From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0E8D2C43334 for ; Wed, 8 Jun 2022 10:15:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236510AbiFHKPR (ORCPT ); Wed, 8 Jun 2022 06:15:17 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36404 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236623AbiFHKNc (ORCPT ); Wed, 8 Jun 2022 06:13:32 -0400 Received: from szxga08-in.huawei.com (szxga08-in.huawei.com [45.249.212.255]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D19D822C827 for ; Wed, 8 Jun 2022 03:00:36 -0700 (PDT) Received: from dggemv704-chm.china.huawei.com (unknown [172.30.72.54]) by szxga08-in.huawei.com (SkyGuard) with ESMTP id 4LJ2jy2Gx0z1K9tT; Wed, 8 Jun 2022 17:58:46 +0800 (CST) Received: from kwepemm600003.china.huawei.com (7.193.23.202) by dggemv704-chm.china.huawei.com (10.3.19.47) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.24; Wed, 8 Jun 2022 18:00:35 +0800 Received: from [10.67.101.67] (10.67.101.67) by kwepemm600003.china.huawei.com (7.193.23.202) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.24; Wed, 8 Jun 2022 18:00:34 +0800 Subject: Re: [PATCH v6 1/2] drivers/coresight: Add UltraSoc System Memory Buffer driver To: Suzuki K Poulose , , CC: , , , References: <20220606130223.57354-1-liuqi115@huawei.com> <20220606130223.57354-2-liuqi115@huawei.com> <4c4af59c-0b71-c5a5-1d5c-80b2e89de4d9@arm.com> From: "liuqi (BA)" Message-ID: <413e09a7-4a03-1beb-f533-9839bff9ddb7@huawei.com> Date: Wed, 8 Jun 2022 18:00:33 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:68.0) Gecko/20100101 Thunderbird/68.6.0 MIME-Version: 1.0 In-Reply-To: <4c4af59c-0b71-c5a5-1d5c-80b2e89de4d9@arm.com> Content-Type: text/plain; charset="utf-8"; format=flowed Content-Language: en-GB Content-Transfer-Encoding: 8bit X-Originating-IP: [10.67.101.67] X-ClientProxiedBy: dggems704-chm.china.huawei.com (10.3.19.181) To kwepemm600003.china.huawei.com (7.193.23.202) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Suzuki, On 2022/6/7 16:33, Suzuki K Poulose wrote: > Hi Qi > > On 06/06/2022 14:02, Qi Liu wrote: >> This patch adds driver for UltraSoc SMB(System Memory Buffer) >> device. SMB provides a way to buffer messages from ETM, and >> store these CPU instructions in system memory. > > nit: "CPU instruction trace" in system memory. > >> >> SMB is developed by UltraSoc technology, which is acquired by >> Siemens, and we still use "UltraSoc" to name driver. >> >> Signed-off-by: Qi Liu >> Tested-by: JunHao He >> --- >>   drivers/hwtracing/coresight/Kconfig        |  10 + >>   drivers/hwtracing/coresight/Makefile       |   1 + >>   drivers/hwtracing/coresight/ultrasoc-smb.c | 663 +++++++++++++++++++++ >>   drivers/hwtracing/coresight/ultrasoc-smb.h | 110 ++++ >>   4 files changed, 784 insertions(+) >>   create mode 100644 drivers/hwtracing/coresight/ultrasoc-smb.c >>   create mode 100644 drivers/hwtracing/coresight/ultrasoc-smb.h >> >> diff --git a/drivers/hwtracing/coresight/Kconfig >> b/drivers/hwtracing/coresight/Kconfig >> index 514a9b8086e3..4380eb1a0a73 100644 >> --- a/drivers/hwtracing/coresight/Kconfig >> +++ b/drivers/hwtracing/coresight/Kconfig > > ... > >> diff --git a/drivers/hwtracing/coresight/Makefile >> b/drivers/hwtracing/coresight/Makefile >> index b6c4a48140ec..344dba8d6ff8 100644 >> --- a/drivers/hwtracing/coresight/Makefile >> +++ b/drivers/hwtracing/coresight/Makefile >> @@ -27,3 +27,4 @@ obj-$(CONFIG_CORESIGHT_CTI) += coresight-cti.o >>   obj-$(CONFIG_CORESIGHT_TRBE) += coresight-trbe.o >>   coresight-cti-y := coresight-cti-core.o    coresight-cti-platform.o \ >>              coresight-cti-sysfs.o >> +obj-$(CONFIG_ULTRASOC_SMB) += ultrasoc-smb.o >> diff --git a/drivers/hwtracing/coresight/ultrasoc-smb.c >> b/drivers/hwtracing/coresight/ultrasoc-smb.c >> new file mode 100644 >> index 000000000000..44b4bceb6f28 >> --- /dev/null >> +++ b/drivers/hwtracing/coresight/ultrasoc-smb.c > > ... > >> +static int smb_open(struct inode *inode, struct file *file) >> +{ >> +    struct smb_drv_data *drvdata = container_of(file->private_data, >> +                    struct smb_drv_data, miscdev); >> +    unsigned long flags; >> +    int ret = 0; >> + >> +    spin_lock_irqsave(&drvdata->spinlock, flags); >> + >> +    if (local_read(&drvdata->reading)) { >> +        ret = -EBUSY; >> +        goto out; >> +    } >> + >> +    if (drvdata->mode == CS_MODE_PERF) { >> +        ret = -EINVAL; >> +        goto out; >> +    } >> + >> +out: >> +    spin_unlock_irqrestore(&drvdata->spinlock, flags); >> +    return ret; >> +} >> + >> +static ssize_t smb_read(struct file *file, char __user *data, size_t >> len, >> +            loff_t *ppos) >> +{ >> +    struct smb_drv_data *drvdata = container_of(file->private_data, >> +                    struct smb_drv_data, miscdev); >> +    struct smb_data_buffer *sdb = &drvdata->sdb; >> +    struct device *dev = &drvdata->csdev->dev; >> +    unsigned long flags; >> +    int to_copy = 0; >> + >> +    spin_lock_irqsave(&drvdata->spinlock, flags); >> + >> +    if (atomic_read(drvdata->csdev->refcnt)) { >> +        spin_unlock_irqrestore(&drvdata->spinlock, flags); >> +        return -EBUSY; >> +    } >> + >> +    if (local_cmpxchg(&drvdata->reading, 0, 1)) { >> +        spin_unlock_irqrestore(&drvdata->spinlock, flags); >> +        return -EBUSY; >> +    } >> + > > Shouldn't this be done in smb_open() ? Otherwise, a subsequent read > will fail with EBUSY ? > i.e, >     fd = open(/dev/ultra_smb0, ..); > >     # size of the SMB buffer = 1M, >     size = read(fd, buf, SZ_4K); >     /* Do something the buf */ >     if (size >= 0) >         size = read(fd, buf, SZ_4K); > > ^^ This would fail, isn't it ? > Yes, I'll change it to: static int smb_open(struct inode *inode, struct file *file) { struct smb_drv_data *drvdata = container_of(file->private_data, struct smb_drv_data, miscdev); unsigned long flags; int ret = 0; spin_lock_irqsave(&drvdata->spinlock, flags); if (local_read(&drvdata->reading)) { ret = -EBUSY; goto out; } if (drvdata->mode != CS_MODE_DISABLED) { ret = -EBUSY; goto out; } local_set(&drvdata->reading, 1); out: spin_unlock_irqrestore(&drvdata->spinlock, flags); return ret; } So SMB data can only be read when SMB is disabled, and could be read subsequently. >> +    if (!sdb->data_size) { >> +        smb_update_data_size(drvdata); >> +        if (!sdb->data_size) >> +            goto out; >> +    } >> + >> +    to_copy = min(sdb->data_size, len); >> + >> +    /* Copy parts of trace data when read pointer wrap around SMB >> buffer */ >> +    if (sdb->rd_offset + to_copy > sdb->buf_size) >> +        to_copy = sdb->buf_size - sdb->rd_offset; >> + >> +    if (copy_to_user(data, (void *)sdb->buf_base + sdb->rd_offset, >> +             to_copy)) { >> +        dev_dbg(dev, "Failed to copy data to user.