type\n");
        }

        if (unlikely(index > 31))
                panic("dma_unmap_single: "
                      "Attempt to unmap an invalid address (0x%llx)\n",
                      dma_addr);

        spin_lock_irqsave(&bar1_lock, flags);
        bar1_state[index].ref_count--;
        if (bar1_state[index].ref_count == 0)
                octeon_npi_write32(CVMX_NPI_PCI_BAR1_INDEXX(index), 0);
        else if (unlikely(bar1_state[index].ref_count < 0))
                panic("dma_unmap_single: Bar1[%u] reference count < 0\n",
                      (int) index);
        spin_unlock_irqrestore(&bar1_lock, flags);
done:
        pr_debug("dma_unmap_single 0x%llx\n", dma_addr);
        return;
#endif
}