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Subject: Re: [PATCH 02/16] bus: mhi: core: Add support for registering MHI
 controllers
From:   Jeffrey Hugo <jhugo@codeaurora.org>
To:     Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>,
        gregkh@linuxfoundation.org, arnd@arndb.de
Cc:     smohanad@codeaurora.org, kvalo@codeaurora.org,
        bjorn.andersson@linaro.org, hemantk@codeaurora.org,
        linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org
References: <20200123111836.7414-1-manivannan.sadhasivam@linaro.org>
 <20200123111836.7414-3-manivannan.sadhasivam@linaro.org>
 <c8fdf0b0-eaec-9672-4f43-f0254d6dbf0e@codeaurora.org>
Message-ID: <e65a43a0-b737-a2cd-5cfe-f150e0831d84@codeaurora.org>
Date:   Sun, 26 Jan 2020 16:58:49 -0700
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On 1/23/2020 10:05 AM, Jeffrey Hugo wrote:
> On 1/23/2020 4:18 AM, Manivannan Sadhasivam wrote:
>> This commit adds support for registering MHI controller drivers with
>> the MHI stack. MHI controller drivers manages the interaction with the
>> MHI client devices such as the external modems and WiFi chipsets. They
>> are also the MHI bus master in charge of managing the physical link
>> between the host and client device.
>>
>> This is based on the patch submitted by Sujeev Dias:
>> https://lkml.org/lkml/2018/7/9/987
>>
>> Signed-off-by: Sujeev Dias <sdias@codeaurora.org>
>> Signed-off-by: Siddartha Mohanadoss <smohanad@codeaurora.org>
>> [jhugo: added static config for controllers and fixed several bugs]
>> Signed-off-by: Jeffrey Hugo <jhugo@codeaurora.org>
>> [mani: removed DT dependency, splitted and cleaned up for upstream]
>> Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
>> ---
>>   drivers/bus/Kconfig             |   1 +
>>   drivers/bus/Makefile            |   3 +
>>   drivers/bus/mhi/Kconfig         |  14 +
>>   drivers/bus/mhi/Makefile        |   2 +
>>   drivers/bus/mhi/core/Makefile   |   3 +
>>   drivers/bus/mhi/core/init.c     | 404 +++++++++++++++++++++++++++++
>>   drivers/bus/mhi/core/internal.h | 169 ++++++++++++
>>   include/linux/mhi.h             | 438 ++++++++++++++++++++++++++++++++
>>   include/linux/mod_devicetable.h |  12 +
>>   9 files changed, 1046 insertions(+)
>>   create mode 100644 drivers/bus/mhi/Kconfig
>>   create mode 100644 drivers/bus/mhi/Makefile
>>   create mode 100644 drivers/bus/mhi/core/Makefile
>>   create mode 100644 drivers/bus/mhi/core/init.c
>>   create mode 100644 drivers/bus/mhi/core/internal.h
>>   create mode 100644 include/linux/mhi.h
>>
>> diff --git a/drivers/bus/Kconfig b/drivers/bus/Kconfig
>> index 50200d1c06ea..383934e54786 100644
>> --- a/drivers/bus/Kconfig
>> +++ b/drivers/bus/Kconfig
>> @@ -202,5 +202,6 @@ config DA8XX_MSTPRI
>>         peripherals.
>>   source "drivers/bus/fsl-mc/Kconfig"
>> +source "drivers/bus/mhi/Kconfig"
>>   endmenu
>> diff --git a/drivers/bus/Makefile b/drivers/bus/Makefile
>> index 1320bcf9fa9d..05f32cd694a4 100644
>> --- a/drivers/bus/Makefile
>> +++ b/drivers/bus/Makefile
>> @@ -34,3 +34,6 @@ obj-$(CONFIG_UNIPHIER_SYSTEM_BUS)    += 
>> uniphier-system-bus.o
>>   obj-$(CONFIG_VEXPRESS_CONFIG)    += vexpress-config.o
>>   obj-$(CONFIG_DA8XX_MSTPRI)    += da8xx-mstpri.o
>> +
>> +# MHI
>> +obj-$(CONFIG_MHI_BUS)        += mhi/
>> diff --git a/drivers/bus/mhi/Kconfig b/drivers/bus/mhi/Kconfig
>> new file mode 100644
>> index 000000000000..a8bd9bd7db7c
>> --- /dev/null
>> +++ b/drivers/bus/mhi/Kconfig
>> @@ -0,0 +1,14 @@
>> +# SPDX-License-Identifier: GPL-2.0
> 
> first time I noticed this, although I suspect this will need to be 
> corrected "everywhere" -
> Per the SPDX website, the "GPL-2.0" label is deprecated.  It's 
> replacement is "GPL-2.0-only".
> I think all instances should be updated to "GPL-2.0-only"
> 
>> +#
>> +# MHI bus
>> +#
>> +# Copyright (c) 2018-2020, The Linux Foundation. All rights reserved.
>> +#
>> +
>> +config MHI_BUS
>> +       tristate "Modem Host Interface (MHI) bus"
>> +       help
>> +     Bus driver for MHI protocol. Modem Host Interface (MHI) is a
>> +     communication protocol used by the host processors to control
>> +     and communicate with modem devices over a high speed peripheral
>> +     bus or shared memory.
>> diff --git a/drivers/bus/mhi/Makefile b/drivers/bus/mhi/Makefile
>> new file mode 100644
>> index 000000000000..19e6443b72df
>> --- /dev/null
>> +++ b/drivers/bus/mhi/Makefile
>> @@ -0,0 +1,2 @@
>> +# core layer
>> +obj-y += core/
>> diff --git a/drivers/bus/mhi/core/Makefile 
>> b/drivers/bus/mhi/core/Makefile
>> new file mode 100644
>> index 000000000000..2db32697c67f
>> --- /dev/null
>> +++ b/drivers/bus/mhi/core/Makefile
>> @@ -0,0 +1,3 @@
>> +obj-$(CONFIG_MHI_BUS) := mhi.o
>> +
>> +mhi-y := init.o
>> diff --git a/drivers/bus/mhi/core/init.c b/drivers/bus/mhi/core/init.c
>> new file mode 100644
>> index 000000000000..5b817ec250e0
>> --- /dev/null
>> +++ b/drivers/bus/mhi/core/init.c
>> @@ -0,0 +1,404 @@
>> +// SPDX-License-Identifier: GPL-2.0
>> +/*
>> + * Copyright (c) 2018-2020, The Linux Foundation. All rights reserved.