\n"); >> +        to_copy = -EFAULT; >> +        goto out; >> +    } >> + >> +    *ppos += to_copy; >> +    sdb->data_size -= to_copy; >> +    sdb->rd_offset += to_copy; >> +    sdb->rd_offset %= sdb->buf_size; >> +    writel(sdb->start_addr + sdb->rd_offset, >> +           drvdata->base + SMB_LB_RD_ADDR); >> +    dev_dbg(dev, "%d bytes copied.\n", to_copy); >> +out: >> +    if (!sdb->data_size) >> +        smb_reset_buffer_status(drvdata); >> +    spin_unlock_irqrestore(&drvdata->spinlock, flags); >> +    return to_copy; >> +} >> + [...] >> + >> +static int smb_set_perf_buffer(struct perf_output_handle *handle) >> +{ >> +    struct cs_buffers *buf = etm_perf_sink_config(handle); >> +    u32 head; >> + >> +    if (!buf) >> +        return -EINVAL; >> + >> +    /* Wrap head around to the amount of space we have */ >> +    head = handle->head & ((buf->nr_pages << PAGE_SHIFT) - 1); >> + >> +    /* Find the page to write to and offset within that page */ >> +    buf->cur = head / PAGE_SIZE; >> +    buf->offset = head % PAGE_SIZE; >> + > > I believe these fields should be dropped and instead use the > handle->head, to determine the page number and offset. See the > TMC-ETR driver for e.g. got it, I'll do this next time. > >> +    local_set(&buf->data_size, 0); >> + >> +    return 0; >> +} >> + [...] >> + >> +static int smb_enable(struct coresight_device *csdev, u32 mode, void >> *data) >> +{ >> +    struct smb_drv_data *drvdata = dev_get_drvdata(csdev->dev.parent); >> +    int ret; >> + >> +    /* Do nothing if trace data is reading by other interface now */ >> +    if (local_read(&drvdata->reading)) >> +        return -EBUSY; >> + > > Is there global switch for all the inports ? Or is there a control for > individual inports to the SMB ? Do we need additional information here > to enable the corresponding port ? There is a global switch to enable and disable all the inports in smb_config_inport() when probe the SMB driver. > >> +    switch (mode) { >> +    case CS_MODE_SYSFS: >> +        ret = smb_enable_sysfs(csdev); >> +        break; >> +    case CS_MODE_PERF: >> +        ret = smb_enable_perf(csdev, data); >> +        break; >> +    default: >> +        ret = -EINVAL; >> +        break; >> +    } >> + >> +    if (ret) >> +        return ret; >> +    dev_dbg(&csdev->dev, "Ultrasoc SMB enabled.\n"); >> + >> +    return 0; >> +} >> + >> + >> +static void smb_free_buffer(void *config) >> +{ >> +    struct cs_buffers *buf = config; >> + >> +    kfree(buf); >> +} >> + >> +static void smb_sync_perf_buffer(struct smb_drv_data *drvdata, >> +                 struct cs_buffers *buf, >> +                 unsigned long data_size) > > You may need to pass the aux_handle here, to determine the handle->head > and the size. See my comments above. ok, I'll do this next time, thanks. > >> +{ >> +    struct smb_data_buffer *sdb = &drvdata->sdb; >> +    char **dst_pages = (char **)buf->data_pages; >> +    unsigned long page_offset = buf->offset; >> +    unsigned int cur = buf->cur; >> +    unsigned long to_copy; >> + >> +    while (data_size) { >> +        unsigned long page_space = PAGE_SIZE - page_offset; >> + >> +        /* Copy parts of trace data when read pointer wrap around */ >> +        if (sdb->rd_offset + page_space > sdb->buf_size) >> +            to_copy = sdb->buf_size - sdb->rd_offset; >> +        else >> +            to_copy = min(data_size, page_space); >> + >> +        memcpy_fromio(dst_pages[cur] + page_offset, >> +                  sdb->buf_base + sdb->rd_offset, to_copy); >> + >> +        page_offset += to_copy; >> +        if (page_offset >= PAGE_SIZE) { >> +            page_offset = 0; >> +            cur++; >> +            cur %= buf->nr_pages; >> +        } >> +        data_size -= to_copy; >> +        sdb->rd_offset += to_copy; >> +        sdb->rd_offset %= sdb->buf_size; >> +    } >> + >> +    sdb->data_size = 0; >> +    writel(sdb->start_addr + sdb->rd_offset, drvdata->base + >> SMB_LB_RD_ADDR); >> + >> +    /* >> +     * Data remained in link cannot be purged when SMB is full, so >> +     * synchronize the read pointer to write pointer, to make sure >> +     * these remained data won't influence next trace. >> +     */ >> +    if (sdb->full) { >> +        smb_purge_data(drvdata); >> +        writel(readl(drvdata->base + SMB_LB_WR_ADDR), >> +               drvdata->base + SMB_LB_RD_ADDR); >> +    } >> +    smb_reset_buffer_status(drvdata); >> +} >> + >> + >> +static int smb_register_sink(struct platform_device *pdev, >> +                 struct smb_drv_data *drvdata) >> +{ >> +    struct coresight_platform_data *pdata = NULL; >> +    struct coresight_desc desc = { 0 }; >> +    int ret; >> + >> +    pdata = coresight_get_platform_data(&pdev->dev); >> +    if (IS_ERR(pdata)) >> +        return PTR_ERR(pdata); >> + >> +    desc.type = CORESIGHT_DEV_TYPE_SINK; >> +    desc.subtype.sink_subtype = CORESIGHT_DEV_SUBTYPE_SINK_BUFFER; >> +    desc.ops = &cs_ops; >> +    desc.pdata = pdata; >> +    desc.dev = &pdev->dev; >> +    desc.groups = smb_sink_groups; >> +    desc.name = coresight_alloc_device_name(&sink_devs, &pdev->dev); > > Please fill in the csdev_access method for the device. will do this next time, thanks. Thanks, Qi >     desc.access = CSDEV_ACCESS_IOMEM(drvdata->base); > >> +    if (!desc.name) { >> +        dev_err(&pdev->dev, "Failed to alloc coresight device name."); >> +        return -ENOMEM; >> +    } >> + >> +    drvdata->csdev = coresight_register(&desc); >> +    if (IS_ERR(drvdata->csdev)) >> +        return PTR_ERR(drvdata->csdev); >> + >> +    drvdata->miscdev.name = desc.name; >> +    drvdata->miscdev.minor = MISC_DYNAMIC_MINOR; >> +    drvdata->miscdev.fops = &smb_fops; >> +    ret = misc_register(&drvdata->miscdev); >> +    if (ret) { >> +        coresight_unregister(drvdata->csdev); >> +        dev_err(&pdev->dev, "Failed to register misc, ret=%d.\n", ret); >> +    } >> + >> +    return ret; >> +} >> + >> +static void smb_unregister_sink(struct smb_drv_data *drvdata) >> +{ >> +    misc_deregister(&drvdata->miscdev); >> +    coresight_unregister(drvdata->csdev); >> +} >> + >> +static int smb_config_inport(struct device *dev, bool enable) >> +{ >> +    u64 func = enable ? 1 : 0; >> +    union acpi_object *obj; >> +    guid_t guid; >> +    u64 rev = 0; >> + >> +    /* >> +     * Using DSM calls to enable/disable ultrasoc hardwares on >> +     * tracing path, to prevent ultrasoc packet format being exposed. >> +     */ >> +    if (guid_parse(ULTRASOC_SMB_DSM_UUID, &guid)) { >> +        dev_err(dev, "Get GUID failed.\n"); >> +        return -EINVAL; >> +    } >> + >> +    obj = acpi_evaluate_dsm(ACPI_HANDLE(dev), &guid, rev, func, NULL); >> +    if (!obj) >> +        dev_err(dev, "ACPI handle failed!