io_uring: reset -EBUSY error when io sq thread is waken up

[thirdparty/linux.git] / drivers / net / ipa / ipa_endpoint.c

// SPDX-License-Identifier: GPL-2.0

/* Copyright (c) 2012-2018, The Linux Foundation. All rights reserved.
 * Copyright (C) 2019-2020 Linaro Ltd.
 */

#include <linux/types.h>
#include <linux/device.h>
#include <linux/slab.h>
#include <linux/bitfield.h>
#include <linux/if_rmnet.h>
#include <linux/dma-direction.h>

#include "gsi.h"
#include "gsi_trans.h"
#include "ipa.h"
#include "ipa_data.h"
#include "ipa_endpoint.h"
#include "ipa_cmd.h"
#include "ipa_mem.h"
#include "ipa_modem.h"
#include "ipa_table.h"
#include "ipa_gsi.h"

#define atomic_dec_not_zero(v)  atomic_add_unless((v), -1, 0)

#define IPA_REPLENISH_BATCH     16

/* RX buffer is 1 page (or a power-of-2 contiguous pages) */
#define IPA_RX_BUFFER_SIZE      8192    /* PAGE_SIZE > 4096 wastes a LOT */

/* The amount of RX buffer space consumed by standard skb overhead */
#define IPA_RX_BUFFER_OVERHEAD  (PAGE_SIZE - SKB_MAX_ORDER(NET_SKB_PAD, 0))

#define IPA_ENDPOINT_STOP_RX_RETRIES            10
#define IPA_ENDPOINT_STOP_RX_SIZE               1       /* bytes */

#define IPA_ENDPOINT_RESET_AGGR_RETRY_MAX       3
#define IPA_AGGR_TIME_LIMIT_DEFAULT             1000    /* microseconds */

#define ENDPOINT_STOP_DMA_TIMEOUT               15      /* milliseconds */

/** enum ipa_status_opcode - status element opcode hardware values */
enum ipa_status_opcode {
        IPA_STATUS_OPCODE_PACKET                = 0x01,
        IPA_STATUS_OPCODE_NEW_FRAG_RULE         = 0x02,
        IPA_STATUS_OPCODE_DROPPED_PACKET        = 0x04,
        IPA_STATUS_OPCODE_SUSPENDED_PACKET      = 0x08,
        IPA_STATUS_OPCODE_LOG                   = 0x10,
        IPA_STATUS_OPCODE_DCMP                  = 0x20,
        IPA_STATUS_OPCODE_PACKET_2ND_PASS       = 0x40,
};

/** enum ipa_status_exception - status element exception type */
enum ipa_status_exception {
        /* 0 means no exception */
        IPA_STATUS_EXCEPTION_DEAGGR             = 0x01,
        IPA_STATUS_EXCEPTION_IPTYPE             = 0x04,
        IPA_STATUS_EXCEPTION_PACKET_LENGTH      = 0x08,
        IPA_STATUS_EXCEPTION_FRAG_RULE_MISS     = 0x10,
        IPA_STATUS_EXCEPTION_SW_FILT            = 0x20,
        /* The meaning of the next value depends on whether the IP version */
        IPA_STATUS_EXCEPTION_NAT                = 0x40,         /* IPv4 */
        IPA_STATUS_EXCEPTION_IPV6CT             = IPA_STATUS_EXCEPTION_NAT,
};

/* Status element provided by hardware */
struct ipa_status {
        u8 opcode;              /* enum ipa_status_opcode */
        u8 exception;           /* enum ipa_status_exception */
        __le16 mask;
        __le16 pkt_len;
        u8 endp_src_idx;
        u8 endp_dst_idx;
        __le32 metadata;
        __le32 flags1;
        __le64 flags2;
        __le32 flags3;
        __le32 flags4;
};

/* Field masks for struct ipa_status structure fields */

#define IPA_STATUS_SRC_IDX_FMASK                GENMASK(4, 0)

#define IPA_STATUS_DST_IDX_FMASK                GENMASK(4, 0)

#define IPA_STATUS_FLAGS1_FLT_LOCAL_FMASK       GENMASK(0, 0)
#define IPA_STATUS_FLAGS1_FLT_HASH_FMASK        GENMASK(1, 1)
#define IPA_STATUS_FLAGS1_FLT_GLOBAL_FMASK      GENMASK(2, 2)
#define IPA_STATUS_FLAGS1_FLT_RET_HDR_FMASK     GENMASK(3, 3)
#define IPA_STATUS_FLAGS1_FLT_RULE_ID_FMASK     GENMASK(13, 4)
#define IPA_STATUS_FLAGS1_RT_LOCAL_FMASK        GENMASK(14, 14)
#define IPA_STATUS_FLAGS1_RT_HASH_FMASK         GENMASK(15, 15)
#define IPA_STATUS_FLAGS1_UCP_FMASK             GENMASK(16, 16)
#define IPA_STATUS_FLAGS1_RT_TBL_IDX_FMASK      GENMASK(21, 17)
#define IPA_STATUS_FLAGS1_RT_RULE_ID_FMASK      GENMASK(31, 22)

#define IPA_STATUS_FLAGS2_NAT_HIT_FMASK         GENMASK_ULL(0, 0)
#define IPA_STATUS_FLAGS2_NAT_ENTRY_IDX_FMASK   GENMASK_ULL(13, 1)
#define IPA_STATUS_FLAGS2_NAT_TYPE_FMASK        GENMASK_ULL(15, 14)
#define IPA_STATUS_FLAGS2_TAG_INFO_FMASK        GENMASK_ULL(63, 16)

#define IPA_STATUS_FLAGS3_SEQ_NUM_FMASK         GENMASK(7, 0)
#define IPA_STATUS_FLAGS3_TOD_CTR_FMASK         GENMASK(31, 8)

#define IPA_STATUS_FLAGS4_HDR_LOCAL_FMASK       GENMASK(0, 0)
#define IPA_STATUS_FLAGS4_HDR_OFFSET_FMASK      GENMASK(10, 1)
#define IPA_STATUS_FLAGS4_FRAG_HIT_FMASK        GENMASK(11, 11)
#define IPA_STATUS_FLAGS4_FRAG_RULE_FMASK       GENMASK(15, 12)
#define IPA_STATUS_FLAGS4_HW_SPECIFIC_FMASK     GENMASK(31, 16)

#ifdef IPA_VALIDATE

static void ipa_endpoint_validate_build(void)
{
        /* The aggregation byte limit defines the point at which an
         * aggregation window will close.  It is programmed into the
         * IPA hardware as a number of KB.  We don't use "hard byte
         * limit" aggregation, which means that we need to supply
         * enough space in a receive buffer to hold a complete MTU
         * plus normal skb overhead *after* that aggregation byte
         * limit has been crossed.
         *
         * This check just ensures we don't define a receive buffer
         * size that would exceed what we can represent in the field
         * that is used to program its size.
         */
        BUILD_BUG_ON(IPA_RX_BUFFER_SIZE >
                     field_max(AGGR_BYTE_LIMIT_FMASK) * SZ_1K +
                     IPA_MTU + IPA_RX_BUFFER_OVERHEAD);

        /* I honestly don't know where this requirement comes from.  But
         * it holds, and if we someday need to loosen the constraint we
         * can try to track it down.
         */
        BUILD_BUG_ON(sizeof(struct ipa_status) % 4);
}

static bool ipa_endpoint_data_valid_one(struct ipa *ipa, u32 count,
                            const struct ipa_gsi_endpoint_data *all_data,
                            const struct ipa_gsi_endpoint_data *data)
{
        const struct ipa_gsi_endpoint_data *other_data;
        struct device *dev = &ipa->pdev->dev;
        enum ipa_endpoint_name other_name;

        if (ipa_gsi_endpoint_data_empty(data))
                return true;

        if (!data->toward_ipa) {
                if (data->endpoint.filter_support) {
                        dev_err(dev, "filtering not supported for "
                                        "RX endpoint %u\n",
                                data->endpoint_id);
                        return false;
                }

                return true;    /* Nothing more to check for RX */
        }

        if (data->endpoint.config.status_enable) {
                other_name = data->endpoint.config.tx.status_endpoint;
                if (other_name >= count) {
                        dev_err(dev, "status endpoint name %u out of range "
                                        "for endpoint %u\n",
                                other_name, data->endpoint_id);
                        return false;
                }