>> + *
>> + */
>> +
>> +#define dev_fmt(fmt) "MHI: " fmt
>> +
>> +#include <linux/device.h>
>> +#include <linux/dma-direction.h>
>> +#include <linux/dma-mapping.h>
>> +#include <linux/interrupt.h>
>> +#include <linux/list.h>
>> +#include <linux/mhi.h>
>> +#include <linux/mod_devicetable.h>
>> +#include <linux/module.h>
>> +#include <linux/slab.h>
>> +#include <linux/vmalloc.h>
>> +#include <linux/wait.h>
>> +#include "internal.h"
>> +
>> +static int parse_ev_cfg(struct mhi_controller *mhi_cntrl,
>> +            struct mhi_controller_config *config)
>> +{
>> +    int i, num;
>> +    struct mhi_event *mhi_event;
>> +    struct mhi_event_config *event_cfg;
>> +
>> +    num = config->num_events;
>> +    mhi_cntrl->total_ev_rings = num;
>> +    mhi_cntrl->mhi_event = kcalloc(num, sizeof(*mhi_cntrl->mhi_event),
>> +                       GFP_KERNEL);
>> +    if (!mhi_cntrl->mhi_event)
>> +        return -ENOMEM;
>> +
>> +    /* Populate event ring */
>> +    mhi_event = mhi_cntrl->mhi_event;
>> +    for (i = 0; i < num; i++) {
>> +        event_cfg = &config->event_cfg[i];
>> +
>> +        mhi_event->er_index = i;
>> +        mhi_event->ring.elements = event_cfg->num_elements;
>> +        mhi_event->intmod = event_cfg->irq_moderation_ms;
>> +        mhi_event->irq = event_cfg->irq;
>> +
>> +        if (event_cfg->channel != U32_MAX) {
>> +            /* This event ring has a dedicated channel */
>> +            mhi_event->chan = event_cfg->channel;
>> +            if (mhi_event->chan >= mhi_cntrl->max_chan) {
>> +                dev_err(mhi_cntrl->dev,
>> +                    "Event Ring channel not available\n");
>> +                goto error_ev_cfg;
>> +            }
>> +
>> +            mhi_event->mhi_chan =
>> +                &mhi_cntrl->mhi_chan[mhi_event->chan];
>> +        }
>> +
>> +        /* Priority is fixed to 1 for now */
>> +        mhi_event->priority = 1;
>> +
>> +        mhi_event->db_cfg.brstmode = event_cfg->mode;
>> +        if (MHI_INVALID_BRSTMODE(mhi_event->db_cfg.brstmode))
>> +            goto error_ev_cfg;
>> +
>> +        mhi_event->data_type = event_cfg->data_type;
>> +
>> +        mhi_event->hw_ring = event_cfg->hardware_event;
>> +        if (mhi_event->hw_ring)
>> +            mhi_cntrl->hw_ev_rings++;
>> +        else
>> +            mhi_cntrl->sw_ev_rings++;
>> +
>> +        mhi_event->cl_manage = event_cfg->client_managed;
>> +        mhi_event->offload_ev = event_cfg->offload_channel;
>> +        mhi_event++;
>> +    }
>> +
>> +    /* We need IRQ for each event ring + additional one for BHI */
>> +    mhi_cntrl->nr_irqs_req = mhi_cntrl->total_ev_rings + 1;
>> +
>> +    return 0;
>> +
>> +error_ev_cfg:
>> +
>> +    kfree(mhi_cntrl->mhi_event);
>> +    return -EINVAL;
>> +}
>> +
>> +static int parse_ch_cfg(struct mhi_controller *mhi_cntrl,
>> +            struct mhi_controller_config *config)
>> +{
>> +    int i;
>> +    u32 chan;
>> +    struct mhi_channel_config *ch_cfg;
>> +
>> +    mhi_cntrl->max_chan = config->max_channels;
>> +
>> +    /*
>> +     * The allocation of MHI channels can exceed 32KB in some scenarios,
>> +     * so to avoid any memory possible allocation failures, vzalloc is
>> +     * used here
>> +     */
>> +    mhi_cntrl->mhi_chan = vzalloc(mhi_cntrl->max_chan *
>> +                      sizeof(*mhi_cntrl->mhi_chan));
>> +    if (!mhi_cntrl->mhi_chan)
>> +        return -ENOMEM;
>> +
>> +    INIT_LIST_HEAD(&mhi_cntrl->lpm_chans);
>> +
>> +    /* Populate channel configurations */
>> +    for (i = 0; i < config->num_channels; i++) {
>> +        struct mhi_chan *mhi_chan;
>> +
>> +        ch_cfg = &config->ch_cfg[i];
>> +
>> +        chan = ch_cfg->num;
>> +        if (chan >= mhi_cntrl->max_chan) {
>> +            dev_err(mhi_cntrl->dev,
>> +                "Channel %d not available\n", chan);
>> +            goto error_chan_cfg;
>> +        }
>> +
>> +        mhi_chan = &mhi_cntrl->mhi_chan[chan];
>> +        mhi_chan->name = ch_cfg->name;
>> +        mhi_chan->chan = chan;
>> +
>> +        mhi_chan->tre_ring.elements = ch_cfg->num_elements;
>> +        if (!mhi_chan->tre_ring.elements)
>> +            goto error_chan_cfg;
>> +
>> +        /*
>> +         * For some channels, local ring length should be bigger than
>> +         * the transfer ring length due to internal logical channels
>> +         * in device. So host can queue much more buffers than transfer
>> +         * ring length. Example, RSC channels should have a larger local
>> +         * channel length than transfer ring length.
>> +         */
>> +        mhi_chan->buf_ring.elements = ch_cfg->local_elements;
>> +        if (!mhi_chan->buf_ring.elements)
>> +            mhi_chan->buf_ring.elements = mhi_chan->tre_ring.elements;
>> +        mhi_chan->er_index = ch_cfg->event_ring;
>> +        mhi_chan->dir = ch_cfg->dir;
>> +
>> +        /*
>> +         * For most channels, chtype is identical to channel directions.