\n"); >> +    else >> +        ACPI_FREE(obj); >> + >> +    return 0; >> +} >> + >> +static int smb_probe(struct platform_device *pdev) >> +{ >> +    struct smb_drv_data *drvdata; >> +    int ret; >> + >> +    drvdata = devm_kzalloc(&pdev->dev, sizeof(*drvdata), GFP_KERNEL); >> +    if (!drvdata) >> +        return -ENOMEM; >> + >> +    drvdata->base = devm_platform_ioremap_resource(pdev, 0); >> +    if (IS_ERR(drvdata->base)) { >> +        dev_err(&pdev->dev, "Failed to ioremap resource.\n"); >> +        return PTR_ERR(drvdata->base); >> +    } >> + >> +    ret = smb_init_data_buffer(pdev, &drvdata->sdb); >> +    if (ret) { >> +        dev_err(&pdev->dev, "Failed to init buffer, ret = %d.\n", ret); >> +        return ret; >> +    } >> + >> +    smb_init_hw(drvdata); >> +    spin_lock_init(&drvdata->spinlock); >> +    drvdata->pid = -1; >> + >> +    ret = smb_register_sink(pdev, drvdata); >> +    if (ret) { >> +        dev_err(&pdev->dev, "Failed to register smb sink.\n"); >> +        return ret; >> +    } >> + >> +    ret = smb_config_inport(&pdev->dev, true); >> +    if (ret) { >> +        smb_unregister_sink(drvdata); >> +        return ret; >> +    } >> + >> +    platform_set_drvdata(pdev, drvdata); >> +    return 0; >> +} >> + >> +static int smb_remove(struct platform_device *pdev) >> +{ >> +    struct smb_drv_data *drvdata = platform_get_drvdata(pdev); >> +    int ret; >> + >> +    ret = smb_config_inport(&pdev->dev, false); >> +    if (ret) >> +        return ret; >> + >> +    smb_unregister_sink(drvdata); >> +    return 0; >> +} >> + >> +static const struct acpi_device_id ultrasoc_smb_acpi_match[] = { >> +    {"HISI03A1", 0}, >> +    {}, >> +}; >> +MODULE_DEVICE_TABLE(acpi, ultrasoc_smb_acpi_match); >> + >> +static struct platform_driver smb_driver = { >> +    .driver = { >> +        .name = "ultrasoc-smb", >> +        .acpi_match_table = ACPI_PTR(ultrasoc_smb_acpi_match), >> +        .suppress_bind_attrs = true, >> +    }, >> +    .probe = smb_probe, >> +    .remove = smb_remove, >> +}; >> +module_platform_driver(smb_driver); >> + >> +MODULE_DESCRIPTION("UltraSoc smb driver"); > > "UltraSoc SMB CoreSight driver" > >> +MODULE_LICENSE("Dual MIT/GPL"); >> +MODULE_AUTHOR("Jonathan Zhou "); >> +MODULE_AUTHOR("Qi Liu "); > >> diff --git a/drivers/hwtracing/coresight/ultrasoc-smb.h >> b/drivers/hwtracing/coresight/ultrasoc-smb.h >> new file mode 100644 >> index 000000000000..a01f869fe122 >> --- /dev/null >> +++ b/drivers/hwtracing/coresight/ultrasoc-smb.h >> @@ -0,0 +1,110 @@ >> +/* SPDX-License-Identifier: (GPL-2.0 OR MIT) */ >> +/* >> + * Siemens System Memory Buffer driver. >> + * Copyright(c) 2021, HiSilicon Limited. >> + */ >> + >> +#ifndef _ULTRASOC_SMB_H >> +#define _ULTRASOC_SMB_H >> + >> +#include >> +#include >> +#include >> + >> +#include "coresight-etm-perf.h" >> +#include "coresight-priv.h" >> + >> +/* Offset of SMB logical buffer registers */ >> +#define SMB_CFG_REG        0x00 >> +#define SMB_GLOBAL_EN        0x04 >> +#define SMB_GLOBAL_INT        0x08 >> +#define SMB_LB_CFG_LO        0x40 >> +#define SMB_LB_CFG_HI        0x44 >> +#define SMB_LB_INT_CTRL        0x48 >> +#define SMB_LB_INT_STS        0x4c >> +#define SMB_LB_LIMIT        0x58 >> +#define SMB_LB_RD_ADDR        0x5c >> +#define SMB_LB_WR_ADDR        0x60 >> +#define SMB_LB_PURGE        0x64 >> + >> +/* Set SMB_CFG_REG register */ >> +#define SMB_BURST_LEN        GENMASK(7, 