Merge tag 'trace-printf-v6.13' of git://git.kernel.org/pub/scm/linux/kernel/git/trace...

[drm/drm-misc.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) 2018-2024 Linaro Ltd.
 */

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

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

/**
 * DOC: IPA Filter and Route Tables
 *
 * The IPA has tables defined in its local (IPA-resident) memory that define
 * filter and routing rules.  An entry in either of these tables is a little
 * endian 64-bit "slot" that holds the address of a rule definition.  (The
 * size of these slots is 64 bits regardless of the host DMA address size.)
 *
 * Separate tables (both filter and route) are used for IPv4 and IPv6.  There
 * is normally another set of "hashed" filter and route tables, which are
 * used with a hash of message metadata.  Hashed operation is not supported
 * by all IPA hardware (IPA v4.2 doesn't support hashed tables).
 *
 * Rules can be in local memory or in DRAM (system memory).  The offset of
 * an object (such as a route or filter table) in IPA-resident memory must
 * 128-byte aligned.  An object in system memory (such as a route or filter
 * rule) must be at an 8-byte aligned address.  We currently only place
 * route or filter rules in system memory.
 *
 * 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.
 *
 * Each filter rule is associated with an AP or modem TX endpoint, though
 * not all TX endpoints support filtering.  The first 64-bit slot in a
 * filter table is a bitmap indicating which endpoints have entries in
 * the table.  Each set bit in this bitmap indicates the presence of the
 * address of a filter rule in the memory following the bitmap.  Until IPA
 * v5.0,  the low-order bit (bit 0) in this bitmap represents a special
 * global filter, which applies to all traffic.  Otherwise the position of
 * each set bit represents an endpoint for which a filter rule is defined.
 *
 * The global rule is not used in current code, and support for it is
 * removed starting at IPA v5.0.  For IPA v5.0+, the endpoint bitmap
 * position defines the endpoint ID--i.e. if bit 1 is set in the endpoint
 * bitmap, endpoint 1 has a filter rule.  Older versions of IPA represent
 * the presence of a filter rule for endpoint X by bit (X + 1) being set.
 * I.e., bit 1 set indicates the presence of a filter rule for endpoint 0,
 * and bit 3 set means there is a filter rule present for endpoint 2.
 *
 * Each filter table entry has the address of a set of equations that
 * implement a filter rule.  So following the endpoint bitmap there
 * will be such an address/entry for each endpoint with a set bit in
 * the bitmap.
 *
 * The AP initializes all entries in a filter table to refer to a "zero"
 * rule.  Once initialized, the modem and AP update the entries for
 * endpoints they "own" directly.  Currently the AP does not use the IPA
 * filtering functionality.
 *
 * This diagram shows an example of a filter table with an endpoint
 * bitmap as defined prior to IPA v5.0.
 *
 *                    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
 *                 ----------------------
 */

/* 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))

/* Check things that can be validated at build time. */
static void ipa_table_validate_build(void)
{
        /* Filter and route tables contain DMA addresses that refer
         * to filter or route rules.  But the size of a table entry
         * is 64 bits regardless of what the size of an AP DMA address
         * is.  A fixed constant defines the size of an entry, and
         * code in ipa_table_init() uses a pointer to __le64 to
         * initialize tables.
         */
        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));
}

static const struct ipa_mem *
ipa_table_mem(struct ipa *ipa, bool filter, bool hashed, bool ipv6)
{
        enum ipa_mem_id mem_id;

        mem_id = filter ? hashed ? ipv6 ? IPA_MEM_V6_FILTER_HASHED
                                        : IPA_MEM_V4_FILTER_HASHED
                                 : ipv6 ? IPA_MEM_V6_FILTER
                                        : IPA_MEM_V4_FILTER
                        : hashed ? ipv6 ? IPA_MEM_V6_ROUTE_HASHED
                                        : IPA_MEM_V4_ROUTE_HASHED
                                 : ipv6 ? IPA_MEM_V6_ROUTE
                                        : IPA_MEM_V4_ROUTE;

        return ipa_mem_find(ipa, mem_id);
}

/* Return true if hashed tables are supported */
bool ipa_table_hash_support(struct ipa *ipa)
{
        return ipa->version != IPA_VERSION_4_2;
}

bool ipa_filtered_valid(struct ipa *ipa, u64 filtered)
{
        struct device *dev = ipa->dev;
        u32 count;

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

                return false;
        }

        count = hweight64(filtered);
        if (count > ipa->filter_count) {
                dev_err(dev, "too many filtering endpoints (%u > %u)\n",
                        count, ipa->filter_count);

                return false;
        }

        return true;
}

/* 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;

        WARN_ON(count > max_t(u32, ipa->filter_count, ipa->route_count));