>> +         * So, if it is not defined then assign channel direction to
>> +         * chtype
>> +         */
>> +        mhi_chan->type = ch_cfg->type;
>> +        if (!mhi_chan->type)
>> +            mhi_chan->type = (enum mhi_ch_type)mhi_chan->dir;
>> +
>> +        mhi_chan->ee_mask = ch_cfg->ee_mask;
>> +
>> +        mhi_chan->db_cfg.pollcfg = ch_cfg->pollcfg;
>> +        mhi_chan->xfer_type = ch_cfg->data_type;
>> +
>> +        mhi_chan->lpm_notify = ch_cfg->lpm_notify;
>> +        mhi_chan->offload_ch = ch_cfg->offload_channel;
>> +        mhi_chan->db_cfg.reset_req = ch_cfg->doorbell_mode_switch;
>> +        mhi_chan->pre_alloc = ch_cfg->auto_queue;
>> +        mhi_chan->auto_start = ch_cfg->auto_start;
>> +
>> +        /*
>> +         * If MHI host allocates buffers, then the channel direction
>> +         * should be DMA_FROM_DEVICE and the buffer type should be
>> +         * MHI_BUF_RAW
>> +         */
>> +        if (mhi_chan->pre_alloc && (mhi_chan->dir != DMA_FROM_DEVICE ||
>> +                mhi_chan->xfer_type != MHI_BUF_RAW)) {
>> +            dev_err(mhi_cntrl->dev,
>> +                "Invalid channel configuration\n");
>> +            goto error_chan_cfg;
>> +        }
>> +
>> +        /*
>> +         * Bi-directional and direction less channel must be an
>> +         * offload channel
>> +         */
>> +        if ((mhi_chan->dir == DMA_BIDIRECTIONAL ||
>> +             mhi_chan->dir == DMA_NONE) && !mhi_chan->offload_ch) {
>> +            dev_err(mhi_cntrl->dev,
>> +                "Invalid channel configuration\n");
>> +            goto error_chan_cfg;
>> +        }
>> +
>> +        if (!mhi_chan->offload_ch) {
>> +            mhi_chan->db_cfg.brstmode = ch_cfg->doorbell;
>> +            if (MHI_INVALID_BRSTMODE(mhi_chan->db_cfg.brstmode)) {
>> +                dev_err(mhi_cntrl->dev,
>> +                    "Invalid Door bell mode\n");
>> +                goto error_chan_cfg;
>> +            }
>> +        }
>> +
>> +        mhi_chan->configured = true;
>> +
>> +        if (mhi_chan->lpm_notify)
>> +            list_add_tail(&mhi_chan->node, &mhi_cntrl->lpm_chans);
>> +    }
>> +
>> +    return 0;
>> +
>> +error_chan_cfg:
>> +    vfree(mhi_cntrl->mhi_chan);
>> +
>> +    return -EINVAL;
>> +}
>> +
>> +static int parse_config(struct mhi_controller *mhi_cntrl,
>> +            struct mhi_controller_config *config)
>> +{
>> +    int ret;
>> +
>> +    /* Parse MHI channel configuration */
>> +    ret = parse_ch_cfg(mhi_cntrl, config);
>> +    if (ret)
>> +        return ret;
>> +
>> +    /* Parse MHI event configuration */
>> +    ret = parse_ev_cfg(mhi_cntrl, config);
>> +    if (ret)
>> +        goto error_ev_cfg;
>> +
>> +    mhi_cntrl->timeout_ms = config->timeout_ms;
>> +    if (!mhi_cntrl->timeout_ms)
>> +        mhi_cntrl->timeout_ms = MHI_TIMEOUT_MS;
>> +
>> +    mhi_cntrl->bounce_buf = config->use_bounce_buf;
>> +    mhi_cntrl->buffer_len = config->buf_len;
>> +    if (!mhi_cntrl->buffer_len)
>> +        mhi_cntrl->buffer_len = MHI_MAX_MTU;
>> +
>> +    return 0;
>> +
>> +error_ev_cfg:
>> +    vfree(mhi_cntrl->mhi_chan);
>> +
>> +    return ret;
>> +}
>> +
>> +int mhi_register_controller(struct mhi_controller *mhi_cntrl,
>> +                struct mhi_controller_config *config)
>> +{
>> +    int ret;
>> +    int i;
>> +    struct mhi_event *mhi_event;
>> +    struct mhi_chan *mhi_chan;
>> +    struct mhi_cmd *mhi_cmd;
>> +    struct mhi_device *mhi_dev;
>> +

You need a null check on mhi_cntrl right here, otherwise you could cause 
a panic with the following if.

>> +    if (!mhi_cntrl->runtime_get || !mhi_cntrl->runtime_put)
>> +        return -EINVAL;
>> +
>> +    if (!mhi_cntrl->status_cb || !mhi_cntrl->link_status)
>> +        return -EINVAL;
>> +
>> +    ret = parse_config(mhi_cntrl, config);
>> +    if (ret)
>> +        return -EINVAL;
>> +
>> +    mhi_cntrl->mhi_cmd = kcalloc(NR_OF_CMD_RINGS,
>> +                     sizeof(*mhi_cntrl->mhi_cmd), GFP_KERNEL);
>> +    if (!mhi_cntrl->mhi_cmd) {
>> +        ret = -ENOMEM;
>> +        goto error_alloc_cmd;
>> +    }
>> +
>> +    INIT_LIST_HEAD(&mhi_cntrl->transition_list);
>> +    spin_lock_init(&mhi_cntrl->transition_lock);
>> +    spin_lock_init(&mhi_cntrl->wlock);
>> +    init_waitqueue_head(&mhi_cntrl->state_event);
>> +
>> +    mhi_cmd = mhi_cntrl->mhi_cmd;
>> +    for (i = 0; i < NR_OF_CMD_RINGS; i++, mhi_cmd++)
>> +        spin_lock_init(&mhi_cmd->lock);
>> +
>> +    mhi_event = mhi_cntrl->mhi_event;
>> +    for (i = 0; i < mhi_cntrl->total_ev_rings; i++, mhi_event++) {
>> +        /* Skip for offload events */
>> +        if (mhi_event->offload_ev)
>> +            continue;
>> +
>> +        mhi_event->mhi_cntrl = mhi_cntrl;
>> +        spin_lock_init(&mhi_event->lock);
>> +    }
>> +
>> +    mhi_chan = mhi_cntrl->mhi_chan;