4) >> +#define SMB_IDLE_PRD        GENMASK(15, 12) >> +#define SMB_MEM_WR        GENMASK(17, 16) >> +#define SMB_MEM_RD        (GENMASK(26, 25) | GENMASK(23, 22)) >> +#define SMB_GLOBAL_CFG        (SMB_IDLE_PRD |    SMB_MEM_WR | >> SMB_MEM_RD | \ >> +                 SMB_BURST_LEN) >> + >> +/* Set SMB_GLOBAL_INT register */ >> +#define SMB_INT_EN        BIT(0) >> +#define SMB_INT_TYPE_PULSE    BIT(1) >> +#define SMB_INT_POLARITY_HIGH    BIT(2) >> +#define SMB_GLB_INT_CFG        (SMB_INT_EN | SMB_INT_TYPE_PULSE |    \ >> +                 SMB_INT_POLARITY_HIGH) >> + >> +/* Set SMB_LB_CFG_LO register */ >> +#define SMB_BUF_EN        BIT(0) >> +#define SMB_BUF_SINGLE_END    BIT(1) >> +#define SMB_BUF_INIT        BIT(8) >> +#define SMB_BUF_CONTINUOUS    BIT(11) >> +#define SMB_FLOW_MASK        GENMASK(19, 16) > > What does the value GENMASK(19, 16) indicate for SMB_FLOW ? That is the > value being passed down. Please add a descriptive name. > .e.g, > > #define SMB_FLOW_MODE_X        GENMASK(19, 16) > > Similarly for SMB_BUF_NOTE_MASK, unless there is an explanation. > >> +#define SMB_BUF_CFG_STREAMING    (SMB_BUF_INIT | SMB_BUF_CONTINUOUS >> |    \ >> +                 SMB_FLOW_MASK | SMB_BUF_SINGLE_END |    \ >> +                 SMB_BUF_EN) >> + >> +#define SMB_BASE_LOW_MASK    GENMASK(31, 0) >> + >> +/* Set SMB_LB_CFG_HI register */ >> +#define SMB_MSG_FILTER        GENMASK(15, 8) >> + >> +/* Set SMB_LB_INT_CTRL */ >> +#define SMB_BUF_INT_EN        BIT(0) >> +#define SMB_BUF_NOTE_MASK    GENMASK(11, 8) >> +#define SMB_BUF_INT_CFG        (SMB_BUF_INT_EN | SMB_BUF_NOTE_MASK) >> + >> +/** >> + * struct smb_data_buffer - Details of the buffer used by SMB >> + * @buf_base    : Memory mapped base address of SMB. >> + * @start_addr    : SMB buffer start Physical address. >> + * @buf_size    : Size of the buffer. > > Please align the field definitions. > >> + * @data_size    : Size of Trace data copy to userspace. >> + * @rd_offset    : Offset of the read pointer in the buffer. >> + * @wr_offset    : Offset of the write pointer in the buffer. >> + * @status    : Status of SMB buffer. >> + */ >> +struct smb_data_buffer { >> +    void __iomem *buf_base; >> +    u32 start_addr; >> +    unsigned long buf_size; >> +    unsigned long data_size; >> +    unsigned long rd_offset; >> +    unsigned long wr_offset; >> +    bool full; >> +}; >> + >> +/** >> + * struct smb_drv_data - specifics associated to an SMB component >> + * @base:    Memory mapped base address for SMB component. >> + * @csdev:    Component vitals needed by the framework. >> + * @sdb:    Data buffer for SMB. >> + * @miscdev:    Specifics to handle "/dev/xyz.smb" entry. >> + * @spinlock:    Only one at a time pls. >> + * @reading:    Synchronise user space access to SMB buffer. >> + * @pid:    Process ID of the process being monitored by the session >> + *        that is using this component. > > Same as above. > >> + * @mode:    how this SMB is being used, perf mode or sysfs mode. >> + */ >> +struct smb_drv_data { >> +    void __iomem *base; >> +    struct coresight_device    *csdev; >> +    struct smb_data_buffer sdb; >> +    struct miscdevice miscdev; >> +    spinlock_t spinlock; >> +    local_t reading; >> +    pid_t pid; >> +    u32 mode; >> +}; >> + >> +#define smb_reg(name, offset)  coresight_simple_reg32(struct >> smb_drv_data, name, offset) >> + >> +#endif > > Suzuki > .