dm writecache: add cond_resched to loop in persistent_memory_claim()

[linux/fpc-iii.git] / drivers / net / ipa / ipa_table.c

// SPDX-License-Identifier: GPL-2.0

/* Copyright (c) 2012-2018, The Linux Foundation. All rights reserved.
 * Copyright (C) 2018-2020 Linaro Ltd.
 */

#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/bits.h>
#include <linux/bitops.h>
#include <linux/bitfield.h>
#include <linux/io.h>
#include <linux/build_bug.h>
#include <linux/device.h>
#include <linux/dma-mapping.h>

#include "ipa.h"
#include "ipa_version.h"
#include "ipa_endpoint.h"
#include "ipa_table.h"
#include "ipa_reg.h"
#include "ipa_mem.h"
#include "ipa_cmd.h"
#include "gsi.h"
#include "gsi_trans.h"

/**
 * DOC: IPA Filter and Route Tables
 *
 * The IPA has tables defined in its local shared memory that define filter
 * and routing rules.  Each entry in these tables contains a 64-bit DMA
 * address that refers to DRAM (system memory) containing a rule definition.
 * A rule consists of a contiguous block of 32-bit values terminated with
 * 32 zero bits.  A special "zero entry" rule consisting of 64 zero bits
 * represents "no filtering" or "no routing," and is the reset value for
 * filter or route table rules.  Separate tables (both filter and route)
 * used for IPv4 and IPv6.  Additionally, there can be hashed filter or
 * route tables, which are used when a hash of message metadata matches.
 * Hashed operation is not supported by all IPA hardware.
 *
 * Each filter rule is associated with an AP or modem TX endpoint, though
 * not all TX endpoints support filtering.  The first 64-bit entry in a
 * filter table is a bitmap indicating which endpoints have entries in
 * the table.  The low-order bit (bit 0) in this bitmap represents a
 * special global filter, which applies to all traffic.  This is not
 * used in the current code.  Bit 1, if set, indicates that there is an
 * entry (i.e. a DMA address referring to a rule) for endpoint 0 in the
 * table.  Bit 2, if set, indicates there is an entry for endpoint 1,
 * and so on.  Space is set aside in IPA local memory to hold as many
 * filter table entries as might be required, but typically they are not
 * all used.
 *
 * The AP initializes all entries in a filter table to refer to a "zero"
 * entry.  Once initialized the modem and AP update the entries for
 * endpoints they "own" directly.  Currently the AP does not use the
 * IPA filtering functionality.
 *
 *                    IPA Filter Table
 *                 ----------------------
 * endpoint bitmap | 0x0000000000000048 | Bits 3 and 6 set (endpoints 2 and 5)
 *                 |--------------------|
 * 1st endpoint    | 0x000123456789abc0 | DMA address for modem endpoint 2 rule
 *                 |--------------------|
 * 2nd endpoint    | 0x000123456789abf0 | DMA address for AP endpoint 5 rule
 *                 |--------------------|
 * (unused)        |                    | (Unused space in filter table)
 *                 |--------------------|
 *                          . . .
 *                 |--------------------|
 * (unused)        |                    | (Unused space in filter table)
 *                 ----------------------
 *
 * The set of available route rules is divided about equally between the AP
 * and modem.  The AP initializes all entries in a route table to refer to
 * a "zero entry".  Once initialized, the modem and AP are responsible for
 * updating their own entries.  All entries in a route table are usable,
 * though the AP currently does not use the IPA routing functionality.
 *
 *                    IPA Route Table
 *                 ----------------------
 * 1st modem route | 0x0001234500001100 | DMA address for first route rule
 *                 |--------------------|
 * 2nd modem route | 0x0001234500001140 | DMA address for second route rule
 *                 |--------------------|
 *                          . . .
 *                 |--------------------|
 * Last modem route| 0x0001234500002280 | DMA address for Nth route rule
 *                 |--------------------|
 * 1st AP route    | 0x0001234500001100 | DMA address for route rule (N+1)
 *                 |--------------------|
 * 2nd AP route    | 0x0001234500001140 | DMA address for next route rule
 *                 |--------------------|
 *                          . . .
 *                 |--------------------|
 * Last AP route   | 0x0001234500002280 | DMA address for last route rule
 *                 ----------------------
 */

/* IPA hardware constrains filter and route tables alignment */
#define IPA_TABLE_ALIGN                 128     /* Minimum table alignment */