>> +    for (i = 0; i < mhi_cntrl->max_chan; i++, mhi_chan++) {
>> +        mutex_init(&mhi_chan->mutex);
>> +        init_completion(&mhi_chan->completion);
>> +        rwlock_init(&mhi_chan->lock);
>> +    }
>> +
>> +    /* Register controller with MHI bus */
>> +    mhi_dev = mhi_alloc_device(mhi_cntrl);
>> +    if (IS_ERR(mhi_dev)) {
>> +        dev_err(mhi_cntrl->dev, "Failed to allocate device\n");
>> +        ret = PTR_ERR(mhi_dev);
>> +        goto error_alloc_dev;
>> +    }
>> +
>> +    mhi_dev->dev_type = MHI_DEVICE_CONTROLLER;
>> +    mhi_dev->mhi_cntrl = mhi_cntrl;
>> +    dev_set_name(&mhi_dev->dev, "%s", mhi_cntrl->name);
>> +
>> +    /* Init wakeup source */
>> +    device_init_wakeup(&mhi_dev->dev, true);
>> +
>> +    ret = device_add(&mhi_dev->dev);
>> +    if (ret)
>> +        goto error_add_dev;
>> +
>> +    mhi_cntrl->mhi_dev = mhi_dev;
>> +
>> +    return 0;
>> +
>> +error_add_dev:
>> +    mhi_dealloc_device(mhi_cntrl, mhi_dev);
>> +
>> +error_alloc_dev:
>> +    kfree(mhi_cntrl->mhi_cmd);
>> +
>> +error_alloc_cmd:
>> +    vfree(mhi_cntrl->mhi_chan);
>> +    kfree(mhi_cntrl->mhi_event);
>> +
>> +    return ret;
>> +}
>> +EXPORT_SYMBOL_GPL(mhi_register_controller);
>> +
>> +void mhi_unregister_controller(struct mhi_controller *mhi_cntrl)
>> +{
>> +    struct mhi_device *mhi_dev = mhi_cntrl->mhi_dev;
>> +
>> +    kfree(mhi_cntrl->mhi_cmd);
>> +    kfree(mhi_cntrl->mhi_event);
>> +    vfree(mhi_cntrl->mhi_chan);
>> +
>> +    device_del(&mhi_dev->dev);
>> +    put_device(&mhi_dev->dev);
>> +}
>> +EXPORT_SYMBOL_GPL(mhi_unregister_controller);
>> +
>> +static void mhi_release_device(struct device *dev)
>> +{
>> +    struct mhi_device *mhi_dev = to_mhi_device(dev);
>> +
>> +    if (mhi_dev->ul_chan)
>> +        mhi_dev->ul_chan->mhi_dev = NULL;
>> +
>> +    if (mhi_dev->dl_chan)
>> +        mhi_dev->dl_chan->mhi_dev = NULL;
>> +
>> +    kfree(mhi_dev);
>> +}
>> +
>> +struct mhi_device *mhi_alloc_device(struct mhi_controller *mhi_cntrl)
>> +{
>> +    struct mhi_device *mhi_dev;
>> +    struct device *dev;
>> +
>> +    mhi_dev = kzalloc(sizeof(*mhi_dev), GFP_KERNEL);
>> +    if (!mhi_dev)
>> +        return ERR_PTR(-ENOMEM);
>> +
>> +    dev = &mhi_dev->dev;
>> +    device_initialize(dev);
>> +    dev->bus = &mhi_bus_type;
>> +    dev->release = mhi_release_device;
>> +    dev->parent = mhi_cntrl->dev;
>> +    mhi_dev->mhi_cntrl = mhi_cntrl;
>> +    atomic_set(&mhi_dev->dev_wake, 0);
>> +
>> +    return mhi_dev;
>> +}
>> +
>> +static int mhi_match(struct device *dev, struct device_driver *drv)
>> +{
>> +    return 0;
>> +};
>> +
>> +struct bus_type mhi_bus_type = {
>> +    .name = "mhi",
>> +    .dev_name = "mhi",
>> +    .match = mhi_match,
>> +};
>> +
>> +static int __init mhi_init(void)
>> +{
>> +    return bus_register(&mhi_bus_type);
>> +}
>> +
>> +static void __exit mhi_exit(void)
>> +{
>> +    bus_unregister(&mhi_bus_type);
>> +}
>> +
>> +postcore_initcall(mhi_init);
>> +module_exit(mhi_exit);
>> +
>> +MODULE_LICENSE("GPL v2");
>> +MODULE_DESCRIPTION("MHI Host Interface");
>> diff --git a/drivers/bus/mhi/core/internal.h 
>> b/drivers/bus/mhi/core/internal.h
>> new file mode 100644
>> index 000000000000..21f686d3a140
>> --- /dev/null
>> +++ b/drivers/bus/mhi/core/internal.h
>> @@ -0,0 +1,169 @@
>> +/* SPDX-License-Identifier: GPL-2.0 */
>> +/*
>> + * Copyright (c) 2018-2020, The Linux Foundation. All rights reserved.
>> + *
>> + */
>> +
>> +#ifndef _MHI_INT_H
>> +#define _MHI_INT_H
>> +
>> +extern struct bus_type mhi_bus_type;
>> +
>> +/* MHI transfer completion events */
>> +enum mhi_ev_ccs {
>> +    MHI_EV_CC_INVALID = 0x0,
>> +    MHI_EV_CC_SUCCESS = 0x1,
>> +    MHI_EV_CC_EOT = 0x2,
>> +    MHI_EV_CC_OVERFLOW = 0x3,
>> +    MHI_EV_CC_EOB = 0x4,
>> +    MHI_EV_CC_OOB = 0x5,
>> +    MHI_EV_CC_DB_MODE = 0x6,
>> +    MHI_EV_CC_UNDEFINED_ERR = 0x10,
>> +    MHI_EV_CC_BAD_TRE = 0x11,
> 
> Perhaps a quick comment expanding the "EOT", "EOB", "OOB" acronyms?  I 
> feel like those might not be obvious to someone not familiar with the 
> protocol.
> 
>> +};
>> +
>> +enum mhi_ch_state {
>> +    MHI_CH_STATE_DISABLED = 0x0,
>> +    MHI_CH_STATE_ENABLED = 0x1,
>> +    MHI_CH_STATE_RUNNING = 0x2,
>> +    MHI_CH_STATE_SUSPENDED = 0x3,
>> +    MHI_CH_STATE_STOP = 0x4,
>> +    MHI_CH_STATE_ERROR = 0x5,
>> +};
>> +
>> +#define MHI_INVALID_BRSTMODE(mode) (mode != MHI_DB_BRST_DISABLE && \
>> +                    mode != MHI_DB_BRST_ENABLE)
>> +
>> +#define NR_OF_CMD_RINGS            1
>> +#define CMD_EL_PER_RING            128
>> +#define PRIMARY_CMD_RING        0
>> +#define MHI_MAX_MTU            0xffff
>> +
>> +enum mhi_er_type {
>> +    MHI_ER_TYPE_INVALID = 0x0,
>> +    MHI_ER_TYPE_VALID = 0x1,
>> +};
>> +
>> +enum mhi_ch_ee_mask {
>> +    MHI_CH_EE_PBL = BIT(MHI_EE_PBL),
> 
> MHI_EE_PBL does not appear to be defined.  Are you perhaps missing an 
> include?