                /* Status endpoint must be defined... */
                other_data = &all_data[other_name];
                if (ipa_gsi_endpoint_data_empty(other_data)) {
                        dev_err(dev, "DMA endpoint name %u undefined "
                                        "for endpoint %u\n",
                                other_name, data->endpoint_id);
                        return false;
                }

                /* ...and has to be an RX endpoint... */
                if (other_data->toward_ipa) {
                        dev_err(dev,
                                "status endpoint for endpoint %u not RX\n",
                                data->endpoint_id);
                        return false;
                }

                /* ...and if it's to be an AP endpoint... */
                if (other_data->ee_id == GSI_EE_AP) {
                        /* ...make sure it has status enabled. */
                        if (!other_data->endpoint.config.status_enable) {
                                dev_err(dev,
                                        "status not enabled for endpoint %u\n",
                                        other_data->endpoint_id);
                                return false;
                        }
                }
        }

        if (data->endpoint.config.dma_mode) {
                other_name = data->endpoint.config.dma_endpoint;
                if (other_name >= count) {
                        dev_err(dev, "DMA endpoint name %u out of range "
                                        "for endpoint %u\n",
                                other_name, data->endpoint_id);
                        return false;
                }

                other_data = &all_data[other_name];
                if (ipa_gsi_endpoint_data_empty(other_data)) {
                        dev_err(dev, "DMA endpoint name %u undefined "
                                        "for endpoint %u\n",
                                other_name, data->endpoint_id);
                        return false;
                }
        }

        return true;
}

static bool ipa_endpoint_data_valid(struct ipa *ipa, u32 count,
                                    const struct ipa_gsi_endpoint_data *data)
{
        const struct ipa_gsi_endpoint_data *dp = data;
        struct device *dev = &ipa->pdev->dev;
        enum ipa_endpoint_name name;

        ipa_endpoint_validate_build();

        if (count > IPA_ENDPOINT_COUNT) {
                dev_err(dev, "too many endpoints specified (%u > %u)\n",
                        count, IPA_ENDPOINT_COUNT);
                return false;
        }

        /* Make sure needed endpoints have defined data */
        if (ipa_gsi_endpoint_data_empty(&data[IPA_ENDPOINT_AP_COMMAND_TX])) {
                dev_err(dev, "command TX endpoint not defined\n");
                return false;
        }
        if (ipa_gsi_endpoint_data_empty(&data[IPA_ENDPOINT_AP_LAN_RX])) {
                dev_err(dev, "LAN RX endpoint not defined\n");
                return false;
        }
        if (ipa_gsi_endpoint_data_empty(&data[IPA_ENDPOINT_AP_MODEM_TX])) {
                dev_err(dev, "AP->modem TX endpoint not defined\n");
                return false;
        }
        if (ipa_gsi_endpoint_data_empty(&data[IPA_ENDPOINT_AP_MODEM_RX])) {
                dev_err(dev, "AP<-modem RX endpoint not defined\n");
                return false;
        }

        for (name = 0; name < count; name++, dp++)
                if (!ipa_endpoint_data_valid_one(ipa, count, data, dp))
                        return false;

        return true;
}

#else /* !IPA_VALIDATE */

static bool ipa_endpoint_data_valid(struct ipa *ipa, u32 count,
                                    const struct ipa_gsi_endpoint_data *data)
{
        return true;
}

#endif /* !IPA_VALIDATE */

/* Allocate a transaction to use on a non-command endpoint */
static struct gsi_trans *ipa_endpoint_trans_alloc(struct ipa_endpoint *endpoint,
                                                  u32 tre_count)
{
        struct gsi *gsi = &endpoint->ipa->gsi;
        u32 channel_id = endpoint->channel_id;
        enum dma_data_direction direction;

        direction = endpoint->toward_ipa ? DMA_TO_DEVICE : DMA_FROM_DEVICE;

        return gsi_channel_trans_alloc(gsi, channel_id, tre_count, direction);
}

/* suspend_delay represents suspend for RX, delay for TX endpoints.
 * Note that suspend is not supported starting with IPA v4.0.
 */
static int
ipa_endpoint_init_ctrl(struct ipa_endpoint *endpoint, bool suspend_delay)
{
        u32 offset = IPA_REG_ENDP_INIT_CTRL_N_OFFSET(endpoint->endpoint_id);
        struct ipa *ipa = endpoint->ipa;
        u32 mask;
        u32 val;

        /* assert(ipa->version == IPA_VERSION_3_5_1 */
        mask = endpoint->toward_ipa ? ENDP_DELAY_FMASK : ENDP_SUSPEND_FMASK;

        val = ioread32(ipa->reg_virt + offset);
        if (suspend_delay == !!(val & mask))
                return -EALREADY;       /* Already set to desired state */

        val ^= mask;
        iowrite32(val, ipa->reg_virt + offset);

        return 0;
}

/* Enable or disable delay or suspend mode on all modem endpoints */
void ipa_endpoint_modem_pause_all(struct ipa *ipa, bool enable)
{
        bool support_suspend;
        u32 endpoint_id;

        /* DELAY mode doesn't work right on IPA v4.2 */
        if (ipa->version == IPA_VERSION_4_2)
                return;

        /* Only IPA v3.5.1 supports SUSPEND mode on RX endpoints */
        support_suspend = ipa->version == IPA_VERSION_3_5_1;

        for (endpoint_id = 0; endpoint_id < IPA_ENDPOINT_MAX; endpoint_id++) {
                struct ipa_endpoint *endpoint = &ipa->endpoint[endpoint_id];

                if (endpoint->ee_id != GSI_EE_MODEM)
                        continue;

                /* Set TX delay mode, or for IPA v3.5.1 RX suspend mode */
                if (endpoint->toward_ipa || support_suspend)
                        (void)ipa_endpoint_init_ctrl(endpoint, enable);
        }
}

/* Reset all modem endpoints to use the default exception endpoint */
int ipa_endpoint_modem_exception_reset_all(struct ipa *ipa)
{
        u32 initialized = ipa->initialized;
        struct gsi_trans *trans;
        u32 count;

        /* We need one command per modem TX endpoint.  We can get an upper
         * bound on that by assuming all initialized endpoints are modem->IPA.
         * That won't happen, and we could be more precise, but this is fine
         * for now.  We need to end the transactio with a "tag process."
         */
        count = hweight32(initialized) + ipa_cmd_tag_process_count();
        trans = ipa_cmd_trans_alloc(ipa, count);
        if (!trans) {
                dev_err(&ipa->pdev->dev,
                        "no transaction to reset modem exception endpoints\n");
                return -EBUSY;
        }

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

                initialized ^= BIT(endpoint_id);

                /* We only reset modem TX endpoints */
                endpoint = &ipa->endpoint[endpoint_id];
                if (!(endpoint->ee_id == GSI_EE_MODEM && endpoint->toward_ipa))
                        continue;

                offset = IPA_REG_ENDP_STATUS_N_OFFSET(endpoint_id);

                /* Value written is 0, and all bits are updated.  That
                 * means status is disabled on the endpoint, and as a
                 * result all other fields in the register are ignored.
                 */
                ipa_cmd_register_write_add(trans, offset, 0, ~0, false);
        }

        ipa_cmd_tag_process_add(trans);