/* Assignment of route table entries to the modem and AP */
#define IPA_ROUTE_MODEM_MIN             0
#define IPA_ROUTE_MODEM_COUNT           8

#define IPA_ROUTE_AP_MIN                IPA_ROUTE_MODEM_COUNT
#define IPA_ROUTE_AP_COUNT \
                (IPA_ROUTE_COUNT_MAX - IPA_ROUTE_MODEM_COUNT)

/* Filter or route rules consist of a set of 32-bit values followed by a
 * 32-bit all-zero rule list terminator.  The "zero rule" is simply an
 * all-zero rule followed by the list terminator.
 */
#define IPA_ZERO_RULE_SIZE              (2 * sizeof(__le32))

#ifdef IPA_VALIDATE

/* Check things that can be validated at build time. */
static void ipa_table_validate_build(void)
{
        /* IPA hardware accesses memory 128 bytes at a time.  Addresses
         * referred to by entries in filter and route tables must be
         * aligned on 128-byte byte boundaries.  The only rule address
         * ever use is the "zero rule", and it's aligned at the base
         * of a coherent DMA allocation.
         */
        BUILD_BUG_ON(ARCH_DMA_MINALIGN % IPA_TABLE_ALIGN);

        /* Filter and route tables contain DMA addresses that refer to
         * filter or route rules.  We use a fixed constant to represent
         * the size of either type of table entry.  Code in ipa_table_init()
         * uses a pointer to __le64 to initialize table entriews.
         */
        BUILD_BUG_ON(IPA_TABLE_ENTRY_SIZE != sizeof(dma_addr_t));
        BUILD_BUG_ON(sizeof(dma_addr_t) != sizeof(__le64));

        /* A "zero rule" is used to represent no filtering or no routing.
         * It is a 64-bit block of zeroed memory.  Code in ipa_table_init()
         * assumes that it can be written using a pointer to __le64.
         */
        BUILD_BUG_ON(IPA_ZERO_RULE_SIZE != sizeof(__le64));

        /* Impose a practical limit on the number of routes */
        BUILD_BUG_ON(IPA_ROUTE_COUNT_MAX > 32);
        /* The modem must be allotted at least one route table entry */
        BUILD_BUG_ON(!IPA_ROUTE_MODEM_COUNT);
        /* But it can't have more than what is available */
        BUILD_BUG_ON(IPA_ROUTE_MODEM_COUNT > IPA_ROUTE_COUNT_MAX);

}

static bool
ipa_table_valid_one(struct ipa *ipa, bool route, bool ipv6, bool hashed)
{
        struct device *dev = &ipa->pdev->dev;
        const struct ipa_mem *mem;
        u32 size;

        if (route) {
                if (ipv6)
                        mem = hashed ? &ipa->mem[IPA_MEM_V6_ROUTE_HASHED]
                                     : &ipa->mem[IPA_MEM_V6_ROUTE];
                else
                        mem = hashed ? &ipa->mem[IPA_MEM_V4_ROUTE_HASHED]
                                     : &ipa->mem[IPA_MEM_V4_ROUTE];
                size = IPA_ROUTE_COUNT_MAX * IPA_TABLE_ENTRY_SIZE;
        } else {
                if (ipv6)
                        mem = hashed ? &ipa->mem[IPA_MEM_V6_FILTER_HASHED]
                                     : &ipa->mem[IPA_MEM_V6_FILTER];
                else
                        mem = hashed ? &ipa->mem[IPA_MEM_V4_FILTER_HASHED]
                                     : &ipa->mem[IPA_MEM_V4_FILTER];
                size = (1 + IPA_FILTER_COUNT_MAX) * IPA_TABLE_ENTRY_SIZE;
        }

        if (!ipa_cmd_table_valid(ipa, mem, route, ipv6, hashed))
                return false;

        /* mem->size >= size is sufficient, but we'll demand more */
        if (mem->size == size)
                return true;