> 
>> +    MHI_CH_EE_SBL = BIT(MHI_EE_SBL),
>> +    MHI_CH_EE_AMSS = BIT(MHI_EE_AMSS),
>> +    MHI_CH_EE_RDDM = BIT(MHI_EE_RDDM),
>> +    MHI_CH_EE_PTHRU = BIT(MHI_EE_PTHRU),
>> +    MHI_CH_EE_WFW = BIT(MHI_EE_WFW),
>> +    MHI_CH_EE_EDL = BIT(MHI_EE_EDL),
>> +};
>> +
>> +struct db_cfg {
>> +    bool reset_req;
>> +    bool db_mode;
>> +    u32 pollcfg;
>> +    enum mhi_db_brst_mode brstmode;
>> +    dma_addr_t db_val;
>> +    void (*process_db)(struct mhi_controller *mhi_cntrl,
>> +               struct db_cfg *db_cfg, void __iomem *io_addr,
>> +               dma_addr_t db_val);
>> +};
>> +
>> +struct mhi_ring {
>> +    dma_addr_t dma_handle;
>> +    dma_addr_t iommu_base;
>> +    u64 *ctxt_wp; /* point to ctxt wp */
>> +    void *pre_aligned;
>> +    void *base;
>> +    void *rp;
>> +    void *wp;
>> +    size_t el_size;
>> +    size_t len;
>> +    size_t elements;
>> +    size_t alloc_size;
>> +    void __iomem *db_addr;
>> +};
>> +
>> +struct mhi_cmd {
>> +    struct mhi_ring ring;
>> +    spinlock_t lock;
>> +};
>> +
>> +struct mhi_buf_info {
>> +    dma_addr_t p_addr;
>> +    void *v_addr;
>> +    void *bb_addr;
>> +    void *wp;
>> +    size_t len;
>> +    void *cb_buf;
>> +    enum dma_data_direction dir;
>> +};
>> +
>> +struct mhi_event {
>> +    u32 er_index;
>> +    u32 intmod;
>> +    u32 irq;
>> +    int chan; /* this event ring is dedicated to a channel (optional) */
>> +    u32 priority;
>> +    enum mhi_er_data_type data_type;
>> +    struct mhi_ring ring;
>> +    struct db_cfg db_cfg;
>> +    bool hw_ring;
>> +    bool cl_manage;
>> +    bool offload_ev; /* managed by a device driver */
>> +    spinlock_t lock;
>> +    struct mhi_chan *mhi_chan; /* dedicated to channel */
>> +    struct tasklet_struct task;
>> +    int (*process_event)(struct mhi_controller *mhi_cntrl,
>> +                 struct mhi_event *mhi_event,
>> +                 u32 event_quota);
>> +    struct mhi_controller *mhi_cntrl;
>> +};
>> +
>> +struct mhi_chan {
>> +    u32 chan;
>> +    const char *name;
>> +    /*
>> +     * Important: When consuming, increment tre_ring first and when
>> +     * releasing, decrement buf_ring first. If tre_ring has space, 
>> buf_ring
>> +     * is guranteed to have space so we do not need to check both rings.
>> +     */
>> +    struct mhi_ring buf_ring;
>> +    struct mhi_ring tre_ring;
>> +    u32 er_index;
>> +    u32 intmod;
>> +    enum mhi_ch_type type;
>> +    enum dma_data_direction dir;
>> +    struct db_cfg db_cfg;
>> +    enum mhi_ch_ee_mask ee_mask;
>> +    enum mhi_buf_type xfer_type;
>> +    enum mhi_ch_state ch_state;
>> +    enum mhi_ev_ccs ccs;
>> +    bool lpm_notify;
>> +    bool configured;
>> +    bool offload_ch;
>> +    bool pre_alloc;
>> +    bool auto_start;
>> +    int (*gen_tre)(struct mhi_controller *mhi_cntrl,
>> +               struct mhi_chan *mhi_chan, void *buf, void *cb,
>> +               size_t len, enum mhi_flags flags);
>> +    int (*queue_xfer)(struct mhi_device *mhi_dev, struct mhi_chan 
>> *mhi_chan,
>> +              void *buf, size_t len, enum mhi_flags mflags);
>> +    struct mhi_device *mhi_dev;
>> +    void (*xfer_cb)(struct mhi_device *mhi_dev, struct mhi_result 
>> *result);
>> +    struct mutex mutex;
>> +    struct completion completion;
>> +    rwlock_t lock;
>> +    struct list_head node;
>> +};
>> +
>> +/* Default MHI timeout */
>> +#define MHI_TIMEOUT_MS (1000)
>> +
>> +struct mhi_device *mhi_alloc_device(struct mhi_controller *mhi_cntrl);
>> +static inline void mhi_dealloc_device(struct mhi_controller *mhi_cntrl,
>> +                      struct mhi_device *mhi_dev)
>> +{
>> +    kfree(mhi_dev);
>> +}
>> +
>> +int mhi_destroy_device(struct device *dev, void *data);
>> +void mhi_create_devices(struct mhi_controller *mhi_cntrl);
>> +
>> +#endif /* _MHI_INT_H */
>> diff --git a/include/linux/mhi.h b/include/linux/mhi.h
>> new file mode 100644
>> index 000000000000..69cf9a4b06c7
>> --- /dev/null
>> +++ b/include/linux/mhi.h
>> @@ -0,0 +1,438 @@
>> +/* SPDX-License-Identifier: GPL-2.0 */
>> +/*
>> + * Copyright (c) 2018-2020, The Linux Foundation. All rights reserved.