        /* XXX This should have a 1 second timeout */
        gsi_trans_commit_wait(trans);

        return 0;
}

static void ipa_endpoint_init_cfg(struct ipa_endpoint *endpoint)
{
        u32 offset = IPA_REG_ENDP_INIT_CFG_N_OFFSET(endpoint->endpoint_id);
        u32 val = 0;

        /* FRAG_OFFLOAD_EN is 0 */
        if (endpoint->data->checksum) {
                if (endpoint->toward_ipa) {
                        u32 checksum_offset;

                        val |= u32_encode_bits(IPA_CS_OFFLOAD_UL,
                                               CS_OFFLOAD_EN_FMASK);
                        /* Checksum header offset is in 4-byte units */
                        checksum_offset = sizeof(struct rmnet_map_header);
                        checksum_offset /= sizeof(u32);
                        val |= u32_encode_bits(checksum_offset,
                                               CS_METADATA_HDR_OFFSET_FMASK);
                } else {
                        val |= u32_encode_bits(IPA_CS_OFFLOAD_DL,
                                               CS_OFFLOAD_EN_FMASK);
                }
        } else {
                val |= u32_encode_bits(IPA_CS_OFFLOAD_NONE,
                                       CS_OFFLOAD_EN_FMASK);
        }
        /* CS_GEN_QMB_MASTER_SEL is 0 */

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

static void ipa_endpoint_init_hdr(struct ipa_endpoint *endpoint)
{
        u32 offset = IPA_REG_ENDP_INIT_HDR_N_OFFSET(endpoint->endpoint_id);
        u32 val = 0;

        if (endpoint->data->qmap) {
                size_t header_size = sizeof(struct rmnet_map_header);

                if (endpoint->toward_ipa && endpoint->data->checksum)
                        header_size += sizeof(struct rmnet_map_ul_csum_header);

                val |= u32_encode_bits(header_size, HDR_LEN_FMASK);
                /* metadata is the 4 byte rmnet_map header itself */
                val |= HDR_OFST_METADATA_VALID_FMASK;
                val |= u32_encode_bits(0, HDR_OFST_METADATA_FMASK);
                /* HDR_ADDITIONAL_CONST_LEN is 0; (IPA->AP only) */
                if (!endpoint->toward_ipa) {
                        u32 size_offset = offsetof(struct rmnet_map_header,
                                                   pkt_len);

                        val |= HDR_OFST_PKT_SIZE_VALID_FMASK;
                        val |= u32_encode_bits(size_offset,
                                               HDR_OFST_PKT_SIZE_FMASK);
                }
                /* HDR_A5_MUX is 0 */
                /* HDR_LEN_INC_DEAGG_HDR is 0 */
                /* HDR_METADATA_REG_VALID is 0; (AP->IPA only) */
        }

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

static void ipa_endpoint_init_hdr_ext(struct ipa_endpoint *endpoint)
{
        u32 offset = IPA_REG_ENDP_INIT_HDR_EXT_N_OFFSET(endpoint->endpoint_id);
        u32 pad_align = endpoint->data->rx.pad_align;
        u32 val = 0;

        val |= HDR_ENDIANNESS_FMASK;            /* big endian */
        val |= HDR_TOTAL_LEN_OR_PAD_VALID_FMASK;
        /* HDR_TOTAL_LEN_OR_PAD is 0 (pad, not total_len) */
        /* HDR_PAYLOAD_LEN_INC_PADDING is 0 */
        /* HDR_TOTAL_LEN_OR_PAD_OFFSET is 0 */
        if (!endpoint->toward_ipa)
                val |= u32_encode_bits(pad_align, HDR_PAD_TO_ALIGNMENT_FMASK);

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

/**
 * Generate a metadata mask value that will select only the mux_id
 * field in an rmnet_map header structure.  The mux_id is at offset
 * 1 byte from the beginning of the structure, but the metadata
 * value is treated as a 4-byte unit.  So this mask must be computed
 * with endianness in mind.  Note that ipa_endpoint_init_hdr_metadata_mask()
 * will convert this value to the proper byte order.
 *
 * Marked __always_inline because this is really computing a
 * constant value.
 */
static __always_inline __be32 ipa_rmnet_mux_id_metadata_mask(void)
{
        size_t mux_id_offset = offsetof(struct rmnet_map_header, mux_id);
        u32 mux_id_mask = 0;
        u8 *bytes;

        bytes = (u8 *)&mux_id_mask;
        bytes[mux_id_offset] = 0xff;    /* mux_id is 1 byte */

        return cpu_to_be32(mux_id_mask);
}

static void ipa_endpoint_init_hdr_metadata_mask(struct ipa_endpoint *endpoint)
{
        u32 endpoint_id = endpoint->endpoint_id;
        u32 val = 0;
        u32 offset;

        offset = IPA_REG_ENDP_INIT_HDR_METADATA_MASK_N_OFFSET(endpoint_id);

        if (!endpoint->toward_ipa && endpoint->data->qmap)
                val = ipa_rmnet_mux_id_metadata_mask();

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

static void ipa_endpoint_init_mode(struct ipa_endpoint *endpoint)
{
        u32 offset = IPA_REG_ENDP_INIT_MODE_N_OFFSET(endpoint->endpoint_id);
        u32 val;

        if (endpoint->toward_ipa && endpoint->data->dma_mode) {
                enum ipa_endpoint_name name = endpoint->data->dma_endpoint;
                u32 dma_endpoint_id;

                dma_endpoint_id = endpoint->ipa->name_map[name]->endpoint_id;

                val = u32_encode_bits(IPA_DMA, MODE_FMASK);
                val |= u32_encode_bits(dma_endpoint_id, DEST_PIPE_INDEX_FMASK);
        } else {
                val = u32_encode_bits(IPA_BASIC, MODE_FMASK);
        }
        /* Other bitfields unspecified (and 0) */

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

/* Compute the aggregation size value to use for a given buffer size */
static u32 ipa_aggr_size_kb(u32 rx_buffer_size)
{
        /* We don't use "hard byte limit" aggregation, so we define the
         * aggregation limit such that our buffer has enough space *after*
         * that limit to receive a full MTU of data, plus overhead.
         */
        rx_buffer_size -= IPA_MTU + IPA_RX_BUFFER_OVERHEAD;

        return rx_buffer_size / SZ_1K;
}

static void ipa_endpoint_init_aggr(struct ipa_endpoint *endpoint)
{
        u32 offset = IPA_REG_ENDP_INIT_AGGR_N_OFFSET(endpoint->endpoint_id);
        u32 val = 0;

        if (endpoint->data->aggregation) {
                if (!endpoint->toward_ipa) {
                        u32 aggr_size = ipa_aggr_size_kb(IPA_RX_BUFFER_SIZE);
                        u32 limit;

                        val |= u32_encode_bits(IPA_ENABLE_AGGR, AGGR_EN_FMASK);
                        val |= u32_encode_bits(IPA_GENERIC, AGGR_TYPE_FMASK);
                        val |= u32_encode_bits(aggr_size,
                                               AGGR_BYTE_LIMIT_FMASK);
                        limit = IPA_AGGR_TIME_LIMIT_DEFAULT;
                        val |= u32_encode_bits(limit / IPA_AGGR_GRANULARITY,
                                               AGGR_TIME_LIMIT_FMASK);
                        val |= u32_encode_bits(0, AGGR_PKT_LIMIT_FMASK);
                        if (endpoint->data->rx.aggr_close_eof)
                                val |= AGGR_SW_EOF_ACTIVE_FMASK;
                        /* AGGR_HARD_BYTE_LIMIT_ENABLE is 0 */
                } else {
                        val |= u32_encode_bits(IPA_ENABLE_DEAGGR,
                                               AGGR_EN_FMASK);
                        val |= u32_encode_bits(IPA_QCMAP, AGGR_TYPE_FMASK);
                        /* other fields ignored */
                }
                /* AGGR_FORCE_CLOSE is 0 */
        } else {
                val |= u32_encode_bits(IPA_BYPASS_AGGR, AGGR_EN_FMASK);
                /* other fields ignored */
        }