        /* Hashed table regions can be zero size if hashing is not supported */
        if (hashed && !mem->size)
                return true;

        dev_err(dev, "IPv%c %s%s table region size 0x%02x, expected 0x%02x\n",
                ipv6 ? '6' : '4', hashed ? "hashed " : "",
                route ? "route" : "filter", mem->size, size);

        return false;
}

/* Verify the filter and route table memory regions are the expected size */
bool ipa_table_valid(struct ipa *ipa)
{
        bool valid = true;

        valid = valid && ipa_table_valid_one(ipa, false, false, false);
        valid = valid && ipa_table_valid_one(ipa, false, false, true);
        valid = valid && ipa_table_valid_one(ipa, false, true, false);
        valid = valid && ipa_table_valid_one(ipa, false, true, true);
        valid = valid && ipa_table_valid_one(ipa, true, false, false);
        valid = valid && ipa_table_valid_one(ipa, true, false, true);
        valid = valid && ipa_table_valid_one(ipa, true, true, false);
        valid = valid && ipa_table_valid_one(ipa, true, true, true);

        return valid;
}

bool ipa_filter_map_valid(struct ipa *ipa, u32 filter_map)
{
        struct device *dev = &ipa->pdev->dev;
        u32 count;

        if (!filter_map) {
                dev_err(dev, "at least one filtering endpoint is required\n");

                return false;
        }

        count = hweight32(filter_map);
        if (count > IPA_FILTER_COUNT_MAX) {
                dev_err(dev, "too many filtering endpoints (%u, max %u)\n",
                        count, IPA_FILTER_COUNT_MAX);

                return false;
        }

        return true;
}

#else /* !IPA_VALIDATE */
static void ipa_table_validate_build(void)

{
}

#endif /* !IPA_VALIDATE */

/* Zero entry count means no table, so just return a 0 address */
static dma_addr_t ipa_table_addr(struct ipa *ipa, bool filter_mask, u16 count)
{
        u32 skip;

        if (!count)
                return 0;

/* assert(count <= max_t(u32, IPA_FILTER_COUNT_MAX, IPA_ROUTE_COUNT_MAX)); */

        /* Skip over the zero rule and possibly the filter mask */
        skip = filter_mask ? 1 : 2;

        return ipa->table_addr + skip * sizeof(*ipa->table_virt);
}

static void ipa_table_reset_add(struct gsi_trans *trans, bool filter,
                                u16 first, u16 count, const struct ipa_mem *mem)
{
        struct ipa *ipa = container_of(trans->gsi, struct ipa, gsi);
        dma_addr_t addr;
        u32 offset;
        u16 size;

        /* Nothing to do if the table memory regions is empty */
        if (!mem->size)
                return;

        if (filter)
                first++;        /* skip over bitmap */

        offset = mem->offset + first * IPA_TABLE_ENTRY_SIZE;
        size = count * IPA_TABLE_ENTRY_SIZE;
        addr = ipa_table_addr(ipa, false, count);

        ipa_cmd_dma_shared_mem_add(trans, offset, size, addr, true);
}

/* Reset entries in a single filter table belonging to either the AP or
 * modem to refer to the zero entry.  The memory region supplied will be
 * for the IPv4 and IPv6 non-hashed and hashed filter tables.
 */
static int
ipa_filter_reset_table(struct ipa *ipa, const struct ipa_mem *mem, bool modem)
{
        u32 ep_mask = ipa->filter_map;
        u32 count = hweight32(ep_mask);
        struct gsi_trans *trans;
        enum gsi_ee_id ee_id;

        if (!mem->size)
                return 0;

        trans = ipa_cmd_trans_alloc(ipa, count);
        if (!trans) {
                dev_err(&ipa->pdev->dev,
                        "no transaction for %s filter reset\n",
                        modem ? "modem" : "AP");
                return -EBUSY;
        }

        ee_id = modem ? GSI_EE_MODEM : GSI_EE_AP;
        while (ep_mask) {
                u32 endpoint_id = __ffs(ep_mask);
                struct ipa_endpoint *endpoint;

                ep_mask ^= BIT(endpoint_id);

                endpoint = &ipa->endpoint[endpoint_id];
                if (endpoint->ee_id != ee_id)
                        continue;

                ipa_table_reset_add(trans, true, endpoint_id, 1, mem);
        }

        gsi_trans_commit_wait(trans);

        return 0;
}

/* Theoretically, each filter table could have more filter slots to
 * update than the maximum number of commands in a transaction.  So
 * we do each table separately.
 */
static int ipa_filter_reset(struct ipa *ipa, bool modem)
{
        int ret;

        ret = ipa_filter_reset_table(ipa, &ipa->mem[IPA_MEM_V4_FILTER], modem);
        if (ret)
                return ret;

        ret = ipa_filter_reset_table(ipa, &ipa->mem[IPA_MEM_V4_FILTER_HASHED],
                                     modem);
        if (ret)
                return ret;