        /* 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,
                                bool hashed, bool ipv6, u16 first, u16 count)
{
        struct ipa *ipa = container_of(trans->gsi, struct ipa, gsi);
        const struct ipa_mem *mem;
        dma_addr_t addr;
        u32 offset;
        u16 size;

        /* Nothing to do if the memory region is doesn't exist or is empty */
        mem = ipa_table_mem(ipa, filter, hashed, ipv6);
        if (!mem || !mem->size)
                return;

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

        offset = mem->offset + first * sizeof(__le64);
        size = count * sizeof(__le64);
        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, bool hashed, bool ipv6, bool modem)
{
        u64 ep_mask = ipa->filtered;
        struct gsi_trans *trans;
        enum gsi_ee_id ee_id;

        trans = ipa_cmd_trans_alloc(ipa, hweight64(ep_mask));
        if (!trans) {
                dev_err(ipa->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, hashed, ipv6, endpoint_id, 1);
        }

        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, false, false, modem);
        if (ret)
                return ret;

        ret = ipa_filter_reset_table(ipa, false, true, modem);
        if (ret || !ipa_table_hash_support(ipa))
                return ret;

        ret = ipa_filter_reset_table(ipa, true, false, modem);
        if (ret)
                return ret;

        return ipa_filter_reset_table(ipa, true, true, modem);
}

/* 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)
{
        bool hash_support = ipa_table_hash_support(ipa);
        u32 modem_route_count = ipa->modem_route_count;
        struct gsi_trans *trans;
        u16 first;
        u16 count;

        trans = ipa_cmd_trans_alloc(ipa, hash_support ? 4 : 2);
        if (!trans) {
                dev_err(ipa->dev, "no transaction for %s route reset\n",
                        modem ? "modem" : "AP");
                return -EBUSY;
        }

        if (modem) {
                first = 0;
                count = modem_route_count;
        } else {
                first = modem_route_count;
                count = ipa->route_count - modem_route_count;
        }

        ipa_table_reset_add(trans, false, false, false, first, count);
        ipa_table_reset_add(trans, false, false, true, first, count);

        if (hash_support) {
                ipa_table_reset_add(trans, false, true, false, first, count);
                ipa_table_reset_add(trans, false, true, true, first, count);
        }

        gsi_trans_commit_wait(trans);

        return 0;
}

void ipa_table_reset(struct ipa *ipa, bool modem)
{
        struct device *dev = ipa->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)
{
        struct gsi_trans *trans;
        const struct reg *reg;
        u32 val;

        if (!ipa_table_hash_support(ipa))
                return 0;

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

        if (ipa->version < IPA_VERSION_5_0) {
                reg = ipa_reg(ipa, FILT_ROUT_HASH_FLUSH);

                val = reg_bit(reg, IPV6_ROUTER_HASH);
                val |= reg_bit(reg, IPV6_FILTER_HASH);
                val |= reg_bit(reg, IPV4_ROUTER_HASH);
                val |= reg_bit(reg, IPV4_FILTER_HASH);
        } else {
                reg = ipa_reg(ipa, FILT_ROUT_CACHE_FLUSH);

                /* IPA v5.0+ uses a unified cache (both IPv4 and IPv6) */
                val = reg_bit(reg, ROUTER_CACHE);
                val |= reg_bit(reg, FILTER_CACHE);
        }

        ipa_cmd_register_write_add(trans, reg_offset(reg), val, val, false);

        gsi_trans_commit_wait(trans);

        return 0;
}

static void ipa_table_init_add(struct gsi_trans *trans, bool filter, bool ipv6)
{
        struct ipa *ipa = container_of(trans->gsi, struct ipa, gsi);
        const struct ipa_mem *hash_mem;
        enum ipa_cmd_opcode opcode;
        const struct ipa_mem *mem;
        dma_addr_t hash_addr;
        dma_addr_t addr;
        u32 hash_offset;
        u32 zero_offset;
        u16 hash_count;
        u32 zero_size;
        u16 hash_size;
        u16 count;
        u16 size;

        opcode = filter ? ipv6 ? IPA_CMD_IP_V6_FILTER_INIT
                               : IPA_CMD_IP_V4_FILTER_INIT
                        : ipv6 ? IPA_CMD_IP_V6_ROUTING_INIT
                               : IPA_CMD_IP_V4_ROUTING_INIT;

        /* The non-hashed region will exist (see ipa_table_mem_valid()) */
        mem = ipa_table_mem(ipa, filter, false, ipv6);
        hash_mem = ipa_table_mem(ipa, filter, true, ipv6);
        hash_offset = hash_mem ? hash_mem->offset : 0;