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

/* A return value of 0 indicates an error */
static u32 ipa_reg_init_hol_block_timer_val(struct ipa *ipa, u32 microseconds)
{
        u32 scale;
        u32 base;
        u32 val;

        if (!microseconds)
                return 0;       /* invalid delay */

        /* Timer is represented in units of clock ticks. */
        if (ipa->version < IPA_VERSION_4_2)
                return microseconds;    /* XXX Needs to be computed */

        /* IPA v4.2 represents the tick count as base * scale */
        scale = 1;                      /* XXX Needs to be computed */
        if (scale > field_max(SCALE_FMASK))
                return 0;               /* scale too big */

        base = DIV_ROUND_CLOSEST(microseconds, scale);
        if (base > field_max(BASE_VALUE_FMASK))
                return 0;               /* microseconds too big */

        val = u32_encode_bits(scale, SCALE_FMASK);
        val |= u32_encode_bits(base, BASE_VALUE_FMASK);

        return val;
}

static int ipa_endpoint_init_hol_block_timer(struct ipa_endpoint *endpoint,
                                             u32 microseconds)
{
        u32 endpoint_id = endpoint->endpoint_id;
        struct ipa *ipa = endpoint->ipa;
        u32 offset;
        u32 val;

        /* XXX We'll fix this when the register definition is clear */
        if (microseconds) {
                struct device *dev = &ipa->pdev->dev;

                dev_err(dev, "endpoint %u non-zero HOLB period (ignoring)\n",
                        endpoint_id);
                microseconds = 0;
        }

        if (microseconds) {
                val = ipa_reg_init_hol_block_timer_val(ipa, microseconds);
                if (!val)
                        return -EINVAL;
        } else {
                val = 0;        /* timeout is immediate */
        }
        offset = IPA_REG_ENDP_INIT_HOL_BLOCK_TIMER_N_OFFSET(endpoint_id);
        iowrite32(val, ipa->reg_virt + offset);

        return 0;
}

static void
ipa_endpoint_init_hol_block_enable(struct ipa_endpoint *endpoint, bool enable)
{
        u32 endpoint_id = endpoint->endpoint_id;
        u32 offset;
        u32 val;

        val = u32_encode_bits(enable ? 1 : 0, HOL_BLOCK_EN_FMASK);
        offset = IPA_REG_ENDP_INIT_HOL_BLOCK_EN_N_OFFSET(endpoint_id);
        iowrite32(val, endpoint->ipa->reg_virt + offset);
}

void ipa_endpoint_modem_hol_block_clear_all(struct ipa *ipa)
{
        u32 i;

        for (i = 0; i < IPA_ENDPOINT_MAX; i++) {
                struct ipa_endpoint *endpoint = &ipa->endpoint[i];

                if (endpoint->ee_id != GSI_EE_MODEM)
                        continue;

                (void)ipa_endpoint_init_hol_block_timer(endpoint, 0);
                ipa_endpoint_init_hol_block_enable(endpoint, true);
        }
}

static void ipa_endpoint_init_deaggr(struct ipa_endpoint *endpoint)
{
        u32 offset = IPA_REG_ENDP_INIT_DEAGGR_N_OFFSET(endpoint->endpoint_id);
        u32 val = 0;

        /* DEAGGR_HDR_LEN is 0 */
        /* PACKET_OFFSET_VALID is 0 */
        /* PACKET_OFFSET_LOCATION is ignored (not valid) */
        /* MAX_PACKET_LEN is 0 (not enforced) */

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

static void ipa_endpoint_init_seq(struct ipa_endpoint *endpoint)
{
        u32 offset = IPA_REG_ENDP_INIT_SEQ_N_OFFSET(endpoint->endpoint_id);
        u32 seq_type = endpoint->seq_type;
        u32 val = 0;

        val |= u32_encode_bits(seq_type & 0xf, HPS_SEQ_TYPE_FMASK);
        val |= u32_encode_bits((seq_type >> 4) & 0xf, DPS_SEQ_TYPE_FMASK);
        /* HPS_REP_SEQ_TYPE is 0 */
        /* DPS_REP_SEQ_TYPE is 0 */

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

/**
 * ipa_endpoint_skb_tx() - Transmit a socket buffer
 * @endpoint:   Endpoint pointer
 * @skb:        Socket buffer to send
 *
 * Returns:     0 if successful, or a negative error code
 */
int ipa_endpoint_skb_tx(struct ipa_endpoint *endpoint, struct sk_buff *skb)
{
        struct gsi_trans *trans;
        u32 nr_frags;
        int ret;

        /* Make sure source endpoint's TLV FIFO has enough entries to
         * hold the linear portion of the skb and all its fragments.
         * If not, see if we can linearize it before giving up.
         */
        nr_frags = skb_shinfo(skb)->nr_frags;
        if (1 + nr_frags > endpoint->trans_tre_max) {
                if (skb_linearize(skb))
                        return -E2BIG;
                nr_frags = 0;
        }

        trans = ipa_endpoint_trans_alloc(endpoint, 1 + nr_frags);
        if (!trans)
                return -EBUSY;

        ret = gsi_trans_skb_add(trans, skb);
        if (ret)
                goto err_trans_free;
        trans->data = skb;      /* transaction owns skb now */

        gsi_trans_commit(trans, !netdev_xmit_more());

        return 0;

err_trans_free:
        gsi_trans_free(trans);

        return -ENOMEM;
}

static void ipa_endpoint_status(struct ipa_endpoint *endpoint)
{
        u32 endpoint_id = endpoint->endpoint_id;
        struct ipa *ipa = endpoint->ipa;
        u32 val = 0;
        u32 offset;

        offset = IPA_REG_ENDP_STATUS_N_OFFSET(endpoint_id);

        if (endpoint->data->status_enable) {
                val |= STATUS_EN_FMASK;
                if (endpoint->toward_ipa) {
                        enum ipa_endpoint_name name;
                        u32 status_endpoint_id;

                        name = endpoint->data->tx.status_endpoint;
                        status_endpoint_id = ipa->name_map[name]->endpoint_id;

                        val |= u32_encode_bits(status_endpoint_id,
                                               STATUS_ENDP_FMASK);
                }
                /* STATUS_LOCATION is 0 (status element precedes packet) */
                /* The next field is present for IPA v4.0 and above */
                /* STATUS_PKT_SUPPRESS_FMASK is 0 */
        }

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

static int ipa_endpoint_replenish_one(struct ipa_endpoint *endpoint)
{
        struct gsi_trans *trans;
        bool doorbell = false;
        struct page *page;
        u32 offset;
        u32 len;
        int ret;

        page = dev_alloc_pages(get_order(IPA_RX_BUFFER_SIZE));
        if (!page)
                return -ENOMEM;

        trans = ipa_endpoint_trans_alloc(endpoint, 1);
        if (!trans)
                goto err_free_pages;

        /* Offset the buffer to make space for skb headroom */
        offset = NET_SKB_PAD;
        len = IPA_RX_BUFFER_SIZE - offset;

        ret = gsi_trans_page_add(trans, page, len, offset);
        if (ret)
                goto err_trans_free;
        trans->data = page;     /* transaction owns page now */

        if (++endpoint->replenish_ready == IPA_REPLENISH_BATCH) {
                doorbell = true;
                endpoint->replenish_ready = 0;
        }

        gsi_trans_commit(trans, doorbell);

        return 0;

err_trans_free:
        gsi_trans_free(trans);
err_free_pages:
        __free_pages(page, get_order(IPA_RX_BUFFER_SIZE));

        return -ENOMEM;
}

/**
 * ipa_endpoint_replenish() - Replenish the Rx packets cache.
 *
 * Allocate RX packet wrapper structures with maximal socket buffers
 * for an endpoint.  These are supplied to the hardware, which fills
 * them with incoming data.
 */
static void ipa_endpoint_replenish(struct ipa_endpoint *endpoint, u32 count)
{
        struct gsi *gsi;
        u32 backlog;

        if (!endpoint->replenish_enabled) {
                if (count)
                        atomic_add(count, &endpoint->replenish_saved);
                return;
        }


        while (atomic_dec_not_zero(&endpoint->replenish_backlog))
                if (ipa_endpoint_replenish_one(endpoint))
                        goto try_again_later;
        if (count)
                atomic_add(count, &endpoint->replenish_backlog);

        return;

try_again_later:
        /* The last one didn't succeed, so fix the backlog */
        backlog = atomic_inc_return(&endpoint->replenish_backlog);

        if (count)
                atomic_add(count, &endpoint->replenish_backlog);