        ret = ipa_filter_reset_table(ipa, &ipa->mem[IPA_MEM_V6_FILTER], modem);
        if (ret)
                return ret;
        ret = ipa_filter_reset_table(ipa, &ipa->mem[IPA_MEM_V6_FILTER_HASHED],
                                     modem);

        return ret;
}

/* The AP routes and modem routes are each contiguous within the
 * table.  We can update each table with a single command, and we
 * won't exceed the per-transaction command limit.
 * */
static int ipa_route_reset(struct ipa *ipa, bool modem)
{
        struct gsi_trans *trans;
        u16 first;
        u16 count;

        trans = ipa_cmd_trans_alloc(ipa, 4);
        if (!trans) {
                dev_err(&ipa->pdev->dev,
                        "no transaction for %s route reset\n",
                        modem ? "modem" : "AP");
                return -EBUSY;
        }

        if (modem) {
                first = IPA_ROUTE_MODEM_MIN;
                count = IPA_ROUTE_MODEM_COUNT;
        } else {
                first = IPA_ROUTE_AP_MIN;
                count = IPA_ROUTE_AP_COUNT;
        }

        ipa_table_reset_add(trans, false, first, count,
                            &ipa->mem[IPA_MEM_V4_ROUTE]);
        ipa_table_reset_add(trans, false, first, count,
                            &ipa->mem[IPA_MEM_V4_ROUTE_HASHED]);

        ipa_table_reset_add(trans, false, first, count,
                            &ipa->mem[IPA_MEM_V6_ROUTE]);
        ipa_table_reset_add(trans, false, first, count,
                            &ipa->mem[IPA_MEM_V6_ROUTE_HASHED]);

        gsi_trans_commit_wait(trans);

        return 0;
}

void ipa_table_reset(struct ipa *ipa, bool modem)
{
        struct device *dev = &ipa->pdev->dev;
        const char *ee_name;
        int ret;

        ee_name = modem ? "modem" : "AP";

        /* Report errors, but reset filter and route tables */
        ret = ipa_filter_reset(ipa, modem);
        if (ret)
                dev_err(dev, "error %d resetting filter table for %s\n",
                                ret, ee_name);

        ret = ipa_route_reset(ipa, modem);
        if (ret)
                dev_err(dev, "error %d resetting route table for %s\n",
                                ret, ee_name);
}

int ipa_table_hash_flush(struct ipa *ipa)
{
        u32 offset = ipa_reg_filt_rout_hash_flush_offset(ipa->version);
        struct gsi_trans *trans;
        u32 val;

        /* IPA version 4.2 does not support hashed tables */
        if (ipa->version == IPA_VERSION_4_2)
                return 0;

        trans = ipa_cmd_trans_alloc(ipa, 1);
        if (!trans) {
                dev_err(&ipa->pdev->dev, "no transaction for hash flush\n");
                return -EBUSY;
        }

        val = IPV4_FILTER_HASH_FLUSH | IPV6_FILTER_HASH_FLUSH;
        val |= IPV6_ROUTER_HASH_FLUSH | IPV4_ROUTER_HASH_FLUSH;

        ipa_cmd_register_write_add(trans, offset, val, val, false);

        gsi_trans_commit_wait(trans);

        return 0;
}

static void ipa_table_init_add(struct gsi_trans *trans, bool filter,
                               enum ipa_cmd_opcode opcode,
                               const struct ipa_mem *mem,
                               const struct ipa_mem *hash_mem)
{
        struct ipa *ipa = container_of(trans->gsi, struct ipa, gsi);
        dma_addr_t hash_addr;
        dma_addr_t addr;
        u16 hash_count;
        u16 hash_size;
        u16 count;
        u16 size;

        /* The number of filtering endpoints determines number of entries
         * in the filter table.  The hashed and non-hashed filter table
         * will have the same number of entries.  The size of the route
         * table region determines the number of entries it has.
         */
        if (filter) {
                count = hweight32(ipa->filter_map);
                hash_count = hash_mem->size ? count : 0;
        } else {
                count = mem->size / IPA_TABLE_ENTRY_SIZE;
                hash_count = hash_mem->size / IPA_TABLE_ENTRY_SIZE;
        }
        size = count * IPA_TABLE_ENTRY_SIZE;
        hash_size = hash_count * IPA_TABLE_ENTRY_SIZE;

        addr = ipa_table_addr(ipa, filter, count);
        hash_addr = ipa_table_addr(ipa, filter, hash_count);

        ipa_cmd_table_init_add(trans, opcode, size, mem->offset, addr,
                               hash_size, hash_mem->offset, hash_addr);
}