        /* Compute the number of table entries to initialize */
        if (filter) {
                /* The number of filtering endpoints determines number of
                 * entries in the filter table; we also add one more "slot"
                 * to hold the bitmap itself.  The size of the hashed filter
                 * table is either the same as the non-hashed one, or zero.
                 */
                count = 1 + hweight64(ipa->filtered);
                hash_count = hash_mem && hash_mem->size ? count : 0;
        } else {
                /* The size of a route table region determines the number
                 * of entries it has.
                 */
                count = mem->size / sizeof(__le64);
                hash_count = hash_mem ? hash_mem->size / sizeof(__le64) : 0;
        }
        size = count * sizeof(__le64);
        hash_size = hash_count * sizeof(__le64);

        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_offset, hash_addr);
        if (!filter)
                return;

        /* Zero the unused space in the filter table */
        zero_offset = mem->offset + size;
        zero_size = mem->size - size;
        ipa_cmd_dma_shared_mem_add(trans, zero_offset, zero_size,
                                   ipa->zero_addr, true);
        if (!hash_size)
                return;

        /* Zero the unused space in the hashed filter table */
        zero_offset = hash_offset + hash_size;
        zero_size = hash_mem->size - hash_size;
        ipa_cmd_dma_shared_mem_add(trans, zero_offset, zero_size,
                                   ipa->zero_addr, true);
}

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

        /* We will need at most 8 TREs:
         * - IPv4:
         *     - One for route table initialization (non-hashed and hashed)
         *     - One for filter table initialization (non-hashed and hashed)
         *     - One to zero unused entries in the non-hashed filter table
         *     - One to zero unused entries in the hashed filter table
         * - IPv6:
         *     - One for route table initialization (non-hashed and hashed)
         *     - One for filter table initialization (non-hashed and hashed)
         *     - One to zero unused entries in the non-hashed filter table
         *     - One to zero unused entries in the hashed filter table
         * All platforms support at least 8 TREs in a transaction.
         */
        trans = ipa_cmd_trans_alloc(ipa, 8);
        if (!trans) {
                dev_err(ipa->dev, "no transaction for table setup\n");
                return -EBUSY;
        }

        ipa_table_init_add(trans, false, false);
        ipa_table_init_add(trans, false, true);
        ipa_table_init_add(trans, true, false);
        ipa_table_init_add(trans, true, true);

        gsi_trans_commit_wait(trans);

        return 0;
}

/**
 * ipa_filter_tuple_zero() - Zero an endpoint's hashed filter tuple
 * @endpoint:   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;
        struct ipa *ipa = endpoint->ipa;
        const struct reg *reg;
        u32 offset;
        u32 val;

        if (ipa->version < IPA_VERSION_5_0) {
                reg = ipa_reg(ipa, ENDP_FILTER_ROUTER_HSH_CFG);

                offset = reg_n_offset(reg, endpoint_id);
                val = ioread32(endpoint->ipa->reg_virt + offset);

                /* Zero all filter-related fields, preserving the rest */
                val &= ~reg_fmask(reg, FILTER_HASH_MSK_ALL);
        } else {
                /* IPA v5.0 separates filter and router cache configuration */
                reg = ipa_reg(ipa, ENDP_FILTER_CACHE_CFG);
                offset = reg_n_offset(reg, endpoint_id);

                /* Zero all filter-related fields */
                val = 0;
        }

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

/* Configure a hashed filter table; there is no ipa_filter_deconfig() */
static void ipa_filter_config(struct ipa *ipa, bool modem)
{
        enum gsi_ee_id ee_id = modem ? GSI_EE_MODEM : GSI_EE_AP;
        u64 ep_mask = ipa->filtered;

        if (!ipa_table_hash_support(ipa))
                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 bool ipa_route_id_modem(struct ipa *ipa, u32 route_id)
{
        return route_id < ipa->modem_route_count;
}

/**
 * ipa_route_tuple_zero() - Zero a hashed route table entry tuple
 * @ipa:        IPA pointer
 * @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)
{
        const struct reg *reg;
        u32 offset;
        u32 val;

        if (ipa->version < IPA_VERSION_5_0) {
                reg = ipa_reg(ipa, ENDP_FILTER_ROUTER_HSH_CFG);
                offset = reg_n_offset(reg, route_id);

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

                /* Zero all route-related fields, preserving the rest */
                val &= ~reg_fmask(reg, ROUTER_HASH_MSK_ALL);
        } else {
                /* IPA v5.0 separates filter and router cache configuration */
                reg = ipa_reg(ipa, ENDP_ROUTER_CACHE_CFG);
                offset = reg_n_offset(reg, route_id);

                /* Zero all route-related fields */
                val = 0;
        }

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

/* Configure a hashed route table; there is no ipa_route_deconfig() */
static void ipa_route_config(struct ipa *ipa, bool modem)
{
        u32 route_id;

        if (!ipa_table_hash_support(ipa))
                return;