        /* Whenever a receive buffer transaction completes we'll try to
         * replenish again.  It's unlikely, but if we fail to supply even
         * one buffer, nothing will trigger another replenish attempt.
         * Receive buffer transactions use one TRE, so schedule work to
         * try replenishing again if our backlog is *all* available TREs.
         */
        gsi = &endpoint->ipa->gsi;
        if (backlog == gsi_channel_tre_max(gsi, endpoint->channel_id))
                schedule_delayed_work(&endpoint->replenish_work,
                                      msecs_to_jiffies(1));
}

static void ipa_endpoint_replenish_enable(struct ipa_endpoint *endpoint)
{
        struct gsi *gsi = &endpoint->ipa->gsi;
        u32 max_backlog;
        u32 saved;

        endpoint->replenish_enabled = true;
        while ((saved = atomic_xchg(&endpoint->replenish_saved, 0)))
                atomic_add(saved, &endpoint->replenish_backlog);

        /* Start replenishing if hardware currently has no buffers */
        max_backlog = gsi_channel_tre_max(gsi, endpoint->channel_id);
        if (atomic_read(&endpoint->replenish_backlog) == max_backlog)
                ipa_endpoint_replenish(endpoint, 0);
}

static void ipa_endpoint_replenish_disable(struct ipa_endpoint *endpoint)
{
        u32 backlog;

        endpoint->replenish_enabled = false;
        while ((backlog = atomic_xchg(&endpoint->replenish_backlog, 0)))
                atomic_add(backlog, &endpoint->replenish_saved);
}

static void ipa_endpoint_replenish_work(struct work_struct *work)
{
        struct delayed_work *dwork = to_delayed_work(work);
        struct ipa_endpoint *endpoint;

        endpoint = container_of(dwork, struct ipa_endpoint, replenish_work);

        ipa_endpoint_replenish(endpoint, 0);
}

static void ipa_endpoint_skb_copy(struct ipa_endpoint *endpoint,
                                  void *data, u32 len, u32 extra)
{
        struct sk_buff *skb;

        skb = __dev_alloc_skb(len, GFP_ATOMIC);
        if (skb) {
                skb_put(skb, len);
                memcpy(skb->data, data, len);
                skb->truesize += extra;
        }

        /* Now receive it, or drop it if there's no netdev */
        if (endpoint->netdev)
                ipa_modem_skb_rx(endpoint->netdev, skb);
        else if (skb)
                dev_kfree_skb_any(skb);
}

static bool ipa_endpoint_skb_build(struct ipa_endpoint *endpoint,
                                   struct page *page, u32 len)
{
        struct sk_buff *skb;

        /* Nothing to do if there's no netdev */
        if (!endpoint->netdev)
                return false;

        /* assert(len <= SKB_WITH_OVERHEAD(IPA_RX_BUFFER_SIZE-NET_SKB_PAD)); */
        skb = build_skb(page_address(page), IPA_RX_BUFFER_SIZE);
        if (skb) {
                /* Reserve the headroom and account for the data */
                skb_reserve(skb, NET_SKB_PAD);
                skb_put(skb, len);
        }

        /* Receive the buffer (or record drop if unable to build it) */
        ipa_modem_skb_rx(endpoint->netdev, skb);

        return skb != NULL;
}

/* The format of a packet status element is the same for several status
 * types (opcodes).  The NEW_FRAG_RULE, LOG, DCMP (decompression) types
 * aren't currently supported
 */
static bool ipa_status_format_packet(enum ipa_status_opcode opcode)
{
        switch (opcode) {
        case IPA_STATUS_OPCODE_PACKET:
        case IPA_STATUS_OPCODE_DROPPED_PACKET:
        case IPA_STATUS_OPCODE_SUSPENDED_PACKET:
        case IPA_STATUS_OPCODE_PACKET_2ND_PASS:
                return true;
        default:
                return false;
        }
}

static bool ipa_endpoint_status_skip(struct ipa_endpoint *endpoint,
                                     const struct ipa_status *status)
{
        u32 endpoint_id;

        if (!ipa_status_format_packet(status->opcode))
                return true;
        if (!status->pkt_len)
                return true;
        endpoint_id = u32_get_bits(status->endp_dst_idx,
                                   IPA_STATUS_DST_IDX_FMASK);
        if (endpoint_id != endpoint->endpoint_id)
                return true;

        return false;   /* Don't skip this packet, process it */
}

/* Return whether the status indicates the packet should be dropped */
static bool ipa_status_drop_packet(const struct ipa_status *status)
{
        u32 val;

        /* Deaggregation exceptions we drop; others we consume */
        if (status->exception)
                return status->exception == IPA_STATUS_EXCEPTION_DEAGGR;

        /* Drop the packet if it fails to match a routing rule; otherwise no */
        val = le32_get_bits(status->flags1, IPA_STATUS_FLAGS1_RT_RULE_ID_FMASK);

        return val == field_max(IPA_STATUS_FLAGS1_RT_RULE_ID_FMASK);
}

static void ipa_endpoint_status_parse(struct ipa_endpoint *endpoint,
                                      struct page *page, u32 total_len)
{
        void *data = page_address(page) + NET_SKB_PAD;
        u32 unused = IPA_RX_BUFFER_SIZE - total_len;
        u32 resid = total_len;

        while (resid) {
                const struct ipa_status *status = data;
                u32 align;
                u32 len;

                if (resid < sizeof(*status)) {
                        dev_err(&endpoint->ipa->pdev->dev,
                                "short message (%u bytes < %zu byte status)\n",
                                resid, sizeof(*status));
                        break;
                }

                /* Skip over status packets that lack packet data */
                if (ipa_endpoint_status_skip(endpoint, status)) {
                        data += sizeof(*status);
                        resid -= sizeof(*status);
                        continue;
                }

                /* Compute the amount of buffer space consumed by the
                 * packet, including the status element.  If the hardware
                 * is configured to pad packet data to an aligned boundary,
                 * account for that.  And if checksum offload is is enabled
                 * a trailer containing computed checksum information will
                 * be appended.
                 */
                align = endpoint->data->rx.pad_align ? : 1;
                len = le16_to_cpu(status->pkt_len);
                len = sizeof(*status) + ALIGN(len, align);
                if (endpoint->data->checksum)
                        len += sizeof(struct rmnet_map_dl_csum_trailer);

                /* Charge the new packet with a proportional fraction of
                 * the unused space in the original receive buffer.
                 * XXX Charge a proportion of the *whole* receive buffer?
                 */
                if (!ipa_status_drop_packet(status)) {
                        u32 extra = unused * len / total_len;
                        void *data2 = data + sizeof(*status);
                        u32 len2 = le16_to_cpu(status->pkt_len);

                        /* Client receives only packet data (no status) */
                        ipa_endpoint_skb_copy(endpoint, data2, len2, extra);
                }

                /* Consume status and the full packet it describes */
                data += len;
                resid -= len;
        }
}

/* Complete a TX transaction, command or from ipa_endpoint_skb_tx() */
static void ipa_endpoint_tx_complete(struct ipa_endpoint *endpoint,
                                     struct gsi_trans *trans)
{
}