int ipa_table_setup(struct ipa *ipa)
{
        struct gsi_trans *trans;

        trans = ipa_cmd_trans_alloc(ipa, 4);
        if (!trans) {
                dev_err(&ipa->pdev->dev, "no transaction for table setup\n");
                return -EBUSY;
        }

        ipa_table_init_add(trans, false, IPA_CMD_IP_V4_ROUTING_INIT,
                           &ipa->mem[IPA_MEM_V4_ROUTE],
                           &ipa->mem[IPA_MEM_V4_ROUTE_HASHED]);

        ipa_table_init_add(trans, false, IPA_CMD_IP_V6_ROUTING_INIT,
                           &ipa->mem[IPA_MEM_V6_ROUTE],
                           &ipa->mem[IPA_MEM_V6_ROUTE_HASHED]);

        ipa_table_init_add(trans, true, IPA_CMD_IP_V4_FILTER_INIT,
                           &ipa->mem[IPA_MEM_V4_FILTER],
                           &ipa->mem[IPA_MEM_V4_FILTER_HASHED]);

        ipa_table_init_add(trans, true, IPA_CMD_IP_V6_FILTER_INIT,
                           &ipa->mem[IPA_MEM_V6_FILTER],
                           &ipa->mem[IPA_MEM_V6_FILTER_HASHED]);

        gsi_trans_commit_wait(trans);

        return 0;
}

void ipa_table_teardown(struct ipa *ipa)
{
        /* Nothing to do */     /* XXX Maybe reset the tables? */
}

/**
 * ipa_filter_tuple_zero() - Zero an endpoint's hashed filter tuple
 * @endpoint_id:        Endpoint whose filter hash tuple should be zeroed
 *
 * Endpoint must be for the AP (not modem) and support filtering. Updates
 * the filter hash values without changing route ones.
 */
static void ipa_filter_tuple_zero(struct ipa_endpoint *endpoint)
{
        u32 endpoint_id = endpoint->endpoint_id;
        u32 offset;
        u32 val;

        offset = IPA_REG_ENDP_FILTER_ROUTER_HSH_CFG_N_OFFSET(endpoint_id);

        val = ioread32(endpoint->ipa->reg_virt + offset);

        /* Zero all filter-related fields, preserving the rest */
        u32_replace_bits(val, 0, IPA_REG_ENDP_FILTER_HASH_MSK_ALL);

        iowrite32(val, endpoint->ipa->reg_virt + offset);
}

static void ipa_filter_config(struct ipa *ipa, bool modem)
{
        enum gsi_ee_id ee_id = modem ? GSI_EE_MODEM : GSI_EE_AP;
        u32 ep_mask = ipa->filter_map;

        /* IPA version 4.2 has no hashed route tables */
        if (ipa->version == IPA_VERSION_4_2)
                return;

        while (ep_mask) {
                u32 endpoint_id = __ffs(ep_mask);
                struct ipa_endpoint *endpoint;

                ep_mask ^= BIT(endpoint_id);

                endpoint = &ipa->endpoint[endpoint_id];
                if (endpoint->ee_id == ee_id)
                        ipa_filter_tuple_zero(endpoint);
        }
}

static void ipa_filter_deconfig(struct ipa *ipa, bool modem)
{
        /* Nothing to do */
}

static bool ipa_route_id_modem(u32 route_id)
{
        return route_id >= IPA_ROUTE_MODEM_MIN &&
                route_id <= IPA_ROUTE_MODEM_MIN + IPA_ROUTE_MODEM_COUNT - 1;
}

/**
 * ipa_route_tuple_zero() - Zero a hashed route table entry tuple
 * @route_id:   Route table entry whose hash tuple should be zeroed
 *
 * Updates the route hash values without changing filter ones.
 */
static void ipa_route_tuple_zero(struct ipa *ipa, u32 route_id)
{
        u32 offset = IPA_REG_ENDP_FILTER_ROUTER_HSH_CFG_N_OFFSET(route_id);
        u32 val;

        val = ioread32(ipa->reg_virt + offset);

        /* Zero all route-related fields, preserving the rest */
        u32_replace_bits(val, 0, IPA_REG_ENDP_ROUTER_HASH_MSK_ALL);

        iowrite32(val, ipa->reg_virt + offset);
}

static void ipa_route_config(struct ipa *ipa, bool modem)
{
        u32 route_id;