>> + *
>> + */
>> +#ifndef _MHI_H_
>> +#define _MHI_H_
>> +
>> +#include <linux/device.h>
>> +#include <linux/dma-direction.h>
>> +#include <linux/mutex.h>
>> +#include <linux/rwlock_types.h>
>> +#include <linux/slab.h>
>> +#include <linux/spinlock_types.h>
>> +#include <linux/wait.h>
>> +#include <linux/workqueue.h>
>> +
>> +struct mhi_chan;
>> +struct mhi_event;
>> +struct mhi_ctxt;
>> +struct mhi_cmd;
>> +struct mhi_buf_info;
>> +
>> +/**
>> + * enum mhi_callback - MHI callback
>> + * @MHI_CB_IDLE: MHI entered idle state
>> + * @MHI_CB_PENDING_DATA: New data available for client to process
>> + * @MHI_CB_LPM_ENTER: MHI host entered low power mode
>> + * @MHI_CB_LPM_EXIT: MHI host about to exit low power mode
>> + * @MHI_CB_EE_RDDM: MHI device entered RDDM exec env
>> + * @MHI_CB_EE_MISSION_MODE: MHI device entered Mission Mode exec env
>> + * @MHI_CB_SYS_ERROR: MHI device entered error state (may recover)
>> + * @MHI_CB_FATAL_ERROR: MHI device entered fatal error state
>> + */
>> +enum mhi_callback {
>> +    MHI_CB_IDLE,
>> +    MHI_CB_PENDING_DATA,
>> +    MHI_CB_LPM_ENTER,
>> +    MHI_CB_LPM_EXIT,
>> +    MHI_CB_EE_RDDM,
>> +    MHI_CB_EE_MISSION_MODE,
>> +    MHI_CB_SYS_ERROR,
>> +    MHI_CB_FATAL_ERROR,
>> +};
>> +
>> +/**
>> + * enum mhi_flags - Transfer flags
>> + * @MHI_EOB: End of buffer for bulk transfer
>> + * @MHI_EOT: End of transfer
>> + * @MHI_CHAIN: Linked transfer
>> + */
>> +enum mhi_flags {
>> +    MHI_EOB,
>> +    MHI_EOT,
>> +    MHI_CHAIN,
>> +};
>> +
>> +/**
>> + * enum mhi_device_type - Device types
>> + * @MHI_DEVICE_XFER: Handles data transfer
>> + * @MHI_DEVICE_TIMESYNC: Use for timesync feature
>> + * @MHI_DEVICE_CONTROLLER: Control device
>> + */
>> +enum mhi_device_type {
>> +    MHI_DEVICE_XFER,
>> +    MHI_DEVICE_TIMESYNC,
>> +    MHI_DEVICE_CONTROLLER,
>> +};
>> +
>> +/**
>> + * enum mhi_ch_type - Channel types
>> + * @MHI_CH_TYPE_INVALID: Invalid channel type
>> + * @MHI_CH_TYPE_OUTBOUND: Outbound channel to the device
>> + * @MHI_CH_TYPE_INBOUND: Inbound channel from the device
>> + * @MHI_CH_TYPE_INBOUND_COALESCED: Coalesced channel for the device 
>> to combine
>> + *                   multiple packets and send them as a single
>> + *                   large packet to reduce CPU consumption
>> + */
>> +enum mhi_ch_type {
>> +    MHI_CH_TYPE_INVALID = 0,
>> +    MHI_CH_TYPE_OUTBOUND = DMA_TO_DEVICE,
>> +    MHI_CH_TYPE_INBOUND = DMA_FROM_DEVICE,
>> +    MHI_CH_TYPE_INBOUND_COALESCED = 3,
>> +};
>> +
>> +/**
>> + * enum mhi_ee_type - Execution environment types
>> + * @MHI_EE_PBL: Primary Bootloader
>> + * @MHI_EE_SBL: Secondary Bootloader
>> + * @MHI_EE_AMSS: Modem, aka the primary runtime EE
>> + * @MHI_EE_RDDM: Ram dump download mode
>> + * @MHI_EE_WFW: WLAN firmware mode
>> + * @MHI_EE_PTHRU: Passthrough
>> + * @MHI_EE_EDL: Embedded downloader
>> + */
>> +enum mhi_ee_type {
>> +    MHI_EE_PBL,
>> +    MHI_EE_SBL,
>> +    MHI_EE_AMSS,
>> +    MHI_EE_RDDM,
>> +    MHI_EE_WFW,
>> +    MHI_EE_PTHRU,
>> +    MHI_EE_EDL,
>> +    MHI_EE_MAX_SUPPORTED = MHI_EE_EDL,
>> +    MHI_EE_DISABLE_TRANSITION, /* local EE, not related to mhi spec */
>> +    MHI_EE_NOT_SUPPORTED,
>> +    MHI_EE_MAX,
>> +};
>> +
>> +/**
>> + * enum mhi_buf_type - Accepted buffer type for the channel
>> + * @MHI_BUF_RAW: Raw buffer
>> + * @MHI_BUF_SKB: SKB struct
>> + * @MHI_BUF_SCLIST: Scatter-gather list
>> + * @MHI_BUF_NOP: CPU offload channel, host does not accept transfer
>> + * @MHI_BUF_DMA: Receive DMA address mapped by client
>> + * @MHI_BUF_RSC_DMA: RSC type premapped buffer
> 
> Maybe its just me, but what is "RSC"?
> 
>> + */
>> +enum mhi_buf_type {
>> +    MHI_BUF_RAW,
>> +    MHI_BUF_SKB,
>> +    MHI_BUF_SCLIST,
>> +    MHI_BUF_NOP,
>> +    MHI_BUF_DMA,
>> +    MHI_BUF_RSC_DMA,
>> +};
>> +
>> +/**
>> + * enum mhi_er_data_type - Event ring data types
>> + * @MHI_ER_DATA: Only client data over this ring
>> + * @MHI_ER_CTRL: MHI control data and client data
>> + * @MHI_ER_TSYNC: Time sync events
>> + */
>> +enum mhi_er_data_type {
>> +    MHI_ER_DATA,
>> +    MHI_ER_CTRL,
>> +    MHI_ER_TSYNC,
>> +};
>> +
>> +/**
>> + * enum mhi_db_brst_mode - Doorbell mode
>> + * @MHI_DB_BRST_DISABLE: Burst mode disable
>> + * @MHI_DB_BRST_ENABLE: Burst mode enable
>> + */
>> +enum mhi_db_brst_mode {
>> +    MHI_DB_BRST_DISABLE = 0x2,
>> +    MHI_DB_BRST_ENABLE = 0x3,
>> +};
>> +
>> +/**
>> + * struct mhi_channel_config - Channel configuration structure for 
>> controller
>> + * @num: The number assigned to this channel
>> + * @name: The name of this channel
>> + * @num_elements: The number of elements that can be queued to this 
>> channel
>> + * @local_elements: The local ring length of the channel
>> + * @event_ring: The event rung index that services this channel
>> + * @dir: Direction that data may flow on this channel
>> + * @type: Channel type
>> + * @ee_mask: Execution Environment mask for this channel
> 
> But the mask defines are in internal.h, so how is a client suposed to 
> know what they are?
> 
>> + * @pollcfg: Polling configuration for burst mode.  0 is default.  
>> milliseconds
>> +         for UL channels, multiple of 8 ring elements for DL channels
>> + * @data_type: Data type accepted by this channel
>> + * @doorbell: Doorbell mode
>> + * @lpm_notify: The channel master requires low power mode notifications
>> + * @offload_channel: The client manages the channel completely
>> + * @doorbell_mode_switch: Channel switches to doorbell mode on M0 
>> transition
>> + * @auto_queue: Framework will automatically queue buffers for DL 
>> traffic
>> + * @auto_start: Automatically start (open) this channel
>> + */
>> +struct mhi_channel_config {
>> +    u32 num;
>> +    char *name;
>> +    u32 num_elements;
>> +    u32 local_elements;
>> +    u32 event_ring;
>> +    enum dma_data_direction dir;
>> +    enum mhi_ch_type type;

Why do we have "dir" and "type" when they are the same thing?