/* Complete transaction initiated in ipa_endpoint_replenish_one() */
static void ipa_endpoint_rx_complete(struct ipa_endpoint *endpoint,
                                     struct gsi_trans *trans)
{
        struct page *page;

        ipa_endpoint_replenish(endpoint, 1);

        if (trans->cancelled)
                return;

        /* Parse or build a socket buffer using the actual received length */
        page = trans->data;
        if (endpoint->data->status_enable)
                ipa_endpoint_status_parse(endpoint, page, trans->len);
        else if (ipa_endpoint_skb_build(endpoint, page, trans->len))
                trans->data = NULL;     /* Pages have been consumed */
}

void ipa_endpoint_trans_complete(struct ipa_endpoint *endpoint,
                                 struct gsi_trans *trans)
{
        if (endpoint->toward_ipa)
                ipa_endpoint_tx_complete(endpoint, trans);
        else
                ipa_endpoint_rx_complete(endpoint, trans);
}

void ipa_endpoint_trans_release(struct ipa_endpoint *endpoint,
                                struct gsi_trans *trans)
{
        if (endpoint->toward_ipa) {
                struct ipa *ipa = endpoint->ipa;

                /* Nothing to do for command transactions */
                if (endpoint != ipa->name_map[IPA_ENDPOINT_AP_COMMAND_TX]) {
                        struct sk_buff *skb = trans->data;

                        if (skb)
                                dev_kfree_skb_any(skb);
                }
        } else {
                struct page *page = trans->data;

                if (page)
                        __free_pages(page, get_order(IPA_RX_BUFFER_SIZE));
        }
}

void ipa_endpoint_default_route_set(struct ipa *ipa, u32 endpoint_id)
{
        u32 val;

        /* ROUTE_DIS is 0 */
        val = u32_encode_bits(endpoint_id, ROUTE_DEF_PIPE_FMASK);
        val |= ROUTE_DEF_HDR_TABLE_FMASK;
        val |= u32_encode_bits(0, ROUTE_DEF_HDR_OFST_FMASK);
        val |= u32_encode_bits(endpoint_id, ROUTE_FRAG_DEF_PIPE_FMASK);
        val |= ROUTE_DEF_RETAIN_HDR_FMASK;

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

void ipa_endpoint_default_route_clear(struct ipa *ipa)
{
        ipa_endpoint_default_route_set(ipa, 0);
}

static bool ipa_endpoint_aggr_active(struct ipa_endpoint *endpoint)
{
        u32 mask = BIT(endpoint->endpoint_id);
        struct ipa *ipa = endpoint->ipa;
        u32 offset;
        u32 val;

        /* assert(mask & ipa->available); */
        offset = ipa_reg_state_aggr_active_offset(ipa->version);
        val = ioread32(ipa->reg_virt + offset);

        return !!(val & mask);
}

static void ipa_endpoint_force_close(struct ipa_endpoint *endpoint)
{
        u32 mask = BIT(endpoint->endpoint_id);
        struct ipa *ipa = endpoint->ipa;

        /* assert(mask & ipa->available); */
        iowrite32(mask, ipa->reg_virt + IPA_REG_AGGR_FORCE_CLOSE_OFFSET);
}

/**
 * ipa_endpoint_reset_rx_aggr() - Reset RX endpoint with aggregation active
 * @endpoint:   Endpoint to be reset
 *
 * If aggregation is active on an RX endpoint when a reset is performed
 * on its underlying GSI channel, a special sequence of actions must be
 * taken to ensure the IPA pipeline is properly cleared.
 *
 * @Return:     0 if successful, or a negative error code
 */
static int ipa_endpoint_reset_rx_aggr(struct ipa_endpoint *endpoint)
{
        struct device *dev = &endpoint->ipa->pdev->dev;
        struct ipa *ipa = endpoint->ipa;
        bool endpoint_suspended = false;
        struct gsi *gsi = &ipa->gsi;
        dma_addr_t addr;
        bool db_enable;
        u32 retries;
        u32 len = 1;
        void *virt;
        int ret;

        virt = kzalloc(len, GFP_KERNEL);
        if (!virt)
                return -ENOMEM;

        addr = dma_map_single(dev, virt, len, DMA_FROM_DEVICE);
        if (dma_mapping_error(dev, addr)) {
                ret = -ENOMEM;
                goto out_kfree;
        }

        /* Force close aggregation before issuing the reset */
        ipa_endpoint_force_close(endpoint);

        /* Reset and reconfigure the channel with the doorbell engine
         * disabled.  Then poll until we know aggregation is no longer
         * active.  We'll re-enable the doorbell (if appropriate) when
         * we reset again below.
         */
        gsi_channel_reset(gsi, endpoint->channel_id, false);

        /* Make sure the channel isn't suspended */
        if (endpoint->ipa->version == IPA_VERSION_3_5_1)
                if (!ipa_endpoint_init_ctrl(endpoint, false))
                        endpoint_suspended = true;

        /* Start channel and do a 1 byte read */
        ret = gsi_channel_start(gsi, endpoint->channel_id);
        if (ret)
                goto out_suspend_again;

        ret = gsi_trans_read_byte(gsi, endpoint->channel_id, addr);
        if (ret)
                goto err_endpoint_stop;

        /* Wait for aggregation to be closed on the channel */
        retries = IPA_ENDPOINT_RESET_AGGR_RETRY_MAX;
        do {
                if (!ipa_endpoint_aggr_active(endpoint))
                        break;
                msleep(1);
        } while (retries--);

        /* Check one last time */
        if (ipa_endpoint_aggr_active(endpoint))
                dev_err(dev, "endpoint %u still active during reset\n",
                        endpoint->endpoint_id);

        gsi_trans_read_byte_done(gsi, endpoint->channel_id);

        ret = ipa_endpoint_stop(endpoint);
        if (ret)
                goto out_suspend_again;

        /* Finally, reset and reconfigure the channel again (re-enabling the
         * the doorbell engine if appropriate).  Sleep for 1 millisecond to
         * complete the channel reset sequence.  Finish by suspending the
         * channel again (if necessary).
         */
        db_enable = ipa->version == IPA_VERSION_3_5_1;
        gsi_channel_reset(gsi, endpoint->channel_id, db_enable);

        msleep(1);

        goto out_suspend_again;

err_endpoint_stop:
        ipa_endpoint_stop(endpoint);
out_suspend_again:
        if (endpoint_suspended)
                (void)ipa_endpoint_init_ctrl(endpoint, true);
        dma_unmap_single(dev, addr, len, DMA_FROM_DEVICE);
out_kfree:
        kfree(virt);

        return ret;
}

static void ipa_endpoint_reset(struct ipa_endpoint *endpoint)
{
        u32 channel_id = endpoint->channel_id;
        struct ipa *ipa = endpoint->ipa;
        bool db_enable;
        bool special;
        int ret = 0;

        /* On IPA v3.5.1, if an RX endpoint is reset while aggregation
         * is active, we need to handle things specially to recover.
         * All other cases just need to reset the underlying GSI channel.
         *
         * IPA v3.5.1 enables the doorbell engine.  Newer versions do not.
         */
        db_enable = ipa->version == IPA_VERSION_3_5_1;
        special = !endpoint->toward_ipa && endpoint->data->aggregation;
        if (special && ipa_endpoint_aggr_active(endpoint))
                ret = ipa_endpoint_reset_rx_aggr(endpoint);
        else
                gsi_channel_reset(&ipa->gsi, channel_id, db_enable);

        if (ret)
                dev_err(&ipa->pdev->dev,
                        "error %d resetting channel %u for endpoint %u\n",
                        ret, endpoint->channel_id, endpoint->endpoint_id);
}

static int ipa_endpoint_stop_rx_dma(struct ipa *ipa)
{
        u16 size = IPA_ENDPOINT_STOP_RX_SIZE;
        struct gsi_trans *trans;
        dma_addr_t addr;
        int ret;