        /* IPA version 4.2 has no hashed route tables */
        if (ipa->version == IPA_VERSION_4_2)
                return;

        for (route_id = 0; route_id < IPA_ROUTE_COUNT_MAX; route_id++)
                if (ipa_route_id_modem(route_id) == modem)
                        ipa_route_tuple_zero(ipa, route_id);
}

static void ipa_route_deconfig(struct ipa *ipa, bool modem)
{
        /* Nothing to do */
}

void ipa_table_config(struct ipa *ipa)
{
        ipa_filter_config(ipa, false);
        ipa_filter_config(ipa, true);
        ipa_route_config(ipa, false);
        ipa_route_config(ipa, true);
}

void ipa_table_deconfig(struct ipa *ipa)
{
        ipa_route_deconfig(ipa, true);
        ipa_route_deconfig(ipa, false);
        ipa_filter_deconfig(ipa, true);
        ipa_filter_deconfig(ipa, false);
}

/*
 * Initialize a coherent DMA allocation containing initialized filter and
 * route table data.  This is used when initializing or resetting the IPA
 * filter or route table.
 *
 * The first entry in a filter table contains a bitmap indicating which
 * endpoints contain entries in the table.  In addition to that first entry,
 * there are at most IPA_FILTER_COUNT_MAX entries that follow.  Filter table
 * entries are 64 bits wide, and (other than the bitmap) contain the DMA
 * address of a filter rule.  A "zero rule" indicates no filtering, and
 * consists of 64 bits of zeroes.  When a filter table is initialized (or
 * reset) its entries are made to refer to the zero rule.
 *
 * Each entry in a route table is the DMA address of a routing rule.  For
 * routing there is also a 64-bit "zero rule" that means no routing, and
 * when a route table is initialized or reset, its entries are made to refer
 * to the zero rule.  The zero rule is shared for route and filter tables.
 *
 * Note that the IPA hardware requires a filter or route rule address to be
 * aligned on a 128 byte boundary.  The coherent DMA buffer we allocate here
 * has a minimum alignment, and we place the zero rule at the base of that
 * allocated space.  In ipa_table_init() we verify the minimum DMA allocation
 * meets our requirement.
 *
 *           +-------------------+
 *       --> |     zero rule     |
 *      /    |-------------------|
 *      |    |     filter mask   |
 *      |\   |-------------------|
 *      | ---- zero rule address | \
 *      |\   |-------------------|  |
 *      | ---- zero rule address |  |   IPA_FILTER_COUNT_MAX
 *      |    |-------------------|   >  or IPA_ROUTE_COUNT_MAX,
 *      |             ...           |   whichever is greater
 *       \   |-------------------|  |
 *        ---- zero rule address | /
 *           +-------------------+
 */
int ipa_table_init(struct ipa *ipa)
{
        u32 count = max_t(u32, IPA_FILTER_COUNT_MAX, IPA_ROUTE_COUNT_MAX);
        struct device *dev = &ipa->pdev->dev;
        dma_addr_t addr;
        __le64 le_addr;
        __le64 *virt;
        size_t size;

        ipa_table_validate_build();

        size = IPA_ZERO_RULE_SIZE + (1 + count) * IPA_TABLE_ENTRY_SIZE;
        virt = dma_alloc_coherent(dev, size, &addr, GFP_KERNEL);
        if (!virt)
                return -ENOMEM;

        ipa->table_virt = virt;
        ipa->table_addr = addr;

        /* First slot is the zero rule */
        *virt++ = 0;

        /* Next is the filter table bitmap.  The "soft" bitmap value
         * must be converted to the hardware representation by shifting
         * it left one position.  (Bit 0 repesents global filtering,
         * which is possible but not used.)
         */
        *virt++ = cpu_to_le64((u64)ipa->filter_map << 1);

        /* All the rest contain the DMA address of the zero rule */
        le_addr = cpu_to_le64(addr);
        while (count--)
                *virt++ = le_addr;

        return 0;
}

void ipa_table_exit(struct ipa *ipa)
{
        u32 count = max_t(u32, 1 + IPA_FILTER_COUNT_MAX, IPA_ROUTE_COUNT_MAX);
        struct device *dev = &ipa->pdev->dev;
        size_t size;

        size = IPA_ZERO_RULE_SIZE + (1 + count) * IPA_TABLE_ENTRY_SIZE;

        dma_free_coherent(dev, size, ipa->table_virt, ipa->table_addr);
        ipa->table_addr = 0;
        ipa->table_virt = NULL;
}