>> +    u32 ee_mask;
>> +    u32 pollcfg;
>> +    enum mhi_buf_type data_type;
>> +    enum mhi_db_brst_mode doorbell;
>> +    bool lpm_notify;
>> +    bool offload_channel;
>> +    bool doorbell_mode_switch;
>> +    bool auto_queue;
>> +    bool auto_start;
>> +};
>> +
>> +/**
>> + * struct mhi_event_config - Event ring configuration structure for 
>> controller
>> + * @num_elements: The number of elements that can be queued to this ring
>> + * @irq_moderation_ms: Delay irq for additional events to be aggregated
>> + * @irq: IRQ associated with this ring
>> + * @channel: Dedicated channel number. U32_MAX indicates a 
>> non-dedicated ring
>> + * @mode: Doorbell mode
>> + * @data_type: Type of data this ring will process
>> + * @hardware_event: This ring is associated with hardware channels
>> + * @client_managed: This ring is client managed
>> + * @offload_channel: This ring is associated with an offloaded channel
>> + * @priority: Priority of this ring. Use 1 for now
>> + */
>> +struct mhi_event_config {
>> +    u32 num_elements;
>> +    u32 irq_moderation_ms;
>> +    u32 irq;
>> +    u32 channel;
>> +    enum mhi_db_brst_mode mode;
>> +    enum mhi_er_data_type data_type;
>> +    bool hardware_event;
>> +    bool client_managed;
>> +    bool offload_channel;
>> +    u32 priority;
>> +};
>> +
>> +/**
>> + * struct mhi_controller_config - Root MHI controller configuration
>> + * @max_channels: Maximum number of channels supported
>> + * @timeout_ms: Timeout value for operations. 0 means use default
>> + * @use_bounce_buf: Use a bounce buffer pool due to limited DDR access
>> + * @m2_no_db: Host is not allowed to ring DB in M2 state
>> + * @buf_len: Size of automatically allocated buffers. 0 means use 
>> default
>> + * @num_channels: Number of channels defined in @ch_cfg
>> + * @ch_cfg: Array of defined channels
>> + * @num_events: Number of event rings defined in @event_cfg
>> + * @event_cfg: Array of defined event rings
>> + */
>> +struct mhi_controller_config {
>> +    u32 max_channels;
>> +    u32 timeout_ms;
>> +    bool use_bounce_buf;
>> +    bool m2_no_db;
>> +    u32 buf_len;
>> +    u32 num_channels;
>> +    struct mhi_channel_config *ch_cfg;
>> +    u32 num_events;
>> +    struct mhi_event_config *event_cfg;
>> +};
>> +
>> +/**
>> + * struct mhi_controller - Master MHI controller structure

Quite a bit of this needs to be initialized by the entity calling 
mhi_register_controller(), but its not clear what.  I'm thinking that 
since we have a config structure, all of that should be copied/moved 
into the config so that the caller of mhi_register_controller() provides 
an empty mhi_controller struct / a populated config struct and receives 
an initialized mhi_controller instance.

>> + * @name: Name of the controller
>> + * @dev: Driver model device node for the controller
>> + * @mhi_dev: MHI device instance for the controller
>> + * @dev_id: Device ID of the controller
>> + * @bus_id: Physical bus instance used by the controller
>> + * @regs: Base address of MHI MMIO register space
>> + * @iova_start: IOMMU starting address for data
>> + * @iova_stop: IOMMU stop address for data
>> + * @fw_image: Firmware image name for normal booting
>> + * @edl_image: Firmware image name for emergency download mode
>> + * @fbc_download: MHI host needs to do complete image transfer
>> + * @sbl_size: SBL image size
>> + * @seg_len: BHIe vector size
>> + * @max_chan: Maximum number of channels the controller supports
>> + * @mhi_chan: Points to the channel configuration table
>> + * @lpm_chans: List of channels that require LPM notifications
>> + * @total_ev_rings: Total # of event rings allocated
>> + * @hw_ev_rings: Number of hardware event rings
>> + * @sw_ev_rings: Number of software event rings
>> + * @nr_irqs_req: Number of IRQs required to operate
>> + * @nr_irqs: Number of IRQ allocated by bus master
>> + * @irq: base irq # to request
>> + * @mhi_event: MHI event ring configurations table
>> + * @mhi_cmd: MHI command ring configurations table
>> + * @mhi_ctxt: MHI device context, shared memory between host and device
>> + * @timeout_ms: Timeout in ms for state transitions
>> + * @pm_mutex: Mutex for suspend/resume operation
>> + * @pre_init: MHI host needs to do pre-initialization before power up
>> + * @pm_lock: Lock for protecting MHI power management state
>> + * @pm_state: MHI power management state
>> + * @db_access: DB access states
>> + * @ee: MHI device execution environment
>> + * @wake_set: Device wakeup set flag
>> + * @dev_wake: Device wakeup count
>> + * @alloc_size: Total memory allocations size of the controller
>> + * @pending_pkts: Pending packets for the controller
>> + * @transition_list: List of MHI state transitions
>> + * @wlock: Lock for protecting device wakeup
>> + * @M0: M0 state counter for debugging
>> + * @M2: M2 state counter for debugging
>> + * @M3: M3 state counter for debugging
>> + * @M3_FAST: M3 Fast state counter for debugging
>> + * @st_worker: State transition worker
>> + * @fw_worker: Firmware download worker
>> + * @syserr_worker: System error worker
>> + * @state_event: State change event
>> + * @status_cb: CB function to notify various power states to bus master
>> + * @link_status: CB function to query link status of the device
>> + * @wake_get: CB function to assert device wake
>> + * @wake_put: CB function to de-assert device wake
>> + * @wake_toggle: CB function to assert and deasset (toggle) device wake
>> + * @runtime_get: CB function to controller runtime resume
>> + * @runtimet_put: CB function to decrement pm usage
>> + * @lpm_disable: CB function to request disable link level low power 