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

/* Configure a filter and route tables; there is no ipa_table_deconfig() */
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);
}

/* Verify the sizes of all IPA table filter or routing table memory regions
 * are valid.  If valid, this records the size of the routing table.
 */
bool ipa_table_mem_valid(struct ipa *ipa, bool filter)
{
        bool hash_support = ipa_table_hash_support(ipa);
        const struct ipa_mem *mem_hashed;
        const struct ipa_mem *mem_ipv4;
        const struct ipa_mem *mem_ipv6;
        u32 count;

        /* IPv4 and IPv6 non-hashed tables are expected to be defined and
         * have the same size.  Both must have at least two entries (and
         * would normally have more than that).
         */
        mem_ipv4 = ipa_table_mem(ipa, filter, false, false);
        if (!mem_ipv4)
                return false;

        mem_ipv6 = ipa_table_mem(ipa, filter, false, true);
        if (!mem_ipv6)
                return false;

        if (mem_ipv4->size != mem_ipv6->size)
                return false;

        /* Compute and record the number of entries for each table type */
        count = mem_ipv4->size / sizeof(__le64);
        if (count < 2)
                return false;
        if (filter)
                ipa->filter_count = count - 1;  /* Filter map in first entry */
        else
                ipa->route_count = count;

        /* Table offset and size must fit in TABLE_INIT command fields */
        if (!ipa_cmd_table_init_valid(ipa, mem_ipv4, !filter))
                return false;

        /* Make sure the regions are big enough */
        if (filter) {
                /* Filter tables must able to hold the endpoint bitmap plus
                 * an entry for each endpoint that supports filtering
                 */
                if (count < 1 + hweight64(ipa->filtered))
                        return false;
        } else {
                /* Routing tables must be able to hold all modem entries,
                 * plus at least one entry for the AP.
                 */
                if (count < ipa->modem_route_count + 1)
                        return false;
        }

        /* If hashing is supported, hashed tables are expected to be defined,
         * and have the same size as non-hashed tables.  If hashing is not
         * supported, hashed tables are expected to have zero size (or not
         * be defined).
         */
        mem_hashed = ipa_table_mem(ipa, filter, true, false);
        if (hash_support) {
                if (!mem_hashed || mem_hashed->size != mem_ipv4->size)
                        return false;
        } else {
                if (mem_hashed && mem_hashed->size)
                        return false;
        }

        /* Same check for IPv6 tables */
        mem_hashed = ipa_table_mem(ipa, filter, true, true);
        if (hash_support) {
                if (!mem_hashed || mem_hashed->size != mem_ipv6->size)
                        return false;
        } else {
                if (mem_hashed && mem_hashed->size)
                        return false;
        }

        return true;
}

/* 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 is a fixed maximum number of 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.
 *
 *           +-------------------+
 *       --> |     zero rule     |
 *      /    |-------------------|
 *      |    |     filter mask   |
 *      |\   |-------------------|
 *      | ---- zero rule address | \
 *      |\   |-------------------|  |
 *      | ---- zero rule address |  |   Max IPA filter count
 *      |    |-------------------|   >  or IPA route count,
 *      |             ...           |   whichever is greater
 *       \   |-------------------|  |
 *        ---- zero rule address | /
 *           +-------------------+
 */
int ipa_table_init(struct ipa *ipa)
{
        struct device *dev = ipa->dev;
        dma_addr_t addr;
        __le64 le_addr;
        __le64 *virt;
        size_t size;
        u32 count;

        ipa_table_validate_build();

        count = max_t(u32, ipa->filter_count, ipa->route_count);

        /* The IPA hardware requires route and filter table rules to be
         * aligned on a 128-byte boundary.  We put the "zero rule" at the
         * base of the table area allocated here.  The DMA address returned
         * by dma_alloc_coherent() is guaranteed to be a power-of-2 number
         * of pages, which satisfies the rule alignment requirement.
         */
        size = IPA_ZERO_RULE_SIZE + (1 + count) * sizeof(__le64);
        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 might
         * need to be converted to the hardware representation by shifting
         * it left one position.  Prior to IPA v5.0, bit 0 repesents global
         * filtering, which is possible but not used.  IPA v5.0+ eliminated
         * that option, so there's no shifting required.
         */
        if (ipa->version < IPA_VERSION_5_0)
                *virt++ = cpu_to_le64(ipa->filtered << 1);
        else
                *virt++ = cpu_to_le64(ipa->filtered);

        /* 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, ipa->route_count);
        struct device *dev = ipa->dev;
        size_t size;

        size = IPA_ZERO_RULE_SIZE + (1 + count) * sizeof(__le64);

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