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

        /* Read into the highest part of the zero memory area */
        addr = ipa->zero_addr + ipa->zero_size - size;

        ipa_cmd_dma_task_32b_addr_add(trans, size, addr, false);

        ret = gsi_trans_commit_wait_timeout(trans, ENDPOINT_STOP_DMA_TIMEOUT);
        if (ret)
                gsi_trans_free(trans);

        return ret;
}

/**
 * ipa_endpoint_stop() - Stops a GSI channel in IPA
 * @client:     Client whose endpoint should be stopped
 *
 * This function implements the sequence to stop a GSI channel
 * in IPA. This function returns when the channel is is STOP state.
 *
 * Return value: 0 on success, negative otherwise
 */
int ipa_endpoint_stop(struct ipa_endpoint *endpoint)
{
        u32 retries = endpoint->toward_ipa ? 0 : IPA_ENDPOINT_STOP_RX_RETRIES;
        int ret;

        do {
                struct ipa *ipa = endpoint->ipa;
                struct gsi *gsi = &ipa->gsi;

                ret = gsi_channel_stop(gsi, endpoint->channel_id);
                if (ret != -EAGAIN)
                        break;

                if (endpoint->toward_ipa)
                        continue;

                /* For IPA v3.5.1, send a DMA read task and check again */
                if (ipa->version == IPA_VERSION_3_5_1) {
                        ret = ipa_endpoint_stop_rx_dma(ipa);
                        if (ret)
                                break;
                }

                msleep(1);
        } while (retries--);

        return retries ? ret : -EIO;
}

static void ipa_endpoint_program(struct ipa_endpoint *endpoint)
{
        struct device *dev = &endpoint->ipa->pdev->dev;
        int ret;

        if (endpoint->toward_ipa) {
                bool delay_mode = endpoint->data->tx.delay;

                ret = ipa_endpoint_init_ctrl(endpoint, delay_mode);
                /* Endpoint is expected to not be in delay mode */
                if (!ret != delay_mode) {
                        dev_warn(dev,
                                "TX endpoint %u was %sin delay mode\n",
                                endpoint->endpoint_id,
                                delay_mode ? "already " : "");
                }
                ipa_endpoint_init_hdr_ext(endpoint);
                ipa_endpoint_init_aggr(endpoint);
                ipa_endpoint_init_deaggr(endpoint);
                ipa_endpoint_init_seq(endpoint);
        } else {
                if (endpoint->ipa->version == IPA_VERSION_3_5_1) {
                        if (!ipa_endpoint_init_ctrl(endpoint, false))
                                dev_warn(dev,
                                        "RX endpoint %u was suspended\n",
                                        endpoint->endpoint_id);
                }
                ipa_endpoint_init_hdr_ext(endpoint);
                ipa_endpoint_init_aggr(endpoint);
        }
        ipa_endpoint_init_cfg(endpoint);
        ipa_endpoint_init_hdr(endpoint);
        ipa_endpoint_init_hdr_metadata_mask(endpoint);
        ipa_endpoint_init_mode(endpoint);
        ipa_endpoint_status(endpoint);
}

int ipa_endpoint_enable_one(struct ipa_endpoint *endpoint)
{
        struct ipa *ipa = endpoint->ipa;
        struct gsi *gsi = &ipa->gsi;
        int ret;

        ret = gsi_channel_start(gsi, endpoint->channel_id);
        if (ret) {
                dev_err(&ipa->pdev->dev,
                        "error %d starting %cX channel %u for endpoint %u\n",
                        ret, endpoint->toward_ipa ? 'T' : 'R',
                        endpoint->channel_id, endpoint->endpoint_id);
                return ret;
        }

        if (!endpoint->toward_ipa) {
                ipa_interrupt_suspend_enable(ipa->interrupt,
                                             endpoint->endpoint_id);
                ipa_endpoint_replenish_enable(endpoint);
        }

        ipa->enabled |= BIT(endpoint->endpoint_id);

        return 0;
}

void ipa_endpoint_disable_one(struct ipa_endpoint *endpoint)
{
        u32 mask = BIT(endpoint->endpoint_id);
        struct ipa *ipa = endpoint->ipa;
        int ret;

        if (!(endpoint->ipa->enabled & mask))
                return;

        endpoint->ipa->enabled ^= mask;

        if (!endpoint->toward_ipa) {
                ipa_endpoint_replenish_disable(endpoint);
                ipa_interrupt_suspend_disable(ipa->interrupt,
                                              endpoint->endpoint_id);
        }

        /* Note that if stop fails, the channel's state is not well-defined */
        ret = ipa_endpoint_stop(endpoint);
        if (ret)
                dev_err(&ipa->pdev->dev,
                        "error %d attempting to stop endpoint %u\n", ret,
                        endpoint->endpoint_id);
}

/**
 * ipa_endpoint_suspend_aggr() - Emulate suspend interrupt
 * @endpoint_id:        Endpoint on which to emulate a suspend
 *
 *  Emulate suspend IPA interrupt to unsuspend an endpoint suspended
 *  with an open aggregation frame.  This is to work around a hardware
 *  issue in IPA version 3.5.1 where the suspend interrupt will not be
 *  generated when it should be.
 */
static void ipa_endpoint_suspend_aggr(struct ipa_endpoint *endpoint)
{
        struct ipa *ipa = endpoint->ipa;

        /* assert(ipa->version == IPA_VERSION_3_5_1); */

        if (!endpoint->data->aggregation)
                return;

        /* Nothing to do if the endpoint doesn't have aggregation open */
        if (!ipa_endpoint_aggr_active(endpoint))
                return;

        /* Force close aggregation */
        ipa_endpoint_force_close(endpoint);

        ipa_interrupt_simulate_suspend(ipa->interrupt);
}

void ipa_endpoint_suspend_one(struct ipa_endpoint *endpoint)
{
        struct device *dev = &endpoint->ipa->pdev->dev;
        struct gsi *gsi = &endpoint->ipa->gsi;
        bool stop_channel;
        int ret;

        if (!(endpoint->ipa->enabled & BIT(endpoint->endpoint_id)))
                return;

        if (!endpoint->toward_ipa)
                ipa_endpoint_replenish_disable(endpoint);

        /* IPA v3.5.1 doesn't use channel stop for suspend */
        stop_channel = endpoint->ipa->version != IPA_VERSION_3_5_1;
        if (!endpoint->toward_ipa && !stop_channel) {
                /* Due to a hardware bug, a client suspended with an open
                 * aggregation frame will not generate a SUSPEND IPA
                 * interrupt.  We work around this by force-closing the
                 * aggregation frame, then simulating the arrival of such
                 * an interrupt.
                 */
                WARN_ON(ipa_endpoint_init_ctrl(endpoint, true));
                ipa_endpoint_suspend_aggr(endpoint);
        }

        ret = gsi_channel_suspend(gsi, endpoint->channel_id, stop_channel);
        if (ret)
                dev_err(dev, "error %d suspending channel %u\n", ret,
                        endpoint->channel_id);
}

void ipa_endpoint_resume_one(struct ipa_endpoint *endpoint)
{
        struct device *dev = &endpoint->ipa->pdev->dev;
        struct gsi *gsi = &endpoint->ipa->gsi;
        bool start_channel;
        int ret;

        if (!(endpoint->ipa->enabled & BIT(endpoint->endpoint_id)))
                return;