>> modes
>> + * @lpm_enable: CB function to request enable link level low power 
>> modes again
>> + * @bounce_buf: Use of bounce buffer
>> + * @buffer_len: Bounce buffer length
>> + * @priv_data: Points to bus master's private data
>> + */
>> +struct mhi_controller {
>> +    const char *name;
>> +    struct device *dev;
>> +    struct mhi_device *mhi_dev;
>> +    u32 dev_id;
>> +    u32 bus_id;
>> +    void __iomem *regs;
>> +    dma_addr_t iova_start;
>> +    dma_addr_t iova_stop;
>> +    const char *fw_image;
>> +    const char *edl_image;
>> +    bool fbc_download;
>> +    size_t sbl_size;
>> +    size_t seg_len;
>> +    u32 max_chan;
>> +    struct mhi_chan *mhi_chan;
>> +    struct list_head lpm_chans;
>> +    u32 total_ev_rings;
>> +    u32 hw_ev_rings;
>> +    u32 sw_ev_rings;
>> +    u32 nr_irqs_req;
>> +    u32 nr_irqs;
>> +    int *irq;
>> +
>> +    struct mhi_event *mhi_event;
>> +    struct mhi_cmd *mhi_cmd;
>> +    struct mhi_ctxt *mhi_ctxt;
>> +
>> +    u32 timeout_ms;
>> +    struct mutex pm_mutex;
>> +    bool pre_init;
>> +    rwlock_t pm_lock;
>> +    u32 pm_state;
>> +    u32 db_access;
>> +    enum mhi_ee_type ee;
>> +    bool wake_set;
>> +    atomic_t dev_wake;
>> +    atomic_t alloc_size;
>> +    atomic_t pending_pkts;
>> +    struct list_head transition_list;
>> +    spinlock_t transition_lock;
>> +    spinlock_t wlock;
>> +    u32 M0, M2, M3, M3_FAST;
>> +    struct work_struct st_worker;
>> +    struct work_struct fw_worker;
>> +    struct work_struct syserr_worker;
>> +    wait_queue_head_t state_event;
>> +
>> +    void (*status_cb)(struct mhi_controller *mhi_cntrl, void *priv,
>> +              enum mhi_callback cb);
>> +    int (*link_status)(struct mhi_controller *mhi_cntrl, void *priv);
>> +    void (*wake_get)(struct mhi_controller *mhi_cntrl, bool override);
>> +    void (*wake_put)(struct mhi_controller *mhi_cntrl, bool override);
>> +    void (*wake_toggle)(struct mhi_controller *mhi_cntrl);
>> +    int (*runtime_get)(struct mhi_controller *mhi_cntrl, void *priv);
>> +    void (*runtime_put)(struct mhi_controller *mhi_cntrl, void *priv);
>> +    void (*lpm_disable)(struct mhi_controller *mhi_cntrl, void *priv);
>> +    void (*lpm_enable)(struct mhi_controller *mhi_cntrl, void *priv);
>> +
>> +    bool bounce_buf;
>> +    size_t buffer_len;
>> +    void *priv_data;
>> +};
>> +
>> +/**
>> + * struct mhi_device - Structure representing a MHI device which binds
>> + *                     to channels
>> + * @dev: Driver model device node for the MHI device
>> + * @tiocm: Device current terminal settings
>> + * @id: Pointer to MHI device ID struct
>> + * @chan_name: Name of the channel to which the device binds
>> + * @mhi_cntrl: Controller the device belongs to
>> + * @ul_chan: UL channel for the device
>> + * @dl_chan: DL channel for the device
>> + * @dev_wake: Device wakeup counter
>> + * @dev_type: MHI device type
>> + */
>> +struct mhi_device {
>> +    struct device dev;
>> +    u32 tiocm;
>> +    const struct mhi_device_id *id;
>> +    const char *chan_name;
>> +    struct mhi_controller *mhi_cntrl;
>> +    struct mhi_chan *ul_chan;
>> +    struct mhi_chan *dl_chan;
>> +    atomic_t dev_wake;
>> +    enum mhi_device_type dev_type;
>> +};
>> +
>> +/**
>> + * struct mhi_result - Completed buffer information
>> + * @buf_addr: Address of data buffer
>> + * @dir: Channel direction
>> + * @bytes_xfer: # of bytes transferred
>> + * @transaction_status: Status of last transaction
>> + */
>> +struct mhi_result {
>> +    void *buf_addr;
>> +    enum dma_data_direction dir;
>> +    size_t bytes_xferd;
> 
> Desription says this is named "bytes_xfer"
> 
>> +    int transaction_status;
>> +};
>> +
>> +#define to_mhi_device(dev) container_of(dev, struct mhi_device, dev)
>> +
>> +/**
>> + * mhi_controller_set_devdata - Set MHI controller private data
>> + * @mhi_cntrl: MHI controller to set data
>> + */
>> +static inline void mhi_controller_set_devdata(struct mhi_controller 
>> *mhi_cntrl,
>> +                     void *priv)
>> +{
>> +    mhi_cntrl->priv_data = priv;
>> +}
>> +
>> +/**
>> + * mhi_controller_get_devdata - Get MHI controller private data
>> + * @mhi_cntrl: MHI controller to get data
>> + */
>> +static inline void *mhi_controller_get_devdata(struct mhi_controller 
>> *mhi_cntrl)
>> +{
>> +    return mhi_cntrl->priv_data;
>> +}
>> +
>> +/**
>> + * mhi_register_controller - Register MHI controller
>> + * @mhi_cntrl: MHI controller to register
>> + * @config: Configuration to use for the controller
>> + */
>> +int mhi_register_controller(struct mhi_controller *mhi_cntrl,
>> +                struct mhi_controller_config *config);
>> +
>> +/**
>> + * mhi_unregister_controller - Unregister MHI controller
>> + * @mhi_cntrl: MHI controller to unregister
>> + */
>> +void mhi_unregister_controller(struct mhi_controller *mhi_cntrl);
>> +
>> +#endif /* _MHI_H_ */
>> diff --git a/include/linux/mod_devicetable.h 
>> b/include/linux/mod_devicetable.h
>> index e3596db077dc..be15e997fe39 100644
>> --- a/include/linux/mod_devicetable.h
>> +++ b/include/linux/mod_devicetable.h
>> @@ -821,4 +821,16 @@ struct wmi_device_id {
>>       const void *context;
>>   };
>> +#define MHI_NAME_SIZE 32
>> +
>> +/**
>> + * struct mhi_device_id - MHI device identification
>> + * @chan: MHI channel name
>> + * @driver_data: driver data;
>> + */
>> +struct mhi_device_id {
>> +    const char chan[MHI_NAME_SIZE];
>> +    kernel_ulong_t driver_data;
>> +};
>> +
>>   #endif /* LINUX_MOD_DEVICETABLE_H */
>>
> 
> 


-- 
Jeffrey Hugo
Qualcomm Technologies, Inc. is a member of the
Code Aurora Forum, a Linux Foundation Collaborative Project.