        /* IPA v3.5.1 doesn't use channel start for resume */
        start_channel = endpoint->ipa->version != IPA_VERSION_3_5_1;
        if (!endpoint->toward_ipa && !start_channel)
                WARN_ON(ipa_endpoint_init_ctrl(endpoint, false));

        ret = gsi_channel_resume(gsi, endpoint->channel_id, start_channel);
        if (ret)
                dev_err(dev, "error %d resuming channel %u\n", ret,
                        endpoint->channel_id);
        else if (!endpoint->toward_ipa)
                ipa_endpoint_replenish_enable(endpoint);
}

void ipa_endpoint_suspend(struct ipa *ipa)
{
        if (ipa->modem_netdev)
                ipa_modem_suspend(ipa->modem_netdev);

        ipa_endpoint_suspend_one(ipa->name_map[IPA_ENDPOINT_AP_LAN_RX]);
        ipa_endpoint_suspend_one(ipa->name_map[IPA_ENDPOINT_AP_COMMAND_TX]);
}

void ipa_endpoint_resume(struct ipa *ipa)
{
        ipa_endpoint_resume_one(ipa->name_map[IPA_ENDPOINT_AP_COMMAND_TX]);
        ipa_endpoint_resume_one(ipa->name_map[IPA_ENDPOINT_AP_LAN_RX]);

        if (ipa->modem_netdev)
                ipa_modem_resume(ipa->modem_netdev);
}

static void ipa_endpoint_setup_one(struct ipa_endpoint *endpoint)
{
        struct gsi *gsi = &endpoint->ipa->gsi;
        u32 channel_id = endpoint->channel_id;

        /* Only AP endpoints get set up */
        if (endpoint->ee_id != GSI_EE_AP)
                return;

        endpoint->trans_tre_max = gsi_channel_trans_tre_max(gsi, channel_id);
        if (!endpoint->toward_ipa) {
                /* RX transactions require a single TRE, so the maximum
                 * backlog is the same as the maximum outstanding TREs.
                 */
                endpoint->replenish_enabled = false;
                atomic_set(&endpoint->replenish_saved,
                           gsi_channel_tre_max(gsi, endpoint->channel_id));
                atomic_set(&endpoint->replenish_backlog, 0);
                INIT_DELAYED_WORK(&endpoint->replenish_work,
                                  ipa_endpoint_replenish_work);
        }

        ipa_endpoint_program(endpoint);

        endpoint->ipa->set_up |= BIT(endpoint->endpoint_id);
}

static void ipa_endpoint_teardown_one(struct ipa_endpoint *endpoint)
{
        endpoint->ipa->set_up &= ~BIT(endpoint->endpoint_id);

        if (!endpoint->toward_ipa)
                cancel_delayed_work_sync(&endpoint->replenish_work);

        ipa_endpoint_reset(endpoint);
}

void ipa_endpoint_setup(struct ipa *ipa)
{
        u32 initialized = ipa->initialized;

        ipa->set_up = 0;
        while (initialized) {
                u32 endpoint_id = __ffs(initialized);

                initialized ^= BIT(endpoint_id);

                ipa_endpoint_setup_one(&ipa->endpoint[endpoint_id]);
        }
}

void ipa_endpoint_teardown(struct ipa *ipa)
{
        u32 set_up = ipa->set_up;

        while (set_up) {
                u32 endpoint_id = __fls(set_up);

                set_up ^= BIT(endpoint_id);

                ipa_endpoint_teardown_one(&ipa->endpoint[endpoint_id]);
        }
        ipa->set_up = 0;
}

int ipa_endpoint_config(struct ipa *ipa)
{
        struct device *dev = &ipa->pdev->dev;
        u32 initialized;
        u32 rx_base;
        u32 rx_mask;
        u32 tx_mask;
        int ret = 0;
        u32 max;
        u32 val;

        /* Find out about the endpoints supplied by the hardware, and ensure
         * the highest one doesn't exceed the number we support.
         */
        val = ioread32(ipa->reg_virt + IPA_REG_FLAVOR_0_OFFSET);

        /* Our RX is an IPA producer */
        rx_base = u32_get_bits(val, BAM_PROD_LOWEST_FMASK);
        max = rx_base + u32_get_bits(val, BAM_MAX_PROD_PIPES_FMASK);
        if (max > IPA_ENDPOINT_MAX) {
                dev_err(dev, "too many endpoints (%u > %u)\n",
                        max, IPA_ENDPOINT_MAX);
                return -EINVAL;
        }
        rx_mask = GENMASK(max - 1, rx_base);

        /* Our TX is an IPA consumer */
        max = u32_get_bits(val, BAM_MAX_CONS_PIPES_FMASK);
        tx_mask = GENMASK(max - 1, 0);

        ipa->available = rx_mask | tx_mask;

        /* Check for initialized endpoints not supported by the hardware */
        if (ipa->initialized & ~ipa->available) {
                dev_err(dev, "unavailable endpoint id(s) 0x%08x\n",
                        ipa->initialized & ~ipa->available);
                ret = -EINVAL;          /* Report other errors too */
        }

        initialized = ipa->initialized;
        while (initialized) {
                u32 endpoint_id = __ffs(initialized);
                struct ipa_endpoint *endpoint;

                initialized ^= BIT(endpoint_id);

                /* Make sure it's pointing in the right direction */
                endpoint = &ipa->endpoint[endpoint_id];
                if ((endpoint_id < rx_base) != !!endpoint->toward_ipa) {
                        dev_err(dev, "endpoint id %u wrong direction\n",
                                endpoint_id);
                        ret = -EINVAL;
                }
        }

        return ret;
}

void ipa_endpoint_deconfig(struct ipa *ipa)
{
        ipa->available = 0;     /* Nothing more to do */
}

static void ipa_endpoint_init_one(struct ipa *ipa, enum ipa_endpoint_name name,
                                  const struct ipa_gsi_endpoint_data *data)
{
        struct ipa_endpoint *endpoint;

        endpoint = &ipa->endpoint[data->endpoint_id];

        if (data->ee_id == GSI_EE_AP)
                ipa->channel_map[data->channel_id] = endpoint;
        ipa->name_map[name] = endpoint;

        endpoint->ipa = ipa;
        endpoint->ee_id = data->ee_id;
        endpoint->seq_type = data->endpoint.seq_type;
        endpoint->channel_id = data->channel_id;
        endpoint->endpoint_id = data->endpoint_id;
        endpoint->toward_ipa = data->toward_ipa;
        endpoint->data = &data->endpoint.config;

        ipa->initialized |= BIT(endpoint->endpoint_id);
}

void ipa_endpoint_exit_one(struct ipa_endpoint *endpoint)
{
        endpoint->ipa->initialized &= ~BIT(endpoint->endpoint_id);

        memset(endpoint, 0, sizeof(*endpoint));
}

void ipa_endpoint_exit(struct ipa *ipa)
{
        u32 initialized = ipa->initialized;

        while (initialized) {
                u32 endpoint_id = __fls(initialized);

                initialized ^= BIT(endpoint_id);

                ipa_endpoint_exit_one(&ipa->endpoint[endpoint_id]);
        }
        memset(ipa->name_map, 0, sizeof(ipa->name_map));
        memset(ipa->channel_map, 0, sizeof(ipa->channel_map));
}

/* Returns a bitmask of endpoints that support filtering, or 0 on error */
u32 ipa_endpoint_init(struct ipa *ipa, u32 count,
                      const struct ipa_gsi_endpoint_data *data)
{
        enum ipa_endpoint_name name;
        u32 filter_map;

        if (!ipa_endpoint_data_valid(ipa, count, data))
                return 0;       /* Error */

        ipa->initialized = 0;

        filter_map = 0;
        for (name = 0; name < count; name++, data++) {
                if (ipa_gsi_endpoint_data_empty(data))
                        continue;       /* Skip over empty slots */

                ipa_endpoint_init_one(ipa, name, data);

                if (data->endpoint.filter_support)
                        filter_map |= BIT(data->endpoint_id);
        }

        if (!ipa_filter_map_valid(ipa, filter_map))
                goto err_endpoint_exit;

        return filter_map;      /* Non-zero bitmask */

err_endpoint_exit:
        ipa_endpoint_exit(ipa);

        return 0;       /* Error */
}